Astronomy Topic Of The Day

A Most Distant Globular Cluster

2012-01-29T20:26:00.032-05:00

Well, I did it! Using Custer Institute's 0.63m (25") flagship instrument, I, along with friends and colleagues, visually observed the most distant globular cluster associated with our Milky Way galaxy! Given that distinction [of being the most distant globular cluster associated with the Milky Way] and as an object of research and study during the completion of my graduate work, observing this intergalactic stepping stone held a special interest and fascination for me. Located in the circumpolar constellation of Lynx and known as the Intergalactic Wanderer, NCG-2419 is at least 52 Kpc distant (52,000 parsecs/ 170,000 light years) or almost 10% of the distance to the Great Spiral Galaxy in Andromeda, M-31!

Known for its dark skies, Custer Institute is located in the town of Southold on Long Island's North Fork. With Lynx almost at the zenith, high in the North-Northwest, the moonless sky on the night of January 28th - 29th was brilliantly clear and dark, one of the most transparent in recent memory.

To get a sense of the scale involved, in time, space and distance, it needs to be understood that the cluster-member stars that we observed and the only stars directly observable with a telescope of this aperture (for such an object at this distance), are evolved, red giant and supergiant stars, stars such as Antares, Betelgeuse and, to a lesser extent (in that it is *only* a giant), Arcturus. Those familiar stars are bright and friendly in our own sky but, when observed at this distance, similar stars are at the limit of detection with averted vision, the brightest presenting at a visual magnitude between 16.5 – 17, barely observable as fleeting points of light. Having evolved off the Main Sequence, these luminous beacons beyond the boundaries of our galaxy and above the Galactic Halo are now using the Helium produced during their 10 billion year Main Sequence lifetime to produce energy. They have been burning bright for over 10 billion years and are among the first stars that formed, dating back to a time when the universe was much younger and quite different. At this cluster’s tremendous distance, any stars that still remain on the Main Sequence would be below the detection capability of this telescope and the telescope of comparable size used to acquire the image below, obtained during my graduate work. As such, the only representative stars available for study would include luminous Horizontal Branch, Asymtotic Giant Branch and Red Giant Branch stars (see HR Turnoff diagram below). As we indicate above, no Main Sequence cluster stars are detectable at this distance with a telescope in this size-class. The sun would be feeble, presenting at visual magnitude +23.5, well beyond the threshold of detection. Given the ancient age of the cluster, the only stars that would still remain on the Main Sequence would be late G (> G5) stars and cooler.

In order to properly understand stellar evolution, a technique used by astronomers is to observe how stars evolve as a group; in this way, we’re able to extrapolate a common origin and, hence, their age. We then compare that result with current models to gauge the model’s accuracy and veracity as well as constrain the age of the universe and the ages and evolutionary trends of galaxies and clusters of galaxies. Globular cluster stars are among the oldest stars in the universe and since NGC-2419 is so distant, well outside of the galactic halo (where most globular clusters reside) and the galaxy proper, this cluster holds a unique opportunity to better understand galactic evolution and how the member stars evolved in an isolated, extragalactic environment.

By comparing the cluster stars brightness at the given distance to where it would normally be if it were a “normal”, Main Sequence star, we can “age” the star and, hence the cluster since it has to be as old as its oldest member stars. The “turn off” point is where the star’s brightness diverges or “turns off” relative to where it should be on the color-brightness diagram, known as the HR Diagram. Since no main sequence stars were observed (Sirius, so bright in our sky, would present at visual magnitude +20), the stars represented in this study are the oldest, most evolved in the cluster, “above” the 10 billion year turnoff point for the cluster. When first building this diagram, it wasn’t shaping up to “look like” a typical globular cluster turnoff diagram until I realized there were no “normal”, main sequence stars represented!

The following image was produced by a 0.61 meter Ritchey-Chretien telescope located in the dark, desert skies of Rodeo, New Mexico, a telescope in the same size class as that used to visually observe the cluster.

NGC-2419 As Imaged by this author
This image, produced using MaxIM DL as an L-RGB image, shows the cluster’s luminous, highly evolved red giant stars as decidedly red/ orange along with the blue stragglers appearing as a combined blue cast in and around the core. At the tremendous distance to this cluster, the individual blue stragglers are below the resolving power for this telescope and, thus, we see their combined light as a blue cast in and around the cluster’s core. Blue Stragglers are a class of star found almost exclusively in these types of clusters and are more luminous than typical Main Sequence stars. The brightest cluster stars in this image are the red giant stars and are fainter than visual magnitude +16; they have exhausted the compliment of hydrogen fuel in their cores and are now using the helium that had been built up over the preceding 12 billion years of normal hydrogen burning. The multitude of faint stars that appear as a halo and surround the central agglomeration have a visual magnitude of +20 and are at the limit of detection with the exposure and observing configuration used. Many of these threshold stars are classified as Horizontal Branch stars (see corresponding B – V Color Diagram, below). As stated earlier, they are of a comparable luminosity (brightness) as the brightest appearing star in our sky,Sirius, a Main Sequence (normal) star that is 25 times more luminous than the sun.

For further reading, my original work on this cluster can be found in the following paper, published as the second in a series of three papers as part of my graduate research: The FITS Imaging Standard in Astronomy

Minor Planet 2012 BX34

2012-01-26T22:10:00.001-05:00

At approximately 10:30 am tomorrow (January 27th), EST, minor planet 2012 BX34 will pass within 60,000 km or 0.0004 AU of earth's surface. A rudimentary calculation, assuming a 4 meter radius, spherical symmetry, an orbital velocity of 30 km/ sec and a density of 5, gives an energy of 600 billion (6 x 10^11) joules released on a direct impact with land. This amount of energy is 2 orders of magnitude (100x) less than the 50 terra-joule energy released with the Hiroshima blast. Although not sufficient to destroy a city, as the Hiroshima bomb was, it would be a local disaster if it impacted a populated area.

Newt is no Gingerich

2012-01-22T00:26:00.006-05:00

If you're wondering what the title of this blog post hast to do with astronomy, please read on. With the subject individual just winning the South Carolina primary, not only is this little tidbit informative, it gives the lie to his sanctimonious, hypocritical lecturing on truth, justice and family values.

It was so troubling to me that this buffoon shared the same surname as the world renown Harvard astronomer of the same surname, Owen Gingerich, I did a little digging. For a micro second I actually had entertained the notion that perhaps they were brothers. To my delight, I found an article that dispelled my fears, an article wherein I learned that he was born a "McPherson": http://nyukcubed.blogspot.com/2009/04/owen-and-newt-newt-and-owen.html

Owen Gingerich

Thirty Meter Telescope Update

2012-01-14T19:41:00.002-05:00

There is an article being shared and apparently going viral regarding India and China joining the Thirty Meter Telescope project. Published by The Daily Mail, the article's headlines claim that China and India are *Creating* the world's largest telescope. This is absolute rubbish and needs to be qualified! They are not creating the TMT at all; they are joining as observers and are contributing over $1 billion towards construction costs. The principal architects are the AURA (Association of Universities for Research in Astronomy), the California Institute of Technology, the University of California System and the Association of Canadian Universities for Research in Astronomy!

An Astronomer's Christmas Message

2011-12-24T22:28:00.003-05:00

On this cold, clear night when the stellar jewels are alight above, take the time, if just for a moment to gaze upwards, to make that visceral connection with that from whence we all came. Regardless of your religious persuasion, if any, we are all connected at the deepest level for those stars, that grand firmament above us, is our origin and our destiny. If for only a day, may true peace reign in our hearts and in our homes; may the guns, bombs and weapons of destruction fall silent, may the sentiment expressed by all the world’s great religions be realized if only for one night.

As you look to the east upon the brilliant jewels of Orion, Venus high and bright in the west, brilliant Sirius beckoning, know that there are others too who are gazing as you do and that this is the nexus that binds us all together, the oneness with that great canopy of stars above, fellow travelers upon this beautiful blue miracle in orbit about our home star. Having almost completed yet another circuit around that star we are reminded that, in our smallness, we are great in that we have this common bond; let us concentrate on that, be one and be at peace.

Image details: Orion from the Everglades, 1986, taken during expedition to observe and photograph Halley's Comet during its 1986 apparition; 30 second exposure on Kodak Ektachrome 400 with 100mm F/2.8, Canon AE-1; Credit: T. Madigan, all rights reserved

Faster than Light Speed? Not so fast!

2011-09-23T17:10:00.005-04:00

Do you realize just how far reaching this result would be if true? Every physics textbook for the past 90 years would have to be rewritten; most, if not all, of modern astrophysics and cosmology would have to rewritten or thrown out completely! All of Relativity (Special and General) would be called into question with every kook who has come along challenging Einstein, claiming he was wrong and chanting "I told you so", validated. And what is this experiment that has the scientific world in such an uproar? This: that 15,000 neutrinos were measured moving at 1 part in 50,000 above light speed as they traveled from Geneva (the location of CERN) to Gran Sasso in the Apennine Mountain Range.

http://press.web.cern.ch/press/PressReleases/Releases2011/PR19.11E.html

Every experiment conducted since Einstein published General Relativity in 1915 has incontrovertibly proven that he was correct and that the speed of light is the universal speed limit. To upend a body of knowledge and understanding that has taken a century to build, you better have something more substantive that what was presented in this paper and you better have additional, independently acquired data where the result is repeatable.

To publicly suggest that such a result was observed without performing due diligence and exhaustive vetting is, at a minimum, irresponsible. In the view of this astronomer, a very simple error has gone undetected and, hopefully, a substantive and qualified errata will be published shortly.

JWST: What Can We Do Now?

2011-08-16T17:44:00.007-04:00

The James Web Space Telescope is the successor to the Hubble Space Telescope, mankind's premier orbiting telescope and observing platform, an instrument that has left an enduring legacy of scientific discovery and achievement. The 6.5 meter primary mirror of the JWST has been completed and the telescope is well on its way to completion. With a mirror 3 times the diameter of HST, JWST will be able to "see" much further back and much earlier into the universe's history, to a time when the very first stars shone bright in space, to a time when the universe was a much different place than it is today. As principally an Infrared observing platform, it will give us the ability to answer fundamental questions about the universe's very beginnings, questions that are beyond the scope of even the vaunted HST. It will be able to detect Infrared sources 9 times fainter than HST and observe objects that are "red shifted" beyond detection with HST. This will all come to pass, if it is ever completed and launched!

Reacting to the widespread economic blight and with the shortsightedness so typical of many politicians eager to cut costs and expenses without considering the larger picture and the consequences of their actions, the U.S. House's Commerce, Justice, Science, and Related Agencies (CJS) Appropriations Subcommittee has recommended funding for JWST be zeroed out in the FY 2012 budget. To say nothing of the extraordinary lack of vision and foresight on the part of this particular subcommittee's leadership, it would be an unprecedented disaster if they were successful in their attempts to scuttle the James Web Space Telescope.

So, what can we do to save JWST? By way of sharing with you the following text, culled from an email sent to all members of the American Astronomical Society (AAS), an organization to which I belong, I hope to have answered that question:

Informational Email 2011-09

JWST: What Can We Do Now?

Debra Elmegreen, AAS President
Jack Burns, Chair of the Committee on Astronomy & Public Policy

Many AAS members appropriately asked, "What can we do now?" following
the shocking and disappointing recommendation by U.S. House's
Commerce, Justice, Science, and Related Agencies (CJS) Appropriations
Subcommittee to zero out funding for the JWST in the FY 2012 budget.
The answer is, "A lot"--using a well-conceived plan with community
input and public support to counter the House's action. The AAS has
been pursuing an active strategic course, but we continue to need your
help and advice as we navigate the long road ahead towards reinstating
funding for the JWST.

What can you do?
We need to sustain a grass-roots effort of education and advocacy for
JWST by reaching out to the general public. During our visit to
Capitol Hill, all the House staffers reiterated that they accept the
message from astronomers on the science merit of the JWST. They
welcome letters about what JWST will do for local communities, and
they especially need to hear from non-astronomers about the public
desire for JWST.

Here are some things you can do to support JWST:
- Write a letter to your member of Congress about what JWST will do
for your local community including jobs and the impact on STEM
education and training.
- Write a letter to the President, with a copy to your Congressmen, in
support of JWST.
- Encourage friends, neighbors, and colleagues to write to their
member of Congress to support the JWST.
- Consider writing an Op-Ed piece for your local paper on the
importance of supporting the JWST.
- Get the word out to support the JWST:
- get on a radio talk show or local news spot
- talk to school groups about JWST
- talk to community service groups such as the Kiwanis, Zonta, or
Lion's Club about JWST and ask them to talk to and write their members
of Congress.
- Continue to be active in social media, such as Facebook
(http://www.facebook.com/SaveJWST?sk=wall and
http://savethistelescope.blogspot.com/) and Twitter
(http://twitter.com/#!/SaveJWST).
- Sign a petition, such as
http://www.change.org/petitions/do-not-cancel-funding-for-the-james-webb-space-telescope.

Helpful material is available on the AURA site, which has compiled a
list of background information, recent articles, and related support
letters from international astronomical organizations:
http://www.aura-astronomy.org/news/news.asp?newsID=264.

What is AAS doing for the JWST?
We traveled to Capitol Hill this past week to continue the work of the
AAS Executive Officer, Kevin Marvel, and the AAS John Bahcall Public
Policy Fellow, Bethany Johns, to resume discussions about the JWST
during the August Congressional recess; it was a time of reduced
tension from the absence of television cameras and Congressional
members on the Hill, and a pleasantly reduced humidity in Washington.
By the end of our conversations, we were encouraged that (1) our
community has done an outstanding job of making the science case to
the Congress and the Administration, (2) that NASA has made major
efforts to re-tool the management of JWST with attention now focused
at the highest levels of the Agency, and (3) that a thorough
rebaselining plan has been completed to put the project on a solid
funding foundation toward launch in 2018.

We began our discussions with Rick Howard and Eric Smith, who are
leading the efforts to revamp the management and funding plans for
JWST at NASA headquarters. We learned that the rebaselining plan,
called for in the Casani report, has been completed, reviewed, and
accepted at all levels of the NASA administration. Most importantly,
NASA accepts the premise that JWST is now an agency priority, and thus
would be managed and funded as such if approved. This is a key change.

Next, we went to the Capitol to visit with staff from the House CJS
Appropriations Subcommittee and from office of the Chairman, Rep. Wolf
(R-VA). We had a frank and honest conversation with the staff about
JWST's recent cost overruns and mismanagement, as outlined in the
Casani report. The staff expressed Rep. Wolf's belief that JWST has an
extremely strong science merit and that this has been well articulated
by members of the AAS. The staff commented that they have been
inundated by social media correspondence about JWST and have made note
of recent editorials in the NY Times and Washington Post. They were
also pleased to learn about NASA's new management plan for JWST and
the attention being paid by the upper management of the Agency. Part
of the motivation for the subcommittee's action was to "get NASA's
attention on these broader, Agency-wide management issues at the
highest levels." Now, the problem remains getting the rebaselined
budget out of the Executive Branch's Office of Management and Budget
(OMB) so that members of the House and Senate can use those numbers in
developing next year's FY2012 federal budget. Time is of the essence.
Our efforts need to be focused next on making the case to the
Administration to have the OMB approve the rebaselined plan, and make
it publicly available as soon as possible.

We also visited the staff from Ranking Minority member of the CJS
subcommittee, Rep. Fattah (D-PA). His staff along with several other
staff members from influential Democratic members of the House,
including Rep. Schiff from southern California, pledged for their
Congressmen to contact the White House to plead for the release of the
rebaselined plan from OMB.

What happens next?
The Debt Limit Deal practically stalled all remaining appropriations
bills from reaching the House floor for a vote. The real action will
be in the House-Senate conference committee to hash out a final budget
for NASA. After Congress returns in September, the action will move
toward the Senate where Senator Mikulski's (D-Maryland) CJS
subcommittee will mark up the NASA bill. We are encouraged by Senator
Mikulski's public support for JWST. We are hopeful that the House and
Senate will be able to work out an agreement to support continued
funding for JWST using the rebaselined budget for NASA.

Continued vigilance, communication with staffers on the Hill, and
public pressure throughout the Fall will be essential if we are to be
successful. This week Roger Blandford will lead another delegation to
NASA and the Hill to continue conversations. We are only in the first
battle of this fight, with months of effort still needed. It will
require a concerted community effort.

We will continue to send regular updates via this e-mail exploder to
seek feedback and to keep you informed. Thank you for all that you've
done so far and for your continuing efforts to keep JWST on track for
launch later in the decade.

The Lure of the Cosmos - Part of my Story

2011-08-05T14:49:00.011-04:00

I'm 55 years old, soon to be 56. The earth has completed almost 56 circuits around the sun since I was born. When you think of life in these terms, it really doesn't seem like a long time. What about 70, 80 or older? Same thing; it really doesn't seem like a long time and it's not. I remember as if it were only yesterday, 50 years ago as a young child, walking along the sidewalks of New York City with my father as he pointed out the stars and constellations which you could still see from Manhattan in 1960. My father, the one who instilled in me the love of the stars and the universe at a very tender, young age has been deceased for 38 years, having died of a heart attack one month before my 19th birthday; my mother, who used to wait for us to return from our evening walks on Manhattan's upper west side so long ago and so far away, is now 87. She has been a proud supporter of this "dyed in the wool" astronomer for his entire life. That childhood wonder of gazing at the night sky is as fresh and as new today as it was 50 years ago; I will forever be drawn by The Lure of the Cosmos. None of us knows how much time we have; my mother could live another 5 or 10 years or could, quite possibly outlive me, her eldest son. I could be gone tomorrow. My father, who I still miss terribly to this very day, was here one day and gone the next so many years ago. The pain of his untimely passing still stings to this very day.

It has often been said that astronomy is a humbling and character-building pursuit. What astronomy has taught me is to accept each day as a gift, to treat each and every individual I encounter the same way I would want to be treated, bearing in mind the very-real possibility that it could be the last time I speak to that person. When you realize how small and insignificant we all are; when you're confronted on a daily basis with our collective mortality, with the enormity and terrible majesty of the cosmos, that we've thrived and flourished during a relatively benign period in our star's evolution, that the home that we so abuse and take for granted continues to provide protections for us on many levels, that we are truly ignorant of just how charmed an existence we really have, that we continue to frolic about with nary a care in the world and that our collective demise could come at orbital speed as it did with the dinosaurs, you then realize the depth and the absurdity of our conceits, of our self-diluted notions of grandeur. It is then that true charity begins; when we realize that there is only today and the knowledge that all we have is each other as wayfarers, fellow-travelers on this beautiful blue oasis adrift in the great enveloping cosmic theater that surrounds us.

During my 55+ years on this planet, I have never watched a rocket launch; I can count on 2 hands how many times I've been in an airplane. I live in a very modest home and just lost my car in an auto accident and, at the moment, I have less than $500 in the bank. By society's standards, I'm not doing so well but I'm happy! I have a wonderful family, Mary, my wife, 3 great kids, my mom, brothers, a great extended family and The Lure of the Cosmos!

I have many friends, some of them also drawn by the lure of the cosmos. Most of them have large telescopes, telescopes that dwarf mine. Indeed, I took ownership of a 0.4 meter (16 inch) diameter telescope last year and there it still sits, largely unused one year later. I have peered into these large telescopes and yes, the views are wonderful but, the telescope that I have had with me my entire adult life, the one I take everywhere with me, to observing events and star parties, to public outreach, to lectures, everywhere, is the one I completed when I was 19 in 1974, a 15cm (6 inch) reflecting telescope, the one whose mirror I made with my own hands. You see, when it comes to The Lure of the Cosmos, its not about how big the telescope is but understanding what you're looking at. This is why I love my binoculars too; I've spent countless hours scanning the summer Milky Way, completely taken in by it's ethereal beauty. When you truly comprehend what you're looking at, time stands still and it doesn't matter how big the telescope is. Yes, you can see more stars with a larger telescope in, for example, the great globular star cluster, M-13 in Hercules; that's just simple physics. In the 15cm telescope, you can see the brightest member stars, evolved, red-giant stars, as faint pinpoints even though they are hundreds of times more luminous than the sun; in the larger telescope, you see the same object somewhat brighter with more of these same stars, albeit somewhat brighter. When you realize the size, power and enormity of these stars and understand that they are so far away that their light took 25,000 years to reach us, you will then understand The Lure of the Cosmos and that, as astronomers, we are also time travelers. If you get the chance, on the next clear night, take a look high in the west at around 9:00 PM and you will spot Arcturus, the brightest star in the western sky. That star is an evolved, red giant star, a star much like the sun will be in about 6 billion years from now; it is now using helium, instead of hydrogen, as a nuclear fuel. When you see Arcturus and, after remarking on it's intrinsic beauty, noting the bright red hue, remember that it is stars just like this bright, friendly star in our night sky that appear as tiny pinpoints, member stars in the great globular star cluster, M-13. When you do this, you would have done something few have done: made that visceral connection with that from whence we all came.

We are all Discoverers, now sitting at the sand, contemplating the sea, waiting for the echo of the distant shore of a whole New World.

One day, from the shores of a new world, we'll gaze at the sea that took us there. And its waves will be stars.

From "We Are at the Prow of the Whole" by Rui Borges, Kepler Mission Outreach: http://kepler.nasa.gov/education/sagan/RuiBorgesEssay

Neptune's Birthday

2011-07-16T12:27:00.031-04:00

Just after midnight on September 24th of this year, Neptune will be exactly 165 earth years older. It was on that date, back in 1846, that German Astronomer Johann Galle, assisted by graduate student Heinrich Louis d’Arrest, trained the 24 centimeter (9 inch) Fraunhofer Refractor of the Berlin Observatory on a patch of sky near the Aquarius-Capricorn border (see illustration below) and observed the small, blue disk of Neptune. On July 12^th of this year, Neptune completed exactly one orbit since its discovery. One hundred and sixty five years ago a series of events played out in France, England and Germany that would culminate in a watershed moment in the history science and astronomy, a discovery that would prove to be unique and unrepeatable. These events were rife with centuries-old rivalries, political conspiracy and intrigue, all mixed together with good mathematics, some good science, some bad science, some luck and much mayhem.

The story of Neptune's discovery persists today as one of the most compelling, most fascinating and most successful triumphs of celestial mechanics on the long road to mankind's full realization of his place in the cosmos. Indeed, its discovery was more than compelling; it was epic! As that small, blue disk was observed 165 years ago, beckoning from across 4.3 billion kilometers of space, the boundaries of our solar system were almost doubled in an instant. We were reminded, once again, of the enormity of the cosmos; ah, if only these lessons in humility came more frequently!

Ever since Newton published his Principia Mathematica and Law of Universal Gravitation (as a section of Principia) in 1687, it was known that Uranus did not behave properly according to the new theory of gravitation. Lacking a sound explanation, the new theory was in jeopardy. It was 159 years from the publication of Newton's seminal work to the discovery of Neptune during which time there were several "non discoveries" by such notables as William Herschel who, the previous century in 1781, discovered Uranus. In fact, Galileo may have been the first to observe Neptune. On two separate occasions, December 28, 1612 and then on January 27, 1613, Galileo noted the "movement of a blue star" but, being preoccupied with other matters, never followed up (this observation can be easily simulated with freely downloadable software such as Stellarium).

With Jupiter and its 4 Galilean satellites, this telescopic view of Neptune is as Galileo would have observed it on 28 December, 1612

Telescopic view of Neptune as Galileo would have observed it on 27 January, 1613

Although these "non discoveries" are remarkable, as one has to wonder why Neptune was repeatedly overlooked by astute, hawk-eyed astronomers, what is most remarkable is that its position on the sky was computed to within one degree of its actual position when the mass and the distance were both unknown! To correctly understand the peculiarities of Uranus, the cause had to be divined from the effects. Mathematical astronomy has matured to such a degree that predictions with millisecond arc precision are common place if all the orbital elements are known. But retrodictions, the teasing out of the position of an unknown body based on the perturbations on a known body, were then and still are, today, fraught with difficulty, especially if the mass, distance and other essential orbital elements are unknown. To this day, the deepest respect and admiration are held by modern astronomers for the brilliant French mathematical astronomer, Urbain Jean Joseph Le Verrier (1811 - 1877).

It was known for almost 3 decades prior to 1846 that something was askew in the outer solar system. In analyzing the positions and movements of Jupiter, Saturn and Uranus, it was noted that they weren't where they were supposed to be according to Newton's Theory of Universal Gravitation. There is a provision therein that allows for small perturbations if the timescales aren't too far into the future. Specific attention was given to Uranus for the time period surrounding 1829 - 1830. It appeared to speed up and then slow down, a phenomenon that could be understood if one adopts the idea of a force, originating from a more distant, unseen body, acting on Uranus, a body that would be moving faster in its orbit than the more distant, unseen body. The unseen body would provide a small but measurable acceleration on Uranus as Uranus approached and passed the point on the sky containing the unseen body. Immediately after passing that point, that same, unseen body, still acting on Uranus, would effectively slow it down by providing the same acceleration but, this time, that acceleration would be opposite in sign, effectively slowing it down in its orbit.

Along with gravity, the Conservation of Angular Momentum, a phenomenon that has been understood since Newton published his Principia and one whose effects we experience in everyday life, is the underlying cause for Kepler’s Laws and is what came out so beautifully and elegantly in Newton’s Principia and his Law of Universal Gravitation. In addition to Gravity, operating according to an inverse square law, it was the root cause for the perturbed path of Uranus as it moves in its orbit around the sun. Any body with a smaller relative orbital radius will necessarily move with greater orbital velocity and, therefore, will have a greater angular momentum. Uranus is closer to the sun than Neptune; it will, therefore, have a greater angular momentum. Neptune’s gravity will also be acting on Uranus, “pulling” on it while it is still “out in front” of the closer Uranus, causing Uranus to move slighter faster in its orbit; since it is moving with a greater orbital velocity than the more distant Neptune, Uranus will eventually pass Neptune and it was at this point, where the two distant planets were in mutual opposition, where no perturbed effects were observed and is what accounts for the brief correspondence of the predicted and observed positions. As Uranus moved ahead of the more distant Neptune, Neptune’s gravity began acting as a brake on the closer Uranus, causing it to move slightly slower in its orbit.

In classical Newtonian mechanics, the 2-body problem is presented as the simplest, workable model but, in reality, it is only an approximation as nature could never be represented so simplistically. The more realistic approximation would be the 3-body problem, a scenario whose solution requires sophisticated numerical integration techniques. The solution to the n-body problem, the scenario that best approximates reality, does not have a precise solution and requires today's modern supercomputers to provide a reasonably accurate result. So how did the mathematical astronomers of the 19th century predict Neptune's position with such precision, so close to where it actually was? To answer that question we recall Newton’s words, uttered towards the end of a long and productive life: “If I have seen further it is by standing on ye shoulders of giants”. As with all of science, we continually build on the discoveries and insights of those who came before us. The discovery of Neptune from the perturbations in Uranus’ orbit was no different. It was known since the early 17^th century, since Kepler published his Astronomia Nova, that the planets orbit in a preferred plane known as the Ecliptic. It was also known since the time of Kepler, codified in his third law of orbital motion and later generalized by Newton in his Principia, that the period, distance and mass were all related. Also published in Principia was Newton’s Universal Law of Gravitation, a law that obeys an “inverse square” relation – a body that is twice as distant as another of equal mass will exert an attractive force equal to one quarter of what it was for the closer body. One must accept that Le Verrier knew all these things and that he would also presume a position for Neptune along the ecliptic. He also knew the properties of the three known gas giant planets that precede Neptune as well as the distances between each, knowledge that would help constrain its mass and distance. Armed with all of this, although difficult, one can see how a skilled mathematical astronomer could derive the position of the unseen planet. LeVerrier met the challenge and published his work in July of 1846, placing Neptune within 1º of its actual position! Despite the confidence in his published work, he was initially unsuccessful in motivating anyone, even in France, to mount a telescopic search for the unseen planet. Eventually, after an additional 2 months and only after writing to Galle at the Berlin Observatory, did he receive an enthusiastic response. The planet was observed along the ecliptic near celestial longitude 325º, a point very close to Saturn (see illustration, below).

Today’s astronomers, professional and amateur alike, can relive that momentous observation that took place 165 years ago by training their telescopes on that small patch of sky in Aquarius; they would observe those same stars that Johann Galle observed, stars that led him to the position of Neptune, causing de’Arrest to remark with delight: “That star is not on the Map”!

Discovery position, midnight, 24 September, 1846

Note: except for the presence of Saturn, this is exactly the field as it would appear today

With high concentrations of methane in its lower atmosphere and high-altitude methane ice in its upper atmosphere, the planet presents decidedly blue. At a distance of over 30 Astronomical Units, Neptune is over 30 times the distance the earth is from the sun. It also has the highest measured wind speed of any planet in the solar system with winds in its high-altitude, equatorial cloud belts clocking in at over 2,100 Km/hr, speeds almost 10 times greater than that of the strongest, category 5 hurricane on earth! With its moon Triton, it is also host to the coldest body in the solar system. Triton exhibits evidence of Cryovolcanic geysers of liquid Nitrogen. Since nitrogen undergoes a phase transition from gas to liquid at 77 Kelvin (77 degrees above absolute zero) and since we’ve observed the atmospheric plumes (see illustration, below) of these liquid nitrogen geysers, we must conclude that the nominal temperature at Triton’s day-night terminator is a frosty 77 Kelvin or lower.

To celebrate Neptune’s Birthday and to honor those who discovered this frigid, blue world at the edge of our solar system, the Hubble Space Telescope has captured the following images last month:

Atmospheric plumes of Nitrogen leveling out over the limb of Triton

Credit NASA, Voyager 2

Enhanced image from the original

Clear Summer Skies

2011-07-01T22:41:00.052-04:00

Today was the third day in a row that we've had brilliantly clear, blue, transparent skies followed by brilliantly clear, dark skies at night. For us, here in the US Northeast, this is a rare treat as we've consistently had rainy, cloudy weather since March. The forecast for the Independence Day weekend calls for increasing humidity over the next 2 or 3 days but sunny, summer weather and clear skies should prevail.

As Lyra climbs high in the northeast during early evening, with its brightest star Vega, a member of the famous trio of stars known as the Summer Triangle (along with Deneb, in Cygnus and Altair, in Aquila) beckoning with its clear, white light, we can have no doubt that summer is upon us and with it, the splendor and brilliance of this season's sky. East of Lyra, we observe Cygnus the Swan, also known as the Northern Cross, embedded in the rich summer Milky Way and mythologically flying south towards Sagittarius and the galactic center.

The late spring and early summer is my favorite time of year, a time that hearkens me back to younger days, to a time when you could see magnitude 5.5 stars and a breathtaking Milky Way from my childhood home in Commack, located in Long Island's western Suffolk County. With the fresh early-summer air, the sweet smell of Lilacs and Honey Suckle wafting about and the temperature and humidity still moderate, it’s truly a pleasure to be out, under the stars.

My present home, located on the south shore of Long Island, looks south, out over the Great South Bay, followed by Fire Island and then the Atlantic Ocean. The distance between my home and Fire Island is less than one kilometer and then just ocean with no land mass until Cuba! Suffice it to say my southern sky is dark and, with the clear, dry weather we've been having, the Milky way from Cygnus, high overhead at 10:00 PM, south through Aquila, Scutum, Ophiuchus and into Sagittarius and the galactic center was stunning!

Binoculars accompanied by a 15 - 20 cm (6" - 8") Richest-field telescope is one of the best observing combinations to truly appreciate the richness of the summer sky, especially the treasure trove of jewels that bedeck the Milky Way along its extent from Cygnus south through Aquila, Scutum, Ophiuchus, Sagittarius and west from Sagittarius, into Scorpius. These past 3 nights, my 9 x 63 binoculars and 15 cm F/4.2 Richest Field reflector provided stunning views of the various clusters, nebulae and other jewels embedded in the summer Milky Way. The memorable favorites such as the Lagoon and Trifid Nebulas (M-8 and M-20) filled the field in the binoculars; the view through the telescope was stunning with the dark rift that gives the Lagoon Nebula its distinctive appearance quite plain. M-11, the Wild Duck cluster in Scutum, was beautiful as was M-16 and M-17, the Eagle and Omega nebulas respectively. One never tires of the subtle beauty of M-4 and M-22, globular clusters in Scorpius and Sagittarius respectively. Appearing as bright globes in the binoculars, these distant agglomerations of stars, many of them evolved, helium-burning red giants, took on a spotty texture in the telescope, a texture consistent with their true nature as implied by their name; the brighter, more luminous members of these huge spheres of stars, collections that number in excess of 100,000, appeared as tiny pin-points set against a black background.

What was really stunning and is a view available only in binoculars, was the area just above the teapot "Spout" of Sagittarius as scanned with the binoculars (see illustration, below). The subtle beauty and tapestry of the dark, cold gas and dust set against the bright nebulae of the Milky Way in and around the galactic center momentarily took my breath away when I realized what I was looking at! I've looked at the sky my entire life, ever since I was a young child and I've been an astronomer my entire adult life but I have never seen anything quite like this! This is the Galactic Center! This is what is seen in deep, wide-field images obtained from desert plateaus or mountain tops! To observe this and to realize what you're looking at is a deeply moving experience and I recommend it for everyone!

There is nothing like observing under a mid-summer night's sky for both the professional astronomer or amateur. It's good for the soul and gives one perspective, providing that visceral connection to the grandeur and magnificence of that from whence we came.

Ophiuchus IS a Sign of the Zodiac

2011-06-20T09:21:00.007-04:00

Since the summer is almost upon us and, with it, all the favorite constellations of summer, including Sagittarius, Scorpius *and* Ophiuchus, it needs to be pointed out quite emphatically that the ecliptic *always* passed through Ophiuchus (anything else would be absurd) and it was the Greeks who did not include Ophiuchus in the Zodiac because it wasn't part of their mythology and it skewed their neat 12 section, 30º mapping of the sky (360º/ 12) = 30º.

If you choose to put credence in astrology, the notion that somehow the position of the planets set against background stars that are light years more distant than they will have an influence on your life and destiny and that you structure your life accordingly, that is your business but please understand that the Astronomical Zodiac is the only accurate mapping. The
"Astrological" Zodiac does not include Ophiuchus and is, therefore, inaccurate and incomplete. The Ecliptic, the path on the sky that the planets follow as they move in their orbits, passes through certain constellations; the Zodiac is the region of sky along the Ecliptic that contains these constellations. Ophiuchus was, is and always will be on that path and, as such, was, is and always will be a member constellation of the Zodiac. You simply cannot eliminate a certain constellation because it poses an inconvenience or that it doesn't fit neatly into your mythology.

Doomsday 2011 - Not Likely

2011-05-20T00:13:00.007-04:00

No one has the ability to predict the future. Those who claim that they can are frauds, plain and simple. Every action, every event, even within the next 5 minutes, is governed by a staggeringly huge set of unknowns and variables that change from instant to instant that not even the combined computing power of all the world's most powerful supercomputers could reliably produce a solution to a seemingly mundane set of circumstances. Time is a human construct, devised to assist us in managing our 3 dimensional world; it is not a river by which we can navigate forwards or backwards. The past is forever gone and the future has not happened yet. In fact, as you read these words, that act of reading, that event, passes forever into the past. All there ever *is*, is the ever-present now.

The world will not end this Saturday or anytime soon.

Doomsday theories come and go but our legacy is eternal; what will it be?
Civilizations will rise and fall over the coming millennia; the kindness and charity we show to each other and to the fellow creatures that share our planet, our stewardship of this fragile, blue miracle floating in a hostile and unforgiving cosmos, will be our enduring legacy (Pale Blue Dot). The physical end to our world will come with a definite certainty, a date that was etched in stone since the sun shone bright in space, at a time when the solar system, the sun and its planets, had just formed. It is not written in the bible, although current adherents believe otherwise; it is not hidden in some dark, obscure corner of some ancient people’s calendar; it is not known by psychics, soothsayers, astrologers, seers or anyone else who purports to know the future – the future is unknowable. The physical end of the world will come in 7.7 billion years when the sun, finally depleting its compliment of hydrogen fuel, swells to become a red giant star. What we do in the meantime is up to us.

What is Your Birth Sign?

2011-01-14T07:55:00.014-05:00

There is much discussion lately regarding horoscopes, individual birth signs and other topics related to this popular topic of discussion and, for some, a means by which they live their lives. There have been some news reports suggesting that your Zodiacal sign has changed because of the "Precession of the Equinoxes". Although the equinoxes do precess, the earth's precession cycle spans some 25,800 years so, over a given human lifetime, the change will be imperceptible. Although your Zodiacal sign is different than what you've been told, it is different for quite a different reason than what has been suggested in these news reports.

Most people know that their Zodiacal sign is based on what constellation of the Zodiac the sun was in on the day of their birth. The Zodiac is the series of constellations that lie along the ecliptic, the apparent path the sun, planets and all other solar system bodies travel as projected on the sky. It represents the two-dimensional plane described by the solar system containing the orbits of the planets that bisects the sun's equatorial plane (eg. the earth's equatorial plane is the imaginary plane that bisects the earth into the northern and southern hemispheres) and projected as a one-dimensional path on the sky. When we observe the planets on the sky, moving from night to night, we're observing them as they move in their orbits as the motion along this one-dimensional Path of the Ecliptic.

Regarding your "birth sign", an astronomer will tell you something quite different than an astrologer. There are 13 constellations of the Zodiac, not 12. Ophiuchus, or the "Serpent Bearer", was eliminated in ancient times because the Greeks chose to divide the 360 degree circle of the ecliptic into 12, equi-distant 30 degree segments. But why eliminate Ophiuchus and not another, after all there were 12 others to choose from?

Ophiuchus is the only constellation in the sky that is patterned after a real person in human history. According to Egyptian Mythology, Ophiuchus traces its origins back to the "mortal-made-god",Imhotep, a powerful deity, on par with Osiris and Thoth, all of whom answered only to Ra. Imhotep, who lived and died 4,600 years ago in the 27th Century BC, was honored by both the Egyptians and Greeks some 2,500 years later, not only as a great man, but as a physician and someone who was able to heal the sick, these skills being attributed to his knowledge of medicine. It has been suggested that Ophiuchus' unique origins in Ancient Egyptian mythology was the basis for its elimination.

Although ancient astrology (and its modern iteration) is based on superstition and a lack of authentic science and a proper understanding of the solar system and its orbital dynamics, the Greeks, being some of the greatest mathematicians, thinkers and scientists of all time, having established the foundations of modern, western civilization, were probably more inclined to eliminate Ophiuchus for more practical reasons. Because the path the sun would appear to travel along the ecliptic in any given constellation of the Zodiac is the shortest for Ophiuchus, spanning scarcely 20 days compared to 30 for the other 12, it stands to reason that Ophiuchus would be eliminated.

What does this mean for the daily Horoscope reader? It means that the Zodiacal sign that they've told you was yours, all your life, is wrong. My birthday is at the end of October and the sun is in Virgo on that day; I am, therefore, a Virgo, not a Libra.

Astronomy is science, it is the oldest of the natural sciences and embodies all of the sciences. Modern astrology is a superstition with no basis in reality; its origins are traceable back to a time before we had a proper scientific understanding of the solar system and its orbital dynamics, when any phenomena that was not understood was attributed to a deity.

If you would like to learn more and discover what your "Astronomical" birth sign is, download and install "Stellarium" at http://www.stellarium.org.

A Sad Day for America

2011-01-09T18:31:00.029-05:00

The title of this post may seem to be off topic for a blog devoted to Astronomy; when one reads the title again, however, it lends itself more towards daily or more frequent discussions of Astronomy and related topics.

Most of the world knows by now what happened yesterday in Tucson, Arizona. Another mentally disturbed individual opened fire on a crowd during a public event in Tucson. Six people were killed and others injured, some critically.

Critically injured was US Congresswoman Gabrielle Giffords, the United States Representative from Arizona's Eighth Congressional District, a Democrat. As is often the case with tragedies, this one is full of ironies. [Ironically], Rep. Giffords openly supports the Second Amendment to the US Constitution, the right to keep and bear arms. Among those killed were US District Judge John Roll, Giffords' aide and 9-year old Christina Taylor Green, [ironically] born on the day of another national tragedy, 9/11/2001 and included in the book "Faces of Hope, Babies Born on 9/11". She was described by her mother as a baby born of hope; hope, just as the Phoenix metaphorically rises from the ashes of tragedy, that life should continue and endure; she will be forever 9 years old, a star shining brightly in a world full of darkness, hatred and ignorance.

The latest prognosis for Rep. Giffords' is "cautiously optimistic".

One may ask, what does all this have to do with astronomy. Everything. Rep. Giffords is married to Navy Pilot and Space Shuttle Astronaut, Captain Mark E Kelly and is a member of the House Science and Technology Committee. In addition to openly endorsing education, an innovative and progressive approach to developing alternative energy solutions that include Solar and Wind Technologies, Rep. Giffords is a strong proponent of space exploration and maintaining this nation's and, more specifically, Arizona's status as a leading center for Astronomy and Astrophysical research. She supports the University of Arizona and the university's Steward Observatory, a leading center for HST-Related programs and research; she has visited the University's Mirror Lab where programs are underway to develop and produce much higher efficiency solar collectors and advanced photovoltaic technologies as part of a larger renewable energy initiative. Representative Giffords represents everything that's good and decent in a human being and a public servant, voting for what's right, instead of what's right for her party or some particular special interest.

Regarding the fierce political rhetoric that has ensued following yesterday's tragedy, it is a sad day for Arizona and, more broadly, a sad day for our Republic, I would suggest the following. If something looks like a rock and feels like a rock, it's probably a rock; this, in response to the extremist fringe on the right who now find themselves in the undesirable position of having to distance themselves from much of the blather and ignorance that has come from the Tea Party and, more significantly, something one of their own leaders and national spokespersons had publicly stated and posted on the Internet. They have been busy all day, issuing public dismissals, stating that it was just the work of a madman and that they and their Tea Party, Climate Change Denier, anti-science, anti-education, Rapture-waiting ilk had nothing to do with. Sorry, it doesn't wash. You can't yell fire in a crowded theater and then, when the stampede tramples someone to death, claim innocence. It's time for responsible public discourse; when fools and ignorami, blathering on about things they know nothing about, going on hate-laden diatribes at Primetime on nationally syndicated networks, are allowed to continue with impunity, an accounting is required and, if necessary, censure. Public officials and those aspiring to national office who post irresponsible and threatening "hitlists" need to be called to account and why wasn't that public figure, the one alluded to above, the one who would have been a heartbeat away from the Whitehouse and [ironically], the Vice Presidential choice of [Arizona] Senator John McCain, been called to account for posting that "hitlist"? I digress.

If there ever was a case to redouble our national attention to authentic education, it was this tragedy. Among all the confusion, with all the self-proclaimed experts, the ignorance, the xenophobia, the religious and ethnic intolerance, the replacement and supplanting of authentic science with a largely hostile, neo-fanatic, anti-science, politico-religious malaise, a properly educated individual would be immune to much of that; they would be the norm, not the exception. Indeed, education is the antidote. The psychopathic madman who committed this horrible atrocity yesterday would be far fewer in number.

I would close this post with an excerpt from from the late, great Carl Sagan:

The Pale Blue Dot
Carl Sagan
11 May 1996

Look again at that dot. That's here. That's home. That's us. On it everyone you love, everyone you know, everyone you ever heard of, every human being who ever was, lived out their lives. The aggregate of our joy and suffering, thousands of confident religions, ideologies, and economic doctrines, every hunter and forager, every hero and coward, every creator and destroyer of civilization, every king and peasant, every young couple in love, every mother and father, hopeful child, inventor and explorer, every teacher of morals, every corrupt politician, every "superstar," every "supreme leader," every saint and sinner in the history of our species lived there – on a mote of dust suspended in a sunbeam.

The Earth is a very small stage in a vast cosmic arena. Think of the rivers of blood spilled by all those generals and emperors so that, in glory and triumph, they could become the momentary masters of a fraction of a dot. Think of the endless cruelties visited by the inhabitants of one corner of this pixel on the scarcely distinguishable inhabitants of some other corner, how frequent their misunderstandings, how eager they are to kill one another, how fervent their hatreds.

Our posturings, our imagined self-importance, the delusion that we have some privileged position in the Universe, are challenged by this point of pale light. Our planet is a lonely speck in the great enveloping cosmic dark. In our obscurity, in all this vastness, there is no hint that help will come from elsewhere to save us from ourselves.

The Earth is the only world known so far to harbor life. There is nowhere else, at least in the near future, to which our species could migrate. Visit, yes. Settle, not yet. Like it or not, for the moment the Earth is where we make our stand.

It has been said that astronomy is a humbling and character-building experience. There is perhaps no better demonstration of the folly of human conceits than this distant image of our tiny world. To me, it underscores our responsibility to deal more kindly with one another, and to preserve and cherish the pale blue dot, the only home we've ever known.

Tuesday's Total Lunar Eclipse

2010-12-20T00:19:00.007-05:00

In the image that follows, Tuesday morning's Total Lunar Eclipse as seen during mid-eclipse (the point where the moon is directly centered in the earth's shadow). For US East coast observers, mid-eclipse occurs at 8:16 UTC (3:16 AM, EST); for West coast observers, this would be 3 hours earlier or 12:16 AM, PST. This eclipse is quite rare as it occurs on the same date as this year's Winter Solstice, 12/21/2010. Although the earth-moon orbital geometry is such that a lunar eclipse *should* occur during a full moon, the orbital inclination of the moon is such that, more often than not, the moon misses the Earth's shadow entirely.

Notice the penny-like appearance of the moon as one of the three corners of a triangle consisting of the moon, Betelgeuse and Aldebaran

Again, invoking geometry, we note that the full moon is 180º diametrically opposite the sun as it sets where a confluence of conditions necessary to produce a lunar eclipse *are almost all present* at both the Winter and Summer solstices. The Winter Solstice is the moment during the year when the sun is at it's lowest point in the sky, 23.5º south of the celestial equator; if the moon weren't inclined to the Earth's equatorial plane we would experience a lunar eclipse every month, including the December full moon (which, incidentally, is referred to as the "Cold" moon for obvious reasons), and this event would be far more common. During the Summer solstice, the earth-moon orbital geometry is exactly opposite.

In closing, it is worth noting that at the Winter solstice, the December full moon, regardless of whether a lunar eclipse occurs, is at it's highest point in the sky all year, a full 47º higher in elevation than the sun was during the corresponding previous day, the calendar date when the sun transits the meridian at it's lowest point all year.

Imagine!

2010-10-09T02:36:00.010-04:00

How poignant and meaningful "Imagine" is today, more than ever. It is just as relevant today as when John first released it 35 years ago.

I've been an astronomer my entire life. What I have learned during my brief sojourn on this planet, and it has been brief, is that all we have is ourselves and that we are compelled to treat each other as we would be treated; we will only be truly happy when we realize and live that. When I contemplate the enormity of the cosmos, its power, majesty and splendor, I am overcome by a profound humility, a deep, visceral and abiding love for mankind, for all creatures, great and small and for all of nature; I am compelled to treat all those, my fellow travelers on this magnificent blue oasis, as I would be treated, not because of some imagined reward but because there is no other choice.

When we truly understand our place in the cosmos and the staggering dimensions of the universe, we will then realize that wonderful, new world that John Lennon Imagined!

In his famous Pale Blue Dot, Carl Sagan said it the best and echoed the sentiments of Imagine:

The more I see of the world, of the cruelty and injustice, I wonder how it could ever be and then, I remember the words and the melody and then….I just imagine.

Click John's image to "Imagine"

Click Emmanuel's image to be moved, utterly

The Late Summer Sky

2010-08-26T01:46:00.125-04:00

As the earth moves in its orbit about the sun, completing one orbit, 360 degrees, in 365 days, it moves approximately one degree eastward in its orbit every day. This orbital motion of the earth is the basis for Sidereal Time, the apparent westward track of the stars with the passing of each day and the means by which astronomers navigate the sky and measure the passage of time. The earth’s rotation, completing one cycle in 24 hours, will bring the sun to the same azimuth every day without fail – this is a certainty; the combined motions of the earth around the sun and it’s daily rotation causes the stars to rise approximately 4 minutes earlier every day – sidereal time is 4 minutes faster, each day, than solar time. Why do I discuss this here and now? With the passage of each season, a whole new set of stars eventually presents itself on the sky.

The Summer Triangle, the famous trio of 3 bright stars is high over head at dusk and will soon be replaced by the stars of Autumn, notably the constellations of Pegasus, Andromeda and Perseus. For now though, lets consider those 3 stars and some of the other jewels of the summer sky. Deneb, Vega and Altair are, each, unique with 2 of the 3, Deneb and Vega, an excellent study in comparative luminosities!

The Summer Triangle with Vega, Deneb and Altair at the Zenith

What is luminosity? It is the total, time-averaged energy output of any energy-producing object – more about this below. With a declination (celestial latitude) of +38, Vega will transit the zenith as it appears to move across the sky for those locations that lie on or near +38 degrees latitude (Richmond, VA, the Delamarva Peninsula, etc). This location on the sky will allow Vega to remain visible for the maximum amount of time possible for those locations. Being 25 light years distant and brighter than first magnitude, astronomers have often used it as a test star and as a standard candle. Like the sun, Vega is a Main Sequence star, a star whose principal source of energy is the conversion of hydrogen into helium in its core at temperatures exceeding 15 million degrees (Kelvin), where the powerful internal gas pressure resulting from those high temperatures is balanced by the ever-present force of gravity. Vega contains a bit more than 2 times the sun’s mass but has a lifespan only 10% that of the sun (approximately 1 billion years compared to the sun’s 12 billion). There is a very strong dependence of luminosity on mass, almost to the fourth power! As we see with Vega, even a star with only 2x the mass of the sun has 10% the lifespan of the sun.

10 second exposure of the field around Vega obtained by this author with the 0.5 meter telescope of the Montauk Observatory. Vega is flanked by 2, 10th magnitude field stars.

Keeping Vega in mind as we look east to Deneb, we note that Deneb is almost as bright. We must remember though, Deneb is almost 100x further away at an estimated 1,800 light years! What does that suggest about the luminosity of Deneb? Also keep in mind that Deneb is no longer a Main Sequence star; it is a helium-burning, blue-white supergiant star with an estimated radius of 110 times that of the sun! Deneb will be a supernova candidate someday. Fortunately for us, it is sufficiently distant so as not to pose a threat when it finally does end its life in a spectacular manner as a supernova. The star that marks the third point of this familiar summer shape is Altair, the brightest star in Aquila, the Eagle. Being slightly less massive and a bit less luminous as Vega but only 16 light years distant, Altair presents with a similar brightness and color but is somewhat cooler and thus will live a bit longer than Vega. Both Vega and Altair are Main Sequence stars but are also rapid rotators and, as such, have pronounced equatorial bulges. Vega is such a rapid rotator that the force of gravity is greater at the poles than at the equator and this difference translates into a greater luminosity at the poles. Known as the Von Zeipel effect, this phenomenon has come under scrutiny in recent studies.

What constellations do these stars identify and what is their significance?

Vega as compared to the sun

Vega, otherwise known as Alpha Lyrae, is the brightest star in Lyra, the harp and marks the western-most point of the triangle. Lyra, according to Greco-Roman lore and mythology, dates from classical antiquity as one of the constellations listed by the 2nd century astronomer Ptolemy. It survives today and is recognized as one of the 88 official constellations recognized by the International Astronomical Union. Located south and east of Vega between the 2 stars that form the southernmost leg of Lyra’s parallelogram is Messier 57, the famous Ring Nebula. Being a “Planetary Nebula”, the name derived from the appearance of a planet as observed in a small telescope, M-57 represents the evolutionary end-state of sun-like stars. Having exhausted its compliment of hydrogen fuel, stars such as our sun will go through similar evolutionary changes. What was once the outer, non-fusing hydrogen envelope surrounding the normal, sun-like star’s core is now a beautiful ring of gas shining by the intense ultraviolet light emitted by the fiercely hot, non-productive white-dwarf central star. M-57 is a long-standing favorite and is easily visible in a modest, amateur telescope 15cm and larger as a stunning little smoke ring.

Wide field view of the region in Lyra containing M-57, the Ring Nebula. Imaged with this author's 15cm Newtonian reflector at prime focus, it presents as a small, red ring between gamma and beta Lyrae. Even in a modest amateur telescope, this object is a stunning smoke ring. Under very dark skies, the central white-dwarf star, the fiercely hot core of what used to be a sun-like star, is visible.

Moving east and slightly south, we encounter Deneb.

A small quadrant of the huge, highly-evolved, blue-white supergiant star Deneb compared to the sun

Otherwise known as Alpha Cygni, the brightest star in Cygnus, the swan, Deneb marks the tail of the swan. Apparently flying south, the swan is aligned with and is “flying” along the Milky Way, the millions of stars, so numerous and so distant that they appear as a beautiful silvery blue-white band that arcs from North to South. This band of light is the disk of our spiral galaxy, the Milky Way, and we, as observers, are looking out through the disk. The central, galactic bulge is huge, measuring approximately 6,000 light years in extent. The head of the swan or the base of the Northern Cross is marked by the beautiful double star Alberio. Presenting in a telescope as a beautiful blue and gold double star, it is one of the most stunning of double stars and a perennial favorite of amateur and professional alike. The gold star is much like our sun, albeit a bit cooler; the blue star is much hotter. If we were to continue along the Milky Way, we encounter Altair, or Alpha Aquilae, the brightest star in Aquila, the Eagle. Continuing our journey south along the Milky Way we find Sagittarius, the Centaur, the location on the sky that contains the galactic center, the center of our home in the universe, the Milky Way galaxy. Lore and legend has it that Sagittarius, half man and half horse, is forever with his bow drawn,aimed at the heart of Scorpio, the heavenly scorpion.

Top: a wide field image of the Milky Way clearly illustrating the galactic bulge and the thin disk of stars, disks that we, being immersed in the disk, observe as the beautiful, silvery-blue band of light arching from one horizon to another.
Bottom: vista of the galactic center with Antares and M-4 to the west (right). Note the regional gas, dust and yellow reflection nebulosity surrounding Antares.

As with all constellations, the lore and mythology reflects the culture of the day. The ancients were conquerors, hunters and gatherers and their great stories, their heroes, villains, kings and queens are forever immortalized in the stars; this was their way of preserving, in perpetuity, those great stories and we honor them and their great cultures today. By retaining the constellations and their boundaries and teaching the lore and mythology, we teach and transmit the values and wisdom of those great, bygone ages and the roots of Western Civilization. Being reflective of the culture, though, it is often difficult to discern the shape of the character represented on the sky. Having largely removed all natural threats and having developed the ability to adapt, twenty first century humanity would be hard-pressed to identify a harp, a centaur, a large bear or lyre, for example. Instead, being culturally reflective, our practical, modern imaginations, would look for tools or those items that are familiar.

Coming back to Sagittarius, modern man identifies a teapot, not a centaur; although not that hard to recognize once identified, our imaginations quickly find a teapot rather than a centaur. Within the centaur, west towards the scorpion and north and west towards Ophiuchus, the serpent bearer, is a veritable treasure trove of beautiful stars, non-stellar objects, star clusters, star clouds and other objects of note, all set against the ethereal beauty of the Milky Way. An all-time favorite, found in Sagittarius, is Messier-8, the Lagoon Nebula. Easily visible with a pair of binoculars, this object is stunning as set against a myriad of stars. Through a telescope, one quickly observes that identifying feature that gives it its name. Being a cloud of hydrogen gas, it shines pink by the intense ultraviolet light of those hot, young stars embedded within. In the foreground, is a lane of cold, black dust that presents as a flowing lagoon against the pink, glowing hydrogen. Scanning north with our binoculars along the Milky Way from the Lagoon Nebula, we encounter Messier-11, the Wild Duck Cluster in Scutum, the shield. Embedded in the Scutum Star Cloud, this beautiful, open star cluster presents in binoculars as a bright patch set against the myriad background stars. Through a modest telescope, it resolves into a stunning jewel box of diamond-like stars shaped like a “V”, the characteristic shape of a cluster of wild ducks.

A great image of the galactic center, illustrating it's extent and featuring many of the stars and objects discussed above.

Scanning westward toward the Scorpion, we find the brilliant red supergiant star, Antares. Because of its striking red presentation, it was named as the “opposite” (ante) of Ares (the Greek God of war). Antares is shrouded and embedded in its own cloud of expelled hydrogen. The fierce stellar wind, derived from the internal dynamics of the star and a consequence of its advanced evolutionary state, have started to drive off the outer layer of hydrogen. This gas is visible under good conditions as an envelope encasing the star. Another consequence of its advanced evolutionary state is its size. All stars, as their compliment of hydrogen fuel runs down, will expand and become a red giant star with the duration, dynamics, magnitude and size of that expansion dependent on the star’s initial mass. Although the sun will expand and become a red giant star, engulfing Mercury, Venus and probably the Earth, it won’t become nearly as bloated and distended as Antares. Clearly, Antares was much more massive than the sun during its productive lifetime.

The red supergiant star, Antares, in the foreground at 600 light years with the much more distant globular cluster, M-4, to the west, at 7,200 light years. Note the self-produced, yellow reflection nebula, a product of Antares' advanced evolutionary state

Continuing due west from Antares, we encounter the relatively close and diminutive globular cluster, Messier 4. As globular clusters go, M-4 is one of two such clusters that are the closest at 7,200 light years and one of the smallest at 75 light years across; globular clusters are typically between 85 – 100 light years across. An interesting study in distance, brightness and luminosity can be had by simply finding Antares in your binoculars and then scanning horizontally (due west) and locating M-4. Any pair of binoculars between 7x50 – 11x80 would be perfect for this. Once you locate M-4, look back east without moving the binoculars and observe Antares and then imagine that the brightest stars in M-4 would be comparable in luminosity to Antares and the only ones visible in a mid-size amateur telescope. Arcturus (discussed in more detail, below), although smaller than Antares, is still in an evolved state and is one such example of the type of star most prominent in globular clusters; more about globular clusters below.

Scanning 60 degrees north and west from Antares, we encounter the red giant star, Arcturus, the brightest star of spring, summer and autumn and the brightest star north of the celestial equator. Much like the sun will be in 4 – 5 billion years, Arcturus is, like Deneb and Antares, in an advanced evolutionary state and is burning Helium in its core. Not as initially massive as Antares nor in as an advanced evolutionary state, Arcturus isn’t nearly as large as Antares. Still dwarfing the sun though, it approaches the size of Mercury’s orbit in radius. Arcturus, being quite prominent in both brightness and color, is the brightest star in Bootes, the herdsman and is thus, easily located. Once located, it makes a great guidepost to find other important stars and constellations, most notably the “Big Dipper”, an asterism with a self-descriptive name and part of the larger constellation Ursa Major, The Great Bear. Using the catchy phrase “arc to Arcturus” in reverse, we scan to the north and west and easily locate the handle of the Big Dipper and then the “pot”, all stars being of comparable brightness. This asterism is one of the most easily recognized patterns on the sky.

We’ll conclude this installment with a discussion of the famous Globular Cluster, M-13 in Hercules. West of Vega and Lyra, Hercules is identified by a large, celestial “H” or Keystone with M-13 midway between the two stars that compose the west side of the keystone.

Wide field view of the great globular star cluster, M-13, imaged with this author's 15cm Newtonian reflector at prime focus. The cluster's most luminous stars, visible in this image as pixel-sized points of light are evolved, red-giant stars such as Arcturus. Stars such as that stunning, bright-red star so beautiful in our sky, are visible at the distance of M-13 as tiny, faint points of light.

Approximately 25,000 light years distant and containing 2 separate populations of stars, old, evolved, sun-like stars and younger “blue-stragglers”, this cluster ranks as one of the most beautiful, most ethereal objects visible in the northern hemisphere. Globular clusters, while not actually contained within the galaxy, orbit the nuclear bulge in a region known as the galactic halo and contain between 50 and 100 thousand stars, all agglomerated in a ball, kept together by the ever-present force of gravity. M-13, due to its relative position above the galactic mid-plane, in a direction where the attenuating gas and dust is minimal, is one of the brightest visible to Northern Hemisphere observers and is a favorite of amateur and professional astronomers, alike. Globular clusters contain some of the oldest stars in the universe, stars that date back about 13 billion years to a point when the universe was a lot younger and a lot different. As seen in a pair of 7x50 or 11x80 binoculars, M-13 presents as a bright ball where one gets the sense that its myriad stars are just beyond resolution. As seen through a modest telescope 15cm and larger, the faint, distant, agglomerated stellar beacons that comprise it, beacons beckoning across galactic time and space with whispers of light so old that they left when we were dwelling in caves, one is able to see those tiny points as one would see fine salt concentrated and glowing on black velvet. The faintest points of light visible in those modest telescopes represent stars somewhat more luminous than the sun with the only way to detect a star such as our sun would be in very deep images obtained with observatory class telescopes, telescopes that include the Hubble Space Telescope. The brightest stars visible through a mid-size amateur telescope of at least 30cm in diameter are stars such as those discussed above, stars like Arcturus. Because of their extreme age, these stars have now evolved off the Main Sequence, the designation identifying them as stable stars, producing energy by fusing 4 hydrogen nuclei (protons) in to one helium nucleus (an alpha particle). The dynamics of this evolutionary state have caused them to expand and, as a result, to become more luminous.

All stars, constellations and non-stellar objects discussed in this installment are still visible as of 11:00 PM EDT, the date of publication.

The Early Summer Western Sky, Alight with Stunning Beauties

2010-07-04T17:49:00.015-04:00

I haven’t posted anything to this blog since early winter and it’s high time that I do so. Even this post will be brief as I am working on a more expansive discussion of the summer sky – look for that over the coming week. At an apparent visual magnitude of –3.95, the brightest it’s been in a very long time and moving through its Greatest Eastern Elongation over the next few days, Venus is beautifully situated high in the west at sunset, separated from the sun by 46 degrees, a scant 1 degree shy of its greatest possible separation. Since the earth rotates 15 degrees for each hour, Venus is visible for at least 3 hours after sunset. Exhibiting phases, just as the moon does, Venus presents now in a “Gibbous” phase. First observed by Galileo, the phases of Venus were an important discovery, providing the necessary empirical evidence for the Heliocentric model of the solar system, a concept that was fiercely contested 400 years ago. Imagine, for a moment, the earth with the inner planets, orbiting the sun. Since Venus is nearer the sun than Earth and we, being observers on the Earth, will see Venus in its relative position to the sun in our sky. Since Venus is always closer to the sun, it will never be more than 47 degrees from the sun, either in the evening (Greatest Eastern Elongation) or in the morning (Greatest Western Elongation).

Further east along the ecliptic, we find Mars, between Regulus, the heart of Leo, the Lion, and Saturn, the true Lord of the Rings. Scanning further east, we find powerful, blue-white Spica, the brightest star in Virgo and a spectroscopic binary star. Both Leo and Virgo are Spring constellations and, as such, we would expect them to be setting now, the first week in July and the beginning of the 3rd week of summer.

Winter's Jewels on Display

2009-12-29T17:08:00.070-05:00

During these cold, clear winter nights in the Northern Hemisphere, the sky is adorned with a veritable treasure trove of jewels, ranging widely in brilliance, splendor and color.

As seen from mid-northern latitudes, the winter sky has one of the highest densities of bright stars for any given region of the sky. Even a casual observer can appreciate the assortment of bright stars, their splendor, density and brilliance unrivaled. Prominently placed, looking south between December and March, one quickly notices Orion, The Hunter with Canis Major, The Great Dog, to the south and east [of Orion].

Contained in Orion and Canis Major, respectively, are the stars Rigel and Sirius, both stars providing an excellent object lesson in comparative luminosities.

Standard, unaided view of Orion showing the 3 familiar belt stars with Saiph at the lower left, Rigel at the lower right, Betelgeuse at the upper left and Bellatrix at the upper right. Visible in this image is the famous Orion Nebula, M-42, the pink patch below the belt stars

Rigel is an evolved, blue supergiant, well into its Helium-burning cycle and possibly beyond and will soon end its life as a supernova.

The Famous Witch-Head nebula, illuminated by powerful Rigel (click for larger image)

At 1.7 solar radii, Sirius is an A1 main sequence star with twice the mass of the sun at a relatively close distance of 8.7 light years.

Telescopic field around Sirius (click for larger image)

At 25.4 times the luminosity of the sun, Sirius is not nearly as intrinsically luminous as Rigel, a star with almost 80,000 times the sun’s luminosity. Both stars, however, are of a comparable brightness. So how do we reconcile these widely disparate luminosities? Rigel owes its luminosity to both its size and its temperature. The luminosity of a star is proportional to the second power of its radius and the forth power of its temperature. At 78 solar radii, Rigel is huge, the size alone accounting for 6,100 times the sun’s luminosity. With a surface temperature of 11,000 K, that result is again multiplied by 13, yielding a comparative luminosity of almost 80,000 solar compared to a paltry 25.4 solar for Sirius. At 800 light years distant and appearing almost as bright as Sirius, one gets a good idea of the awesome power of Rigel compared to the sun or even Sirius. Suppose we were to transpose the positions of Rigel and Sirius, how would they appear in our sky? Rigel would have an apparent magnitude of -9.5, the brightness of the first-quarter moon but concentrated in a point source, a source so bright that you could easily read by its light! Sirius, at the distance of Rigel, would have an apparent magnitude of 8.3 and would be invisible to the unaided eye! Rigel is the most luminous star in our local region of the Milky Way and when the day comes that it ends its life as a supernova, the light show will be spectacular, equal in brightness to the full moon and visible during daylight! Imagine, if you will, all the light of the full moon concentrated into a point source and you have a good idea of just how bright Rigel will appear when it does go. This, at its distance of 800 light years! What if it were at the distance of Sirius when it went supernova? It would rival the brightness of the noon day sun and extinguish all life on earth!

Rigel, as seen from the distance of Neptune, would appear 42x brighter and twice as large as the sun does in our own sky (click for larger image)

In addition to Rigel and Sirius, this showcase of notable gems includes Betelgeuse, Orion’s right shoulder, an evolved, red supergiant star so bloated and huge that the planet Jupiter would orbit inside the star! Procyon, to the north and east of Sirius is almost as bright as Sirius, all appearing as if someone had scattered a veritable jewel box onto the sky. Sirius, Rigel and Procyon are as diamonds in the sky; Betelgeuse as a ruby; the three stars that make-up Orion's belt: Mintaka, Alnitak and Alnilam are as 3 lesser sapphires. The ethereal beauty of the winter Milky Way running south through Orion and skirting Canis Major on its eastern boundary as a most-elegant jeweled necklace, more beautiful and sublime than the mind of man can imagine, fills the observer with profound humility and a deep sense of awe. No holiday ornaments, no festive lights, nothing that can be created or imagined by the mind of man can replace these natural jewels in majesty, beauty and splendor. It is no wonder that the winter sky looks as it does, ablaze with these stellar jewels: the sun is located in the "Orion Spur", a rich, star-forming region of our Milky Way galaxy.

Wide-field binocular view of Orion, showing the 3 familiar belt stars, M-42 and Saiph, to the lower left (click for larger image)

Visible in the wide-field view of Orion, above, the most famous in the winter showcase of celestial jewels is the Great Nebula in Orion, Messier 42. Located in the "Sword of Orion" and flanked by Messier 43 to the left and shining by the intense ultraviolet light of the luminous O and B stars collectively known as the Trapezium (Theta Orionis), the ethereal beauty of this H-II region is legendary.

The Great Nebula in Orion, M-42 (click for larger image)

Aside from the old favorites, I would like to briefly discuss three stunning open star clusters, M-41, M-46, NGC2362 and a stunning, little planetary nebula, NGC 2438 that, while superposed within M-46, is not physically associated with it. South-southwest of Sirius in Canis Major lies the beautiful open cluster, Messier-41 (M-41, for short). It is no accident that, along with the other, brilliant gems scattered throughout this region of the sky, there is no shortage of galactic (open) clusters. Being associated with star-forming regions, these types of star clusters would be found in the arms of the host spiral galaxy. The conditions surrounding their formation playing a critical role in their evolution, these stars will live very short, punctuated lives with many of the more massive ones ending their lives as supernovae.

Canis Major as seen from the Everglades, showing brilliant Sirius, Messier 41 directly south of (below) Sirius, Tau Canis Majoris and NGC-2362 (click for larger image)

Stunning in binoculars and visible in the wide-field view above (below Sirius towards the right-hand side), M-41 is a winter favorite.

Stunning in this large scale view of M-41 are the hot, young, luminous stars so characteristic of open (galactic) clusters, clusters that generally form in the arms of spiral galaxies. Compare this view with the wide-field view above (click for larger image).

Puppis, south of Canis Major is another constellation that is often overlooked but is, nonetheless, home to a real gem. Messier-46 contains a 10th magnitude planetary nebula (the end-state for stars similar to our sun), NGC2438 that is easily visible in a small to mid-sized amateur telescope. This beautiful little smoke ring appears to float in front of the background stars. M46 can be easily found by scanning due east of Sirius with a wide-field eyepiece. Once found, higher magnification will show the stunning little smoke ring.

The beautiful open cluster, M-46 with the stunning, little smoke ring NGC-2438 (click for larger image)

Another gem in this treasure chest that is the winter sky in and around Canis Major and Orion is Tau Canis Majoris and the associated open cluster NGC 2362.

New General Catalog (NGC)-2362 with 4.4 magnitude Tau Canis Majoris front and center (click for larger image). Like Rigel, Tau is a luminous O supergiant, 3200 light years distant.

It is uncertain if this luminous, powerful star is gravitationally bound to the cluster. If it is, as mounting evidence seems to indicate, Tau Canis Majoris would be one of the most luminous supergiant stars known with an absolute magnitude of -7.0 and an aggregate luminosity of almost 100,000 solar luminosities. This beautiful little cluster is a personal favorite, is made up of about 60 stars and is only about 25 million years old. To locate NGC 2362, scan approximately 1º northeast of Wezen (Delta Canis Majoris - see wide-field view) and this neat little cluster will dance into view. Imagine, if you will, a planet orbiting (Tau) Canis Majoris, a luminous O8 star embedded in NGC 2362 and surrounded by dozens of young, luminous stars. What would your night sky look like? Then also image that this star will live no more than 20 million years and is a likely candidate for a Type II supernova, the same fate that will befall 1 (Theta-1) Orionis, a luminous, blue-white O6 star, the most luminous of the stars in the Trapezium and the principal source of the intense UV light that is causing M-42 to shine. In about 20 million years we had better keep our eyes on this part of the sky because, as the Chinese astronomers of 1054 observed in Taurus, we will be witness to the terrible beauty of a Type II Supernova, the most energetic event in the universe, a spectacle that will be observed in a location none other than what used to be the sword of Orion!

Except for the Witch-head nebula, image credit: Thomas Madigan. Wide-field images of Orion and Canis Major acquired in the Everglades, February 1986. Hi resolution images of Sirius, M-41, M-42 and NGC-2362 obtained with 20cm (8") Newtonian reflector at F/7.2 Prime focus. Images of M-46 and NGC 2438 obtained with the 0.61m R-C Reflector of LightBuckets on 13 March 2010.

2012 – Fact and Fiction

2009-11-16T13:59:00.002-05:00

2012 – Fact and Fiction

The opening entry in my blog implies a duality of subject: fact and fiction. There is fact and there is fiction and it is my intention to provide some clarity to this widely hyped and misunderstood date.

This past weekend, Hollywood’s long-anticipated movie regarding the end of the Mayan calendar and its significance has debuted. It is only fitting that such a film be released during the waning days of the International Year of Astronomy 2009, a worldwide event that celebrates the birth of the scientific method, at a time, 400 years ago, when it was dangerous to challenge deeply entrenched notions of the cosmos and our place in it with revolutionary new ideas. These new ideas would, forever, alter the way we see ourselves against the backdrop of a profoundly rich cosmos whose enormity and scale is truly staggering. Four hundred years ago, Galileo was the first to use the telescope as an instrument of science to unequivocally demonstrate that the sun was the center of the solar system. The simple act of training his telescope on the sky would forever alter the course of history. This year we mark the 400^th anniversary of that seminal event and celebrate the rich history of science and discovery that has ensued. This celebration, I would suggest, is an antidote to the pseudoscience, hysteria, ignorance and superstition that surrounds this date and this movie. Of those who have spent $225,000,000 at the box office to watch 2012 over the weekend, how many would now visit their local planetarium for a dose of real science? Sadly, very, very few.

As I write this, a certain irony occurs to me and this, perhaps, is the undercurrent, the “question that begs asking”: Have we really progressed over the past 400 years or, as the throngs flock to theaters to watch this movie, are we still mired in the past, slaves to superstation and ignorance?

First, let’s consider some of the facts

Fact 1: the Mayan calendar does end on 12/21/2012. This date marks the Winter Solstice for 2012. What is the Winter Solstice? It is the day when the sun reaches its southernmost point in the sky as it transits the meridian at local noon and has, traditionally, marked the beginning of winter. Like many peoples of long ago, the Mayans were very much in tune with nature; they observed the motions of the sun, the moon and the planets, an activity that has, today, been almost universally supplanted with illusory and transitory activities; many people would, sadly, rather wallow in the hyped-up fantasy that is this movie. The big question is, and this is where things get murky, what significance does the ending of this calendar hold?

An authentic reading and interpretation of the 2012 end-date would be one of change, not destruction, change being the one constant in all of nature; indeed the natural universe, on every scale, continues to evolve and change, something the Mayans and the other advanced civilizations of old were very much in tune with. Stonehenge, another ancient legacy to the passing of the seasons, is a place built by Iron-age man to mark the passage of the seasons: the Vernal Equinox, the Summer Solstice, the Autumnal Equinox and finally, the Winter Solstice.

Fact 2: there is no grand alignment of the planets. In fact, the planets are rather dispersed on this date:

Mighty Jupiter stands by itself, high in the east-northeast at sunset while the inferior planets, Mercury and Venus are east of the sun, preceding it at sunrise the next day; Mars is visible for about an hour and follows the setting sun. Even if the planets were aligned, an exceedingly rare event, there would be no measurable tidal effect, something portrayed in the movie as a cataclysmic, worldwide upheaval, the wholesale destruction of all the major cities, worldwide conflagration, huge tsunamis, earthquakes, and total, worldwide devastation. Of the 4 fundamental forces of nature, Gravity is the weakest (by many orders of magnitude) and behaves according to an inverse square law: an object that is twice as distant will have ¼ the force of attraction. Using Jupiter and Saturn as examples, and for the sake of argument, adopting a mass equivalence for both (actually, Saturn is about ¼ the mass of Jupiter), since Saturn is twice the distance from the sun as Jupiter, its gravitational contribution to any alignment effects would be ¼ of Jupiter’s. Bear in mind that these 2 planets are the most massive of all the planets and would represent the lion’s share of any tidal or gravitational effect.

Fact 3: there is no mysterious and, heretofore, undiscovered planet Nibiru. Modern orbital dynamics have been perfected to an art, perfected to the point where we can predict the path and location of any object in the solar system with a high degree of accuracy and precision. Any unknown or invisible planet would cause perturbations on the rest of the planets and its location, mass and orbital path would have already been determined. Indeed, we have discovered planets orbiting other stars based on the perturbations in the paths and light levels of those stars. There will be no unknown or uninvited guest looming large and ominous in our sky.

Fact 4: regarding celestial alignments, we turn our attention to the alignment of the Winter Solstice with the Galactic Center, the central agglomerated mass of our galaxy. There are two principal motions of the earth that regulate and govern the daily rising and setting of the sun, our climate and the seasons: the earth’s daily rotation and its annual orbit about the sun. Because the earth is tilted approximately 23½ degrees to the vertical, the sun’s energy received at the surface of the earth will vary throughout the year as it orbits the sun – this is the principal reason for the seasons. There are other, extended and more subtle motions in addition to the earth’s rotation and orbit around the sun. One of those motions is the earth’s precession. Just like a top wobbling on its axis, the earth wobbles or precesses, completing one precession cycle in approximately 26,000 years. This “Precession of the Equinoxes” causes the four principal seasonal markers discussed above to precess westward along the ecliptic. The vernal equinox is the astronomical beginning of spring because it is the point where the ecliptic crosses the celestial equator. As was the case regarding the purported devastating tidal effects caused by the alignment of the planets, the concern here is that the alignment of the galactic center with the winter solstice will result in equally devastating tidal effects. In fact, some of the more fervent 2012 adherents are concerned about the combined tidal effects of the galactic center alignment and the planetary alignment.

We unequivocally dismiss the possibility of any tidal effects resulting from the alignment of the winter solstice and the galactic center. There is no deep natural resonance or cosmic significance to the equinoxes or the solstices – they are a local phenomenon specific only to the earth. Aside from the physics involved regarding the vanishingly small gravitational or tidal forces felt here at the earth’s location at the outer 1/3 of the Milky Way galaxy, the dimensions and scales involved are staggering. The distance to the galactic center is 25,000 light years or, put in more familiar terms, 2.4 x10^17 kilometers – that would be 2.4 with 16 zeros in kilometers – when we observe the galactic center, the light striking our cameras or eyes left it at a time when we were still dwelling in caves. It is absurd and ridiculous in the extreme to suggest that the difference in the position of the sun in our sky between some insignificant date and some other equally insignificant date, a position resulting from some locally peculiar orbital characteristics, as set against a point so far away that its light took 25,000 years to arrive, would have any measurable effect on our lives. Indeed, it is the height of hubris to think that it would matter – its time we got over our anthropomorphism and truly dispense with the geocentric or, more appropriately, our homocentric and self-aggrandized notions of our place in the cosmos.

The world will not end in 2012. Doomsday theories come and go but our legacy is eternal; what will it be? Civilizations will rise and fall over the coming millennia; the kindness and charity we show to each other and to the fellow creatures that share our planet, our stewardship of this fragile, blue miracle floating in a hostile and unforgiving cosmos, will be our enduring legacy (Pale Blue Dot). The physical end to our world will come with a definite certainty, a date that was etched in stone before the sun shone bright in space, at a time when the solar system, the sun and its planets, were formed. It is not written in the bible; it is not hidden in some dark, obscure corner of some ancient people’s calendar; it is not known by psychics, soothsayers, astrologers, seers or anyone else who purports to know the future – the future is unknowable; in fact what you will do within the next five minutes is governed by a staggeringly large set of variables that don’t even exist yet. The physical end of the world will come in 7.7 billion years when the sun, finally depleting its compliment of hydrogen fuel, swells to become a red giant star. What we do in the meantime is up to us.