Debunking Comet ISON Conspiracy Theories (No, ISON is Not Nibiru)

ISON as seen from Hubble. (credit: NASA)

Comets always seem to bring ‘em out of the wood work.

There’s a scene from the 1998 movie Deep Impact where the president, played by Morgan Freeman, reveals a terrible truth… the U.S. government has known for over a year that a doomsday comet is headed straight towards Earth, with Hollywood CGI destruction sure to follow.

While dramatic, the scenario is also extremely implausible. On any given evening, amateur astronomers are sweeping the skies using telescopes mounted in backyard observatories that are the envy of many major universities. This effort to discover comets is collaborative and worldwide. If the “Big One” were headed our way, even the likes of Morgan Freeman couldn’t keep it secret.

Trouble is, many unfounded claims are already making their way around the internet about this years’ much anticipated “Comet of the Century,” C/2012 S1 ISON.

Many of these conspiracy theories seem to be a recycling of last years’ Nibiru nonsense. The train of thought runs something like this: Does NASA know something that they’re not telling us? Why are they so interested in this comet? We’ve even had folks ask us why certain patches of Google Earth are “blacked out!”

What ARE they hiding, man?

It’s funny how pseudoscience seems to bubble to the top on YouTube, but I won’t give these conspiracy videos the exposure of the Universe Today platform. With hundreds of thousands of hits, they certainly don’t seem to need it. A simple YouTube search of “ISON” will scare up many wacky ideas about the comet.

In any event, we’ve already fielded several questions from friends and the public on the “dangers” posed by this comet, so we can only imagine that these will grow in intensity as the comet approaches the inner solar system, especially if it performs up to expectations.

What are some of the conspiracy theories out there about Comet ISON?

One currently circulating claim states that Comet ISON has “companions” that have been imaged trailing it. While comets do indeed fragment on occasion, the culprits that can be seen in the .gif animation circulating the internet are easily identified by photography experts as hot pixels in the camera.

Another even more extravagant claim is that Comet ISON will somehow appear “as bright as the Sun.” Even if Comet ISON reaches an expected magnitude equal to that of the full Moon at -13, it will do so when it is less than a degree  from the Sun. Our Sun shines at magnitude -26.74, or over 158,000 times brighter, so it would be very difficult for this comet to compete with the Sun’s brightness in the daytime!

Others seem to worry that this comet — or particles from ISON — could impact Earth. Comet ISON will be making its inner solar system passage safely 0.426 A.U., or a little over 63 million kilometers from Earth even on its closest approach on December 26th. Scientists have defined this comet’s orbit very precisely, and it won’t hit Earth. So, no Comet ISON is not Nibiru — that ‘tenth planet’ destined to destroy Earth that conspiracy lovers can’t seem to let go of.

The debris — which might create a very nice meteor shower — is made up of extremely tiny grains of dust, no more than a few microns wide. Since they will be hitting Earth’s atmosphere at speeds up to 200,000 km/hr (125,000 miles per hour), the particles will burn up.

Here’s a video NASA released about the potential meteor shower from ISON:

Other claims focus on how this comet may cause earthquakes or wreak other untold havoc on Earth. This type of comet hysteria is nothing new. Name a bright comet in history, and you can find a historical event for a convenient tie-in. When haven’t there been earthquakes, pandemics, and wars in history? Plus, according to the US Geological Survey, on any given day there will be an average of 2,750 earthquakes around the world of which 275 are large enough to be felt by humans. But only about 100 earthquakes a year are large enough to cause any damage.

And so, its too easy to tie the “causes” of earthquakes and other events to comets in the sky. Comets have been seen before and during the Norman invasion of England in 1066, an outbreak of the Black Plague in London in 1665, and much more. Gary Kronk maintains a wacky and wonderful list of historical (and sometimes comical) comet “signs and omens” on his Cometography site.

Comet Lovejoy as seen from the International Space Station.
Another brilliant sungrazer, Comet Lovejoy as seen from the International Space Station on December, 2011. (Credit: NASA).

Halley’s Comet produced one of the first great comet hypes of the 20th century with its 1910 passage. Ironically, another comet made a brilliant passage just a few months prior, which became known as the Great Comet of 1910. In fact, many viewers in the general public actually saw this comet and confused it with Halley’s! The recent discovery of cyanogen in the comet’s spectra sparked a panic in the public as hucksters made a small fortune hawking “comet pills” and gas masks to panicked buyers. Never mind that folks ingest more toxic carcinogens from their daily environment than are ever seeded by the tenuous tails of comets.

Another curious bit of hype sprung up in 2011 around Comet Elenin, which promptly broke up and dissipated without even putting on a show. And the supposed earthquakes that conspiracy theorists predicted? Well, the evidence speaks loudly: nothing happened. And the same will be true of Comet ISON. It won’t cause any earthquakes or other disasters. As Don Yeomans from NASA said about Comet Elenin, “It will have an immeasurably miniscule influence on our planet. By comparison, my subcompact automobile exerts a greater influence on the ocean’s tides than comet Elenin ever will.”

So, what’s the harm in all the comet hysteria? Well, one only has to look at the mass suicide of the Heaven’s Gate cult in 1997 to realize that it can be no laughing matter. The suicide was sparked by the idea popularized on the late night Coast to Coast with Art Bell radio show that a spacecraft had been spotted following Comet Hale-Bopp.

Dozens of comets are discovered every year. A great majority are tiny iceballs in unfavorable orbits that never rise above magnitude +10 and are thus of little interest to backyard observers. A couple of times a year, a comet might reach magnitude +6 to +10 and become a fine binocular object.

When a discovery is made — be it by amateur or professional — the first task is to gain enough observations of the object to ascertain its orbit. Once again, we see the international collaborative methods employed by modern science. Already, the cosmic cat’s out of the bag as observatories worldwide make follow up measurements. There are no secrets about Comet ISON that hundreds of astronomers could keep quiet.

You get the idea... a 1687 leaflet depicting the havoc that a comet is sure to bring. (Wikimedia Commons image in the Public Domain).
You get the idea… a 1687 leaflet depicting the havoc that a comet is sure to bring. (Wikimedia Commons image in the Public Domain).

But here are some facts about Comet C/2012 S1 ISON. It was discovered last September by Russian amateurs Vitali Nevski and Artyom Novichonok while making observations for the International Scientific Optical Network (ISON), hence the comet’s name. At the time, it was farther than Jupiter and impossibly faint, but once ISON’s orbit was determined, astronomers realized the comet would pass only 1.1 million miles from center of the Sun (680,000 miles above its surface) on November 28, 2013.

Comet ISON belongs to a special category of comets called sungrazers. As the comet performs a hairpin turn around the Sun on that date, its ices will vaporize furiously in the intense solar heat. Assuming it defies death by evaporation, ISON is expected to become a brilliant object perhaps 10 times brighter than Venus, or maybe even brighter. But that would only occur for a brief time around at perihelion (closest approach to the Sun).

In the end, Comet ISON may put on a good show, but don’t believe the hype.

Comets are notoriously unpredictable when it comes to brightness estimations. To quote comet-hunter David Levy, “Comets are like cats… they have tails, and they do exactly what they want.” But they cannot, however, violate the laws of orbital mechanics!

The orbit and orientation of Comet ISON the day after Christmas 2013 on closest approach to the Earth. (Credit: NASA/JPL's Small-Body Database Browser).
The orbit and orientation of Comet ISON the day after Christmas 2013 on it closest approach to the Earth. (Credit: NASA/JPL’s Small-Body Database Browser).

Catch Comet Lemmon While You Can

On May 6 a beautiful thin moon will be near Comet Lemmon at dawn. This map shows the sky about 1 1/4 hours before sunrise. Stellarium

If you honed your observing chops on Comet PANSTARRS this spring, consider dropping in on Comet Lemmon, now returning to the dawn sky. Southern hemisphere observers saw this comet at its brightest in March when it briefly became dimly visible with the naked eye. It’s now faded to around magnitude 6, the same as the faintest stars you can see under a rural sky.

Because it’s been “vacationing” in the southern constellations, northerners have had to wait until now to see it.

Comet Lemmon with gas (left) and dust tails on April 24. Click to see a short movie showing rapid changes in the comet's tail in 25 minutes. Credit: Gerald Rhemann
Comet Lemmon with gas (left) and dust tails on April 24. Click to see a short movie showing rapid changes in the comet’s tail in 25 minutes. Credit: Gerald Rhemann

Like PANSTARRS, C/2012 F6 Lemmon is visible in modest-sized binoculars (7x35s, 10x50s) as a small, fuzzy ball of light with perhaps a faint tail. Watch for it to slowly track along the eastern side of the Great Square of Pegasus for the remainder of April and May. It competes with twilight low in the eastern sky this week but gradually becomes better placed for viewing as May unfolds. The best time to look is about an hour and a half before sunrise now and 2 hours before sunrise by mid-May.

The waning moon interferes some until around May 5. On the 6th, watch for the thin lunar crescent moon to pass 8 degrees below the comet. Around that time, we’ll finally get a good view of Lemmon in a dark, moonles sky just before the start of dawn.

On May 6 a beautiful thin moon will be near Comet Lemmon at dawn. This map shows the sky about 1 1/4 hours before sunrise. Stellarium
On May 6 a beautiful thin moon will be near Comet Lemmon at dawn. This map shows the sky about 1 1/4 hours before sunrise. Stellarium

Comet Lemmon will fade from naked eye limit to a dim binocular smudge of 7.5 magnitude  by mid-May. If you have a telescope, look for a pair of tails – a short, diffuse one of dust particles and the straight, streak-like gas tail fluorescing in the sun’s ultraviolet light. The tails point approximately to the south-southwest. Catch this comet while you can!

Comet Lemmon, Now in STEREO

Animation of Comet 2012 F6 Lemmon as seen from NASA's STEREO ahead spacecraft. (Credit: NASA/GFSC; animation created by Robert Kaufman).

An icy interloper was in the sights of a NASA spacecraft this past weekend.

Comet 2012 F6 Lemmon passed through the field of view of NASA’s HI2A camera as seen from its solar observing STEREO Ahead spacecraft. As seen in the animation above put together by Robert Kaufman, Comet Lemmon is now displaying a fine ion and dust tail as it sweeps back out of the inner solar system on its 10,750 year plus orbit.

Comet Lemmon has been a dependable performer for southern hemisphere observers early in 2013. As we reported earlier this month for Universe Today, this comet is now becoming a binocular object low in the dawn sky for northern hemisphere astronomers.

Comet Lemmon passed perihelion at 0.73 astronomical units from the Sun on March 24th. It’s currently in the +4th to +5 magnitude range as it heads northward through the constellation Pisces.

NASA’s twin Solar TErrestrial RElations Observatory (STEREO) spacecraft often catch sungrazing comets as they observe the Sun. Known as STEREO A (Ahead) & STEREO B (Behind), these observatories are positioned in Earth leading and trailing orbits. This provides researchers with full 360 degree coverage of the Sun. Launched in 2006, STEREO also gives us a unique perspective to spy incoming sungrazing comets. Recently, STEREO also caught Comet 2011 L4 PanSTARRS and the Earth as the pair slid into view.

Another solar observing spacecraft, the European Space Agencies’ SOlar Heliospheric Observatory (SOHO) has been a prolific comet discoverer. Amateur comet sleuths often catch new Kreutz group sungrazers in the act. Thus far, SOHO has discovered over 2400 comets since its launch in 1995. SOHO won’t see PanSTARRS or Lemmon in its LASCO C3 camera but will catch a glimpse of Comet 2012 S1 ISON as it nears the Sun late this coming November.

Like SOHO and NASA’s Solar Dynamics Observatory, data from the twin STEREO spacecraft is available for daily perusal on their website. We first saw this past weekend’s animation of Comet Lemmon passing through STEREO’s field of view on the Yahoo STEREOHunters message board.

Here’s a cool but largely unrecognized fact about comets. As they move back out of the solar system, their dust tail streams out ahead of them, driven by the solar wind. I’ve even seen a few science fiction flicks get this wrong. We simply expect comets to always stream their tails out behind them!

Another observatory in our solar observing arsenal has also moved a little closer to operability recently. The Interface Region Imaging Spectrograph (IRIS) arrived at Vandenberg recently in preparation for launch this summer on June 26th. IRIS will be deployed from a Pegasus XL rocket carried aloft by an L-1011. NuSTAR was launched in a similar fashion in 2012. A Pegasus XL rocket will also launch the TESS exoplanet hunting satellite in 2017.

Keep an eye out for Comet Lemmon as it emerges from the dawn twilight in the days ahead. Also, be sure to post those pics to Universe Today’s Flickr community, and keep tabs on the sungrazing action provided to us by SOHO and STEREO!

 

Comet PANSTARRS: The Show’s Not Over Yet!

Comet PANSTARRS as seen over Payson, Arizona on April 24, 2013. Credit and copyright: Chris Schur

While Comet C/2011 L4 (PANSTARRS) is fading to barely naked-eye and binocular visibility (the comet has lost a full magnitude approximately every week since perihelion on March 9), astrophotographers are still able to track down the comet as it moves away from the Sun. This deep color exposure by Chris Schur in Arizona is still able to show surprising detail and Chris said via email that he was “surprised how beautifully colored the stars are in this part of the Milky Way.” Chris’s shot is a 25 minute exposure, and is an LRGB (Luminance, Red, Green and Blue — is a photographic technique used in amateur astronomy for producing good quality color photographs by combining a high-quality black-and-white image with a color image).

See some more recent PANSTARRS images from around the world, below, plus an awesome new timelapse from TWAN (The World At Night) photographer P-M Hedén:

The Visitor – Comet PanStarrs from P-M Hedén on Vimeo.

Comet C/2011 L4 (PANSTARRS) on April 23, 2013. Credit and copyright:  Paul M. Hutchinson.
Comet C/2011 L4 (PANSTARRS) on April 23, 2013. Credit and copyright: Paul M. Hutchinson.
Comet PANSTARRS and star trails on April 21, 2013. Credit and copyright: David G. Strange.
Comet PANSTARRS and star trails on April 21, 2013. Credit and copyright: David G. Strange.
Comet C/2011 L4 PanSTARRS in false color, 'sigma combined and rotational gradient filter (inset) C8 @ f/2 85mins. exposure. April 19, 2013. Credit and copyright: David G. Strange.
Comet C/2011 L4 PanSTARRS in false color, ‘sigma combined and rotational gradient filter (inset) C8 @ f/2 85mins. exposure. April 19, 2013. Credit and copyright: David G. Strange.
Comet C.2011 L4 (PANSTARRS) on April 15, 2013. A 5 minute exposure with a Zeiss 80mm astrograph with DSLR camera. Credit and copyright: Chris Schur.
Comet C.2011 L4 (PANSTARRS) on April 15, 2013. A 5 minute exposure with a Zeiss 80mm astrograph with DSLR camera. Credit and copyright: Chris Schur.

This shot was taken on April 2 when Comet PANSTARRS was snuggling up in the sky with the Andromeda Galaxy, but this beautiful image is a recent addition to Universe Today’s Flickr page. You can see more images of PANSTARRS and the Andromeda Galaxy here and here.

13 frame stack of Comet PanSTARRS and the Andromedaa Galaxy on April 2, 2013 as seen over Leitrim, Ireland. Canon 200mm. Credit and copyright: Martin Campbell.
13 frame stack of Comet PanSTARRS and the Andromedaa Galaxy on April 2, 2013 as seen over Leitrim, Ireland. Canon 200mm. Credit and copyright: Martin Campbell.

Want to get your astrophoto featured on Universe Today? Join our Flickr group or send us your images by email (this means you’re giving us permission to post them). Please explain what’s in the picture, when you took it, the equipment you used, etc.

Hubble Telescope Captures Image of Comet ISON

Comet ISON was used in a search for time travelers. NASA’s Hubble Space Telescope provides a close-up look of Comet ISON (C/2012 S1), as photographed on April 10. Credit: NASA, ESA, J.-Y. Li (Planetary Science Institute), and the Hubble Comet ISON Imaging Science Team.

Here’s our first good look at Comet (C/2012 S1) ISON. The Hubble Space Telescope captured this shot on April 10, when the comet was slightly closer than Jupiter’s orbit at a distance of 634 million kilometers (394 million miles) from Earth. Later this year, this comet could become a brilliant object in the sky, perhaps 10 times brighter than Venus.

Astronomers say preliminary measurements from the Hubble images suggest that the nucleus of ISON is no larger than 4-6 km (3-4 miles) across.


The astronomers said this is remarkably small considering the high level of activity observed in the comet so far. Astronomers are using these images to measure the activity level of this comet and constrain the size of the nucleus, in order to predict the comet’s activity when it will come with 1.1 million km (700,000 miles) of the Sun on November 28, 2013.

Even though Comet ISON was 620 million km from the Sun when this image was taken, the comet is already active as sunlight warms the surface and causes frozen volatiles to sublimate. A detailed analysis of the dust coma surrounding the solid, icy nucleus reveals a strong, jet blasting dust particles off the sunward-facing side of the comet’s nucleus.

The comet’s dusty coma, or head of the comet, is approximately 5,000 km (3,100 miles) across, or 1.2 times the width of Australia. A dust tail extends more than 92,000 km (57,000 miles), far beyond Hubble’s field of view.

Comet ISON belongs to a special category of comets called sungrazers. As the comet performs a hairpin turn around the Sun in November, its ices will vaporize in the intense solar heat. Assuming it defies death by evaporation, some predict it could become as bright as the full Moon. If so, that would occur for a brief time around at perihelion (closest approach to the Sun) when the comet would only be visible in the daytime sky very close to the Sun. When safely viewed, ISON might look like a brilliant, fuzzy star in a blue sky.

More careful analysis is currently underway to improve these measurements and to predict the possible outcome of the sungrazing perihelion passage of this comet.

ISON stands for International Scientific Optical Network, a group of observatories in ten countries who have organized to detect, monitor, and track objects in space. ISON is managed by the Keldysh Institute of Applied Mathematics, part of the Russian Academy of Sciences.

Source: NASA

New Calculations Effectively Rule Out Comet Impacting Mars in 2014

This computer graphic depicts the orbit of comet 2013 A1 (Siding Spring) through the inner solar system. Image credit: NASA/JPL-Caltech

NASA’s Near-Earth Object Office says that new observations of comet C/2013 A1 (Siding Spring) have allowed further refinements of the comet’s orbit, helping to determine the chances it could hit Mars in October of 2014. Shortly after its discovery in December 2012, astronomers thought there was an outside chance that a newly discovered comet might be on a collision course with Mars.

While the latest orbital plot places the comet’s closest approach to Mars slightly closer than previous estimates, the new data now significantly reduces the probability the comet will impact the Red Planet, JPL said, from about 1 in 8,000 to about 1 in 120,000.

The closest approach is now estimated at about 68,000 miles (110,000 kilometers). The most previous estimates had it whizzing by at 186,000 miles (300,000 kilometers).

The latest estimated time for close approach to Mars is about 11:51 a.m. PDT (18:51 UTC) on Oct. 19, 2014. At the time of closest approach, the comet will be on the sunward side of the planet.

The comet was discovered in the beginning of 2013 by comet-hunter Robert McNaught at the Siding Spring Observatory in New South Wales, Australia. When the discovery was initially made, astronomers at the Catalina Sky Survey in Arizona looked back over their observations to find “prerecovery” images of the comet dating back to Dec. 8, 2012. These observations placed the orbital trajectory of comet C/2013 A1 right through Mars orbit on Oct. 19, 2014.

JPL says future observations of the comet are expected to refine the orbit further. The most up-to-date close-approach data can be found at JPL’s Small Body Database.

Source: JPL

Comet PANSTARRS … Going … Going … Not Gone Yet!

Comet C/2011 L4 PANSTARRS on the evening of April 9, 2013 from Austria. Dust released when the sun vaporizes the comet's ice is pushed back by the pressure of sunlight to form the tail. Click to enlarge. Credit: Michael Jaeger

It’s falling out of the news but Comet PANSTARRS still lives! You can still see it in a clear sky near you with nothing more than a pair of binoculars. And thanks to guidance from the bright zigzag of Cassiopeia, it’s easier than ever to find. Would that we had had this star group to point up comet-ward in March when PANSTARRS was brightest!

The comet marches along through Cassiopeia the Queen in April. The map shows the sky facing northwest about 90 minutes after sunset. Comet positions are shown every 5 nights. Stellarium
The comet marches along through Cassiopeia the Queen in April. The map shows the evening sky facing northwest about 90 minutes after sunset. Comet positions are shown every 5 nights. Stellarium

Start looking about 75-90 minutes after sunset or the same amount of time before sunrise. Yes, the comet is visible now at both dusk and dawn. Currently it shines at about 4.5-5 magnitude and might still be faintly visible with the naked from a very dark sky location. In 35-50mm binoculars it will look like a faint, fuzzy streak of light with a brighter head. Telescopes still give a wonderful view of the bright nucleus and shapely tail.

While the northern U.S., Canada and Europe have good views of PANSTARRS at both dusk and dawn, sky watchers in the southern U.S. have their best views at dawn. This map shows the sky facing northeast about 90 minutes before sunrise. Stellarium
While the northern U.S., Canada and Europe have good views of PANSTARRS at both dusk and dawn, sky watchers in the southern U.S. have their best views at dawn. This map shows the sky at the start of dawn facing northeast about 90 minutes before sunrise. Stellarium

The other night a student who helps run our local planetarium described it as looking like a “real comet” through the telescope, the way textbook and online photos had led him to anticipate. Binoculars or telescope will show a misty, plume-like tail, but wide-field, time-exposure photography reveals the comet’s unbelievably broad fan of dust.

Comet PANSTARRS moves along a steeply tilted orbit that takes it far above and below the plane of the planets. Right now it’s high above Earth’s north pole and we see its tail broadside. The comet takes about 106,000 years to complete an orbit around the sun. Credit: NASA/JPL/Bob King
Comet PANSTARRS moves along a steeply tilted orbit that takes it far above and below the plane of the planets. Right now it’s high above Earth’s north pole and we see its tail broadside. The comet takes about 106,000 years to complete an orbit around the sun. Credit: NASA/JPL/Bob King

The reason for this unusual appearance has much to do with perspective. PANSTARRS is sailing back into deep space directly above the plane of the planets. With the tail blown back by the pressure of sunlight, we look up and across a distance of more than 125 million miles (201 million km) to see it spread like a deck of cards across the constellation Cassiopeia.

Comet PANSTARRS a week ago when it passed near the Andromeda Galaxy (at left). Details: 300mm f/2.8, ISO 800 and 90-second exposure. Credit: Bob King
Comet PANSTARRS a week ago when it passed near the Andromeda Galaxy (at left). Details: 300mm f/2.8, ISO 800 and 90-second exposure. Credit: Bob King

In the northern U.S., Cassiopeia is higher up in both morning and evening skies and easy to spot. Once you’ve found its familiar shape, focus your binoculars on the brightest star nearest the comet, and slowly work your way in its direction. Skywatchers in the northern U.S., Canada and Europe are favored because Cassiopeia is a northern constellation and higher up in the sky at both dusk and dawn. Observers in the southern U.S. will get their best views around the start of dawn.

A Detailed Look at the Coma of Comet PANSTARRS

Image and variations of Comet C/2011 L4 (PANSTARRS) taken on 2013, April 7, 2013 remotely from New Mexico. Credit: Ernesto Guido, Nick Howes, and Martino Nicolini.

Comet PANSTARRS has peaked, but astronomers are still keeping an eye on this comet to try and determine what its future might hold. The team from the Remanzacco Observatory has just produced some really interesting views of Comet PANSTARRS, with a little help from Martino Nicolini and his Astroart software.

Team member Nick Howes called this software “one of the best astronomical image processing and acquisition tools around,” and explained how these views can tell astronomers more about what is happening with the comet.

“The isophotes image (color coded) is a good way to see the morphology/structure of the coma,” he told Universe Today, adding that comparing the images here is “a very good way to determine any major events like a fragmentation. We’re hopeful that once PANSTARRS gets a bit higher, we’ll be able to look at it in even more detail with the 2 meter Faulkes scopes.

And with the image processing in the image on the far right, it’s possible to see a bright shell in the coma of comet C/2011 L4 (PANSTARRS).

“The last elaboration in that image has been obtained using the M.C.M. (Median Coma Model), a filter that has the purpose of creating — from an image of a comet — a synthetic model of the ‘regular’ coma,” said Ernesto Guido, from the Remanzacco team. “That is obtained by mapping all the pixels that compose the image and averaging them together. In doing so we delete all the morphological “non-uniformity” contained in the coma itself. This regular coma will then be subtracted from the original image highlighting all the details that are normally immersed in the uniform brightness of the coma.”

Check out the Remanzacco website for more information and their continued updates.

Was the Repeating Passage of Halley’s Comet Known of in Ancient Times?

Comet P/Halley as seen on its last inner solar system passage on March 8th, 1986. (Credit: W. Liller/NASA GSFC/ International Halley Watch Large Scale Phenomena Network).

An interesting and largely unknown tale of ancient astronomy recently came our way while reading author and astrophysicist Mario Livio’s blog. The story involves the passage of the most famous of all comets.  

It’s fascinating to consider ancient knowledge of the skies. While our knowledge of ancient astronomy is often sparse, we know that cultures lived and perished by carefully monitoring the passage of the heavens.  A heliacal rising of Sirius might coincide with the impending flooding of the life-giving waters of the Nile, or the tracking of the solstices and equinoxes might mark the start of the seasons.

To the ancients, comets were “hairy stars” which appeared unpredictably in the sky. We generally attribute the first realization that comets are periodic to Sir Edmond Halley, who successfully utilized Newton’s laws of gravity and Kepler’s laws of planetary motion to predict the return of Halley’s Comet in 1758. Such a prediction was a vindication of science.

But an interesting tale comes to us from the 1st century CE that Rabbi & Jewish Scholar Yehoshua Ben Hananiah may have known something of “a star that appears every 70 years.” The tale, as told in the Horayoth (rulings) of the Talmud and described in Mr. Livio’s blog is intriguing:

Rabbi Gamliel and Rabbi Yehoshua went together on a voyage at sea. Rabbi Gamliel carried a supply of bread. Rabbi Yehoshua carried a similar amount of bread and in addition a reserve of flour. At sea, they used up the entire supply of bread and had to utilize Rabbi Yehoshua’s flour reserve. Rabbi Gamliel then asked Rabbi Yehoshua: “Did you know that this trip would be longer than usual, when you decided to carry this flour reserve?” Rabbi Yehoshua answered: “There is a star that appears every 70 years and induces navigation errors. I thought it might appear and cause us to go astray.”   

The Rabbi’s assertion is a fascinating one. There aren’t a whole lot of astronomical phenomena on 70 cycles that would have been noticeable to ancient astronomers. With an orbital period of 75.3 years, Halley’s Comet seems to fit the bill the best. The earliest confirmed description of Halley’s comes from Chinese astronomers during its 240 BCE passage. Later subsequent passages of the comet through the inner solar system were noted by the Babylonians in 164 & 87 BCE.

Of course, there’s no further evidence that ancient scholars identified those passages as the same comet. Some great comets such as Hale-Bopp seen in 1997 and this year’s anticipated Comet C/2012 S1 ISON are on orbits spanning thousands of years that outlast most Earthly civilizations.

Mr. Livio also notes that historical knowledge of ancient apparitions of Halley’s may have been accessible to the Great Knesset scholars during the Babylonian exile of the 6th century BCE.

One of the chief objections raised to the Halley hypothesis is the circumstances of the appearance of Halley’s Comet in the Rabbi’s lifetime. Remember, most folks didn’t live for 70 years in the 1st century. Any tales of a periodic comet would have been handed down by generations. You would be lucky to see Halley’s Comet once in your lifetime. Plus, not all apparitions of Halley’s Comet are favorable. For example, Halley’s was bright enough to induce “comet hysteria” with the public in 1910. In contrast, few northern hemisphere members of the general public got a good view of it during its 1986 passage.

Medieval woodcut depicting the supposed destructive influence of a 4th century comet. (Credit: Stanilaus Lubienietski's Theatrum Cometicum, Amsterdam 1668).
Medieval woodcut depicting the supposed destructive influence of a 4th century comet. (Credit: Stanilaus Lubienietski’s Theatrum Cometicum, Amsterdam 1668).

Halley’s Comet was visible on and around January 25th, 66 CE during the Rabbi’s lifetime. However, the Rabbi would have been in his 20’s and have been a student (and not yet a Rabbi) himself. One can imagine that if he was fearful of a “false star” leading them astray, he must’ve known that the 70 year period was just about neigh.

The 66 CE apparition of Halley’s Comet would have appeared around the time of the Jewish Rebellion and just four years before the destruction of the Second Temple in Jerusalem by the Romans in 70 CE.

One other possible astronomical culprit has been cited over the years. The classic variable star Mira (Omicron Ceti) currently has a 332 day cycle which ranges from magnitude +3.5 to below naked eye visibility at +8.6 to +10.1. The variability of Mira was first discovered by astronomer David Fabricius on August 3rd 1596. There are suggestions that ancient Chinese and Babylonian astronomers may have known of this “vanishing star”.

The variable star Mira as imaged by the Hubble Space Telescope. (Credit: NASA/STScl/Margarita Karovska at the Harvard-Smithsonian Center for Astrophysics).
The variable star Mira as imaged by the Hubble Space Telescope. (Credit: NASA/STScl/Margarita Karovska at the Harvard-Smithsonian Center for Astrophysics).

Mira is expected to reach maximum for 2013 from July 21st to 31st.

Not all maxima for Mira are of equal brightness. Mira can peak anywhere from magnitude +2.0 to +4.9 (a 15-fold difference) and there’s evidence to suggest it may have been brighter in the past. Astronomer Philippe Veron noted in 1982 that a larger oscillation period of 60 years for the peak maxima of Mira falls just a decade short of Rabbi Yehoshua’s mention of an errant star.

Whatever the case, its fascinating to consider what celestial object might’ve been referred to, and how many other astronomical tales might be awaiting discovery in ancient texts. We’ve got lots of comets to ponder this year as Comet PanSTARRS, Lemmon, and ISON grace our skies in 2013. Halley’s will make its next visit to the inner solar system in 2061. I’ll open it up to you, the astute Universe Today reading public; was the Rabbi’s Star a comet, a variable star, a meteor storm, or none of the above?

Halley's Comet as seen from latitude 30 north on the morning of July 31st, 2061. (Created by the author using Starry Night software).
Halley’s Comet as seen from latitude 30 north on the morning of July 31st, 2061. (Created by the author using Starry Night software).

-Dr. Mario Livio blogs at A Curious Mind. Be sure to check out his new book Brilliant Blunders: From Darwin to Einstein – Colossal Mistakes by Great Scientists That Changed Our Understanding of Life in the Universe out on May 14th!

 

Comet PANSTARRS Meets the Andromeda Galaxy — More Amazing Images

Comet PANSTARRS and M31 on April 4, 2013, as seen from Sweden. Credit and copyright: Göran Strand.

More of our readers had success in capturing the awesomeness of seeing Comet PANSTARRS encounter the Andromeda Galaxy (M31) in the night sky. Göran Strand sent us this absolutely gorgeous image, taken from 70 km north of Östersund, Sweden — a really dark site with no light pollution. “This photo is a 30 minute exposure through my 300mm/f2.8 lens using my full format Nikon D3s camera,” Göran said. “Besides seeing the comet and the galaxy, I also got to see 4 elks, 2 meteors, 1 bolide and 1 aurora. So all in all, it was a good night!”

That’s for sure!

See more images below of this great meet-up in the skies, and see our earlier post of our readers’ images here.

Comet C/2011 L4 Panstarrs and the Andromeda Galaxy: Two Frame Mosaic from New Mexico Skies, April 4, 2013. Taken from New Mexico Skies at 23:22  UT using an FSQ 10.6-cm and STL11K camera.  Credit and copyright: Joseph Brimacombe.
Comet C/2011 L4 Panstarrs and the Andromeda Galaxy: Two Frame Mosaic from New Mexico Skies, April 4, 2013.
Taken from New Mexico Skies at 23:22 UT using an FSQ 10.6-cm and STL11K camera. Credit and copyright: Joseph Brimacombe.
The encounter between Comet PANSTARRS and the Andromeda Galaxy, as seen from Ireland. 'A difficult image to capture due to low cloud, the low altitude of the target and tracking Issue.'  Image details: Date: 03 Apr 2013, 22:30-23:30 Exposure: 9 x 5min, ISO 1600, F5, 6 x dark frames, 6 x flats frames. Equipment: Canon 1000D, CG5 Mount, Sigma 70-300mm set at 200mm. Credit and copyright: Brendan Alexander.
The encounter between Comet PANSTARRS and the Andromeda Galaxy, as seen from Ireland. ‘A difficult image to capture due to low cloud, the low altitude of the target and tracking Issue.’ Image details: Date: 03 Apr 2013, 22:30-23:30
Exposure: 9 x 5min, ISO 1600, F5, 6 x dark frames, 6 x flats frames.
Equipment: Canon 1000D, CG5 Mount, Sigma 70-300mm set at 200mm. Credit and copyright: Brendan Alexander.
Comet PANSTARRS and M31 taken from the Scottish Dark Sky Observatory on April 3, 2013. Credit and copyright: Dave Hancox via Google+.
Comet PANSTARRS and M31 taken from the Scottish Dark Sky Observatory on April 3, 2013. Credit and copyright: Dave Hancox via Google+.
Comet C/2011 L4 (PANSTARRS) and M31 (Andromeda Galaxy) taken from just outside St Clears, Carmarthenshire, Wales on 29th March 2013 around 9pm. Credit and copyright: Pete Newman.
Comet C/2011 L4 (PANSTARRS) and M31 (Andromeda Galaxy) taken from just outside St Clears, Carmarthenshire, Wales on 29th March 2013 around 9pm. Credit and copyright: Pete Newman.

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