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Farmers Almanac
The 2014 Farmers Almanac
Farmers' Almanac

This Month: Comet PANSTARRS

This Month: Comet PANSTARRS

A newfound comet, discovered by astronomers using a telescope in Hawaii, will swing through the inner solar system in 2013, with both astronomers and sky watchers hoping for a cosmic spectacle when it arrives.

Most comets are rather unimpressive sights. They are faint fuzzballs, visible only with a telescope or binoculars. Every once in a while, however, a large comet will approach the Sun and become much brighter–enough to be visible to the naked eye without optical aid. Such comets are infrequent, appearing maybe once or twice a decade. Not only may such comets be much brighter than most, but they may also have a bright appendage extending out, popularly called the tail.

When you can see a bright comet without the need of a telescope or binoculars, it makes for a rare and unique sight in the sky. So unusual, in fact, that the ancient stargazers thought that comets were omens of evil; “bad” stars. In fact, the word “disaster” comes from the Greek dis (against) and aster (star). So the belief was that to see a long-tailed comet meant there was a star that was against you!

Comets are usually named after their discoverers, but in this case, because a large team of observers, computer scientists, and astronomers was involved, the comet was named after the telescope. Found on June 6, 2011, while searching the sky for potentially hazardous asteroids–ones that may someday hit Earth–the comet was named C/2011 L4 (PANSTARRS). For the record, that odd acronym stands for the Panoramic Survey Telescope And Rapid Response System. The Pan-STARRS Project is being led by the University of Hawaii at Mānoa’s Institute for Astronomy.

Comet PANSTARRS most likely originated in the Oort cloud, a cloud of comet-like objects located in the distant outer solar system. When Comet PANSTARRS was discovered in the constellation Libra, it was a 19th-magnitude object–so faint that only telescopes with sensitive electronic detectors could pick it up–some 759 million miles (1.2 billion kilometers) from the sun. (Astronomers measure the brightness of objects in space on a reverse scale; the higher the number an object’s magnitude is, the dimmer it appears to observers.)

The comet’s closest approach to the sun, its perihelion, will occur on March 10, 2013. At that time, the distance between Comet PANSTARRS and the sun will have shrunk to 28 million miles (45.1 million km).

Such an enormous change in solar distance would cause a typical comet to increase in intrinsic luminosity by about 14 magnitudes. Put another way, Comet PANSTARRS could become about 300,000 times brighter. Furthermore, the comet’s distance from Earth, which was 666 million miles (1.1 billion km) at its discovery, will shrink to around 102 million miles (164.5 million km) at perihelion, meaning it could appear an additional four magnitudes brighter. That could make it a first-magnitude object when it passes closest to the sun. But …

First-Timer or Old-Timer?
So far, all of the orbital data for Comet PANSTARRS points to it being a new comet, moving in a parabolic orbit. In other words, it may never have passed near the sun before. 

That’s bad news, because astronomers believe that such comets can be covered with highly volatile materials like frozen nitrogen, carbon monoxide, and carbon dioxide. These ices vaporize far from the sun, giving a distant comet a short-lived surge in brightness which often raises very unrealistic expectations.
Put another way, as the comet gets closer to the Sun, solar heating would progressively strip off that volatile coating and leave just a small, dark, solid lump of material; we might not be able to see it at all.

Sizzler or Fizzler?
Those of a certain age may recall Comet Kohoutek in 1973; ballyhooed as potentially the “Comet of the Century.” But Kohoutek fell far short of becoming a spectacular object and disappointed countless millions. I remember watching The Tonight Show when Johnny Carson–whose hobby was astronomy– joked that astronomers should have known that Kohoutek was going to be a bomb because it was the only comet that ever came with a fuse attached to it.

But if, on the other hand, Comet PANSTARRS is making a return loop around the sun, its highly volatile materials could have been shed already, and what we may ultimately see could be a comet becoming bright and potentially spectacular. 
In fairness, I should note that not all new comets evolve into duds. In April 1957, for instance, first-time Comet Arend-Roland put on a wonderful show, so there are exceptions. 

When and Where to Look
Our first good view of Comet PANSTARRS won’t occur until mid-March, after it has swung past the sun. If it develops into a celestial showpiece, then it will put on its best show during late March and early April, low above the west-northwest horizon, about an hour after sunset. Its head (called the coma) might shine as bright as first or second magnitude, while hopefully it could also sprout a conspicuous tail that may appear to jut upward from the comet’s head.

Or it might pull a Kohoutek and fail to get bright at all; perhaps you’ll need binoculars or a telescope to locate it; and if you do, Comet PANSTARRS will appear as nothing more than a dimly glowing fuzzball. Unfortunately, comets are notoriously unpredictable. We can only make an educated guess as to how bright it will get and how long the tail will be. We’re simply going to have to just wait and see what happens.

If this story has a moral, it is in the words of the legendary comet expert, Fred L. Whipple: “If you must bet, bet on a horse, not a comet!”

What is a Comet Made Of?
Comets are mostly of ice (water ice, as well as carbon dioxide[dry ice] and several other frozen gasses), dust, and rocks. In addition, comets possess small amounts of organic (carbon-based) compounds similar to soot. All this material is contained in a solid object, called the comet nucleus, that is typically only a few miles across (though occasionally they can be much smaller or larger). Comets are often referred to as ”dirty snowballs” because of their contents. The brighter ones tend to be bigger. Halley’s Comet was found to be shaped like a potato and measured roughly 5 miles wide by 9 miles long. Comet Hale-Bopp was estimated to be 25 miles wide. We have no clue exactly how big Comet PANSTARRS is; therein lies one of the problems in forecasting just how bright it might become–we’ve never seen it before.


1 Reagan Barr { 03.13.13 at 11:56 am }

I think I saw the comet last night. I was looking hard toward the west on the beach in Pass Christian, MS. There was a faint dot close to the moon. But the cars on Hwy. 90 obstructed some of the view of that comet. Now when I looked up, I was amazed at the sight of Orion, Jupiter, Taurus, & Canis Major. THAT was pretty awesome!! Will be on the beach again to (try to) view the comet again!!!!

P.S.: I had a better time looking at the crescent moon & the scarlet sunset than trying to find the comet. If only I had a telescope. :/

2 Gay Brinkerhoff { 03.10.13 at 5:23 pm }

I live in So. Utah. What are my chances of seeing it? We, (all my Family) enjoy star gazing. Last year with the eclipse was exciting. We had a great view. Thanks for a great web site!

3 Jaime McLeod { 03.10.13 at 6:23 am }

Everyone in the country should have a chance to see it at some point. It’s low on the horizon right now, so an unobstructed view is key, but it will get higher over the next couple of weeks.

4 Jessica D. { 03.09.13 at 8:10 pm }

Will I be able to see it in Winchester, Va?!?! I live out in the country and might have a better chance of seeing it if it passes. :-)

5 Paula { 03.07.13 at 4:56 pm }

Will we be able to see it in Atlanta, GA?

6 Jaime McLeod { 03.07.13 at 9:20 am }

Yes, Billy, it should be visible in Pa. It will depend on the weather, but it’s going to be visible for a while, so you should have a few clear nights in the time.

7 Gary { 03.06.13 at 12:46 pm }

Where does the water come from to make a comet ?

8 ben larsen { 03.06.13 at 12:08 pm }

interesting ,,,, i sseen something last nite 3-5 2013 from texas at dusk. i was really wondering what it was11 thanks ben

9 Billy { 03.06.13 at 9:38 am }

would love to see it !!! any chance in Pa ??????

10 Irlene Reynolds { 03.04.13 at 2:21 pm }

My family has read the Farmers Almanac,before i was born and i am 62 ,great stories and planting guides we always follow,thanks for still being with us

11 Irlene Reynolds { 03.04.13 at 2:16 pm }

this is a very interesting read,hope i get to see it i am in Oklahoma,thanks for the great story

12 Dena { 03.04.13 at 1:27 pm }

Thank you for all of that information.
Will we be able to see this from New England ? CT ?
Or is it a crap shoot ?
Thanks again.

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