When C/2012 S1 (ISON), popularly known as ISON, was first spotted in September of 2012, astronomers quickly realized that it could be one of the biggest and brightest comets to grace the Earth’s night sky and was even being hailed as the potential “Comet of the Century.” There was, however, one caveat to this title: it had to survive a very close encounter with the sun. While tomorrow is supposed to mark ISON’s closest approach to the sun, there is evidence that it might succumb to the sun’s blistering heat. Even if ISON doesn’t survive to dazzle us with its presence, it will be one of the largest comet disintegrations ever recorded, which is still pretty cool.
ISON was named for the International Scientific Optical Network in Russia, where it was first spotted by Vitaly Nevsky and Artyom Novichonok. Comet ISON was soon imaged by several other telescopes, including the Hubble, Swift, Deep Impact, Spitzer, STEREO, and countless smaller and lesser known telescopes. Observations indicated that ISON was emitting over 122 million pounds (55 million kilograms) of dust and carbon dioxide gas through its tail every single day. ISON likely originated in the Oort cloud, which is chock full of icy rocky bodies.
In the days leading up to ISON’s solar approach, it appears to be getting much brighter. This could be a good sign, meaning it is reflecting the light of the sun and hasn’t boiled off or disintegrated. The latest reports from the NASA/ESA Solar and Heliospheric Observatory (SOHO) from this morning indicates that while ISON has lost a few chunks along the way, it may be in good shape, but there’s no way to tell for sure right now. The most recent images of ISON show that it has two tails right now. One is made from the pressure of the sun’s light, while the other is a response to the solar wind.
If ISON is unable to withstand the sun’s heat, it will give researchers a never-before-seen look at how comets are formed and what material is inside of it. The downside to that is that it means we are going to miss out on one heck of a skywatching experience next month. But, it’s basically a win for science no matter what the outcome.
Tomorrow, NASA is hosting a special Google+ hangout to discuss ISON’s fate at 1 pm EST. There will be a live feed from NASA’s Solar Dynamics Observatory, scientists from Arizona’s Kitt Peak Observatory, and astronomer extraordinaire, Phil Plait. Will these scientists have yet another thing to be thankful for? We’ll just have to watch and find out.