Later this year, the world could be in for a once-in-a-century astronomical treat: Comet ISON may become as bright as a full moon and be a daytime comet. Yes, on a clear day, you should be able to go outside and see ISON hanging in a blue abyss (just as Comet McNaught did in 2007, pictured above).
The comet, designated C/2012 S1, was discovered last year by the Russian International Scientific Optical Network (ISON - hence the comet's name) and it quickly became apparent that it could be the "Comet of the Century." If it lives up to the hype, we'll be in for a very exciting nighttime and daytime show this November. However, astronomers urge caution: comets don't always behave as expected.
It appears that ISON is a pristine comet freshly ejected from the Oort Cloud (a hypothetical population of comets that surround the solar system around one light-year from the sun), so it could be a pretty robust object packed with primordial ice and dust that was created during the solar system's formative years. If this is the case, it could survive its death-defying journey past the sun, creating a wonderful tail of ice, gas and dust as it does so.
As pointed out by NASA's Tony Philips at Spaceweather.com:
"Comet ISON is a sungrazer. On Nov. 28, 2013, it will fly through the sun's outer atmosphere only 1.2 million km from the stellar surface below. If the comet survives the encounter, it could emerge glowing as brightly as the Moon, visible near the sun in the blue daylight sky. The comet's dusty tail stretching into the night would create a worldwide sensation."
Or, it might be a dud. But it's good to be prepared for something awesome.
Spaceweather.com has the scoop on new observations of Comet ISON as it continues its dive toward the inner solar system.
Image: As Comet McNaught made close approach to the sun in 2007, it became so bright that it was observable in broad daylight. But ISON could be a lot brighter. Credit: NASA/Stefan Seip