Comet ISON, widely anticipated as the "Comet of the Century," may not have completely disintegrated after all, according to astronomers who've spotted a tiny glimmer of potential activity in Solar and Heliospheric Observatory (SOHO) images after the comet's Thanksgiving flyby.
Although the comet is too faint to be called a true detection with certainty, the hint of comet-like activity is "unexpected and fascinating," says Karl Battams of the U.S. Naval Research Lab, who led the analysis of the images and shared the results on his Sungrazer Project blog and other social media sites.
Comet ISON thrilled skywatchers in November as it brightened rapidly toward its close pass by the sun on Thanksgiving Day, Nov. 28, 2013. But when the comet emerged from behind the sun, observers were disappointed to find only faint traces of a comet, much dimmer than predicted. Many assumed the comet had disintegrated.
But there is a possibility, however unlikely, that ISON will become bright enough to be seen visually again.
ISON's demise wasn't entirely unanticipated. In fact, some astronomers had predicted the comet's possible fate. They cited the fact that comets that come from the distant Oort Cloud, like ISON, often don't hold together because they've never experienced the sun's intense heat before.
Here's what happened:
When ISON first arrived on the scene in September 2012, it was already beginning to break apart. This was evident from the presence of a dust cloud surrounding the cometary nucleus. The dust was being shed as the comet approached the sun and its icy structure began to melt and evaporate.
As ISON got closer to the sun, the rate at which it broke up accelerated. By the time it reached perihelion (its closest point to the sun) on Nov. 28, 2013, the comet had been completely shattered into a stream of dust and gas.
Even after ISON had broken apart, some scientists still believed that its nucleus might remain intact. They hoped that the nucleus would begin to regenerate once it cooled down. However, those hopes were dashed when follow-up observations failed to detect any sign of the comet's nucleus.
What happens next:
At the moment, there is no scientific consensus on what will happen to ISON. Some scientists believe that the comet will continue to disintegrate and eventually disappear. Others believe that it may eventually rebuild its nucleus and become a viable comet once again.
Only time will tell what the fate of ISON will be. In the meantime, scientists can only continue to observe and study the comet and hope to learn more about its unique behavior.
Significance:
The fate of ISON is a reminder that comets are unpredictable objects. Even the most well-studied comets can surprise us. ISON's demise serves as a cautionary tale for astronomers who are overly confident in their predictions of comet behavior.
More importantly, ISON's story highlights the importance of continued observations. Without the dedication and hard work of astronomers, we would have never learned about ISON's unique fate. Their persistence has helped us to better understand comets and their role in the solar system.
