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Incoming Comet; Outgoing CME
A bright comet fell into the sun on October 2, 2011 in synch with a coronal mass ejection bursting out on the other side. Credit: ESA/NASA/LASCO C2
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On October 2, 2011, an exceptionally bright comet headed toward the sun and disintegrated. Moments later a large coronal mass ejection (CME) blew off the other side of the sun, making for this captivating movie from the SOlar Heliospheric Observatory (SOHO).

While it looks to the casual observer that the comet triggered the ejection, the apparent relationship between an incoming comet and a CME is only a coincidence. At this stage of the solar cycle, the sun is producing many mass ejections -- in fact there were several earlier in the day -- and it is only chance that one of them burst off the sun at the same time the comet approached. Some researchers have been looking for a more direct relationship, but nothing has yet come out of these efforts.

The comet shown here was a comet known as a Kreutz sungrazer. When a comet comes this close to the sun, it is almost always destroyed -- we see the comet going in, but not going back out.

What is a coronal mass ejection?

For answers to these and other space weather questions, please visit the Spaceweather Frequently Asked Questions page.


Karen C. Fox
NASA's Goddard Space Flight Center