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As ISON approached the Sun, astronomers – both professional and amateur – from all over the world got very excited. ISON started to flare up and get very bright, and then it vanished.

 

The comet started to dim and “smear” as it entered the occulter guarding NASA’s Solar and Heliospheric Observatory’s (SOHO) cameras, the Solar Dynamic Observatory caught some glimpses of “bright pixels,” but it wasn’t an astonishingly bright event. The early speculation was that ISON had completely disintegrated as it passed the Sun.

 

But, that’s not where the story ends…

 

As Phil Plait says, “It’s still possible that the initial reports of ISON’s death were somewhat exaggerated.” New images from SOHO show that ISON might still be fighting, just barely.

 

The “Comet of the Century” has had a lot of hype over the last year and a half, since it’s discovery in 2012. ISON is a new visitor to the inner solar system and it was set to pass within 1.2-million kilometers (730,000 miles) of the Sun. The potential to study both the origins of the Solar System and the structure of the Sun’s corona – all in the same event – was to good to pass up.

 

Image Credit: NASA/SOHO

As I stated before, as the comet approached the Sun, something happened and ISON started to smear. It looked like the comet fizzed out before it even got started. Even if ISON disintegrated, scientists were suppose to see debris left over (which would be better for professional study, though not so good for amateur astronomy), but everything, the comet, the tail, everything, just vanished. Dean Pesnell, a project scientist with SDO summarized it most eloquently by saying “I’d like to know what happened to our half a mile of material that was going around the sun. Now’ it’s broken up and I didn’t see anything.”

 

Currently, material has reemerged from the other side of the Sun’s Corona. This is either a continuation of the tail that ISON left behind, or the comet itself. Current speculation is the dust that we see is simply dust, orbiting exactly as it should. The nucleus is probably lost.

 

So, what did we learn from this comet?

 

  1. We learned a lot about the original conditions of the solar system.
  2. Because the comet fizzed out so spectacularly, we learned that our models for comets and their composition has some serious problems; we need to figure out what those are so we can fix them.

 

As with all good celestial events, we are also left with a mystery… What happened to ISON while it was in SOHO’s occulter and invisible to SDO’s vision? As always, there is more than one possible answer to this mystery…

 

 

 

Image Credit: NASA/SOHO

**UPDATE: 11/28 22:10 Eastern** It looks like part of ISON might have survived. We are seeing some brightening of ISON as it leaves the Sun. According to Phil Plait, comet astronomers are baffled and he is refusing to predict the comet’s actions any further. It keeps brightening, smearing, and vanishing without warning or a discernible pattern. We’ll keep you informed as the event continues to unfold.


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