
Astronomers capture best view ever of disintegrating comet - upen
http://sciencebulletin.org/archives/5303.html
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M_Grey
That was very interesting, and I only have one major question after reading
it. The article states that it's believed the comet's spin is essentially
flinging away chunks, but I'm not clear on the cause of the spinning. The
article makes it sound like that starts to occur as it approaches the Sun, so
is it a result of a jet of sublimating ice what started this spin, or was it
intrinsic from the comet's early formation?

If it's the latter, why is it only starting to fragment now?

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MaulingMonkey
> The article makes it sound like that starts to occur as it approaches the
> Sun, so is it a result of a jet of sublimating ice what started this spin,
> or was it intrinsic from the comet's early formation?

My reading of this part of the article suggests they think the former might
play a role:

>> Based on the Hubble data, the research team suggests that sunlight heated
the surface of the comet, causing it to expel jets of dust and gas. Because
the nucleus is so small, these jets act like rocket engines, spinning up the
comet’s rotation, Jewitt said.

That said, it could be a bit of Column A, a bit of Column B type situation?

> If it's the latter, why is it only starting to fragment now?

The sun could be weakening bonds of ice, to the point where they're weaker
than the preexisting centrifugal forces. I know many (all?) materials start to
lose their strength as they approach their melting points... it seems to me
that either the bonds must weaken, or the forces opposing those bonds must
strengthen or spike...

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craneca0
Image caption: "The comet debris consists of a cluster of building-size chunks
near the center of the image. They form a 3,000-mile-long trail, larger than
the width of the continental U.S."

What am I not getting here? If the cluster in that image is 3K+ miles wide,
then those are city sized dots, not building sized. I'm guessing the long tail
is not actually in the image?

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privong
> What am I not getting here? If the cluster in that image is 3K+ miles wide,
> then those are city sized dots, not building sized. I'm guessing the long
> tail is not actually in the image?

It's probably two things. I think you're probably correct that the entirety of
the tail is not in the image. Also, the size of the dots in the image probably
reflects the resolution limit of Hubble, rather than the true angular size on
the sky of the chunks.

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privong
For those interested, here's a link to the associated preprint:
[https://arxiv.org/abs/1609.04452](https://arxiv.org/abs/1609.04452)

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elchief
So here's a small, low-res JPEG of it...wtf

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ceejayoz
High-res is available at
[http://hubblesite.org/newscenter/archive/releases/2016/35/im...](http://hubblesite.org/newscenter/archive/releases/2016/35/image/a/)
([http://imgsrc.hubblesite.org/hu/db/images/hs-2016-35-a-full_...](http://imgsrc.hubblesite.org/hu/db/images/hs-2016-35-a-full_jpg.jpg)).

It's not much better than the image in the article, as they're looking at
objects a few football fields wide from 67 million miles away.

