Astronomers capture best view ever of disintegrating comet | Hacker News Reader

Astronomers capture best view ever of disintegrating comet

sciencebulletin.org

68 pointsupen7 comments

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?

> 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...

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?

> 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.

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

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

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

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.

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