View Full Version : Comets Seem to Be Icy Dirtballs

2005-Oct-13, 08:06 PM
SUMMARY: The traditional view of comets is that they're "dirty snowballs"; mostly water ice, covered by a layer of dust picked up as they travel through the Solar System. But after Deep Impact's collision with Comet Tempel 1, scientists are reversing that description: they're more like "icy dirtballs". When Deep Impact smashed into the comet, it released more dust than water vapour. This means that comets are mostly dust and rocks, held together by a water ice "glue".

View full article (http://www.universetoday.com/am/publish/comets_icy_dirtballs.html)
What do you think about this story? post your comments below.

2005-Oct-13, 09:45 PM
Interesting :think:

2005-Oct-13, 10:40 PM
Or perhaps a survey of one is just a bit limited. My "guess" is they run the range from mostly dirt, to mostly ice. And of course, everything in between.

2005-Oct-13, 11:44 PM
It's a good finding, but as spinners and Tu Tone seem to suggest, there does seem to be a bit of a rush to generalise from isolated examples ... we've seen it a lot in science reports for public consumption - and we've been quick to point them out and reserve judgement... onya guys! :)

It seems that every time we push the boundary of our ignorance, we find that things are more varied, more complex, or even more weird, than previous speculation would claim...

That said, even one example is a 100% improvement on no example ... and it's a good and interesting finding :D

2005-Oct-14, 04:45 PM
Ongoing discussion of Deep Impact science results here. (http://www.bautforum.com/showthread.php?t=19336&highlight=deep+impact)

2005-Oct-14, 06:18 PM
Thread re-opened since we've had a complaint (http://www.bautforum.com/showthread.php?t=33691).

2005-Oct-14, 06:31 PM
Thank you ToSeek.
I had a look at the thread you mentioned, and I did gather from the first couple of posts that the idea of considering a single source/formation/evolution for comets was (and should have been) under question - that makes the generalisation in this more recent article even more mystifying. :think:

2005-Oct-14, 10:01 PM
I don't see how this is news. I've been reading that for years.

2005-Oct-15, 03:56 AM
I don't see how this is news. I've been reading that for years.
Which? That comets are more dust than ice?
Or that 'all comets are this way, because one is...'?

Maha Vailo
2005-Oct-16, 07:55 PM
You know what I think? I wouldn't be surprised if we found out that comets varied in composition just like meteorites. Tempel 1 might be an "icy dirtball", but other comets might well fit the classic "dirty snowball" stereotype.

The universe isn't a homogenous place.

- Maha "who ya callin' dirtball?" Vailo

2005-Oct-16, 10:29 PM
'Snowball', 'dirtball' ... I think you're 'on the ball' there, Maha...
Just when some begin to think they have a 'handle' on the universe (or even on the Solar system), the universe (or Solar system) chucks in a 'curve-ball'...