PDA

View Full Version : Question on Comets



Reverend J
2004-Jun-16, 01:41 PM
I'm just full of them right now (questions that is)

1) Do comets rotate? I'm pretty sure they do, but I'm wondering if there is any actual proof of it?

2) What causes the comets to leave the Oort Cloud and fall towards the sun? Are they're any good theories on this (other then the Planet X ones) such as collisions, etc.?

Thanks,
Reverend J

Tranquility
2004-Jun-16, 02:23 PM
1) You could tell from regular variations in the light reflected by the comet's nucleus that it's rotating.

2) The Oort Cloud was proposed as a place where the residual matter from the formation of the Solar System was left over, and some of it accumulated to form comets. Jan Oort himself proposed that some of these "residual comets" are moved into elliptical orbits due to gravitational influences of nearby stars. On the other hands, the known comets don't sort of reside in the Oort Cloud waiting to be pushed around. These comets already have highly eccentric or elliptical orbits that bring them much closer to the Sun and then much farther away. These are natural orbits of these comets, and these orbits can be affected to a great extent by the giant planets Jupiter, Saturn, Uranus and Neptune. There may also be collisions with other larger KBOs (Kuiper Belt Objects) that nudge these comets into orbit.

Jpax2003
2004-Jun-16, 10:23 PM
Here's some info about Comet Hale-Bopp that shows it was clearly rotating. The gas/dust jet would turn on in the sun and off when it rotated away from the sun, thus giving a banded or spiral appearance. Check it out here (http://www.lowell.edu/users/farnham/hb/imaging.html).

The Bad Astronomer
2004-Jun-17, 03:06 AM
I will remind you that there is a website attached to this bulletin board (http://www.badastronomy.com/bitesize/hbhoods.html).

beskeptical
2004-Jun-17, 05:43 AM
I will remind you that there is a website attached to this bulletin board (http://www.badastronomy.com/bitesize/hbhoods.html).We like to be reminded. :D

That is a really nice comet page, Phil.

Tranquility
2004-Jun-17, 03:57 PM
I will remind you that there is a website attached to this bulletin board (http://www.badastronomy.com/bitesize/hbhoods.html).

Oops :oops:
Great page though, thanks =D>