|
|
Thread Tools | Display Modes |
#1
|
|||
|
|||
How meteors became dense?
With my layman's understanding of meteors, they are very dense objects
(as compared to loosely compacted comets). At least dense enough to survive falling through Earth's atmosphere to hit the ground. If they formed from a dust cloud as the rest of the solar system did, how did they compact so densely? They aren't large enough for gravity to compact them. Thanks. |
#2
|
|||
|
|||
How meteors became dense?
John wrote:
With my layman's understanding of meteors, they are very dense objects (as compared to loosely compacted comets). At least dense enough to survive falling through Earth's atmosphere to hit the ground. If they formed from a dust cloud as the rest of the solar system did, how did they compact so densely? They aren't large enough for gravity to compact them. Thanks. I think they are from planetessimals that got big enough and hot enough to melt metals and rocky materials (and, perhaps separate those materials) at one point in their formation, that were subsequently blasted into small fragments by large collisions. |
#3
|
|||
|
|||
How meteors became dense?
John, All small meteoroids orbiting the Sun now are fragments of larger objects. Still, none of those larger objects was ever as large as Earth, and the largest must be Mars, from which several meteorites have been found. The smallest meteoroids are slowed in their orbits by the Poynting-Robertson effect, which causes them to slowly spiral closer to the Sun. If they don't run into a planet first, they are vaporized by the Sun's heat and the vapor is blown away by solar wind. So small objects are constantly removed from the Solar System. Iron and many stony meteoroids were once part of asteroids large enough to melt and separate by density. Heavy iron and nickle sank to the center of the asteroid and lighter rock stayed at the surface. When asteroids collided, a variety of different meteoroid compositions emerged from the rubble. Chondritic meteoroids are interesting in that they have never been part of asteroids which melted. Yet they can be quite compact. I have handled chondritic meteorites which have been sawn open, and they are very solid rock. But the separate grains, or chondrules, are obvious. They have been pressed together very tightly by gravity in asteroids one or two hundred kilometers in diameter. There are still some less dense, less-compacted bodies in orbit around the Sun, including carbonaceous chondrites. They usually disintigrate completely when they enter Earth's atmosphere, leaving behind no identifiable meteorites. -- Jeff, in Minneapolis |
Thread Tools | |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
Perseid Meteors to Peak August 11–13, 2005 (Forwarded) | Andrew Yee | Astronomy Misc | 0 | August 5th 05 04:22 PM |
Scientists Use Meteors to Investigate Climate Change and Giant Waves at the 'Edge of Space' | [email protected] | Astronomy Misc | 0 | May 23rd 05 05:31 PM |
Perseid Meteors to Peak Late on the Night of August 11th (Forwarded) | Andrew Yee | Astronomy Misc | 0 | August 10th 04 03:08 PM |
Meteor Activity Outlook for Dec. 12-18, 2003 | Robert Lunsford | Amateur Astronomy | 0 | December 10th 03 07:49 PM |
Electrophonic Meteors | David Entwistle | UK Astronomy | 38 | October 18th 03 01:03 PM |