Mike Brown's Planets, season 4: sabbatical |
Mike Brown's Planets, season 4: sabbatical |
Oct 29 2010, 11:59 AM
Post
#1
|
|
Senior Member Group: Members Posts: 3516 Joined: 4-November 05 From: North Wales Member No.: 542 |
Now on sabbatical, Mike Brown has recently reactivated his mainly Transneptunian blog. Here is a tasty two-parter on Sedna for starters: http://www.mikebrownsplanets.com/2010/10/t...ere-part-2.html
|
|
|
Nov 13 2013, 09:45 PM
Post
#2
|
|
Senior Member Group: Members Posts: 2346 Joined: 7-December 12 Member No.: 6780 |
To me the most plausible solution to form km-size objects from dust/sand/stones/snowflakes is via gravitational pull of a sufficiently large and sufficiently dense cloud of such bodies with very low relative velocities. Part of the cloud will collapse, part of it will be ejected.
At low temperatures near absolute zero ice/snow won't adhere much different from silicates. In the outermost part of the solar system (up to 1 lightyear resp. 63,000 au from the sun) relative velocities of objects, which remain in the solar system, should be below a range of between 100 m/s and 1 km/s, depending on the distance to the sun (otherwise particles escape). Collisions / friction should reduce relative velocities further until the precondition for gravitational collapsing clouds is fulfilled. Collisions of sufficiently large and fast bodies may lead to densified fragments, besides fine debris. The accretion process will take quite a bit longer than Wiles needed to show the Taniyama–Shimura–Weil conjecture. The Sedna orbit may be explainable e.g. by an instable ternary system of Kuiper objects, which eventually split into a binary system ejecting Sedna near Sedna's perihelion. I don't see the necessity for a big planet or star to explain the orbit. |
|
|
Lo-Fi Version | Time is now: 20th June 2024 - 02:02 PM |
RULES AND GUIDELINES Please read the Forum Rules and Guidelines before posting. IMAGE COPYRIGHT |
OPINIONS AND MODERATION Opinions expressed on UnmannedSpaceflight.com are those of the individual posters and do not necessarily reflect the opinions of UnmannedSpaceflight.com or The Planetary Society. The all-volunteer UnmannedSpaceflight.com moderation team is wholly independent of The Planetary Society. The Planetary Society has no influence over decisions made by the UnmannedSpaceflight.com moderators. |
SUPPORT THE FORUM Unmannedspaceflight.com is funded by the Planetary Society. Please consider supporting our work and many other projects by donating to the Society or becoming a member. |