Theoretical question time :=3

[lionkingcmsl]

Assume you are in the Oort cloud and away from other planets' gravitational effects.

You start "assembling" a planet by bringing asteroid sized pieces together. At first you would need some way to hold the pieces together: magnets, glue, rivets, whatever.

My question is: At what point would you start to notice an appreciable gravity well forming. We know that once you got to the size of the smaller moons you would notice it, but how much before that size would it be noticeable. Also at what point would gravity start holding the pieces together by itself?

Some idle musings from the railroading lion. :=3

Comments

[shockwave77598.livejournal.com]

atoms collect together to form stones and such via electrostatic attraction first. After enough of this accumulation (a few miles diameter) you begin to have enough gravity that your asteroid can catch more stones via gravity. It is speculated that not enough charged particles from the sun to get the process started in the excessively sparse oort.

[thefoxaroo.livejournal.com]

Although I have no idea of the answer I would certainly like to know myself, as I've wondered about such things myself.

There's a serial from the classic Dr Who series called "Underworld." It wasn't popular due to extensive use of the chroma-key video effect, but the story fascinated me. One spaceship was persuing an identical sister spaceship that had vanished over 100,000 years earlier. They had tracked the ship to a spiral nebula; a gas cloud coalescing to form a new star system. It transpired that the lost ship had been the nucleus which attracted the inter-stellar matter, and the searching ship nearly suffered the same fate. I suspect that the gravitational effects were somewhat exaggerated though, as the debris from the nebula seemed to be attracted to the searching ship too quickly.

An episode of Star Trek the Next Generation also had a slight take on this, where an alien archive was found inside a comet, having attracted stellar matter on its voyage.