Quote:
Originally Posted by Dana Gold
You've not given the mass and density of the objects (gas giant and rock-like object) of either scenario; therefore it cannot be determined... http://en.wikipedia.org/wiki/Roche_limit
Unless you would perhaps know of a solution, in which case, please enlighten me.
Dana |
I have imagined two extreme situations involving tidal forces.
One:
A planet orbiting a gas giant just outside its Roche Limit, (but far enough out to keep its atmosphere from spilling out of the LaGrange points). It was further away when it formed, so it is a bit rounder than tidal forces allow in its current orbit. So the tides stretch the atmosphere more than the planet, such that the planets atmosphere and oceans are split in two. There is air and an ocean on both the near and farside end, with a band of vaccuum around the "waist". Between the oceans and the vaccuum are regions analogous to various elevations on earth. Near the vaccum there will be permafrost and glaciers. Near the oceans there will be tropical marshes, savannas, and maybe even a desert or two. Midway there will be climate similar to the forests in the foothills of mountain ranges. From space, the planet will resemble a giant easter egg. What is interesting is that there are two separate bioszones, each with potential for wildly divergent evolution. With a little luck, the system might remain stable for hundreds of million years before the tides shift the planet out of its current orbit.
(for a similar but inverse situation, read about the planet
Jinx in Larry Niven's
Known Space.)
Two:
A terrestrial planet with a large rocky moon in close orbit. The moon raises tides so large that the main ocean is mobile, moving around the planet every few days. Above a certain latitude there will be normal dry land, but in the "ocean" zone there will be an enteresting ecology. Not unlike tidepools, but
much more extreme.
If the moon's orbit is longer than the day, then tidal friction will push the moon outward and the tides will weaken with time.
It the moon's orbit is shorter then the day, then it will spiral inward towards its Roche limit until it breaks up and forms a pretty ring like Saturn's. Of course prior to this, volcanism and earthquakes will increase along with the tidal ocean movement to likely make the primary planet uninhabitable....
If humans can imagine such worlds, I am sure that nature will come up with even more interesting ones....