In sci.space.policy Henry Spencer wrote:
In article ,
Sander Vesik wrote:
No, *some* of them are *possibly* rubble piles. Some are definitely not;
Eros, in particular, appears to be essentially solid rock. Even for the
low-density ones, the matter is not entirely settled...

Surely also at least the double asteroids (two asteroids orbiting each other
closely) are also not rubble piles?

They might be. A close encounter with a planet can split a rubble pile
into a pair of rubble piles, by tidal interaction. (In fact, one of the
points offered in support of the rubble-pile hypothesis is precisely that
we see a suspiciously large number of double asteroids, which ought to be
fairly rare unless there is some specific mechanism that creates them.)

But if you have two piles of rubble orbiting each other, then surely
tidal forces would over time convert these to fuzzy rubble-balls that would
then coalesce into a single body?

--
Sander

+++ Out of cheese error +++