🚀 go-pugleaf

kopfj@bert.Tymnet.COM (John Kopf, X6305) writes:

> I assume that a "contact binary" consist of a number of pieces bound into
> contact by gravity which is not strong enough to make them join together.

     That is correct.

> What happens when one of these falls onto a planet (earth)?

     Once the pieces get inside the Earth's Roche limit, the pieces come
apart and make independent entries into the atmosphere.

> Is this how bolides work, or are they a single "rock" that explodes
> because of the heat of entry?

     The latter.

> Would the planet's gravity field cause them to seperate?  because of
> tidal forces?  could this explain clusters of craters (such as the
> Argentine crater cluster described in Sky & Telescope recently)?

     Yes.  Yes.  And yes.

     The most interesting point about the prevalence of contact binaries is
what it tells us about origins.  The rms velocity between any two asteroids
is about 5 km/s -- somewhat more near the Earth's orbit.  Collisions
between such objects would be catastrophically destructive.  So the joined
fragments must have been previously in orbit as satellites of the asteroid,
brought down gradually by tidal forces until a gentle contact occurred.
Although the satellite would roll across the surface after touchdown, there
would be no destructive collision.

     And the only way that asteroids can get lots of satellites orbiting
them with anything like the observed abundance is in the explosive breakup
of a much larger parent body.  The prediction that asteroid satellites are
numerous and commonplace originates from the exploded planet hypothesis.
There is presently no other known way to produce abundant asteroids with
current or former satellites.  -|Tom|-

-- 
Tom Van Flandern / Washington, DC / metares@well.sf.ca.us
Meta Research was founded to foster research into ideas not otherwise
supported because they conflict with mainstream theories in Astronomy.