[meteorite-list] Russia mega meteor and asteroid 2012DA14 related, yes I think so...

[Rob Matson]

Hi Michael,

> ... I have learned to be more and more skeptical about the common/obvious
> knowledge over the years... You might be right... but be careful about your
> high level of "certainty"...

The level of celestial mechanical certainty involved here is comparable to the
uncertainty that 1+1 = 2. That said, I will play Devil's Advocate and mention
that
there is one rather far-out scenario which is probably still dynamically
impossible,
but I mention it out of completeness. Imagine an object (that was once part
of 2012 DA14) leading it by nearly a day on a slightly different trajectory.
(Forget for the moment that days if not weeks before the 2012 DA14 flyby
it would have been detected by astronomers that were already tracking
the larger asteroid.) Suppose this unlikely object happens to make an
extremely grazing pass of the lunar farside such that its direction is
drastically
bent by ~90 degrees -- in precisely the right direction for a grazing intercept
with Earth, say, 6 to 10 hours later. Such a 3-body solution is the ONLY way to
bring about the situation you require, and yet I would argue that the
probability
of it happening by chance is much, much smaller than that of two smallish
asteroids making a close pass by earth within 24 hours of each other.

Really, though, the failure to telescopically detect the second object ahead
of 2012 DA14 when it was being tracked by so many professionals and
citizen scientists throws a bit of cold water on the whole crazy scenario.

--Rob