

NASA is tracking 93% of all giant asteroids that could smash into Earth - danberger
http://www.calgaryherald.com/technology/Relax+asteroids+endanger+Earth+NASA/5478593/story.html#ixzz1ZNaMxwKz

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firebones
How do they come up with the estimated number of asteroids larger than 1 km?
Is it based simply on sampling a volume of observed space and extrapolating?
Or do they have some way of inferring based on gravitational effects and
anomalies?

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Nick_C
> Is it based simply on sampling a volume of observed space and extrapolating

Yes, that's pretty much it. It's not as bad as perhaps it sounds. The age of
the solar system means that the asteroid belt is mostly stable, which means
the distribution can be inferred.

The Kuiper belt and Oort cloud may throw some outliers in occasionally,
though. We don't know enough about them yet.

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feral
Is 93% really an acceptable amount of the 'giant asteroids that could smash
into Earth' to track?

Clearly, its a better number than, for example, 50%; and its great that NASA
is doing any tracking; but this is an species level existential threat that's
being talked about.

I'd really prefer to live in a world whereby a joint international effort
(ideally; or just anyone) was tracking 99.9999% of such asteroids, as a matter
of priority.

I think that the LHC, or the moon landings, were great projects - but
shouldn't we do this, first?

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Nick_C
The issue is how. It's the old 80/20 rule, although perhaps in this case it is
more like the 93/07 rule.

We've got the "easy" ones, but we infer there are others we haven't detected.
How do we detect them? Space is really really big.

