60 Second Adventures in Astronomy. Number
fourteen, Gaia and The Killer Asteroids.
If Hollywood has taught us one thing it’s
that an asteroid crashing into the Earth is
not exactly
something to look forward to.
The asteroids most likely to attack us are
the Aten and Apollo asteroids – the ones
with an
orbit closest to our own. Talk about annoying
neighbours.
And unfortunately, these asteroids are pretty
difficult to keep track of – because, to
see them
from the Earth, you'd have to look directly
towards the Sun.
Fortunately, the Gaia spacecraft is going
to be positioned 1.5 million kilometres beyond
the
Earth at a point where gravity will keep it
in a fixed orbit. This is the second Lagrangian
point
– or L2 to its friends.
From this vantage point, Gaia can look back
towards the Sun to spot any potentially
dangerous asteroids that we may otherwise
have missed. Like a lookout in the crows nest
–
or Kevin Costner in The Bodyguard.
But while it’s obviously good to know if
a killer asteroid is, indeed, on the way – the
next
challenge will be what we’re going to do
about it if Gaia spots one.
