
Two Asteroids Zipping Past Earth Today - toni
http://www.dailygalaxy.com/my_weblog/2010/09/neo-watch-two-asteroids-zipping-past-earth-today.html?
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jacquesm
I can see why it is fascinating to keep an eye on these things but we 'need'
to keep an eye on them just as much as we need to keep an eye out for invading
aliens.

We'll know it when it happens, trust me on that one.

Until then it doesn't matter. If and when it happens we'll be dealing with the
aftermath long before we'll be able to have a handle on what we can do about
the event itself.

You could even argue that this is one of the few cases where foreknowledge
would not help at all, especially not in the case of a very near miss (or is
that a near hit ;) ).

~~~
rbanffy
> We'll know it when it happens, trust me on that one.

But wouldn't it be nice to know it before a giant tsunami wipes out the whole
pacific coastline?

How costly is it compared to what damage it could generate? How costly would
be to avert such a disaster compared to the cost of digging a mile-wide crater
in central Europe?

If we knew of a mountain-sized rock headed towards Earth we would be able to
prevent a disaster, provided we had an early warning system in place. IIRC, a
Delta IV heavy can carry a Tsar-bomba-sized device, plus a booster to put in
the correct trajectory. It wouldn't take long to assemble a couple devices
like this and try a couple approaches, from deflection to blasting it to small
pieces (yes, I would prefer a couple hundred airblasts over a single mountain
hitting the surface).

I think the politics of putting a gigaton device on top of a rocket are much
more complicated than the engineering.

~~~
jacquesm
I think you are overestimating our capabilities in terms of logistics and
engineering.

That's not to be fatalistic about it, it's just harsh reality that if we knew
that a major impact was to take place in 6 months to a years time (which would
leave an enormous amount of room for error in terms of things that look really
scary but turn out to be misses after all) there would not be much that we'd
be able to do about it at all, even if we we could get all the politicians to
pull in the same direction for once.

Just imagine, at that distance the difference in trajectory measured versus
actual would have be only a fraction of an arc-second to turn an all out
disaster in to a spectacular display of fireworks.

So the timeframe within which we can determine with real certainty that there
will be a strike _and_ where it will hit is very short, short enough that you
could evacuate all you want, you might be sending people in the exact wrong
direction.

It's a cosmic crapshoot and the speeds and distances involved are such that
we'd need to improve our game considerably before we'll be able to make an
accurate prediction.

And then there's the next problem, which would be to convince people that this
time the prediction is accurate (see
[http://www.sciencedaily.com/releases/2008/01/080129212723.ht...](http://www.sciencedaily.com/releases/2008/01/080129212723.htm)
for a nice example).

Against such forces of nature we are but ants, and all our technological
achievements of the moment amount to preciously little. It's possible that in
the future we'll be able to do something about this sort of event.

My best bet is that we should spread to multiple places in the solar system
first, the galaxy at a later point. After all, we have a single point of
failure situation here, all our eggs are in this single basket called 'Earth'
and if one of these cosmic freight trains hits us hard enough it could well be
game over for humanity.

~~~
rbanffy
While I agree we would not be able to do anything in a 6 month timeframe, any
100+m rock with large enough impact probability would command much more
attention (and better instruments - all of them, most probably) and have much
better data than current tracked objects. If we ignore the threats we can do
nothing about (the island-sized ones) and focus on the ones we can (mountain
and smaller) the picture is much better. While we can do nothing about freight
trains, we can deflect (or fragment) golf balls.

Certain extinction is a powerful incentive. Humans put a man on the Moon
because a dead president promised that. I certainly imagine a global disaster
can focus out attentions.

------
rkowalick
_In general there is one major impact every million years -a mere blink of the
eye in geological time._

If the universe is only a few billion years old, how is a million years a
"blink of the eye"?

~~~
jat850
Just a convenient turn of phrase, probably.

Assuming the universe is around 14 billion years old, a million years is like
comparing a blink to about 70 minutes (average speed of a blink being
somewhere between 300ms and 400ms).

Does a blink feel short in comparison to 70 minutes? That's a matter of
perception, I guess...

~~~
hugh3
Wow, I can't believe we both replied in exactly the same way, including the
same damn approximations, simultaneously.

~~~
jonsen
Happens once in a million years ;-)

A little spooky it happened on _this_ post, isn't it.

------
moron4hire
"Keeping an eye on NEO is extremely important, given the large number of
unknown space rocks that lurk in outer space."

So it's important to keep track of the few that we know of, because of the
unknown numbers of ones we don't know of? And what if we do track them? What
do we do with this information? It's not like we're going to move the things
or move the planet out of the way. Tracking NEOs does nothing for us, with
maybe the exception of mapping trajectories for deep space probes. How many of
those do we launch in a year? And given that we don't know the full
implications such an impact would have, isn't the psychological effect on
hysterical populations enough of a reason to heed "ignorance is bliss"?

~~~
mike-cardwell
If we don't track them, we wont develop better technology to track more of
them. The more we track, the more information we have about what's out there.
The more information we have, the better decisions we can make about the risks
and how to reduce them.

What's the alternative. Ignore the issue until the inevitable happens?

