Asteroid hunter is a real job at NASA. Brut spoke to one of them.
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00:00I have here a space rock. This is an asteroid that fell to Earth in 2017.
00:04And my job is to find objects like this when they're far away from us in space
00:08so that we don't accidentally get hit by one that we don't know about.
00:16Every 11 seconds, we look for anything that moves.
00:19Anything that moves against the background stars.
00:22If we see something that moves, we suspect it could be a candidate asteroid or comet.
00:26And so we go chase it down and figure out exactly what it is.
00:34A near-Earth object can be any asteroid or comet
00:37that gets within about 30% or more of the distance between the Earth and the Sun.
00:43The asteroids tend to be more rocky.
00:45Sometimes they can even be solid slabs of metal, more or less.
00:48Whereas the comets tend to be more of a mixture of ices and rocks, all mangled together.
00:57The Planetary Defense Coordination Office? Is that a real place?
01:02That really is a real thing.
01:04The job of this Planetary Defense Coordination Office
01:06is to basically coordinate all the activities that NASA has
01:10to search for the objects that can get close to the Earth,
01:13to make detailed predictions of their orbits and their trajectories,
01:17and also to coordinate with other governments around the world
01:20and other observers all over the place
01:22to try to keep an eye out for what is going on in the skies.
01:37Lucky for us, it is really, really, really unlikely
01:40that any sort of gigantist impact would happen.
01:43Something that's capable of wiping out a large fraction of life on Earth.
01:46We know where more than 90% of all the really large objects
01:51near-Earth asteroids are.
01:53These are objects that are larger than a kilometer across.
01:56So things big enough to cause really, truly global devastation.
01:59And none of them pose any impact hazard over the next 100 years.
02:02So that's great.
02:04But when we get down to smaller sizes,
02:06down to sizes of objects that are big enough to cause
02:08what I would call severe regional destruction,
02:11the news is not as rosy.
02:13We have found maybe between 30% and 40% of those objects,
02:16and the rest are still out there waiting for us to find them.
02:19When we get down to really small sizes,
02:21things say capable of causing damage to a city,
02:24there we only know of a few percent of the objects at best.
02:27So we still have a lot of work to do to map out what is out there in the skies.
02:39In 2013, there was an asteroid that exploded over Russia.
02:43And this was a very tiny asteroid, actually.
02:45It was only about 17 to 20 meters across.
02:48So that's about the size of a small house.
02:50It's not even a particularly big object.
02:52But it exploded high up in the Earth's atmosphere,
02:55and the shockwave broke a lot of windows,
02:57and it sent about 1,600 people to the hospital,
03:00mostly from flying broken glass.
03:09We have to find them far enough in advance,
03:12because if we don't have much warning,
03:14then there's a lot less you can do about it.
03:16But if we find these objects when they're years to decades away
03:19from any potential close approaches,
03:20now our option space opens up quite a bit.
03:23The simplest thing we could try is to simply bump a spacecraft into an asteroid,
03:27and we call that a kinetic impactor.
03:29NASA's DART mission, the Double Asteroid Redirection Test,
03:32is supposed to test that kinetic impactor technology
03:35by just bumping into an asteroid
03:37and just changing its orbit ever so slightly.
03:40You can have other techniques that are more complicated,
03:43such as just parking a really big spacecraft next to an asteroid
03:46and then just kind of let the force of gravity pull it aside.
03:50That takes a long time, though, and the object can't be too big.
03:53If the object is very large, or if we just don't have a lot of time,
03:57then the only option becomes to use some sort of nuclear device.
04:01Obviously, that is a last resort,
04:03and we'd really like to find the objects far enough in advance
04:05that we can use simpler and less invasive techniques,
04:08like the kinetic impactor technique.
04:13What are the chances of an asteroid and comet impact?
04:20Asteroid and comet impacts are really unlikely,
04:23so the probability is very low that something will happen,
04:26but the consequences can be high.
04:28And that, to us in the spacecraft world, means it's sort of a medium risk.
04:31You don't need to run around with your hair on fire,
04:33but you don't want to completely ignore the problem either.
04:36On the other hand, we have climate change.
04:38The probability of it happening is extremely high,
04:41and the consequences are high.
04:43That means this is a very, very risky thing that's happening to our planet.
04:47It's really urgent.
04:48We need to take steps now so that we can avert the worst possible consequences.