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  • Thanks.

  • My name is Ed Lu,

  • and I'm building a space telescope,

  • together with the B612 Foundation.

  • (Applause)

  • It's called Sentinel,

  • and simply put, its mission is to protect the Earth.

  • In 2018 we're going to launch this thing,

  • and it's big, by the way,

  • it's about the size of a FedEx delivery van.

  • We're going to launch into an orbit around the Sun.

  • So it's going to be about 500,000 times further

  • from the Earth than the Hubble space telescope.

  • And we are going to find and track

  • threatening asteroids before they find us.

  • How'd we end up on this crazy quest,

  • other than the fact that everybody needs a space telescope?

  • Right?

  • Our organization started out about 10 years ago.

  • We started it with a different goal,

  • we were working with a different project, related.

  • And then something happened about a year and a half ago.

  • Interesting, a guy came up and asked me a question,

  • and it crystallized our thinking.

  • What we realized is that we had to change our course,

  • and that we had no choice but to actually do this, instead.

  • And I want to tell you the story

  • about how we ended up there and what we're doing.

  • Why should you care about asteroids?

  • Well, if you're a scientist, they're very, very interesting,

  • they're parts, left over parts of the solar system

  • from the formation of it.

  • But if you're a citizen of planet Earth,

  • and you all are, I hope,

  • (Laughter)

  • asteroids are important because they hit the Earth.

  • So if you roll this video,

  • anybody here has ever seen an asteroid impact site?

  • They're all over the Earth.

  • These are some of the known ones on planet Earth.

  • An awful lot, it's kind of a surprising lot?

  • But there's way more than this.

  • They hit the Earth all the time.

  • Just look up at the Moon.

  • The Moon is covered in craters,

  • and actually the Earth is hit more often than the Moon.

  • So the reason you don't actually see them on the Earth

  • is because they get covered up by the ocean,

  • or wind and weather, and things like that get rid of them.

  • They sometimes actually hit the Earth,

  • even in modern times.

  • 1908 Tunguska, this is the aftermath.

  • It looks like a bunch of telephone poles laying on its side.

  • This is an impact site called Tunguska.

  • It's thankfully in Siberia,

  • where an asteroid, fairly small, about 40 meters across --

  • so I would say that's about the size of this room --

  • it hit in Siberia moving at a velocity

  • of about 20 kilometers per second.

  • Anybody here whoever took High School physics knows

  • that the energy is one half M V squared.

  • When you have a big number and you square it,

  • you get a huge number, and that was an enormous amount of energy.

  • It was about a thousand times larger

  • than the energy in the bomb dropped on Hiroshima.

  • So, it wiped out a huge area.

  • It's about 2,500 square kilometers of total destruction.

  • So, for example, just to put that in perspective,

  • if you drew a circle between

  • the Golden Gate Bridge and San Jose,

  • it took about that size.

  • That's the area that was wiped out.

  • Again, a thousand times larger than the Hiroshima bomb.

  • That was only 100 years ago.

  • These hit the Earth about every 100 to 200 years.

  • So, flip a coin, that's the odds that somewhere on Earth,

  • during your lifetime, it's going to happen again.

  • Random spot, most of the world's unpopulated,

  • but wouldn't it be a shame if it was a populated area?

  • (Laughter)

  • About 10 years ago, we decided that we'd work

  • on the problem of deflecting asteroids.

  • There was a bunch of really bad Hollywood movies out.

  • Armageddon, Deep Impact,

  • we thought we'd be the heroes,

  • we're going to figure out how to deflect an asteroid.

  • And if you roll this little movie,

  • over the last 10 years, we together with a lot of other scientists,

  • have worked on this problem, and now we understand

  • that it's actually not that difficult to deflect an asteroid.

  • What you have to do is either run into it with a spacecraft, like this,

  • and boom! You actually change the velocity slightly.

  • It's like playing billiards.

  • It turns out that with sufficient notice

  • you only need to change the velocity of an asteroid

  • by about a millimeter per second

  • to turn a hit into a miss,

  • if you do it early enough.

  • A millimeter per second. That's about this fast.

  • Okay? So you don't need to change the velocity a lot,

  • you don't need oil miners, and Bruce Willis, and stuff.

  • (Laughter)

  • It turns out that there are actually even controllable ways of doing this.

  • If we take the next video here.

  • This is something that me and another astronaut,

  • named Stan Love, yes he is Doctor Love, invented.

  • It's called a gravity tractor.

  • It's very, very simple. You just hover a spacecraft nearby,

  • and the mutual attraction of gravity between them,

  • very, very tiny, adds up and if you can hover for months,

  • so if you run this, you'll see that you can actually tow asteroids

  • and give them the required fraction of a millimeter per second

  • needed to precisely put this where you want.

  • What we realized after about 10 years of working on this,

  • and the community has realized,

  • is that deflecting asteroids is actually not that hard.

  • We actually have the technology to do things like this.

  • So what's the problem?

  • The problem is, if you don't know where asteroids are,

  • there's nothing you can do about it, right?

  • As my friend Don Yeomans likes to say,

  • "The 3 rules of deflecting asteroids are:

  • Find them early, find them early, and find them early."

  • So let's look at the big picture.

  • What does the Solar System look like?

  • If you could run this...

  • The green circle there is the orbit of the Earth,

  • and then you can see the orbits of the other planets.

  • And these are all the known asteroids,

  • and these are actual real positions. (audience murmuring)

  • The wizards at the California Academy of Sciences

  • put this together, these are real orbits.

  • All of this is real data,

  • those are the locations of all the known asteroids.

  • So the Earth again, look at the green line.

  • You see all the stuff flying around.

  • It's a very crowded place in our Solar System.

  • It's a little deceptive, because you have to make them bigger

  • so you can see it, but very, very crowded.

  • That's the good -- So here's the bad news, though.

  • We know what tiny area of the Solar System

  • we've actually surveyed thus far,

  • we know that it's not very much.

  • There's a hundred times more than you see here.

  • And those are undiscovered right now,

  • and we really have no way to discover them from the ground.

  • So what does the real Solar System look like?

  • Multiply this by 100 and you get what the real Solar System looks like,

  • it looks like this.

  • This is actually the situation --

  • follow the green line of the Earth,

  • and follow all the things that go whizzing past the Earth.

  • Every time you hear in the news

  • that an asteroid has whizzed past the Earth

  • you should think, "So what, it's happening all the time,

  • 99 out of 100 we don't know about."

  • So that's what the situation looks like in the Solar System,

  • and that's what we want to change.

  • Because if you know where every single one of these is,

  • we can tell you where it's going.

  • Because we understand something called "Orbital Mechanics".

  • It turns out that if you tell me the velocity

  • and the location of each one of these things,

  • I'll tell you where it is any point out in the future.

  • Okay, that's how we send probes to Mars, for instance.

  • We ended up in a situation where

  • we know how to deflect asteroids,

  • but we're not looking for them.

  • We're driving around the Solar System with our eyes closed, essentially.

  • And that seems kind of crazy, right?

  • Because these things do hit the Earth,

  • as evidenced by this guy here.

  • As you all know, an asteroid impact is what wiped out the dinosaurs

  • and we don't want to be like him.