How to defend Earth from asteroids | Phil Plait | TEDxBoulder
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0:08 - 0:10I want to talk to you about something
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0:10 - 0:12kind of big.
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0:14 - 0:16We'll start here.
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0:17 - 0:1965 million years ago
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0:20 - 0:22the dinosaurs had a bad day.
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0:23 - 0:25(Laughter)
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0:25 - 0:28A chunk of rock six miles across,
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0:29 - 0:31moving something like 50 times
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0:31 - 0:33the speed of a rifle bullet,
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0:33 - 0:34slammed into the Earth.
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0:34 - 0:37It released its energy all at once,
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0:37 - 0:39and it was an explosion that was
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0:39 - 0:40mind-numbing.
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0:40 - 0:43If you took every nuclear weapon
ever built -
0:43 - 0:45at the height of the Cold War,
-
0:45 - 0:47lumped them together and blew them up
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0:47 - 0:49at the same time,
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0:49 - 0:51that would be one one-millionth
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0:51 - 0:54of the energy released at that moment.
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0:54 - 0:57The dinosaurs had a really bad day.
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0:58 - 0:59Okay?
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0:59 - 1:01Now, a six-mile-wide rock is very large.
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1:01 - 1:03We all live here in Boulder.
-
1:03 - 1:06If you look out your window
and you can see Long's Peak, -
1:06 - 1:07you're probably familiar with it.
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1:07 - 1:09Now, scoop up Long's Peak,
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1:09 - 1:10and put it out in space.
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1:10 - 1:13Take Meeker, Mt. Meeker.
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1:13 - 1:15Lump that in there,
and put that in space as well, -
1:15 - 1:18and Mt. Everest, and K2,
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1:18 - 1:20and the Indian peaks.
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1:20 - 1:22Then you're starting to get an idea
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1:22 - 1:24of how much rock
we're talking about, okay? -
1:24 - 1:25We know it was that big
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1:25 - 1:28because of the impact
it had and the crater it left. -
1:28 - 1:30It hit in what we now know as Yucatan,
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1:30 - 1:32the Gulf of Mexico.
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1:32 - 1:33You can see here,
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1:33 - 1:36there's the Yucatan Peninsula,
if you recognize Cozumel -
1:36 - 1:37off the east coast there.
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1:37 - 1:40Here is how big of a crater was left.
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1:41 - 1:42There we go.
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1:43 - 1:44It was huge.
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1:44 - 1:47To give you a sense of the scale,
okay, there you go. -
1:47 - 1:49The scale here is 50 miles on top,
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1:49 - 1:51a hundred kilometers on the bottom.
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1:51 - 1:54This thing was 300 kilometers across
- 200 miles - -
1:54 - 1:56an enormous crater that excavated out
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1:56 - 1:59vast amounts of earth
that splashed around the globe -
2:00 - 2:02and set fires all over the planet,
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2:02 - 2:05threw up enough dust to block out the sun.
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2:05 - 2:08It wiped out 75 percent
of all species on Earth. -
2:09 - 2:11Now, not all asteroids are that big.
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2:12 - 2:14Some of them are smaller.
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2:14 - 2:17Here is one that came in
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2:17 - 2:19over the United States
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2:19 - 2:21in October of 1992.
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2:21 - 2:23It came in on a Friday night.
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2:23 - 2:24Why is that important?
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2:24 - 2:26Because back then, video cameras
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2:26 - 2:28were just starting to become popular,
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2:28 - 2:31and people would bring them,
parents would bring them, -
2:31 - 2:34to their kids' football games
to film their kids play football. -
2:34 - 2:36And since this came in on a Friday,
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2:36 - 2:38they were able to get this great footage
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2:38 - 2:40of this thing breaking up as it came in
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2:40 - 2:42over West Virgina, Maryland, Pennsylvania
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2:42 - 2:44and New Jersey until it did that
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2:44 - 2:46to a car in New York.
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2:46 - 2:47(Laughter)
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2:47 - 2:50Now, this is not a 200-mile-wide crater,
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2:51 - 2:53but then again you can see the rock
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2:53 - 2:54which is sitting right here,
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2:54 - 2:56about the size of a football,
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2:56 - 2:58that hit that car and did that damage.
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2:58 - 3:00Now this thing was probably about the size
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3:00 - 3:02of a school bus when it first came in.
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3:02 - 3:04It broke up through atmospheric pressure,
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3:04 - 3:06it crumbled,
and then the pieces fell apart -
3:06 - 3:08and did some damage.
-
3:08 - 3:10Now, you wouldn't want that
falling on your foot -
3:10 - 3:13or your head,
because it would do that to it. -
3:13 - 3:15That would be bad.
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3:15 - 3:17But it won't wipe out, you know,
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3:17 - 3:19all life on Earth, so that's fine.
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3:19 - 3:22But it turns out, you don't need
something six miles across -
3:22 - 3:24to do a lot of damage.
-
3:24 - 3:26There is a median point between tiny rock
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3:26 - 3:28and gigantic rock, and in fact,
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3:28 - 3:31if any of you have ever been
to near Winslow, Arizona, -
3:31 - 3:33there is a crater in the desert there
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3:33 - 3:36that is so iconic
that it is actually called Meteor Crater. -
3:37 - 3:40To give you a sense of scale,
this is about a mile wide. -
3:40 - 3:43If you look up at the top,
that's a parking lot, -
3:44 - 3:46and those are recreational vehicles
right there. -
3:46 - 3:49So it's about a mile across,
600 feet deep. -
3:49 - 3:52The object that formed this
was probably about -
3:52 - 3:5530 to 50 yards across,
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3:55 - 3:58so roughly the size
of Macky Auditorium here. -
3:59 - 4:01It came in at speeds that were tremendous,
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4:01 - 4:04slammed into the ground, blew up,
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4:04 - 4:06and exploded with the energy of roughly
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4:06 - 4:08a 20-megaton nuclear bomb -
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4:08 - 4:09a very hefty bomb.
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4:09 - 4:11This was 50,000 years ago,
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4:11 - 4:14so it may have wiped out
a few buffalo or antelope, -
4:14 - 4:17or something like that out in the desert,
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4:17 - 4:19but it probably would not have caused
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4:19 - 4:20global devastation.
-
4:20 - 4:22It turns out that these things
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4:22 - 4:25don't have to hit the ground
to do a lot of damage. -
4:26 - 4:28Now, in 1908, over Siberia,
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4:28 - 4:30near the Tunguska region -
for those of you -
4:30 - 4:33who are Dan Aykroyd fans
and saw "Ghostbusters," -
4:33 - 4:35when he talked about
the greatest cross-dimensional rift -
4:35 - 4:38since the Siberia blast
of 1909, where he got the date wrong, -
4:39 - 4:41but that's okay. (Laughter)
-
4:41 - 4:44It was 1908. That's fine.
I can live with that. -
4:44 - 4:45(Laughter)
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4:45 - 4:48Another rock came
into the Earth's atmosphere -
4:48 - 4:50and this one blew up above the ground,
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4:51 - 4:53several miles up above
the surface of the Earth. -
4:53 - 4:55The heat from the explosion
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4:55 - 4:57set fire to the forest below it,
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4:58 - 5:01and then the shock wave came down
and knocked down trees -
5:01 - 5:04for hundreds of square miles, okay?
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5:04 - 5:06This did a huge amount of damage.
-
5:06 - 5:09And again, this was a rock
probably roughly -
5:09 - 5:11the size of this auditorium
that we're sitting in. -
5:11 - 5:13In Meteor Crater it was made of metal,
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5:13 - 5:14and metal is much tougher,
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5:14 - 5:16so it made it to the ground.
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5:16 - 5:18The one over Tunguska
was probably made of rock, -
5:18 - 5:20and that's much more crumbly,
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5:20 - 5:21so it blew up in the air.
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5:21 - 5:25Either way, these
are tremendous explosions, 20 megatons. -
5:26 - 5:28Now, when these things blow up,
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5:28 - 5:31they're not going to do
global ecological damage. -
5:31 - 5:34They're not going to do something
like the dinosaur-killer did. -
5:34 - 5:36They're just not big enough.
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5:36 - 5:38But they will do global economic damage,
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5:39 - 5:41because they don't have to hit,
necessarily, -
5:41 - 5:43to do this kind of damage.
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5:43 - 5:45They don't have to do global devastation.
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5:45 - 5:47If one of these things were to hit
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5:47 - 5:49pretty much anywhere,
it would cause a panic. -
5:49 - 5:52But if it came over a city,
an important city - -
5:52 - 5:54not that any city is more
important than others, -
5:54 - 5:56but some of them we depend on them more
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5:56 - 5:57on the global economic basis -
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5:57 - 6:00that could do
a huge amount of damage to us -
6:00 - 6:02as a civilization.
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6:02 - 6:06So, now that I've scared
the crap out of you... -
6:06 - 6:07(Laughter)
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6:07 - 6:09what can we do about this?
All right? -
6:09 - 6:11This is a potential threat.
-
6:11 - 6:15Let me note that we have not had
a giant impact -
6:15 - 6:17like the dinosaur-killer
for 65 million years. -
6:17 - 6:18They're very rare.
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6:18 - 6:20The smaller ones happen more often,
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6:20 - 6:23but probably on the order of a millennium,
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6:23 - 6:26every few centuries
or every few thousand years, -
6:26 - 6:28but it's still something to be aware of.
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6:28 - 6:30Well, what do we do about them?
-
6:30 - 6:32The first thing we have to do
is find them. -
6:32 - 6:36This is an image of an asteroid
that passed us in 2009. -
6:36 - 6:38It's right here.
-
6:38 - 6:41And this is supposed to be animated,
so, it's okay though. -
6:41 - 6:44But you can see that it's extremely faint.
-
6:44 - 6:47I don't even know if you can see that
in the back row. -
6:47 - 6:48These are just stars.
-
6:48 - 6:51This is a rock that was about
30 yards across, -
6:51 - 6:53so roughly the size
of the ones that blew up -
6:53 - 6:55over Tunguska and hit Arizona
50,000 years ago. -
6:55 - 6:57These things are faint.
-
6:57 - 6:59They're hard to see,
and the sky is really big. -
6:59 - 7:01We have to find these things first.
-
7:01 - 7:03Well the good news is,
we're looking for them. -
7:03 - 7:06NASA has devoted money to this.
-
7:06 - 7:07The National Science Foundation,
-
7:07 - 7:09other countries are very
interested in doing this. -
7:09 - 7:12We're building telescopes
that are looking for the threat. -
7:12 - 7:15That's a great first step,
but what's the second step? -
7:15 - 7:18The second step is that we see
one heading toward us, -
7:18 - 7:19we have to stop it.
-
7:19 - 7:20What do we do?
-
7:20 - 7:22You've probably heard
about the asteroid Apophis. -
7:22 - 7:24If you haven't yet, you will.
-
7:24 - 7:27If you've heard about
the Mayan 2012 apocalypse, -
7:27 - 7:29you're going to hear about Apophis,
-
7:29 - 7:32because you're keyed in
to all the doomsday networks anyway. -
7:33 - 7:37Apophis is an asteroid
that was discovered in 2004. -
7:37 - 7:39It's roughly 250 yards across,
-
7:39 - 7:41so it's pretty big - big size, you know,
-
7:41 - 7:43bigger than a football stadium -
-
7:43 - 7:46and it's going to pass by the Earth
in April of 2029. -
7:46 - 7:48And it's going to pass us so close
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7:48 - 7:50that it's actually
going to come underneath -
7:50 - 7:52our weather satellites.
-
7:52 - 7:54The Earth's gravity
is going to bend the orbit -
7:54 - 7:57of this thing so much
that if it's just right, -
7:57 - 7:59if it passes through this region of space,
-
7:59 - 8:03this kidney bean-shaped region
called the keyhole, -
8:03 - 8:05the Earth's gravity will bend it
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8:05 - 8:07just enough that seven years later
-
8:07 - 8:09on April 13, which is a Friday, I'll note,
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8:09 - 8:12in the year 2036... (Laughter)
-
8:12 - 8:14- you can't plan that kind of stuff -
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8:14 - 8:16Apophis is going to hit us.
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8:16 - 8:18And it's 250 meters across,
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8:18 - 8:20so it would do unbelievable damage.
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8:20 - 8:22Now the good news is that the odds of it
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8:22 - 8:24actually passing through this keyhole
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8:24 - 8:27and hitting us next go-around
are one in a million, roughly -
8:27 - 8:28very, very low odds,
-
8:28 - 8:30so I personally
am not lying awake at night -
8:30 - 8:31worrying about this at all.
-
8:31 - 8:33I don't think Apophis is a problem.
-
8:33 - 8:35In fact, Apophis
is a blessing in disguise, -
8:35 - 8:38because it woke us up
to the dangers of these things. -
8:38 - 8:40This thing was discovered
just a few years ago -
8:40 - 8:42and could hit us a few years from now.
-
8:42 - 8:46It won't, but it gives us a chance
to study these kinds of asteroids. -
8:46 - 8:48We didn't really necessarily understand
these keyholes, -
8:48 - 8:50and now we do and it turns out
-
8:50 - 8:54that's really important, because
how do you stop an asteroid like this? -
8:54 - 8:55Well, let me ask you,
-
8:55 - 8:58what happens if you're standing
in the [middle of] the road -
8:58 - 8:59and a car's headed for you?
-
8:59 - 9:01What do you do?
You do this. -
9:01 - 9:02Right? Move. The car goes past you.
-
9:02 - 9:05But we can't move the Earth,
at least not easily, -
9:05 - 9:07but we can move a small asteroid.
-
9:07 - 9:09And it turns out, we've even done it.
-
9:09 - 9:12In the year 2005, NASA launched a probe
-
9:12 - 9:15called Deep Impact, which slammed into -
-
9:15 - 9:17slammed a piece of itself
into the nucleus of a comet. -
9:17 - 9:19Comets are very much like asteroids.
-
9:20 - 9:22The purpose wasn't to push it
out of the way. -
9:22 - 9:24The purpose was to make
a crater to excavate -
9:24 - 9:26the material and see what was underneath
-
9:26 - 9:29the surface of this comet,
which we learned quite a bit about. -
9:29 - 9:31We did move the comet a little tiny bit,
-
9:31 - 9:33not very much, but that wasn't the point.
-
9:33 - 9:35However, think about this.
-
9:35 - 9:37This thing is orbiting the Sun
-
9:37 - 9:39at 10 miles per second,
20 miles per second. -
9:39 - 9:42We shot a space probe
at it and hit it. Okay? -
9:42 - 9:45Imagine how hard that must be,
and we did it. -
9:45 - 9:47That means we can do it again.
-
9:47 - 9:49If we see
an asteroid that's coming toward us -
9:49 - 9:51and it's headed right for us,
-
9:51 - 9:54and we have two years to go, boom!
We hit it. -
9:54 - 9:57You can try to - you know,
if you watch the movies, -
9:57 - 9:58you might think about,
-
9:58 - 10:00why don't we use a nuclear weapon?
-
10:00 - 10:03It's like, well, you can try that,
but the problem is timing. -
10:03 - 10:05You shoot a nuclear weapon at this thing,
-
10:05 - 10:07you have to blow it up
within a few milliseconds -
10:07 - 10:09of tolerance or else you'll just miss it.
-
10:09 - 10:12And there are a lot of other problems
with that. -
10:12 - 10:13It's very hard to do.
-
10:13 - 10:15But just hitting something?
That's pretty easy. -
10:15 - 10:17I think even NASA can do that,
-
10:17 - 10:19and they proved that they can. (Laughter)
-
10:19 - 10:21The problem is, what happens
if you hit this asteroid, -
10:21 - 10:22you've changed the orbit,
-
10:22 - 10:24you measure the orbit
and then you find out, -
10:24 - 10:26oh, yeah, we just pushed
it into a keyhole, -
10:26 - 10:29and now it's going to hit
us in three years. -
10:29 - 10:30Well, my opinion is, fine. Okay?
-
10:30 - 10:33It's not hitting us in six months.
That's good. -
10:33 - 10:36Now we have three years
to do something else. -
10:36 - 10:37And you can hit it again.
-
10:37 - 10:38That's kind of ham-fisted.
-
10:38 - 10:41You might just push it into
a third keyhole or whatever, -
10:41 - 10:42so you don't do that.
-
10:42 - 10:45And this is the part,
it's the part I just love. -
10:46 - 10:48(Laughter)
-
10:48 - 10:50After the big macho "Rrrrrrr BAM!
-
10:50 - 10:52We're gonna hit this thing
in the face," -
10:52 - 10:55then we bring in the velvet gloves.
-
10:55 - 10:57(Laughter)
-
10:57 - 11:00There's a group of scientists,
engineers and astronauts -
11:00 - 11:02and they call themselves
The B612 Foundation. -
11:02 - 11:05For those of you who've read
"The Little Prince," -
11:05 - 11:07you understand that reference, I hope.
-
11:07 - 11:09The little prince who lived
on an asteroid, called B612. -
11:09 - 11:11These are smart guys - men and women -
-
11:11 - 11:13astronauts, like I said, engineers.
-
11:13 - 11:16Rusty Schweickart, who was
an Apollo 9 astronaut, is on this. -
11:16 - 11:18Dan Durda, my friend who made this image,
-
11:18 - 11:21works here at Southwest Research Institute
in Boulder, -
11:21 - 11:23on Walnut Street.
-
11:23 - 11:24He created this image for this,
-
11:24 - 11:27and he's actually one of the astronomers
who works for them. -
11:27 - 11:29If we see an asteroid
that's going to hit the Earth -
11:29 - 11:31and we have enough time,
-
11:31 - 11:33we can hit it to move it
into a better orbit. -
11:33 - 11:36But then what we do is we launch
-
11:36 - 11:38a probe that has to weigh a ton or two.
-
11:38 - 11:41It doesn't have to be
huge - couple of tons, not that big - -
11:41 - 11:43and you park it near the asteroid.
-
11:43 - 11:44You don't land on it,
-
11:44 - 11:46because these things
are tumbling end over end. -
11:46 - 11:48It's very hard to land on them.
-
11:48 - 11:49Instead you get near it.
-
11:49 - 11:51The gravity of the asteroid
pulls on the probe, -
11:51 - 11:53and the probe
has a couple of tons of mass. -
11:53 - 11:55It has a little tiny bit of gravity,
-
11:55 - 11:58but it's enough
that it can pull the asteroid, -
11:58 - 12:01and you have your rockets set up,
so you can - -
12:01 - 12:04oh, you can barely see it here,
but there's rocket plumes - -
12:04 - 12:07and you basically, these guys
are connected by their own gravity, -
12:07 - 12:09and if you move the probe very slowly,
-
12:09 - 12:12very, very gently,
you can very easily -
12:12 - 12:15finesse that rock into a safe orbit.
-
12:15 - 12:17You can even put in orbit around the Earth
-
12:17 - 12:20where we could mine it,
although that's a whole other thing. -
12:20 - 12:22I won't go into that.
(Laughter) -
12:22 - 12:24But we'd be rich!
-
12:24 - 12:27(Laughter)
-
12:29 - 12:31So think about this, right?
-
12:32 - 12:34There are these giant rocks
flying out there, -
12:34 - 12:37and they're hitting us,
and they're doing damage to us, -
12:37 - 12:39but we've figured out how to do this,
-
12:39 - 12:41and all the pieces
are in place to do this. -
12:41 - 12:44We have astronomers
with telescopes looking for them. -
12:44 - 12:45We have smart people,
-
12:45 - 12:48very, very smart people,
who are concerned about this -
12:48 - 12:50and figuring out how to fix the problem,
-
12:50 - 12:52and we have the technology to do this.
-
12:52 - 12:54This probe actually
can't use chemical rockets. -
12:54 - 12:57Chemical rockets provide
too much thrust, too much push. -
12:57 - 12:59The probe would just shoot away.
-
12:59 - 13:01We invented something called an ion drive,
-
13:01 - 13:04which is a very, very,
very low-thrust engine. -
13:04 - 13:07It generates the force
a piece of paper would have on your hand, -
13:07 - 13:08incredibly light,
-
13:08 - 13:11but it can run for months and years,
-
13:11 - 13:13providing that very gentle push.
-
13:13 - 13:16If anybody here is a fan
of the original "Star Trek," -
13:16 - 13:17they ran across an alien ship
-
13:17 - 13:19that had an ion drive, and Spock said,
-
13:19 - 13:21"They're very technically sophisticated.
-
13:21 - 13:24They're a hundred years ahead of us
with this drive." -
13:24 - 13:26Yeah, we have an ion drive now.
(Laughter) -
13:26 - 13:29We don't have the Enterprise,
but we've got an ion drive now. -
13:29 - 13:32(Applause)
-
13:32 - 13:34Spock.
-
13:34 - 13:36(Laughter)
-
13:36 - 13:37So...
-
13:39 - 13:42that's the difference,
between us and the dinosaurs. -
13:43 - 13:45This happened to them.
-
13:45 - 13:47It doesn't have to happen to us.
-
13:47 - 13:50The difference
between the dinosaurs and us -
13:50 - 13:53is that we have a space program
-
13:53 - 13:54and we can vote,
-
13:54 - 13:57and so we can change our future.
-
13:57 - 13:58(Laughter)
-
13:58 - 14:01We have the ability to change our future.
-
14:01 - 14:0265 million years from now,
-
14:02 - 14:04we don't have to have our bones
-
14:04 - 14:06collecting dust in a museum.
-
14:06 - 14:08Thank you very much.
-
14:08 - 14:09(Applause)
- Title:
- How to defend Earth from asteroids | Phil Plait | TEDxBoulder
- Description:
-
What's six miles wide and can end civilization in an instant? An asteroid - and there are lots of them out there. With humor and great visuals, Phil Plait enthralls the audience with all the ways asteroids can kill, and what we must do to avoid them.
- Video Language:
- English
- Team:
- closed TED
- Project:
- TEDxTalks
- Duration:
- 14:13
TED Translators admin edited English subtitles for How to defend Earth from asteroids | Phil Plait | TEDxBoulder | ||
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Ivana Korom edited English subtitles for How to defend Earth from asteroids | Phil Plait | TEDxBoulder | ||
Ivana Korom edited English subtitles for How to defend Earth from asteroids | Phil Plait | TEDxBoulder | ||
Ivana Korom edited English subtitles for How to defend Earth from asteroids | Phil Plait | TEDxBoulder | ||
TED Translators admin edited English subtitles for How to defend Earth from asteroids | Phil Plait | TEDxBoulder | ||
TED Translators admin edited English subtitles for How to defend Earth from asteroids | Phil Plait | TEDxBoulder |