Nobody sees it coming. An unidentified asteroid, just a couple miles wide, shatters Earth’s atmosphere with a deafening bang, craters its surface with the energy of a few million nuclear bombs. The shockwave flattens buildings like they’re made of dust. Millions of people, incinerated in an instant.After the initial blast, molten debris is ejected into the atmosphere and into Earth’s orbit, such that civilization’s final act is set in a rain of fire.
This isn’t the beginning of a History Channel doomsday script. It’s a dramatization of a highly unlikely but nonetheless plausible asteroid impact event that would spell the end for humanity as we know it. After all, dinosaurs ruled Earth the last time a city-sized asteroid hit. And look what happened to them.
When it comes to asteroid’s capable of wiping out a city, we’re practically as in the dark as the dinosaurs, having identified just about 1.5 percent of the million or so out there. Meanwhile, astronomers think they’ve found between 90-95 percent of the civilization-ending space rocks, none of which pose an immediate threat to the planet. It’s the 5-10 percent we don’t know about that are the problem though. If one of those bad boys drops by unannounced, the consequence would be catastrophic.
Asteroid impacts don’t keep Bill Nye up at night but, like a swimmer with a fear of sharks, it’s the ones we don’t see that have him worried. “It’s a low probability event with an enormous consequence,” he tells Digital Trends. “The only preventable natural disaster.” Discovering the remaining 5-10 percent of those asteroids is key. After that, engineers will set out to deflect any inbound asteroids. From nuclear blasts that knock the asteroid off its path to swarms of laser-beaming spacecraft to nudge it in the other direction, the technology may sound straight out of science fiction but Nye says it’s all within our technological reach.
As CEO of The Planetary Society, the fun-loving and often irreverent science guy is currently spearheading a Kickstarter campaign called Kick Asteroid!, which aims to raise money and awareness about these outer space threats and nudge lawmakers into action. Offering merchandise like shirts and posters, the campaign met its $50,000 funding goal but continues to take pledges with a couple days left to go.
So, we spoke to Bill Nye about the possibility of asteroid impact events, why we should worry, and what we can do about it.
Digital Trends: Asteroid impacts make for compelling movie scripts but seem less rooted in reality. How often do they actually happen and how worried we should be?
Bill Nye: Well there was a significant one in 2013 that was 20 meters or so that hit the atmosphere [in Chelyabinsk, Russia]. Everybody ran to the windows and dozens of seconds later the shockwave hit the ground, blew glass in their faces, and hurt a thousand people. Some of them had very serious injuries and had to go to the emergency room. And in 1908 there was the Tunguska airburst in Siberia that leveled two-thousand square kilometers of trees. 10 million trees were knocked down in an instant. And 1908 wasn’t very long ago. If that airburst had happened over Paris or New York or Sydney, that would be the end of any of those places. And what finally did the dinosaurs in was an asteroid impact, which is now reckoned to have been off the coast of Mexico.
The smaller ones happen a couple times a century, the big ones happen every few centuries, and the huge ones happen every few million years. It’s a very low probability event but with enormous consequence. It would be just “Control-Alt-Delete” for civilization.
So are we past due for one of the big ones?
Nobody knows. We speculate about that all the time. Lisa Randall wrote a cool book where she speculated that the Earth is passing through a disk of dark matter every few million years and the periodicity of 35 million years of asteroid impacts is related to matter we don’t understand yet. It’s a very cool idea but neither here nor there. All it would take is one. We’ve identified about 90 percent of the catastrophic ones but that leaves 10 percent, which is more than enough to be troublesome.
You said if one did hit it would be essentially Control-Alt-Delete scenario. What would the aftermath of a big asteroid impact look like?
In the impact [that killed the dinosaurs], what we now call the Chicxulub crater, the cone of ejected material is thought to be bigger in diameter than the diameter of the Earth. This red hot debris ended up essentially in Earth’s orbit for days or weeks. That caused global fires and killed off whatever the large animals ate, so they couldn’t make a living. The only creatures that lived through it were living underground in burrows and stuff.
Say we were going to be hit by one of the 10 percent of unknown asteroids. How long beforehand would we have a warning? Would we be able to see it approaching?
Probably not. Let’s say it’s 30 kilometers in diameter. That’s big compared to a football stadium but tiny compared to the vastness of space. So as we like to “hilariously” joke looking for asteroids is like looking for a charcoal briquette in the dark. They’re very hard to see but with the right instruments, especially infrared telescopes, we can see them. They glow about 150 degrees Celsius above absolute zero. So we want to advocate for space to build systems to look for these things, so that we get 20 or 30 years notice. If we have 30 years notice then we can send a spacecraft out to give it a nudge so it doesn’t cross the Earth’s orbit when we are there.
What sort of nudges are we talking about? How would we deflect an asteroid?
Well you can just run into it with the spacecraft going at a high speed, using a kinetic impactor, as they’re called. Maybe detonate a nuclear weapon near it so that it causes some of the asteroid’s surface material to shoot off into space, to oblate. The Planetary Society sponsored a cool line of research where we’ve proposed building spacecraft with lasers on them. We’d then we have a swarm of our laser “bees” and they would beam laser light at the surface of an asteroid and cause the surface to burn off, to ablate a little bit. That momentum of that ejected stuff would give the asteroid a little push through space. I’ve always been charmed by that idea.
But whatever we do it’s almost certain to not require anything new. By that I mean new technology. It would be a whole new spacecraft with a whole new set of gizmos, but it would be made from the existing spacecraft technology and components.
What sort of investment would we be talking here to build one of these spacecraft?
I don’t know, but compare it to what a flagship mission cost. This would be something akin to Cassini, which flew for 20 years for four billion dollars. That’s not that much but, still, say it’s 10 times that. Compare that to the destruction of humankind. We should probably come up with the cash. And all the money is spent in space is really spent on Earth! Don’t forget that! There would be no aerospace contractors we presume involved and, as I like to say, space brings out the best in us. We solve problems that have never been solved before.
The Kick Asteroid! campaign is in part about raising awareness for asteroid threats, and to light a fire under lawmakers to fund some of these missions. What are lawmakers currently doing to mitigate the risk of asteroids and what they can do better and your better?
We can dedicate more resources for a more thorough search. We have the NEOWISE spacecraft (Near-Earth Object Wide-field Infared Survery Explorer) but we could use two or three more of those things. 10 percent of the asteroid population may end life as we know. That’s a lot of asteroids.
But you used the word mitigation and I’m all for it. I mean in Chelyabinsk it would have been good if there were some type of public warning, maybe like an AMBER Alert on your phone. “Stay away from the windows for the next three minutes!” Something like that. But better yet would be to not have to do that at all and just deflect every one of them.
This last question comes courtesy of our emerging tech editor: “Deep Impact” or “Armageddon”? Which film is more scientifically accurate when it comes to a potential asteroid impact?
The one where they didn’t blow up the asteroid is better. (Note: he means “Deep Impact” is better.) Blowing up an asteroid is problematic.
But, by the way, in one of them (He means “Deep Impact” again.) the premise was that a kid had seen an asteroid that no one else saw. Well, a lot of asteroids are identified by amateur astronomers. Amateur astronomers are different from amateur golfers, in that amateur astronomers genuinely contribute to the science of astronomy. This is real science done by regular people. The thing that amateur astronomers are able to contribute is what we call “tracking.” Somebody’ll find it and then all these hundreds or thousands of astronomers around the world train their telescopes to the same part of the sky to see if they get agreement on watching this thing move across the sky against the background stars, stars that are so fantastic that they don’t seem to move from our point of view.
So the Planetary Society supports amateur astronomers with we call the Shoemaker NEO grants, named after the famous astronomer who studied asteroids and comets. Every two years we give away grants to amateur astronomers to improve their equipment or their systems associated with their telescopes to track these objects.