Space

13,000 lethal near-Earth asteroids, and what the White House plans to do about them

13,000 lethal near-Earth aster...
Artist's impression of a large meteor impact
Artist's impression of a large meteor impact
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Small asteroids that disintegrated in the atmosphere between 1994-2013
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Small asteroids that disintegrated in the atmosphere between 1994-2013
Some of the 80 million-odd trees knocked over by the mighty Tunguska event, which flattened a 2,000 square kilometer area of Russian forest
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Some of the 80 million-odd trees knocked over by the mighty Tunguska event, which flattened a 2,000 square kilometer area of Russian forest
This chart shows the orbits of known, potentially dangerous asteroids with orbits that bring them in close proximity to Earth. The outer ring is Jupiter's orbit. This gives you a sense of the scale of the problem, as it represents a small percentage of what's out there.
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This chart shows the orbits of known, potentially dangerous asteroids with orbits that bring them in close proximity to Earth. The outer ring is Jupiter's orbit. This gives you a sense of the scale of the problem, as it represents a small percentage of what's out there.
Artist's impression of a large meteor impact
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Artist's impression of a large meteor impact
Artist's impression of a large meteor impact
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Artist's impression of a large meteor impact

The Earth is regularly peppered with small, harmless asteroid impacts, but there's an estimated 13,000 giant asteroids, most of which we can't find yet, that could potentially release cataclysmic destruction on the planet. Here's how the White House plans to locate, track, and deflect or destroy them.

Space is a vast, mainly empty expanse, but ours is most certainly not the only giant rock hurtling through it. Earth's orbit frequently crosses paths with asteroids of various sizes – NASA tracked some 556 atmospheric fireballs caused by meteorites between 1 and 20 meters in diameter over a 19-year period between 1994 and 2013.

Small asteroids that disintegrated in the atmosphere between 1994-2013
Small asteroids that disintegrated in the atmosphere between 1994-2013

These were all harmless enough, and indeed the vast majority of near-Earth objects, or NEOs, that enter our atmosphere are small enough to burn up in the atmosphere without causing any problems. But there are plenty of bigger, faster and denser space rocks out there.

Take a look at this incredible compilation of videos of what a single asteroid 20 meters across can do when it hits our atmosphere. The 2013 Chelyabinsk meteor exploded about 30 kilometers above the Earth's surface like a 500-kiloton bomb, releasing nearly 30 times more energy than the Hiroshima atom bomb over a small Russian city. It hospitalized 1,500 people, a remarkably small toll.

Back in 1903, the famous Tunguska impact happened, again over Russia although thankfully in a sparsely populated area. A meteor somewhere over 60 meters wide detonated over a forested area, flattening 80 million trees across some 2,000 square miles of forest. The blast shock, it's estimated, would have measured 5.0 on the Richter scale.

Some of the 80 million-odd trees knocked over by the mighty Tunguska event, which flattened a 2,000 square kilometer area of Russian forest
Some of the 80 million-odd trees knocked over by the mighty Tunguska event, which flattened a 2,000 square kilometer area of Russian forest

And in relative terms, those two were babies. In the last 10,000 years, we've been hit by at least 8 asteroids that left impact craters more than 100 meters across, including one in Argentina with a 4.5 kilometer diameter.

If you're prepared to go back millions of years, you start finding confirmed impact craters 300 kilometers across. There's some evidence suggesting there's a 600-kilometer wide crater in Australia's Northern territory, and dozens upon dozens of craters more than 20 kilometers wide. These things would have rained utter destruction on everything beneath them, unleashing power many times beyond the scope of the world's entire nuclear arsenal and causing enormous climate and ecological shifts, including mass extinctions and giant glacial melts.

Large meteors will hit Earth again. It's only a matter of time. And while we may have a few technological ideas on how to deflect a big space rock away before it hits us, we still don't have anywhere near a comprehensive set of information about the Near Earth Objects we stand a chance of being hit by.

Cataloguing and tracking these things is no small task. As of December 2016, we know for sure of some 15,342 NEOs between 1 meter and 32 kilometers in diameter. The current estimate is that there are about a thousand out there larger than a kilometer wide, and about 13,000 that are more than 140 meters across – real killers, each with their own speed, direction and orbits through the galaxy.

After two decades of searching, only about 28 percent of the estimated total number of NEOs bigger than 140 meters across have been found and tracked. That's far short of the 90 percent that US Congress directed NASA to get a handle on by 2020, and it leaves a global blind spot of more than 9,000 potential extinction-level threats that we could potentially do something about if we gave ourselves enough warning.

To give you a sense of the scale of the problem, here's a NASA chart showing the orbits of currently known, potentially dangerous asteroids with orbits that bring them close to Earth. The outer ring is Jupiter, and this chart only represents the small percentage of these objects we're currently able to track.

This chart shows the orbits of known, potentially dangerous asteroids with orbits that bring them in close proximity to Earth. The outer ring is Jupiter's orbit. This gives you a sense of the scale of the problem, as it represents a small percentage of what's out there.
This chart shows the orbits of known, potentially dangerous asteroids with orbits that bring them in close proximity to Earth. The outer ring is Jupiter's orbit. This gives you a sense of the scale of the problem, as it represents a small percentage of what's out there.

In December 2016, the US White House released its National NEO Preparedness Strategy, a curt 19-page document showing that it understands the problematic potential of NEOs and is working toward addressing it, albeit at the speed of politics.

It details seven strategic goals:

  1. Enhance NEO detection and tracking capabilities.
  2. Develop methods for deflecting or disrupting incoming asteroids.
  3. Improve modeling and predictions capabilities.
  4. Develop emergency procedures for NEO impact scenarios.
  5. Establish impact response and recovery procedures.
  6. Leverage and support international co-operation.
  7. Establish co-ordination and communication protocols and thresholds for taking action.

Certainly the most urgent aspects would appear to be the first two. In this regard the paper suggests one way to greatly speed up the detection, tracking and categorization of the missing NEOs would be to build a space-based observatory – an exciting possibility for astronomers in and of itself.
In terms of dealing with imminent asteroid collisions, the paper suggests starting out with a fast-response reconnaisance craft that could send back critical information on an approaching NEO's composition, mass and structure to help with decision-making on what the next step should be.

At this point, assuming we've got the time to act, the next step would be to decide whether to try to deflect it, using a "kinetic impactor" that could use fast gravity slingshots and orbital transfers to build up speed and knock the thing off course like a pool ball. This would require very precise aim, as well as high-acceleration maneuvering capability to make sure of a direct hit on a very small, fast-moving target.

For bigger objects or ones that are detected with little time to spare, a "disruption" technique might be the best hope of disaster mitigation. This is an effort to break the asteroid into smaller pieces that might do less harm when they hit.

Either of these ideas will require gigantic amounts of energy, as well as a huge planning, construction and co-ordination effort.

This is obviously a tricky problem in terms of funding. The potential consequences of a decent sized asteroid hit are enormous ... just ask the dinosaurs, who, it's believed, were wiped out by a 10-kilometer wide rock impact that, according to a report by NPR, briefly made the Earth's surface act like a liquid, flinging up a "splash" of rock from as much as six miles below the surface.

On the other hand, the chances of it happening in a given political term are very low. So it's good to know the folks in charge are at least taking this sort of thing seriously.

Source: Whitehouse.gov

11 comments
VincentWolf
We have more to fear from politics than from asteroids.
BobKropp
Sure, in the outgoing Obama Whitehouse. The Scientifically Challenged Trump 'Lights-On-Nobody-Home' whitehouse will scrap it at the advise of Mike 'Teach-The-Bible-In-Science-Class' Pence who gleefully anticipates and welcomes planet wide destruction as the biblical 'End of Times.'
MarylandUSA
Why is this a White House problem alone? Like global warming, an existential threat like an asteroid calls for all able countries to meet the challenge together.
habakak
Laughable. I guess we have to plan. But people watch too much scifi and overestimate our abilities. I've heard so many stories of people watching 'The Martian' asking or commenting that it was based on a true story! The best we have is hope. For now. Eventually we will be able to build a fast-response and effective system for early detection and mitigation, but it will not be in the near term. There are events we just can't protect ourselves from. Like volcanoes, earthquakes, hell, even regular old floods or tornadoes. NEO are simply in a totally different ball-game. It's like a cave-man thinking he has a stick to kill animals and now he can possibly go to the moon. He had to wait a few millenia for the tech to roll in. We will just be vulnerable in the mean time.
ljaques
Mentioned are "glacial ice melts" and the Mexico meteor/dinosaurs, but nothing at all was mentioned about the global winter caused by the "splash" of rock going into the atmosphere. THAT is what killed the dinosaurs. Cooling, not warming. I'd hate to see us sling massive chunks of nickel iron at a meteor, miss, and allow it to go kill some other planet in another galaxy. Vince is right that global politics might end us before either could happen. We need a space-based transmogrifier which will convert the rocks to feathers so they can be caught in space. Then we can transmogrify them into nickel iron for use in building our intergalactic space ships. And then I woke up.
Nairda
No attenuation in space. Maybe a space based nuclear powered laser could be used to superheat ice on on side of the asteroid causing a localized jet to cause it to go off original track.
Mzungu_Mkubwa
But we've got Bruce Willis and Nukes! 'Murica! Yeah!
oldguy
This Just In From Our Commander In Chief. Big rock just landed on one of my golf courses, wiping out Scotland. Losing money while we rebuild. SAD
Bob Flint
Twitter will be ablaze........
keith14
Simple really just get hold of Bear Grylls and he will knock them out of the Earths atmosphere!