A meteorite trail is seen above a residential apartment block in the Urals city of Chelyabinsk, on February 15. A heavy meteor shower rained down on central Russia, sowing panic as the hurtling space debris smashed windows and injured dozens of stunned locals, officials said.
By Erika Bolstad
Although the probability of a meteorite crashing in their backyards shouldn’t keep ordinary people up at night, scientists who study such matters are worried.
The meteor that streaked across the Russian sky on Friday startled scientists worldwide with its audacity, even as it triggered a window- and roof-rattling shockwave that injured more than 1,000 people in the city of Chelyabinsk.
Astronomers on February 15 had their eyes skyward on a separate object, the much larger asteroid known as 2012 DA14. It was coincidence that it came so close to Earth at the same time a meteoroid flamed into the atmosphere over Russia’s Ural Mountains, National Aeronautical and Space Administration (Nasa) scientists said.
Still, scientists are paying attention to the paths of future near-Earth objects.
One non-profit space research foundation plans an infrared telescope that will be able to detect more meteorites that have potential to inflict damage on world cities.
“This is public safety. We’re doing this because we believe it needs to be done,” said former Apollo astronaut Rusty Schweickart, the chairman emeritus of the B612 Foundation, a non-profit dedicated to protecting Earth from asteroids.
Its name comes from the children’s book by Antoine de Saint-Exupery. B612 is the asteroid home cared for by the Little Prince.
There is no surefire system to scan the skies for threatening asteroids, particularly ones that came in at the angle of the meteor over Russia. So in the near future, the best hope is better monitoring of the meteorites that, typically, orbit in a belt between Mars and Jupiter.
Science also has few options for knocking incoming asteroids off course, which was part of the early work done by the B612 Foundation. Scientists are researching how to avoid a major asteroid impact, but they have nothing workable yet.
Scientists, led by Nasa, track thousands of such near-Earth objects. They’re only a fraction of the asteroids in the solar system, however. There are about 500,000 near-Earth asteroids the size of 2012 DA14. Of those, less than 1% have been discovered, Nasa said.
Until 20 years ago, there was even less ability to track them — and Asteroid 2012 DA14 itself was discovered by amateur astronomers at the La Sagra Sky Survey operated by the Astronomical Observatory of Mallorca in Spain.
The gaps in knowledge are precisely why B612 was founded, Schweickart said. They have plans to deploy in 2018 an infrared space telescope; its purpose will be to discover asteroids that could do serious damage to Earth.
Their telescope still would be unable to capture asteroids the size of the one that entered the atmosphere near Chelyabinsk, Schweickart said. But it will capture many more of those the size of Asteroid 2012 DA14.
“The purpose is to discover most — we’re not going to get all — of the asteroids that are out there,” Schweickart said. “All of them are much bigger than the one that hit Russia. I’m not counting things that break glass, I’m talking about things that will wipe out cities or more.”
There’s little appetite in Congress right now to increase spending, but Friday’s double-whammy may have changed some minds.
“As the world leader in space exploration, America has made great progress for mankind,” the chairman of the Science, Space, and Technology Committee, Representative Lamar Smith, Republican-Texas, said in a statement. “But our work is not done. We should continue to study, research and explore space to better understand our universe and better protect our planet.”
It’s also a matter of national security, said Representative Rush Holt, Democrat-New Jersey, a physicist and the former assistant director of the Princeton Plasma Physics Laboratory.
He cited congressional testimony from 2002, when a meteor exploded over the Mediterranean at a time of particularly tense relations between India and Pakistan.
If the meteor had exploded over India or Pakistan, one military leader warned, it might have been misidentified as a nuclear attack.
“There should be some tens of millions [of dollars] in annual funding in order to meet the goal that Congress has set, which is to follow anything of significance in the asteroid/meteor category,” Holt said. “And we’re not doing anything close to that.”
And yet, Smith said in his statement, “Fifty years ago, we would have had no way of seeing an asteroid like this coming.”
Astronomers were giddy Friday as Nasa broadcast live from one of the best space-viewing points in the world, the Gingin Observatory near Perth, Australia.
“What an exciting day. It’s like a shooting gallery,” said Paul Chodas of Nasa’s Near-Earth Object programme at the Jet Propulsion Laboratory in California. “We have two rare events of near-objects approaching the Earth on the same day.”
The two objects had different trajectories, and the asteroid monitored worldwide on Friday was much larger — about the length of half a football field.
The asteroid was the closest known — or accurately predicted — object of its size to fly by Earth.
Unlike the Russian meteor, scientists were aware of it and accurately predicted that it would come closer than some weather and communication satellites but leave them unharmed. Those satellites orbit about 23,000 miles up; the meteorite came within about 17,000 miles from Earth.
There was never a risk the large asteroid would collide with Earth, but if one of its size were to hit here, “its crater would be larger than Monaco,” astrophysicist Neil deGrasse Tyson, host of the StarTalk radio programme, said Friday on Twitter.
Smaller meteorites crash to Earth daily — they can be seen as “shooting stars.” But most aren’t found, said Marc Fries, a research associate at Smithsonian’s Museum of Natural History. Many fall into the ocean, which covers 70% of the Earth. Or they enter the atmosphere in remote places where they go unseen.
Few are as dramatic or as big as the one caught on video in Russia. Thanks to the dashboard-mounted cameras that many Russians use to deter police corruption, the asteroid’s meteoric path was filmed from cars. — MCT
Laser system could
vaporise dangerous
asteroids, says group
By Amina Khan
Earth dodged a gigantic space bullet on Friday when the 143,000-tonne asteroid known as 2012 DA14 came within 17,200 miles of the Indian Ocean. Scientists and engineers are looking for ways to head off such close calls by targeting potentially dangerous asteroids well before they’re in a position to do us any harm.
A group called the B612 Foundation (a reference to the home asteroid of the Little Prince in the classic French novella) recently announced a mission to build a spacecraft that would track dangerous mid-size asteroids, and a fledgling company called Deep Space Industries has floated a plan to build swarms of robots that could mine — and even destroy — space rocks.
Now, two California scientists have a new proposal to deploy an array of lasers that could vaporise asteroids from as far away as 93mn miles — the distance between Earth and the sun. Working in synchrony, the lasers could destroy a menacing asteroid outright or at least knock it off course. They call their device Directed Energy Solar Targeting of Asteroids and exploRation, or DE-STAR for short.
Philip Lubin, a cosmologist at the University of California at Santa Barbara, and Gary Hughes, a statistician at California Polytechnic at San Luis Obispo, discussed their plan with the Los Angeles Times.
Why is it important to have a laser-shooting asteroid hunter?
GARY HUGHES: There is a realistic threat of a comet or an asteroid hitting the Earth and doing untold devastation to the world. I think we should be compelled to search for realistic ways to mitigate that threat. And so that’s exactly why Phil and I are so interested in this particular system.
PHILIP LUBIN: We’re trying to begin evaporating the asteroids when they’re on a collision course with Earth yet still sufficiently far away to not yet be a threat. So it’s sort of like a car coming at you, and you’re taking some evasive action. The evasive action we’re taking here is to vaporise it.
How would your device work?
LUBIN: You don’t blow up an asteroid like the Death Star in Star Wars, where you push a button and the planet explodes. You basically take a blowtorch to it in the form of a laser beam and you begin to evaporate it.
The evaporation can take place over time. In our case, it takes about a few months to evaporate an asteroid the size of a few hundred metres in diameter — which is an asteroid that, if it hit the Earth, would do severe damage. The one that killed the dinosaurs was about 10,000m in diameter, or about 6 miles.
How hot does an asteroid have to get to evaporate?
LUBIN: You have to raise the surface temperature up to above 3,000° Kelvin (or nearly 5,000°F). We can raise it to about 6,000° Kelvin, which is roughly the surface temperature of the sun. When you get up to such high temperatures, all the materials that we know about essentially evaporate. So if you point this thing to a piece of concrete, the concrete will simply vaporise.
A single laser can do that?
LUBIN: No. It’s not sufficient to simply have a lot of power in a light beam; because of the wave-like nature of light, light will diffract in such a way that the beam will spread out. You have to focus that power in order to raise the temperature to the point at which it basically begins to boil. In order to focus a light beam over large distances, you need a large, spatially extended structure.
Can it evaporate any asteroid?
LUBIN: What we’re proposing is to try to go after asteroids that are about up to 500m in diameter by direct evaporation. For asteroids that are larger than that, what we propose is to modify their orbit by forming a jet plume on the surface using the same technique: Raising the temperature, and then having that hot surface act as a rocket jet.
This sounds like science fiction. Is it possible with today’s technology?
LUBIN: This is not a system we can go out and build tomorrow. This is a system that’s sort of on the cusp of technology at this point.
What we’re proposing is to expand the existing technology. There will have to be some significant technology developments, but it doesn’t need any miracles.
How does your idea stack up against the competition?
HUGHES: Some of the initiatives that I’ve heard about are to go blasting the thing out of the sky with some sort of other weapon like a nuclear bomb, or deflect it with a bomb so that it misses the Earth. I think some of those may be viable, but I think they’re also difficult.
Are there other uses for this technology?
HUGHES: There’s a big idea about mining rare earth elements — they’re rare on Earth but enriched in things like asteroids. Everybody’s trying to find new sources of these elements for things like hybrid car batteries. So a lot of people are looking at asteroids for their economic potential for just that reason. Once you vaporise the surface of an asteroid with a laser, by analysing the absorption lines, we could tell exactly what that asteroid is made of.
LUBIN: The ability to destroy asteroids is one important aspect of what we’re doing, but it may not even be the most important aspect. We feel the same technology can be used to propel spacecraft into our solar system at much higher speeds than can be done with chemical propellants. We worked out the numbers and it looks like we might be able to propel a small robotic craft to Mars in a matter of a few days. — Los Angeles Times/MCT
