UN takes new measures to stop Earth being struck by deadly asteroids

The United Nations has founded the 'International Asteroid Warning Group' to enable countries to share information about potential threats from outer space.

Astronauts and astrophysicists alike came together last week to warn of the scale of the danger that asteroids currently pose to the Earth, in a panel discussion at the American Museum of National History in New York.

“Asteroid impacts have dramatically altered the course of life on Earth and a rogue asteroid will certainly
strike Earth, posing a global threat to human life and society,” astronaut Tom Jones stated in his opening remarks."

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Scientists estimate that there are roughly 1 million near-Earth asteroids that could potentially pose a threat to the planet, but only a small fraction of these have actually been detected by telescopes. "There are about 100 times more asteroids lurking in space than have ever been located", said Edward Lu, a former NASA astronaut and co-founder of the non-profit B612 Foundation advocating asteroid defense strategies. "Our challenge is to find these asteroids first, before they find us," he added.

In February, an asteroid the size of a truck exploded above Chelyabinsk, in Siberia, injuring more than 1000 people. It exploded with a force of 440,000 kilotons - nearly 30 times the energy released by the atomic bomb detonated in Hiroshima in 1945. It was completely undetected by scientists.

Search efforts to date have discovered just 1% of potentially hazardous near-Earth objects such as the Chelyabinsk meteor. As well as enabling UN member states to alert each other to dangers they have identified, the agreement reached on Friday called for scientists to go further in detecting potentially harmful near-Earth objects (NEOs).

The Association of Space Explorers (ASE) called for the UN and individual countries to allocate the necessary funds to detect all of the 1million NEOs that currently pose a threat to the Earth, using a space telescope, by 2020.

Construction on such a telescope is already underway. Former NASA astronaut Edward Lu is the chairman and CEO of the B612 Foundation, a non-profit organisation that last year unveiled the Sentinel Initiative, which plans to launch an infrared space telescope by 2018 to survey NEOs bigger than 40m across.

Scientists are already good at tracking asteroids that might destroy the planet - with 10,000 NEOs already tracked and logged by astronomers around the world, accounting for 90% of such threats. But tracking anything smaller than 1km across is more difficult.

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Lu and the other astronauts from the ASE also called upon NASA to conduct a trial mission to alter the course of an asteroid, to prove that it can be done. The so-called 'international deflection demonstration' would entail altering the course of a small asteroid.

"The question is, which way do you move [the asteroid]?" former NASA astronaut and B612 co-founder Russell Schweickart said in the news conference. "If something goes wrong in the middle of the deflection, you have now caused havoc in some other nation that was not at risk. And, therefore, this decision of what to do, how to do it and what systems to use have to be coordinated internationally. That's why we took this to the United Nations."

Various methods for 'deflecting' a large asteroid have been proposed, including nuclear explosions, pushing the asteroid off its path or using a so-called 'gravity tractor' - a body larger than the asteroid which can exert a gravitational pull over the asteroid over a lengthy period of time to tug it out of a collision.

Other potential technologies that have been suggested include attaching an engine or a solar sail to the asteroid to propel or steer it onto a different course.