![]() "Astronomers estimate there are tens of thousands of near-Earth asteroids close to 500ft (150m) wide and larger, big enough to cause regional devastation if they actually hit Earth. When it burned up in the atmosphere and exploded it briefly outshone the sun and the heat from the blast inflicted severe burns on observers below, as well as smashing windows and rattling buildings.Īccording to Johns Hopkins Applied Physics Laboratory, the Chelyabinsk meteor created "an airburst and shockwave that struck six cities across the country - and a stark reminder that dangerous objects can enter Earth's atmosphere at any time". That asteroid is believed to have been roughly 20 metres in size and was completely undetected before it entered the atmosphere, in part because it approached Earth from the direction of the sun - meaning it reflected no light to telescopes on Earth revealing its approach. Subscribe to the Daily podcast on Apple Podcasts, Google Podcasts, Spotify, Spreaker ![]() Listen to "Mars missions and space exploration - bang for our buck?". Never mind deflecting an asteroid off-course, hours wouldn't even offer enough time to evacuate a town.īut astronomers hope and expect that new technologies and monitoring systems will improve our ability to make these predictions in the future - giving us more time - and the DART mission is just the first step in us proving that there is something we can do about it when we know something is coming. This timeline offers much less wriggle-room than the five years between the DART mission getting approval at NASA and its scheduled rendezvous with Dimorphos next year. There have been more than 1,200 impacts of asteroids larger than a metre in size since 1988 and of those impacts humanity has only predicted five in advance - less than 0.42% - and even those predictions came with just hours to spare. Humanity's ability to detect asteroids before they impact the planet is still in its infancy, in part because of limits set by the laws of physics - our ability to survey asteroids in the dark of space in our solar system depends on them reflecting light towards us, and that depends on direction of their approach relative to the sun and the phase of the moon. Moment of spacecraft's 'successful deployment' ![]()
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