A huge asteroid collision created so much dust it started the world's first ice age - Don Davis, Southwest Research In

Around half-a-billion years ago, a 93-mile wide asteroid broke up between Jupiter and Mars sending a vast dust cloud into the Solar System, blocking sunlight and plunging Earth into a lengthy ice age.

Now scientists have suggested that a similar man-made event could protect us from run-away global warming.

The plan would involve towing or pushing an asteroid to a Lagrange point in space, where gravitational forces even out to provide a static ‘parking spot’.

The asteroid could then be drilled into, or blown up, to create an ‘anchored dust cloud’ shielding Earth from the Sun.

It might seem extreme, but governments across the world are already looking for ways to deflect or explode asteroids in the event of an incoming space rock, so it may soon be possible to carry out astro-engineering.

View photos

New research from scientists at Lund University in Sweden and Chicago’s Field Museum shows that creating a dust cloud would definitely have the desired goal of significantly cooling the climate, because it has happened before.

Around 466 million years ago the seas started to ice over and the planet began to freeze. But the cause of this first major ice age has always proved a mystery.

The team discovered huge amounts of dust from asteroids buried in the geological record from the time period, suggesting that the falling temperatures were linked to space debris blocking out sunlight.

“Normally, Earth gains about 40,000 tons of extraterrestrial material every year,” said Dr Philipp Heck, a curator at the Field Museum, associate professor at the University of Chicago, and one of the paper's authors.

“Imagine multiplying that by a factor of a thousand or ten thousand.”

View photos A 466-million-year-old fossil meteorite, created in the same asteroid collision that caused the dust that led to an ice age. Credit: Field Museum /John Weinstein More

The cloud cooled temperatures to such an extent that seas the climate changed from being more or less homogeneous to becoming divided into the zones we known today - from Arctic conditions at the poles, to tropical conditions at the equator.

The newly diversified climate triggered an explosion of species known as the Great Ordovician Biodiversification Event (GOBE), and the dust created by the asteroid was so great that it is still responsible for a third of meteorites which fall on Earth today.

"It is analogous to standing the middle of your living room and smashing a vacuum cleaner bag, only at a much larger scale", said Dr Birger Schmitz, professor of geology at Lund University and the leader of the study.

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