Sharp-shooting scientists hit comet

A hole was blasted out of the side of a comet today as US scientists showed off their sharp-shooting skills 133 million miles from Earth.

A hole was blasted out of the side of a comet today as US scientists showed off their sharp-shooting skills 133 million miles from Earth.

The spectacle that followed the deliberate crashing of a probe into comet Tempel 1 outclassed any of the firework celebrations the Americans were enjoying today on Independence Day.

Yesterday, scientists in charge of the Deep Impact mission released an 820-pound copper and aluminium missile the size of a washing machine into the path of the comet, which was hurtling through space at 23,000mph.

At about 6.52am, Irish time, today the two collided.

Images beamed back to earth from the mother craft showed a blinding flash of white light as a plume of icy debris exploded out from the bottom of the potato-shaped object.

The aim was to blow away a chunk of the comet’s surface so scientists could observe and analyse what lay beneath.

The information is expected to provide clues to the origins of the solar system, and possibly life on Earth, never obtained before.

Material within comets has remained unchanged since the solar system was formed 4.6 billion years ago.

Scientists think the “dirty snowballs” filled the Earth’s early oceans with water and deposited complex organic molecules that may have helped to trigger life.

Mission controllers at the American space agency Nasa’s Jet Propulsion Laboratory in Pasadena, California, clapped, cheered and hugged each other when the impactor struck.

“What a way to kick off America’s Independence Day,” said project manager Rick Grammier.

Andy Dantzler, director of Nasa’s Solar System Division, added: “This mission is truly a smashing success. Tomorrow and in the days ahead we will know a lot more about the origins of our solar system.”

Hitting the Tempel 1 “bullseye” was an incredible technical achievement which involved targeting a fast-moving object less than 3.7 miles wide from a distance of 537,000 miles.

British scientists watching via a special live link in London were also jubilant.

More images of the event were obtained from Earth-based telescopes, including ones operated by British astronomers in Hawaii, Australia and the Canary Islands.

Children at King’s School, Canterbury, were given a once-in-a-lifetime chance to view the impact using the Faulkes robot telescope at Maui, Hawaii, and process the raw data.

In fact they beat astronomers around the world by obtaining the first ground telescope images of the collision.

The blast, equivalent to the energy released by 4.8 tonnes of TNT, was so bright that scientists expect it to be visible to the naked eye from Earth.

Just after sunset it should appear as a faint new star low in the south-west, to the left of the planet Jupiter.

Dr Andrew Coates, from the Mullard Space Laboratory at University College London, said: “This is one of the most audacious experiments that’s been undertaken ever.

“It’s a fantastic day for cometary exploration. In terms of historical events, this is the first large-scale experiment since Apollo on a solar system object.”

Colleague Professor Iwan Williams, from Queen Mary, London University, said: “What we’ve seen so far is absolutely fantastic.

“It’s obviously very, very big – much bigger than any of us expected the plume to be. Much more material has been thrown out than we expected.”

Scientists do not yet know what damage the impactor has inflicted on the comet.

The crater left by the smash could be as small as a house or as large as a football stadium.

Much depends on the comet’s composition. Early indications are that the comet’s outer crust is surprisingly frail.

Scientists have compared the event to a “mosquito hitting a 747 passenger jet”.

They say there is no risk of Tempel 1 being deflected and endangering the Earth. But data from the mission may help scientists work out ways to stop a comet that really does pose a threat.

Monica Grady, Professor of Planetary and Space Sciences at the Open University, said one of the most exciting episodes in the mission was the view from a camera on the impactor of the comet looming closer and closer.

“We saw some really amazing images,” she said. “OK, it was a grey, fuzzy blob, but you could see there were craters on the surface, and that’s absolutely fantastic. We had no real idea of what the surface would look like.”

Professor Keith Mason, director of the Mullard Space Science Laboratory, said: “Never before have we penetrated the nucleus of a comet. The resulting data should provide us with the most comprehensive set of scientific measurements ever obtained of a comet – unprecedented information on the genesis of our solar system.”

Deep Impact was launched on January 13 from Cape Canaveral, Florida, and has travelled a distance of 268 million miles.

A European Space Agency spacecraft, Rosetta, is now on a 10 year voyage to another comet, Churyumov-Gerasimenko. It will aim to land a probe there in 2014.

Rosetta is now using its instruments to monitor the Deep Impact event.

Prof Williams, who is one of the Rosetta scientists, said: “At a distance of some 50 million miles from Tempel 1, Rosetta will be in the most privileged position to observe the event from space.”

Tempel 1, which is about half the size of Manhattan Island in New York, was first spotted in 1867 by the German astronomer Ernst Wilhelm Tempel from an observatory in Marseilles, France.

It orbits the Sun every five and a half years. Like other comets, Tempel 1 is made of ice and dust.

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