Asteroid 2012 DA14 in record-breaking Earth pass

16 February Daily Tselegraph, BBC

An asteroid as large as an Olympic swimming pool has raced past the Earth at a distance of just 27,700km (17,200mi) the closest ever predicted for an object of that size.It passed far closer even than the geosynchronous satellites that orbit the Earth, but there was no risk of impacts or collisions.Its closest approach was at 19:25 GMT.For regions in darkness, it should remain visible until about midnight through good binoculars or a telescope.

The asteroid's arrival was preceded by a damaging meteor event in Russia on Friday but indications from the meteor's path suggest that the two events are entirely unrelated - just a “cosmic coincidence”, as Alan Fitzsimmons of Queens University Belfast told BBC News.

The asteroid orbits the Sun in 368 days a period similar to Earth's year but it does not orbit in the same plane as the Earth.As it passes at 7.8km/s (17,450 mi/hr) it will come from “under” the Earth and return back toward the Sun from “above”.

It passed directly over the eastern Indian Ocean, making for the best viewing in Eastern Europe, Asia and Australia.But keen viewers everywhere used several live streams of the event on the internet, including a feed from the Jet Propulsion Laboratory at Nasa.2012 DA14 was first spotted in February 2012 by astronomers at the La Sagra Sky Survey in Spain - once a fairly small-scale, amateur effort to discover and track asteroids that has in recent years become a significant contributor to our knowledge of these “near-Earth objects”.

They caught sight of the asteroid after its last pass, at a far greater distance.rom their observations, they were able to calculate the asteroid's future and past paths and predict Friday's near-miss which will be the closest the object comes for at least 30 years.Prof Fitzsimmons said that it is a scientific opportunity not to be missed.

“When asteroids come this close, it's very important to try to learn about them - it's become so bright, so it's so easy to study,” he told BBC News.We get an additional insight into these small objects, which are the most likely impactors on Earth.

The notion that it is these smaller, tens-to-hundreds of metres-sized objects that pose the greatest potential threat to Earth is explored in the BBC feature article Can we know about every asteroid? .The asteroid will only be visible from some regions on Earth. Click through these maps produced by Dr Geert Barentsen, of the University of Hertfordshire, to see when the asteroid should be visible in different areas:

The asteroid due to zoom past Earth later this week could be worth £125 billion ($195bn) - if only it was on a different orbit, according to a space company.Asteroid 2012 DA14 is likely to contain a variety of valuable resources including metals such as iron and nickel, and water which can be used in space as rocket fuel.

But because the space rock's trajectory is tilted away from Earth, the cost of sending a probe to mine it would be too high to make such a pursuit worthwhile, experts said.

Asteroids are seen by some space companies as a valuable future resource which could supply fuel for interplanetary missions and provide metals to help build and repair satellites.

Water can be broken down into hydrogen and oxygen - two key components of rocket fuel - while metals could be used to engineer new or replacement parts for space equipment. Using these materials in space would reduce the need for companies to launch fuel, water and building materials into orbit, a process which currently costs £6.5 million ($10m) per tonne.

Deep Space Industries, a US firm which hopes to pioneer asteroid mining, calculated that if just five per cent of the estimated amount of water on 2012 DA14 were retrieved, it could be worth up to £42 billion ($65bn).If 10 per cent of the rock consisted of metals which could easily be recovered they could be worth another £84 billion ($130bn), the company added.The estimates were based on a presumed weight for the asteroid of about 130,000 tonnes, although experts admitted it could weigh as little as 16,000 tonnes or as much as one million tonnes.

David Gump, chief executive of the company, said: “Even with conservative estimates of the potential value of any given asteroid, if we begin to utilize them in space they are all the equivalent of a space oasis for refueling and resupply.”

Asteroid 2012 DA14 is unsuitable for mining because its orbit around the Sun is more inclined than Earth's, meaning it would take a vast amount of energy to reach it, but DSI said there could be thousands more which would be easier to “chase down”.

The company last month announced plans to send a fleet of probes to examine asteroids passing Earth in 2015, before launching a mission to return a sample to Earth within the next decade.Chairman Rick Tumlinson said: “The challenge right now is to get out there soon so we can inspect and sample them. Whether for mining, science or planetary defence, we really need to begin getting close up and personal with these objects.