The Earth will dodge a cosmic bullet this week when a 50-meter wide asteroid skims past our planet. The flyby, by a space rock labelled 2012 DA14, is the closest near-miss ever predicted in advance for an object so large.
The asteroid will come so close on Friday, 15 February, that it flies 27,650 kilometers (17,150 miles) above the Earth, coming between us and TV and communications satellites in their high, geosynchronous orbits.
The asteroid’s path will carry it from the far southern part of the sky past the constellation of Crux, the Southern Cross, through Virgo and into the Plough.
It will give stargazers in the UK and across Europe a treat by becoming visible in binoculars as it races across the sky against the starry background at 7.82 kilometers (4.8 miles) per second.
Robin Scagell, vice president of the UK’s Society for Popular Astronomy, said: “It will be quite tricky to see because you will need to know the sky quite well so that you look at the right spot. But it’ll be a unique chance to see such a close asteroid. I’ve never witnessed anything like it in many years of skywatching.”
Robin has produced a useful guide for the Society for Popular Astronomy on how to observe the close approach. The asteroid was discovered in February last year by the La Sagra Sky Survey in Spain.
The National Radio Astronomy Observatory in the US and NASA space telescopes will closely monitor the asteroid during its flyby to check its spin. This will help them calculate its orbit better for the future.
If asteroid DA14 were to hit a city it could cause devastation because the energy from its speed is converted into a huge explosion on impact, blasting a crater much bigger than the rock itself. However, there is absolutely no danger of an impact. NASA experts have precisely calculated DA14’s orbit to show it will not hit Earth.
An asteroid of a similar size blasted the famous Barringer Meteor Crater out of the ground in Arizona around 50,000 years ago. Another similar-sized but more crumbly object exploded in the air over a remote region of Tunguska, Siberia, in 1908, flattening forests for hundreds of square miles around.
The event is a timely reminder that Solar System can be like a cosmic shooting gallery. Most of the hundreds of thousands of asteroids circle the Sun between the orbits of the planets Mars and Jupiter.
But more than a thousand are known which cross the Earth’s orbit. Nearly 900 of these so-called Potentially Hazardous Objects are around 500 ft wide, which is big enough to destroy a city or cause a tsunami if it hit the sea.
Near-Earth asteroids like this one are of interest to the new space mining companies, Planetary Resources and Deep Space Industries. DA144 itself, which is thought to have a mass of around 130,000 metric tons, is in too steep an orbit for these prospectors to chase. Otherwise its minerals that could provide water, rocket fuel and precious metals could be worth up to $195 billion.