Keep calm! Giant asteroid to come closer than Moon but won’t hit us
Published 07/11/2011 | 10:27
A SPACE rock the size of an aircraft carrier will come closer to Earth than the Moon on Tuesday, but experts say there is no cause for alarm.
The 1,300ft wide rock, 2005 YU55, will miss by 201,700 miles. It may be visible to amateur astronomers with suitable equipment.
If 2005 YU55 hit Earth it would unleash a 4,000–megaton blast, many times the yield of the most powerful nuclear bomb. The impact could wipe out a city the size of London or New York. If it landed in the sea it would cause a 70ft high tsunami. But experts stress there is no chance of such a disaster happening because the asteroid's trajectory is well understood.
They calculate that it will approach to within 0.85 times the distance of the Moon from the Earth at 10.28pm GMT tomorrow.
Dr Robert Massey, of the British Royal Astronomical Society, said: ''Even when something of a reasonable size is that close to the Earth the fact that it's pretty hard to see tells you something about how little warning you have. But the distance between us and the asteroid is still many times the diameter of the Earth, so it doesn't present any risk to us at all. There really is nothing to worry about.''
Only a ''fairly violent'' force would be able to shift the object on to a collision course, he said.
However, he added: ''It does demonstrate that occasionally things do come very close. It's comforting to know that some of the work to identify these objects has been very successful.''
Nasa has set up its Near Earth Object Programme, known as ''Spaceguard'', to co-ordinate efforts to identify and track potentially hazardous space objects.
By the end of the decade, it aims to locate at least 90pc of an estimated 1,000 asteroids and comets larger than one kilometre in diameter.
Objects of this size are big enough to cause the mass extinction of most life on Earth. The asteroid believed to have wiped out the dinosaurs 65 million years ago measured seven kilometres across.
Observations made of 2005 YU55 last year show it to be roughly spherical in shape and slowly spinning.
Largely made of carbon, it has a surface darker than charcoal.
Amateur astronomers with telescopes having an aperture at least six inches wide stand a chance of catching a glimpse of the asteroid, according to Nasa.
But Dr Massey said spotting the object would be a challenge. ''It's 100 times fainter than anything the naked eye can see,'' he said.