Scientists are looking at ways to 'nudge' an asteroid if it was a threat to Earth, as blowing it up would only result in debris falling to Earth, they said.
Tonight an asteroid will approach Earth, passing closer than ever before.
Scientists have said it will be possible to see the asteroid as it flies past the Earth tonight.
It will appear as a faint dot of light, moving at a "steady rate" between the stars.
It'll be thousands of times fainter than Jupiter and 250 times fainter than the stars of the Plough.
The trick will be to find the area in advance and wait for it to come through. You can use the star maps to find exactly the right part of the sky. If you hold your binoculars steady you will see this tiny point of light crawling across your field of view in about seven or eight minutes.
It's not easy, but you will have the thrill of knowing you are seeing a little object in space the size of an office block.
– Robin Scagell, vice-president of the Society for Popular Astronomy
Asteroid will approach from 'underneath' the Earth
An asteroid will fly past the Earth tonight, entering the orbit of telecommunication and weather satellites.
The trajectory of the asteroid 2012 DA14 on 15th February 2013 Credit: NASA/JPL-Caltech
This image shows the asteroid's movements, looking down from above Earth's north pole.
Trajectory of asteroid 2012 DA14 during its close approach Credit: NASA/JPL-Caltech
This image shows why the asteroid will not be visible to the northern hemisphere's observers, until very close to the Earth, because it is approaching from "underneath" the planet.
An asteroid big enough to destroy London will narrowly miss the Earth as it flies past tonight, according to NASA.
The 150ft-wide rock has no chance of hitting the Earth scientists say, but it will enter the orbits of more than 100 telecommunication and weather satellites, just over 17,000 miles away from the planet.
The passage of asteroid 2012 DA14 through the Earth-moon system Credit: Reuters/NASA
It is thought it will reach its nearest point to Earth at 7.30pm (GMT) tonight.
The asteroid, 2012 DA14, was discovered by a spanish observatory a year ago.