An asteroid thrice the size of the Taj Mahal will pass close to the earth on July 25. According to NASA’s database of Near-earth objects, the asteroid ‘2008 GO20,’ sized about 220 metres in diameter, will reach its closest approach to Earth at around 3 am on July 25 (Indian Standard Time).
The asteroid is to pass at a distance of 4.7 million kilometres from Earth. Despite its approach being 12 times the distance of the moon from the earth, the asteroid is being considered a near-earth object. “Near,” on the astronomical scale is still quite large from our daily lives’ perspective. Any asteroid or other small solar system body within a distance of 194 million kilometres from the earth is considered a near-earth object.
Though the asteroid is hoped to safely pass by the earth’s orbit, still NASA has flagged the space rock as a potentially hazardous object, given it is more than 150 metres in diameter and within a distance of 7.5 million kilometres. Potentially hazardous objects are closely observed by the space agency as they can be influenced by the gravitational tug of planets and can potentially change their orbit to collide with our planet. If a potentially hazardous asteroid hits the earth, it can cause significant damage.
Fortunately, NASA has developed a planetary defence system that is capable of diverting dangerous asteroids. In November, NASA is set to send a spacecraft on a Double Asteroid Redirection Test( DART) Mission, which will crash itself on a 780 metres sized asteroid Didymos’ moonlet with a speed of 6.6 kilometres per second. The crashing, which is expected to happen in October 2022, is supposed to provide a kinetic impact and deflect the asteroid from its orbit to the desired orbit away from earth.
If the DART mission becomes successful, it will enhance our security from extraterrestrial threats such as asteroids and other small solar system bodies. Having a robust planetary defence from asteroids is important because a large enough asteroid can wreak havoc if it collides with earth. About 66 million years ago, when an asteroid a few kilometres in diameter collided with earth wiping three-fourths of its entire life.