Though asteroids are small, rocky objects that orbit the Sun, they can bring tsunamis, shock waves and flattening winds that could be catastrophic and we are well aware of that. The space rocks approach towards the Earth due to the gravitational forces that affect them. It is said that one day, all life on Earth will extinct and an asteroid could be the possible reason. Shocked to hear that? Well, about 66 million years ago, a gigantic asteroid (space rock) collided with Earth, creating an explosion over 6,500 times more powerful than the nuclear bomb the US dropped on Hiroshima. The impact sent clouds of debris and sulphur into Earth's atmosphere, blocking the sun's light and warmth for about two years. Photosynthesis ground to a halt, which meant no more plant growth and due to which surviving dinosaurs starved to extinction. It is worth mentioning here that a car-sized asteroid slams into the Earth's atmosphere about once in a year. On the other hand, an asteroid large enough to threaten the existence of life on Earth arrives once in every few million years. According to a report published by spacetelescope.org, there are more than 7 lakh asteroids that have been found in space. Of these 7 lakh asteroids, four asteroids that could strike the Earth are identified as Asteroid 101955 Bennu, Asteroid 2014 JO25, Asteroid 2014 AG5 and Asteroid Apophis.
Asteroid 2014 JO25 – Year 2027
Size - 650 Metres in diameter
Probability of hitting Earth - 1/8300
2014 JO25 is a near-Earth asteroid. It was discovered in May 2014. 2014 JO25 belongs to the Apollo asteroids, which cross the orbit of Earth. Apollos are the largest group of near-Earth objects with nearly 10 thousand known members. It is also a potentially hazardous asteroid due to its sufficiently large size and it’s Earth-MOID of less than 0.05 AU.
Asteroid 2014 AG5 – Year 2040
Size - 140 Metres in diameter
Probability of hitting Earth - 1/625
Asteroid 2014 AG5 is a sub-kilometer asteroid, classified as near-Earth object and potentially hazardous asteroid of the Apollo group. It was removed from the Sentry Risk Table on December 21, 2012 and as such it now has a rating of 0 on the Torino Scale. 2011 AG5 was discovered on 8 January 2011.
Asteroid Apophis – Year 2068
Size - 370 Metres in diameter
Probability of hitting Earth - 1/1,50,000
99942 Apophis was discovered on June 19, 2004. Apophis's surface composition probably matches that of LL chondrites. On April 12, 2068 the odds of impact are 1 in 1,50,000 in large part because the line of variation (LOV) extends over 840 million km.
Asteroid 101955 Bennu – Year 2182
Size - 560 Metres in diameter
Probability of hitting Earth - 1000/1
Asteroid Bennu is a carbonaceous asteroid in the Apollo group discovered by the LINEAR Project on 11 September 1999. It has a mean diameter of approximately 492 metre (the size of the Empire State building) and is expected to collide with our planet in 2182. The gigantic asteroid has an estimated weight of 79 billion kilograms has been observed extensively with the Arecibo Observatory planetary radar and the Goldstone Deep Space Network.
Earlier, the US space agency had the plans to deflect this asteroid using the planetary defence weapon. However, several experts believe that the space agency will not succeed in deviating the collision course of Bennu due to its gigantic size and weight.
Although probability is less, if any of these four asteroids strike the Earth then humans may extinct from the Earth. It is really unfortunate that so far we do not have any weapon to destroy those asteroids, neither we have any other means to save ourselves.