So, assuming Apophis with a diameter of about 350 metres is really headed for a collision with Earth in 2068, when will we take notice and do anything? Will humankind just metaphorically kick the can down the road and hope someone else sorts it out?
Even though it wouldn't be an ELE, a collision with a body as large as Apophis would likely result in the deaths of a substantial portion of mankind. Its kinetic energy would be the equivalent of about two thousand one-megaton bombs. On land, an impact would throw a huge amount of debris into the upper atmosphere, blocking sunlight for many months and causing widespread crop failure. In the ocean, it would create a destructive megatsunami that could devastate or destroy many countries.
Even though it wouldn't be an ELE, a collision with a body as large as Apophis would likely result in the deaths of a substantial portion of mankind. Its kinetic energy would be the equivalent of about two thousand one-megaton bombs. On land, an impact would throw a huge amount of debris into the upper atmosphere, blocking sunlight for many months and causing widespread crop failure. In the ocean, it would create a destructive megatsunami that could devastate or destroy many countries.
Last edited: