Yes, because it’s happened before. Science has identified 20 times during which earthly life has faced a “mass extinction event” caused by a natural phenomena. On some occasions over 90 percent of the life forms on the planet was wiped out.
Extinction of one life form to make room for the next is the way life has evolved on Earth. For instance, the dinosaurs’ extinction made possible the emergence and eventual domination of mammals . . . none of which is all that comforting if yours is the species facing extermination.
-- Does the fact it happened in the past mean it will happen again?
Absolutely – because many threats are cyclical in nature: Asteroid strikes, rise of poisonous atmospheric gases such as methane, geological upheavals such as super-volcanic detonations, ice ages and other radical climate changes are all events that occur in cycles.
It’s been said that life is a circle – and in many respects the universe operates that way. A good example of that is the near-miss asteroid on March 3, 2009. This chunk of speeding space rock was the size of the one that destroyed 800 square miles of Siberian forest in the early 1900s. This one swept “darn close,” as a JPL scientist put it. If it had hit a major metro area like New York or L.A., millions would have died.
The most frightening thing is that we only had about two days notice when it suddenly appeared closer to earth (about 48,000 miles) then most of our satellites . . . and it is coming back for another shot at us.
Five years ago a major asteroid missed the earth by only 4,000 miles, and we had only 19 hours warning.
In 2036 a massive planet-killing asteroid is estimated to have 1 in 5500 in hitting us. Given the scope and duration of its orbit, that impact is “too close to call.”
In 2013 the US will have a chance to approach the asteroid and attach a transponder to it, after which we could monitor its 2036 approach with scientific precision. We would have to begin that mission immediately, which no one is doing. The US seems indifferent to a potential extinction event 27 years from now.
Something even bigger could be coming at us and we are unable to spot it because space objects are tracked as they race across the line of sight – ones that come directly at us are not seen until they are almost on top of us.