“Bringing an asteroid back to Earth? What’s that have to do with space exploration? If we were moving outward from there, and an asteroid is a good stopping point, then fine. But now it’s turned into a whole planetary defense exercise at the cost of our outward exploration.” -Buzz Aldrin
Between recent statements from NASA, the American Geophysical Union and Los Alamos National Laboratory, you might think that humanity is overdue for a catastrophic impact from outer space. Indeed, it’s been a long time since we’ve had one that was very destructive, and other than the 1908 Tunguska blast, we haven’t had one that even registered on the Torino Scale in millennia.
Meteor (Barringer) crater, in the Arizona desert, is over 1.1 km (0.7 mi) in diameter, and represents only a 3-10 MegaTon release of energy. A 300-400 meter asteroid strike would release 10-100 times the energy. Image credit: USGS/D. Roddy.
But the lack of recent events doesn’t mean that our odds of having one are increased in the near future. Quite to the contrary: they are likely a symptom of the fact that we’re living in an epoch where the odds of an impact are among the lowest they’ve ever been in human history. While the probability is still non-zero in any given year, and while space exploration and studying our Universe is of great importance, it isn’t to save our world from a killer rock from outer space.
Asteroids in the early Solar System were more numerous, and cratering was catastrophic. The rate has plummeted over the past 4.5 billion years. Image credit: NASA / GSFC, BENNU’S JOURNEY – Heavy Bombardment.
from ScienceBlogs http://ift.tt/2gL4Ctx
“Bringing an asteroid back to Earth? What’s that have to do with space exploration? If we were moving outward from there, and an asteroid is a good stopping point, then fine. But now it’s turned into a whole planetary defense exercise at the cost of our outward exploration.” -Buzz Aldrin
Between recent statements from NASA, the American Geophysical Union and Los Alamos National Laboratory, you might think that humanity is overdue for a catastrophic impact from outer space. Indeed, it’s been a long time since we’ve had one that was very destructive, and other than the 1908 Tunguska blast, we haven’t had one that even registered on the Torino Scale in millennia.
Meteor (Barringer) crater, in the Arizona desert, is over 1.1 km (0.7 mi) in diameter, and represents only a 3-10 MegaTon release of energy. A 300-400 meter asteroid strike would release 10-100 times the energy. Image credit: USGS/D. Roddy.
But the lack of recent events doesn’t mean that our odds of having one are increased in the near future. Quite to the contrary: they are likely a symptom of the fact that we’re living in an epoch where the odds of an impact are among the lowest they’ve ever been in human history. While the probability is still non-zero in any given year, and while space exploration and studying our Universe is of great importance, it isn’t to save our world from a killer rock from outer space.
Asteroids in the early Solar System were more numerous, and cratering was catastrophic. The rate has plummeted over the past 4.5 billion years. Image credit: NASA / GSFC, BENNU’S JOURNEY – Heavy Bombardment.
from ScienceBlogs http://ift.tt/2gL4Ctx
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