Did you know that NASA is going to send a spacecraft on a suicide mission in an attempt to change the trajectory of a massive space rock? The good news is that the space rock that NASA will be crashing this spacecraft into is not on a collision course with Earth. It is only a test. But why has NASA suddenly become so concerned with figuring out how to defend the Earth from giant asteroids? Could it be possible that there is something heading toward Earth in the future that they haven’t told us about yet?
Of course there is something heading toward Earth in the future. The Earth is struck by thousands of small bodies every day.
The interesting question is whether they’d tell us about a big new one they’d just found.
Would they want to start a global panic?
They might not know until it arrives. Nobody saw the 20 metre Chelyabinsk rock before it arrived on 15 February 2013. It came from out of the morning sun at 9:30 local time (03:20 UTC).
It would have been equally invisible if it had been heading toward the Sun, a dark body in the night sky. Many comets behave this way, only becoming visible when heated by the Sun to outgas water.
The only way they could launch rockets to hit it would have been if they’d had several days notice if its arrival.
Assuming that the asteroid is moving in the orbital plane of the Earth, high latitude impacts will tend to be grazing impacts like Chelyabinsk 2013 and Tunguska 1908. But impacts near the equator are more likely to be direct impacts, as Chicxulub in Yucatan. And equatorial impacts are more likely than near-polar impacts
Since 70% of the Earth’s surface is ocean, chances are that any impact would create a tsunami radiating from the impact point.
Islands would be in greatest danger from a tsunami: nowhere to run. Examples include Japan, Hawaii, Caribbean, Iceland. A tsunami striking Britain would likely hit the south coast. It would also hit southern and western Ireland. Low-lying coastal regions would be in greatest danger.
Oddly enough, China is also planning to fire rockets at approaching asteroids.
Perhaps they do know something we don’t know.