Last Friday a relatively small asteroid passed within 9000 miles of earth, and only 15 hours after it was actually discovered. Now 9000 miles would seem like a rather large distance, but in astronomical terms that's an extremely close call. Consider the moon averages around 250,000 miles in distance from earth. It passed so close that the trajectory of the asteroids path was actually changed by earth's gravity.
Scientists fairly quickly determined that this small asteroid would miss us. Even if the small ball of rock came right for us it wasn't big enough to cause major catastrophic damage.
It does serve as a reminder that the possibility of something hitting earth, and one much bigger is certainly a possibility. The 15 hour detection time really wouldn't have allowed anyone to prepare or do anything about this had it been on a collision course anyway. Part of the reason for only 15 hours of detection time was due to the tiny size of this particular asteroid. Had it been bigger there should have been more warning.
It does prove just how unprepared we are at finding and dealing with objects in space heading for earth.
Will there be another? Absolutely! When? Nobody knows for certain, and with the lack of searching and monitoring it could really happen any time. The good news is the odds are very slim that one big enough to cause catastrophic damage will happen in our lifetime.
