Some interesting and somewhat backwater research has shown strong evidence that massive impacts happen much more often then common wisdom suggests. Scientists have used large land formations called chevrons that may be caused by massive tsunami--600 feet tall, in fact--to find underwater craters. Several of these craters have been dated within the last 20,000 years. This doesn't match with the observed evidence of stellar objects, but it is fascinating to think that impacts may be far more common than we think.

But that's okay...I'm not going to live that long anyway...