It spreads around the Earth as a rock vapor cloud that eventually condenses and forms droplets that solidify into spherules, which rain back down onto the surface.

We're approaching the end of a fantastic voyage. This is the farthest anything from Earth has traveled and come back. Soon we'll be able to examine the building blocks that formed the solar system 4.6 billion years ago.

It would have taken only a second or two for a meteor that's 20 kilometers in diameter to pass through the ocean and impact the rock beneath.

It was horrifying to watch. The front of the house was totally engulfed by the time I got there.

When the meteor hits the surface, it instantaneously melts and vaporizes rock, and that rock vapor is sucked right back up the hole into the atmosphere,

The most advanced organisms at the time were bacteria, so there isn't a big extinction event you can identify as cut-and-dry as the extinction of the dinosaurs.