Earth Impacts II 
Two-and-a-half million years ago, a fireball worthy of a fire-breathing dragon slammed into the southeastern Pacific Ocean. It created a massive tsunami, and may have helped change Earth’s climate. It also smashed rocks at the bottom of the ocean, creating a structure known today as Eltanin. It’s named for a research ship, which in turn was named for the brightest star of Draco, the dragon, which is low in the northwest at nightfall.
Earth has been smashed by many asteroids and comets. All traces of most of those impacts have been erased by our dynamic planet. But a few remnants are still around. Most of the ones identified so far are on land, but a few are in the oceans.
Eltanin was identified as a possible impact structure more than 30 years ago. Rocks beneath the ocean floor show evidence of a powerful collision, and impact debris is scattered over a wide area.
The impact was with an asteroid that was a mile or two in diameter. Simulations show that it created giant tsunamis that slammed into South America, Antarctica, New Zealand, and Australia. The waves could have been hundreds of feet high.
Researchers in Australia have suggested that the impact could have hastened the start of the last major Ice Age. Earth was already cooling off by then. But the water vapor and other debris blasted into the atmosphere could have caused it to cool more dramatically — a cold era kick-started by a fiery collision.
More about cosmic collisions tomorrow.
Script by Damond Benningfield, Copyright 2013