The so called "parent" of the dinosaur killing asteroid, which presumably struckd Earth 65 million years ago creating the 180 kilometer wide Chicxulub crater, was a mammoth asteroid called Baptistina. 160 million years ago, Baptistina, approximately 170 kilometers in diameter, was struck by a different asteroid (that was at least 60 kilometers in diameter). As a result of the collision, the two huge asteroids disintegrated into hundreds of †"small" asteroids (each more than 10 kilometers in diameter) and about 140,000 smaller asteroids (each over 1 kilometer in diameter). This new information was derived both by analysis of material from the Chicxulub crater and from new computer simulations performed by a joint U.S.-Czech team from the Southwest Research Institute (SwRI) and the Charles University in Prague.
According to the simulations, about 20% of the multi-kilometer-sized asteroids drifted away from the asteroid belt crossing path with Earth. About 2 percent of these asteroid belt refugees hit Earth, while a smaller fraction of them struck the Moon. The researchers speculate that it is possible that a large asteroid fragment from this collision created the 85-kilometer Tycho crater on the Moon approx. 108 million years ago, while a larger asteroid fragment hit Earth creating the Chicxulub crater.†
Possible evidence for the team's recent findings can be seen in the impact history of the Earth and the Moon, both of which show evidence of a two-fold increase in the formation rate of large craters over the last 100 to 150 million years.
TFOT recently covered several space related stories including the possible discovery of planets with 4 suns using NASA's Spitzer Space Telescope, First Water on an Extrasolar Planet and a star with a tail of dust 13 light-years long.†
More information on the U.S. and Czech research can be found on the SwRI website.