WASHINGTON -- Already 99.9 (and about 58 more 9s) percent of the universe -- it is expanding lickety-split -- is beyond Earth's atmosphere. Into what is it expanding? Hard to say. We can say there is lots of stuff in space: Hold up a penny at arm's length and you block from your field of vision three galaxies -- billions of stars and other things -- 350 million light-years away, which is right next door in our wee corner of the universe.
But there is much more space than there is stuff in space: If there were only three bees in America, the air would be more crowded with bees than space is with stars. But there is much stuff besides stars whizzing around, and 65 million years ago -- the day before yesterday on the calendar of the 14 billion-year-old universe -- big bits of stuff entered Earth's atmosphere traveling faster than a high-caliber rifle bullet.
One result was a 16,000-foot mountain, Bombay High, that has never been climbed because it is underwater off India's west coast. Another result was the "worldwide collapse of the climate and ecosystems" leading to the mass extinctions of the dinosaurs and two-thirds of marine animals, and the destruction of much of the planet's flora. So surmises Sankar Chatterjee of Texas Tech University.
"Catastrophism," the study of calamitous episodes in Earth's geological history, has long postulated a cosmic collision that resulted in sudden extinctions. There are "iridium anomalies" -- concentrations of that material that suggest extraterrestrial origins. There also is 10,000 times more carbon than normal in the geologic time zone 65 million years ago, a worldwide layer of soot from fires kindled by the impact of a gigantic asteroid.
A consensus developed that it created Mexico's 110-mile-wide Chicxulub crater. But Chatterjee says there is a crater, Shiva, more than 300 miles wide, off western India, probably formed by an asteroid or a part of one, 25 miles in diameter.