"the young Earth was a hot, dry, desolate landscape interspersed with seas of magma and inhospitable for life. Even if some organism had somehow popped into existence, the old story went, surely it would soon have been extinguished in the firestorm of one of the giant meteorites that slammed into the Earth when the young solar system was still crowded with debris."
When Norman Sleep, a professor at Stanford, wrote an article in 1986 calculating the odds that life could have survived the impact of one those giant meteorites, it was rejected for publication because it was impossible. Nothing could have lived on the earth then.
Now, however, what was thought to be absolutely true just two decades ago has been shown to be wrong by new research and new discoveries. Instead, scientists now believe that
"by 4.2 billion years ago, the Earth was a pretty placid place, with both land and oceans. Instead of hellishly hot, it may have frozen over. Because the young Sun put out 30 percent less energy than it does today, temperatures on Earth might have been cold enough for parts of the surface to have been covered by expanses of ice."
Once again, we need to remember that some of what passes as today’s scientific truth will be tomorrow’s discarded theories.
--------------
Note: Thanks to James Taranto of "Best of the Web Today" for a pointer to this story.
Comments