The pressure on Venus's surface is about 90 times that of Earth, equivalent to being deep in the ocean, making it ...

Perhaps all three could have been primed for life. But as Mars lost its atmosphere and Venus' atmosphere experienced a runaway greenhouse effect, only Earth could support life by the end.

Hansen—a climate scientist who’d turned his attention from studying the searing conditions on Venus to Earth’s human-changed atmosphere—concluded bluntly that “the greenhouse effect has ...