Source: Time
One of the hard facts of our solar system is that even with eight perfectly nice planets, Earth remains the only house on the block with its lights on—at least in terms of life. Mars, it’s increasingly clear, was once a warm, watery planet and had a shot at cooking up biology, but only until numerous environmental cataclysms turned it dry and cold.
Now, according to environmental models run by NASA’s Goddard Institute for Space Studies (GISS) and reported in Geophysical Research Letters, Venus coulda’ been a contender too. For up to two billion years, the investigators believe, our cosmic neighbor may have been an entirely hospitable place for life.
If Venus was indeed once habitable, you wouldn’t know to look at it today. Its surface temperatures climbs as high as 864º F (462º C) and its atmosphere—almost entirely carbon dioxide—is 90 times thicker than ours, leading to a runaway greenhouse effect. Yet Earth and Venus formed out of the same primordial cloud, are almost the exact same size and are located in at least a similar proximity to the sun. If we have liquid water it’s highly likely Venus once did too—a fact confirmed by American space probes which found chemical signatures of water in the Venusian atmosphere.
What’s more, Venus’s surface also features elevated land masses and comparatively shallow ocean basins like Earth does, meaning that water on the surface would have had places to pool. But Venus has problems too.
For starters, its greater proximity to the sun means it receives 40% more heat and light than Earth does. At first, that wasn’t a problem since the sun was 30% dimmer in the early days of the solar system, but its brightness—and heat—increased over time.
Worse, Venus’s rotation is exceedingly slow; a single Venusian day takes about 117 Earth days. Such a slow day-night cycle means a sort of permanent rotisserie spin, with the fires of the close-in sun broiling the planet slowly on all sides. Earth’s much speedier rotation never lets any one part of the planet get heated for too long.
Categories: Biology, Space Exploration, The Muslim Times