Our Planet's Leaky Atmosphere

Photo: Loss of certain gases, especially hydrogen, has transformed Earth. It is one of the reasons that oxygen built up in the atmosphere. In the future, the depletion of hydrogen will dry out our oceans and all but shut down geologic cycles that stabilize the climate. Life may still be able to hold out in the polar regions. Earth past: 3 billion years ago (left) Earth present (center) Earth future: 3 billion years from now (right) Alfred T. Kamajian

From Scientific American:

As Earth's air slowly trickles away into space, will our planet come to look like Venus?

Key Concepts

* Many of the gases that make up Earth’s atmosphere and those of the other planets are slowly leaking into space. Hot gases, especially light ones, evaporate away; chemical reactions and particle collisions eject atoms and molecules; and asteroids and comets occasionally blast out chunks of atmosphere.
* This leakage explains many of the solar system’s mysteries. For instance, Mars is red because its water vapor got broken down into hydrogen and oxygen, the hydrogen drifted away, and the surplus oxygen oxidized—in essence, rusted—the rocks. A similar process on Venus let carbon dioxide build up into a thick ocean of air; ironically, Venus’s huge atmosphere is the result of the loss of gases.

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