Looking for Life's garbage



This picture shows NASA's Deep Space Network, which searches the sky for radio signals.
Click on image for full size version (48K GIF)
Image from: JPL/NASA
Most forms of life leave evidence behind that they are there. Plants use up carbon dioxide and release oxygen. Some bacteria are known to release nitrogen into the environment. People leave behind smog, radio signals, and garbage.

Io, Titan, and perhaps Triton, show some of the waste products of life, including molecules of oxygen, nitrogen, or the more sophisticated hydrocarbons such as Polycyclic-Aromatic-Hydrocarbons (PAH's). These constituents are not present in the environments of most planets and moons.

This means that there is no evidence that sophisticated creatures are present.




Looking for Life's Garbage



This picture shows NASA's Deep Space Network, which searches the sky for radio signals.
Click on image for full size version (48K GIF)
Image from: JPL/NASA
Most forms of life leave behind evidence that they are there. Plants help make oxygen and use up carbon dioxide. Some creatures help make nitrogen. People leave behind smog, television signals, and garbage.

Scientists find life by looking for the things that creatures leave behind. Io, Titan, and maybe Triton show some of the things that creatures make, including molecules of oxygen and nitrogen.

Most planets and moons do not have the common garbage which life forms leave behind. This means that life does not seem to live there.




Looking for Life's Garbage



This picture shows NASA's Deep Space Network, which searches the sky for radio signals.
Click on image for full size version (48K GIF)
Image from: JPL/NASA
Most forms of life leave behind signs that they are there. Plants help make oxygen and some creatures help make nitrogen. People leave behind smog, television signals, and garbage.

Scientists find life by looking for the things that creatures leave behind. Io, Titan, and maybe Triton, seem to include the things that creatures make.

Most planets and moons do not have signs that life has lived there, which means that they are probably lifeless.





Last modified November 18, 1996 by the Windows Team

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