extraterrestrial life: Quick Facts

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Planet TOI 700e

Diagram of a tree leaf illustrating photosynthesis, with arrows showing sunlight, water, and carbon dioxide entering the leaf and sugars and oxygen being produced. A person is shown beside the tree to demonstrate the exchange of oxygen and carbon dioxide between plants and animals.

Multiple tall telecommunications towers with red lights stand on a hilltop at dusk in Phoenix, Arizona, silhouetted against a darkening sky.

Saturn: surface of Titan

Diagram showing Mars's orbit around the Sun with four positions illustrating its axial tilt of 24.9 degrees and the resulting Martian seasons: northern winter and summer, northern spring and fall, and their southern hemisphere counterparts. The orbit highlights points nearest and farthest from the Sun, with arrows indicating the direction of revolution.

Mars as seen by Hubble Space Telescope compared with an 1894 map of Mars

the possibility of life on Mars

Know about the icy surface of Jupiter's moon Europa and the possibility of life beneath it

Examine the speculation of the presence on Mars of life that originated on Earth and, alternatively, life on Earth that originated on Mars

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Topics

panspermia extraterrestrial intelligence Kardashev scale alien The Fermi Paradox: Where Are All the Aliens?Fermi paradox Drake equation science fiction UFO group extraterrestrial hypothesis last universal common ancestor evolution cell Metabolism heredity death Biology coloration photosynthesis Sex

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Key People

Carl Sagan

Carl Sagan

American astronomer

Learn about Niels Bohr and the difference of opinion between Bohr and Albert Einstein on quantum mechanics

Paul Davies

British physicist and astrobiologist

Freeman Dyson

Freeman Dyson

American physicist

Percival Lowell

Percival Lowell

American astronomer