Ask Me Everything7

Are we alone?

We just don’t know. We know that lite exists on Earth, but what about elsewhere in the universe?

Most astronomers believe in extraterrestrial lite —we just haven’t found it yet. Ali Earth’s living things are madę out of Chemical elements found throughout the universe, so it would be extraordinary if some form of life hadn’t developed elsewhere.

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Recipe for life

Many scientists think that extraterrestrial life will be similar in origin to Earth’s. Here, life started in biochemical reactions in water at around 68° F (20°C). The Chemical elements needed are:

#    Carbon

#    Hydrogen

#    Oxygen

#    Nitrogen

#    Sulfur

#    Phosphorus

#    Tracę amounts of 12 or so other elements

Earth

This is the only place we know that life exists, with 1.5 million distinct types of life discovered so far.

Mars

Microscopic life may have developed 'tu. here when Mars ■f was young. So far no signs of life have been found.

Europa

This moon of Jupiter has an icy surface. Bk Underneath it is ■ a liquid water wĘf ocean that may i m¥ be a haven for life.

WHATS ANAME?

The organized search for signals from space is called SETI (Search for ExtraTerrestrial Intelligence). It analyzes radio signals, looking for signs of alien communication.

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Messages from Earth

Launched in 1972, Pioneer 10 was the

*    first spacecraft set on a course that would l tat<e it out of the solar system. A plaque on board indicates where it has come from and explains how to get in touch in case intelligent life should find the craft.

The first deliberate radio message

*    intended for extraterrestrials was sent in 1974. The Arecibo radio telescope in Puerto Rico transmitted a three-minute radio message toward the star cluster M13. It will arrive in around 25,000 years’ time.

The farthest artificial body from Earth

*    is Voyager 1, which launched in 1977.

It ćarried a gold-plated disk of sounds and images of life on Earth. It will be 40,000 years before it approaches another planetary system.

What about me?

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