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  • Astronomers have discovered thousands of planets orbiting stars other than the Sun.

  • They come in all sizes,

  • at different orbital distances from their stars.

  • The closest of them are trillions of miles away,

  • and even the largest are just fuzzy patches

  • in the fields of high-powered telescopes.

  • But if one of these planets is close in size to the Earth

  • and orbits not too close and too far away from its parent star,

  • it could be rocky and warm enough to have oceans

  • and perhaps life.

  • Astronomers discover these potentially habitable planets,

  • and their eyes get big and wide.

  • Could one of these distant worlds carry the building blocks of life?

  • Or even a living, breathing, civilization?

  • Is the question, "Are we alone in the universe?" about to be answered?

  • But wait.

  • Maybe we should ask a different question first.

  • Should we try to find out if we're alone in the universe?

  • If we do find the atmospheric fingerprints of life

  • on one of these small, distant worlds,

  • should we try to contact any beings who may live there?

  • Is that wise?

  • Three decades ago, NASA decided the answer was yes.

  • Voyager 1 and 2 were launched in 1977

  • to explore the giant planets in the solar system.

  • Each spacecraft carried a golden phonograph record,

  • a time capsule of sorts that included clues and messages

  • meant to convey the story of human civilization.

  • The contents of these gold-plated copper disks were chosen by a committee

  • chaired by American astronomer and author Carl Sagan.

  • They included over 100 images,

  • and a range of sounds from the natural world:

  • ocean waves,

  • thunder,

  • the sounds of birds

  • and whales.

  • The records also included music from many different time periods and cultures,

  • greetings in 55 languages,

  • and messages from the President of the United States,

  • and the UN Secretary General.

  • They also included a map.

  • Each golden record displays the location of our solar system

  • with respect to fourteen pulsars.

  • Their precise, unique frequencies were indicated

  • so that intelligent, extraterrestrial lifeforms

  • could use them to find the Earth.

  • Many years later, renowned physicist Stephen Hawking said

  • that it was a mistake to give an alien species a roadmap to our planet.

  • Hawking suspected that any extraterrestrial life

  • probably wasn't any more complex than microbes,

  • but he warned that if an advanced alien species did visit Earth,

  • it could be as catastrophic as Christopher Columbus's arrival was

  • for the Native Americans.

  • Meanwhile, the golden records continue their journeys.

  • In 1990, both Voyager spacecraft passed beyond the orbit of Pluto.

  • Voyager 1 entered interstellar space in 2012,

  • and will reach the nearest stellar system in 40,000 years.

  • If either spacecraft is discovered by extraterrestrial life,

  • there's a possibility that they could decipher the clues from the golden record

  • and one day reach our planet.

  • That's particularly true

  • if theirs is a much more technologically advanced civilization.

  • That life could be benevolent,

  • as we would hope to be if humans are one day able to achieve interstellar travel.

  • Or it could be hostile.

  • Searching for planets that might have life means staring into a great abyss.

  • We'll likely have no clear knowledge of the evolutionary stage,

  • sentience,

  • character,

  • or intentions of the first form of life we discover.

  • So it's a risk to turn our eyes outwards.

  • We risk our very way of life.

  • But it may be a greater risk not to look,

  • to deny the very pioneering spirits that help shape our own species.

  • We are all born curious about the world and the universe.

  • Pursuing that curiosity is one of humankind's greatest achievements.

  • Perhaps there is room to push the frontiers of science,

  • provided that we cradle alongside our fervor

  • Another of humankind's greatest assets:

  • hope.

Astronomers have discovered thousands of planets orbiting stars other than the Sun.

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B2 US TED-Ed voyager extraterrestrial life spacecraft golden

【TED-Ed】Should we be looking for life elsewhere in the universe? - Aomawa Shields

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    Jamie 榕 posted on 2016/07/27
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