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  • Somewhere out there in that vast universe

  • there must surely be countless other planets teeming with life,

  • but why don't we see any evidence of it?

  • Well, this is the famous question asked by Enrico Fermi in 1950:

  • "Where is everybody?"

  • Conspiracy theorists claim that UFOs are visiting all the time

  • and the reports are just being covered up,

  • but honestly, they aren't very convincing.

  • But that leaves a real riddle.

  • In the past year, the Kepler space observatory has found

  • hundreds of planets just around nearby stars,

  • and if you extrapolate that data,

  • it looks like there could be half a trillions planets

  • just in our own galaxy.

  • If any one in 10,000 has conditions

  • that might support a form of life, that's still

  • 50 million possible life-harboring planets

  • right here in the Milky Way.

  • So here's the riddle.

  • Our Earth didn't form until about 9 billion years after the Big Bang.

  • Countless other planets in our galaxy

  • should have formed earlier and given life a chance to get underway

  • billions, or certainly many millions, of years

  • earlier than happened on Earth.

  • If just a few of them had spawned intelligent life

  • and started creating technologies,

  • those technologies would have had millions of years

  • to grow in complexity and power.

  • On Earth,

  • we've seen how dramatically

  • technology can accelerate in just 100 years.

  • In millions of years, an intelligent alien civilization

  • could easily have spread out across the galaxy,

  • perhaps creating giant energy-harvesting artifacts

  • or fleets of colonizing spaceships

  • or glorious works of art that fill the night sky.

  • At the very least, you'd think they'd be revealing their presence,

  • deliberately or otherwise,

  • through electromagnetic signals

  • of one kind or another. And yet we see no convincing evidence of any of it.

  • Why?

  • Well, there are numerous possible answers,

  • some of them quite dark.

  • Maybe a single, super-intelligent civilization

  • has indeed taken over the galaxy,

  • and has imposed strict radio silence

  • because it's paranoid of any potential competitors.

  • It's just sitting there ready to obliterate

  • anything that becomes a threat.

  • Or maybe they're not that intelligent,

  • or perhaps the evolution of an intelligence

  • capable of creating sophisticated technology

  • is far rarer than we've assumed.

  • After all, it's only happened once on Earth in 4 billion years.

  • Maybe even that was incredibly lucky.

  • Maybe we are the first such civilization in our galaxy.

  • Or perhaps civilization carries with it

  • the seeds of its own destruction

  • through the inability to control the technologies it creates.

  • But there are numerous more hopeful answers.

  • I mean, for a start, we're not looking that hard. And we're spending a pitiful amount of money on it.

  • Only a tiny fraction of the stars in our galaxy

  • have really been looked at closely for signs of interesting signals.

  • And perhaps we're not looking the right way.

  • Maybe as civilizations develop,

  • they quickly discover communication technologies

  • far more sophisticated and useful than electromagnetic waves.

  • Maybe all the action takes place

  • inside the mysterious recently discovered dark matter,

  • or dark energy, that appear to account for most of the universe's mass.

  • Or maybe we're looking at the wrong scale.

  • Perhaps intelligent civilizations come to realize

  • that life is ultimately just complex patterns of information

  • interacting with each other in a beautiful way,

  • and that that can happen more efficiently at a small scale.

  • So, just as on Earth clunky stereo systems

  • have shrunk to beautiful, tiny iPods, maybe intelligent life itself,

  • in order to reduce its footprint on the environment,

  • has turned itself microscopic,

  • so the Solar System might be teeming with aliens, and we're just not noticing them.

  • Maybe the very ideas in our heads are a form of alien life.

  • Well, okay, that's a crazy thought.

  • The aliens made me say it.

  • But it is cool that ideas do seem to have a life all of their own

  • and that they outlive their creators.

  • Maybe biological life is just a passing phase.

  • Well, within the next 15 years,

  • we could start seeing real spectroscopic information

  • from promising nearby planets that will reveal just how life-ready they might be.

  • And meanwhile SETI, the Search for Extra-Terrestrial Intelligence,

  • is now releasing its data to the public

  • so that millions of citizen scientists, maybe including you,

  • can bring the power of the crowd to join the search.

  • And here on Earth, amazing experiments are being done

  • to try to create life from scratch,

  • life that might be very different from the DNA forms we know.

  • All of this will help us understand

  • whether the universe is teeming with life

  • or whether, indeed, it's just us.

  • Either answer, in its own way,

  • is awe-inspiring,

  • because even if we are alone,

  • the fact that we think and dream and ask these questions

  • might yet turn out to be one of the most important facts about the universe.

  • And I have one more piece of good news for you.

  • The quest for knowledge and understanding never gets dull.

  • It doesn't. It's actually the opposite. The more you know,

  • the more amazing the world seems.

  • And it's the crazy possibilities, the unanswered questions,

  • that pull us forward. So stay curious.

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B1 TED-Ed galaxy intelligent life teeming civilization

【TED-Ed】Why can't we see evidence of alien life? - Chris Anderson

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    VoiceTube posted on 2013/03/23
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