Where are all the aliens? | Stephen Webb

The universe is incredibly old, astoundingly vast and populated by trillions of planets -- so where are all the aliens? Astronomer Stephen Webb has an explanation: we're alone in the universe. In a mind-expanding talk, he spells out the remarkable barriers a planet would need to clear in order to host an extraterrestrial civilization -- and makes a case for the beauty of our potential cosmic loneliness. "The silence of the universe is shouting, 'We're the creatures who got lucky,'" Webb says.

The TED Talks channel features the best talks and performances from the TED Conference, where the world's leading thinkers and doers give the talk of their lives in 18 minutes (or less). Look for talks on Technology, Entertainment and Design -- plus science, business, global issues, the arts and more.

[AllThingsAndrew]

Me: I should probably go to sleep it’s like 3 am.

Brain: WHERE are all the ALIENS?!

[malcolmdale]

Arthur C. Clarke — 'Two possibilities exist: either we are alone in the Universe or we are not. Both are equally terrifying.'

[Mikeb]

the universe is so large finding Earth is like finding a small diamond that fell off your ring while at the beach- but not knowing which beach

[TaterChip]

When he said, "I think we are alone" that totally caught me off guard. Did not expect that at all.

[twisted]

When aliens fly by our planet they roll up their windows and avoid eye contact.

[eternalreign]

Humans have been broadcasting radio waves for about 100 years, so our furthest signal is about 100 light years away. If the universe (~93 billion light years across) were the size of the pacific ocean (~11, 000 km across), then our furthest radio waves have reached about 12 millimeters. But we can't even observe our nearest star in any detail and that's only 4 light years away (~half a millimeter). On this scale the Milky Way galaxy is about 12 meters across and Pluto would be about 75, 000th of a millimeter away.

So it'll be about another 90k years before our signal reaches the edge of just our own galaxy, and then double that to receive a response. A civilization could have started much sooner than ours and have been broadcasting a lot sooner as well, but depending on how far away it is, it could take 1000's of years to respond, so we might as well be alone. A conversation with Mars could take up to 20 minutes for a response, so I couldn't imagine how excruciating it would be to try to have a conversation with someone 10k light years away lol.

[ChairmanMeow]

Ive always thought we're alone for many of these same reasons. I never found it depressing either, I found myself feeling incredibly lucky.

[SocialEXperimented]

Earth might be one of a kind gift from the universe. There are no word in our vocabulary to define how precious it is.

[Nautilus]

Tyson said it best. Humans take a glass of water from the ocean and say "There are no whales in the ocean!"

[unknownentity]

i am 20 and i just wish that atleast before i die, i get to see a real proof of intelligent aliens.i just dont wanna die knowing that we dont share this incredible universe with any other intelligent being.

[sam_asare]

THIS GUY IS AN ALIEN TRYING TO DEFLECT HIS EXISTENCE IN OUR MINDS! 😂

[Penpaper]

Scientists: where are all the aliens??
Aliens: dude we’re literally buzzing your navy ships

[michaelbannerman-roberts]

If aliens are anything like us then lets hope there aren't any.

[Burrick]

Where are all the aliens?
Alien places, probably doing alien things.

[firemusic]

This gentleman speaks for about 13 minutes and doesn’t say “umm” even once. That’s more impressive than the possibility of aliens.

[MrTorn]

I love this idea...that we are possibly the first civilization that will in time ( a long time) visit other planets and lend a hand overcoming the barriers those younger life forms face...we have a lot of growing up to do here in the meantime...

[high_visions]

Nobody:

Me: looks up aliens on YouTube @ 4am

[ccole]

"In any YouTube discussion of aliens, two possibilities exist: either someone will cite Arthur C Clarke's "alone in the universe" quote within the first 20 comments, or within the first 50 comments... both are equally annoying"
-me

[brandonwilson]

I never hear scientists explain how time might be a crucial factor. Considering we've only been around for a short time, isn't it possible other intelligent life could have existed during before multi-cell species on Earth existed? Or maybe after we're gone? I'm not sure if these theories and their equations take time into account.

[SP-sldj]

I don’t think that in the entire universe the conditions required for life is exactly the same as here. I think there will be all sorts of outcomes on different planets that we would never understand.