Are We Alone? | How the Universe Works

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the universe is a very big place

there are trillions of galaxies each one

home to millions of stars and an

unimaginable number of planets so where

is everybody one of the most basic

philosophical questions is are we alone

are we the only ones looking out and

thinking what is all this is it all just

for us or do we get to share it with

anyone I mean that's about as

fundamental a question as you get what

are the odds of life existing somewhere

else we just don't have a good insight

how probable life is anywhere at the

universe life could possibly be forming

everywhere we we don't quite know

there's a lot about life that we don't

understand all we know is that it

happened at least once but beyond this

one little planet we don't know whether

or not it happened anywhere else

the universe is an unfriendly place

planets with lava oceans circle too

close to their stars pulsars blaze with

deadly gamma rays and x-rays black holes

consume everything in their path

temperatures plummets close to absolute

zero it may seem impossible for life to

survive in such hostile environments but

here on earth life exists against the

odds in some very strange places life is

actually permeated every part of our

planet there are places where you're

like how did you even get there

at first glance a beautiful lake might

seem like a good place for life but

California's Salton Sea is no paradise

the toxic salt waters are killer

surrounded by scorched desert and

volcanic geothermal fields

it's a deadly environment

one of the last places on earth you'd

expect to find life would be in boiling

mud fence start to hear these vents

because there's gas and there's water

and mud slurry that's coming out right

here so these are active volcanoes but

life is resilient finding a home even

here inside volcanic vents in the

California desert we're in the middle of

a really hot desert and as the mud comes

up it's coming up hot and gets kind of

acid and yet there can be microbes in

environments like this happily thriving

away this is an environment that is

actually conducive to life even though I

think it might not be almost every inch

of the Earth's surface is teeming with

microscopic life-forms the thing about

life on Earth is that it's exists in so

many different environments under such

harsh extreme conditions it's like it

hangs on no matter what you throw at it

very dry high pressure very hot even in

high radiation environments which would

kill a human within seconds

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life even survives being bombed with

asteroids and meteorites

we have a wonderful indirect example of

just how tenacious life is and that's

the fact that it survived the late heavy

bombardment the late heavy bombardment

was a violence assault on young earth

where life had just gotten the foothold

experts think around four billion years

ago asteroids comets and space debris

rained down on the inner solar system

this rocky barrage would have melted

parts of the Earth's crust and boiled

away oceans it was a violent time called

the Hadean period the Hadean named off

to hades named off the underworld off to

hell it was a brutally unpleasant place

to be whispering its own in its sound

surface and this intense cycle of hot

volcanism

if life on earth overcame these hellish

conditions then perhaps life can survive

anywhere I think if it can happen on

earth I think it can happen on other

planets I think life finds a way and I

think we need to go looking for it the

question is what exactly are we looking

for

what is life you know that seems like a

simple question but it's not that easy

to answer life is incredibly hard to

define right it's sort of like you know

it when you see it but how do you write

down the rules every time we think we

have a grasp there's this new form that

comes about and completely questions

that entire definition as a joke in

astrobiology if you ask 200 scientists

for a definition of life you'll get 200

different answers life can be as

intricate as us humans or as simple as

single-celled organisms like bacteria

but there are some things all life-forms

do in broad terms life consumes things

it breathes it eats it excretes it grows

it reproduces it's complex

life has transformed the earth in all

sorts of ways but life is still just an

accident

life as I see it it's just a chemical

reaction but it's the most important and

special chemical reaction in the

universe if life is just a product of

chemistry then what are the odds of it's

starting anywhere in the universe one

thing we know about chemistry is that

given the right conditions the same

chemical reaction will reliably occur

it's like a game of chance for life to

win the conditions need to be just right

but to figure out the odds we need to

understand what those conditions are and

how common they are so it comes down to

a numbers game it's about statistics and

probabilities and likelihoods it's like

having to roll a 6 for each condition

for life

but how many sixes would you need how

many precise conditions does life

require to get going you might have a

hundred dice roll them all get all sixes

only then do their life you could need

hundreds or hundreds of thousands of

dice

we just don't know we honestly have no

clue how common or rare life is in the

universe we don't know how life

originated here on earth where we kind

of understand the conditions there are a

lot of different ways life could have

started his life rare is life common we

don't know where it lands

putting odds on life existing is a waste

of time until we understand it better

and maybe our answers don't lie here on

earth

one way to crack this problem is to go

looking for life elsewhere if we can

find other examples of life we can

immediately begin to put a quantitative

answer to how probable it is for life to

happen anyway and the best place to look

for life might be in our own backyard

Mars if life can start here that maybe

life could conquer the universe

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