This video was based on the series alien worlds on netflix i definitely recommend it giving it
a watch if you want 20 off your first three months of netflix sign up using a link in the
wait what's that netflix doesn't sponsor us
darn well we might not have a sponsorship but what we do have are planets tons of them
there are more than 400 billion planets in our galaxy and even if only one in a million were
habitable that would leave us with more than a million worlds teeming with life when we
search the cosmos for life we usually search for planets that look like earth after all if earth
can support life why couldn't a similar planet but not all planets look like earth just in our solar
system there are planets 20 times smaller and 100 times bigger and some far warmer and others far
colder with the diversity of planets it's worth asking what would life look like on alien worlds
5 000 light years away lies a ringed world more than double the size of earth with twice as much
gravity this is atlas how would life adapt to such a heavy world with twice the gravity trees can't
stand up tall like they do on earth and instead stay close to the surface but yet seeds can float
through the sky that's because gravity here is so strong air molecules are densely packed together
creating a thick buoyant atmosphere that allows seeds to drift across the planet and where there
are seeds there are sky grazers giant herbivores with wings that ride on the dense pillows of air
they're heavier than any bird on earth but the thick atmosphere and long wings keep them airborne
aided by the updrafts of wind across the planet's rugged features like albatrosses here on earth
they use these updrafts to conserve energy and can float without needing to flap their wings but
herbivores don't always have a peaceful life as on earth grazers attract predators using hydrogen to
produce bacteria to inflate their air sacs these predators can become lighter than the air and take
to the skies like hyenas hunting elephants here on earth these predators alone are no match for their
prey they're far too small so instead they hunt in a pack waiting for a skygrazer to stray from the
group when they found a target they expel their gas and attack from above landing on the grazer
the predators make their move deploying their cupped wings to create drag enough drag to pull
the sky grazer right out of the air but if a grazer can shake off these predators
they take to the skies there males compete for females males oversized tails are handicapped
making it harder to fly but to the females they're a sign of good genes these traits are an example
of sexual dimorphism if a male can support such an extravagant waste of biological energy they must
have strong genes genes that would be a deal for a mate we see these energy-intensive traits all
the time on earth from peacock's extravagant plumage to orangutan's cheek flaps to lion's
glorious manes all part of an effort to prove to picky females that you've got the good stuff
when the time comes for a female to lay her eggs she'll have to come down to land but because of
the increased gravity she's too heavy to launch herself back into the sky the only time one of
these herbivores will ever see the ground is at the start and end of their lives so to create new
life she has to give up her own when the babies eventually hatch they'll need to get off the
ground and into the air diving off the planet's rocky cliffs they can give just enough momentum
to take to the skies but they're not alone like 12 year olds in a call of duty lobby predators
lie trying to spawn camp boneless creatures with no skeleton to give them form kill by enveloping
and dissolving their prey the young sky grazers sit on the brink of the cliff right on the edge
of danger but they have no choice they have to fly even here we can find similarities to earth
barnacle geese protect their young from predators by nesting high on cliffs but this strategy has
a drawback to start their lives young geese must survive a harrowing fall usually hundreds of feet
as soon as 24 hours after hatching ghostlings need to leave the nest to feed on grass which their
parents won't feed them to get to the grass the birds must plummet from their high altitude nests
survival can be a game of chance but still life goes on from one generation to the next
at least for now the strong gravity of atlas pulls asteroids onto a collision course most
will burn up in the atmosphere but there is a constant threat that something big will get
through and reset the course of life on the planet if a big enough asteroid hits atlas
the sky grazers and predators would be doomed they're just too specialized to cope with change
the generalists are the boneless scavengers like crocodiles delete anything and live anywhere and
like our mammal ancestors after the fall of the dinosaurs in this imagined high gravity
world they could be the great survivors this is how these circumstances could give rise
to life on this imagined alien world but what would life look like under other circumstances
across the galaxy we find a red dwarf star the most common type of star in our galaxy
imagine a planet in such a close orbit that its rotation is locked by the star's gravity
so it always shows the same face to its sun like how we only ever see the same side of the moon
this is janus how would life adapt to such an extreme world on one side of the planet it's
always daytime a searing desert on the other side it's forever night a frozen shadow land
squeezed in between the two a sliver of perpetual twilight running water flows from the coal side
carving canyons through the landscape even here where the planet is most hospitable there's
little vegetation but deep in these canyons lives an extraordinary five-legged creature
a pentapod no bigger than a cat it's the dominant life form on janus capable of adapting to any
conditions masters of polyphenism when a single species can display multiple forms based on its
needs and surroundings we see polyphenism all across earth in an ant colony there are soldiers
workers in a queen an ant colony depends on the division of labor different castes have
different jobs and they come in all shapes and sizes we can see that even within the
same species ants can look wildly different but they all started from the same larvae
all ants in a colony are closely related they share most of the same genes but as they grow up
some genes are switched on and others are switched off all depending on the food they're fed this is
what makes ants so cool any of the ants could become a worker forger or soldier like ants
pentapods are able to develop into different forms on the coal side pentapods are stalking hairy on
the hot side they're shiny slender and skittish they become whatever they need to be to survive
with five legs pentapods can skitter in any direction and with 10 eyes nothing escapes their
sight if they sense a meal they use feelers to root it out and their venom to paralyze their prey
but hunting alone is risky sometimes the hunter can become the hunted even a venomous predator is
powerless against a swarm meanwhile on the cold side of the planet things are just as tough in
perpetual darkness and with no energy from the sun how can anything survive all life needs some form
of energy on the hot side of janus energy comes in the form of sunlight and on the cold face it comes
from deep within the planet as volcanic pressure forces water to the surface in geothermal events
here pentapods are after the grubs that gather around these geothermal pools
but hunting grubs isn't so easy the grubs have evolved to self-defense when frightened they
jump and flash a warning signal to the others working together to stay alive in life we often
see competitive arms races when two species are constantly forcing each other to evolve to survive
as crabs ate mollusks over time the mollusks evolved to have thicker shells which forced the
crabs to evolve more powerful claws over millennia both forced the other to get stronger and stronger
on janus the grubs evolve light to stay alive but over time life found a way life uh
finds a way and their system was hacked bioluminescence originally evolved among fireflies
as a warning to predators that they were packed with toxins and should be avoided at all costs
but today that same mechanism is used for finding a mate the firefly produces light from an organ on
its abdomen called a lantern male fireflies will fly around flashing their lights looking for a
mate the females are waiting on the ground below when they see a male they like they flash back
this means if your parents ever took you to watch fireflies in a field at night
you were basically peeping on a sex club but using light to communicate is inherently risky and some
species have evolved to create fake signals this is a predatory firefly we can tell it's
a different species by examining their lantern it has a different shape to it but to a male firefly
it's nearly identical so when a male flies by and flashes this predatory firefly flashes back
to get the male to come over but they don't want a mate they want a meal this is a classic example of
a predator using mimicry one species copying the behavior of another back here on janus
pentapods have mastered the art of mimicry by catching a few grubs the pentapods absorb their
bioluminescence and copy their warning signals the grubs instinctively jump away from flashing lights
but this time it's a trap the pentapods have them right where they want them again adaptability is
the secret to their survival despite light years between these planets life across the universe
needs the same basics to survive food and a reason to reproduce despite the vast differences
in life forms these common needs could result in some remarkable similarities across the cosmos
if you like this video and want to see a part 2 on what life would look like on two more imaginary
worlds be sure to let us know in the comment section below and remember there is always more to
learn
you