उपशीर्षक (168)
0:00Can we survive the heat death of the universe?
0:04One day, the last star will die, galaxies
will dissolve and black holes will evaporate.
0:10The cosmos will become a forever expanding,
empty void where nothing happens. Forever.
0:16A place without life, purpose, or meaning.
0:23But there might be a loophole in the laws of physics
for a future civilization to survive the death of everything.
0:31And go on having fun and internet arguments
for googols of years, maybe even forever.
0:37To explain how this works we
need to go through a few steps,
0:40so strap in if you want
consciousness to live forever.
0:44How to Outlast the Stars
0:46Let’s travel 100 trillion years into the
future, when the last stars are about to die
0:51and the cosmos starts turning dark forever.
0:54Here, in this dying universe we find the
Noxans, the last civilization still alive.
1:01Compared to them we are cave dwellers, they have
solved physics and can do things we can only dream of.
1:08Still, the same rules of reality apply to them as to us.
1:12The Noxans like being alive and
don’t want to vanish with the last stars.
1:16So they are enacting the plan to
keep consciousness around forever.
1:20The first issue is energy.
1:22If you want to keep a civilization running you need a
lot of it – but actually not that much in cosmic terms.
1:29With five hours of the full energy emitted by the Sun, we
could power present day humanity for about 10 billion years.
1:37So the Noxans harvest the last stars and build a gigantic complex of batteries around their home star.
1:45In principle, this energy could keep
them alive for a few hundred trillion years,
1:49a long time but not even close to forever.
1:52So now the hard part of the plan begins.
1:55The Noxans need to change the nature of life itself.
2:03Being alive means doing things – eating,
playing video games and very importantly: thinking.
2:08And each of those things costs energy.
2:12There is an idea from a famous paper we’ll
mercilessly simplify and call Dyson's Cold Thoughts
2:18– In a nutshell the idea is that the lower your temperature,
the less energy it takes to do something.
2:24Your brain runs at a temperature
of 310 degrees above absolute zero.
2:29Zero is the temperature where
nothing can happen anymore.
2:32At 310 degrees your brain needs 20
joules of energy to think a simple thought
2:37that takes one second to think,
like “I should wear a funny hat”.
2:41If your brain worked at colder temperatures, say
155 kelvin instead of 310, a few things would change.
2:49First of all, you’d think at half the speed and
the same thought would now take two seconds.
2:54But in return, the energy you’d need to think
the thought, now halves from 20 joules to only 10.
3:01If Dyson's Cold Thoughts are correct, then the colder
you go, the less energy you need to think a thought.
3:07At one tenth your current temperature, the same
thought would take 10 seconds but only require 2 joules.
3:13And this has wild implications.
3:16Because it means that we actually
might be able to play this game forever.
3:20How could this work in reality?
3:22Cooling down a living organism isn’t easy.
3:24If we put you in a fridge, you’ll die from hypothermia.
3:27The reality is that this plan will be
impossible to do with flesh and blood,
3:31so the Noxans have to take a huge step.
3:34Before we cool anything down, consider this:
3:36Maybe the real trick is stepping back and
seeing ideas from different perspectives.
3:40Because even with more efficient brains, we’re
still prone to the same biases we face today.
3:45Nothing highlights this issue more
than our modern media landscape.
3:48Thankfully, Ground News, the sponsor of
this video, is working to confront these issues.
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4:03reliability, ownership, and summaries
that show what each side leaves out.
4:08You even get to compare headlines
to see how bias affects framing.
4:11Luckily, it seems both sides agree
that robots still have a long way to go.
4:15Thinking critically about the news we consume has become
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4:21And Ground News makes it easier to do just that.
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4:32Using this link supports our channel and helps
make the media landscape a more transparent place.
4:37And now back to cooling brains!
4:39They have to leave biology behind and transfer
their minds into some kind of artificial brain.
4:45Or even better, become completely virtual minds and
build a digital world as good or better than the real one.
4:52This is getting pretty sci-fi, so to be fair we
don’t know how to build such brains or computers.
4:58But remember, we are 100 trillion years in the future,
5:01the Noxans are desperate and the
laws of physics should allow this.
5:05So now we have a pretty big battery
with a huge, but finite, amount of energy.
5:09And a lot of brains or a computer that can cool down.
5:14Ok this is great and all, but how do you
stay around with limited energy, forever?
5:18Well, this is at the core of the plan: Each time the
Noxans get colder, they need less energy to stay alive
5:25– sure they will be slower, but this isn't relevant to them.
5:28So from the Noxan's perspective, as long
as they can keep getting colder fast enough,
5:32their battery's energy is growing proportionally
and could keep them alive forever.
5:37Let's see how their plan unfolds.
5:41As the last star in the universe goes
out and the universe turns dark forever,
5:45the Noxans activate their batteries
and start cooling down their brains.
5:49The way they do it is extremely simple.
How do you cool down a light bulb?
5:53Well, you unplug it so it
can radiate away its heat.
5:57So the Noxans switch off their
brains and start to hibernate.
6:00They enter a state with no
activity, thoughts or even dreams,
6:04and let their “bodies” radiate
heat away to cool down a bit.
6:08When they activate again after some
time, they are now colder than before.
6:12They think slower and each thought
uses up less energy from their battery.
6:16They enter into a new cycle of
cosmic days and cosmic nights.
6:20During the days they are alive and awake,
doing all the stuff they want to do,
6:24hanging out with friends, thinking about things,
eating virtual cheeseburgers, simulating universes
6:30 – whatever type 3
civilizations think fun is in the future.
6:33And during the night they are switched
off, lost in dreamless non-existence.
6:38Not even noticing anything isn’t happening
while cooling down their brains even more.
6:44At the beginning the nights will be
very short and the days extremely long.
6:48A day can last a million years
while night is only a few hours.
6:52But warm things shed heat
much faster than cold ones
6:56 – cooling from 300 to 299 degrees takes
much less time than going from 100 to 99.
7:03So as the Noxan brains become colder,
the nights will have to grow longer and longer.
7:08So, how long could they actually do this
and how is this a way to live forever?
7:13How Long Could the Noxans Actually Do this?
7:16The reason Dyson's Cold Thoughts are so
incredibly powerful is how incredibly they scale.
7:21As eons pass in the dying universe, the
Noxans keep cooling down and waking up.
7:26After a 100 trillion years of this cycle, their temperature
has only dropped to 230 degrees above absolute zero.
7:34A simple thought now takes 1.3 seconds instead of 1.
7:38Each cosmic night is now 400,000 years long.
7:42But even accounting for their slower speeds and
long hibernations, the Noxans have experienced
7:47the equivalent of 76 trillion years of life.
7:51Over 5000 times the age of the current universe.
7:55This is frankly just an unsettling idea.
7:58What is way scarier than being dead?
8:03So we need to detach ourselves a little bit –
we simply have no concept how conscious beings
8:07would deal with the opportunity
to actually live that long.
8:10Maybe our Noxans delete their memories regularly,
maybe they create new worlds and new life,
8:16maybe at some point
they decide to sleep forever.
8:19Maybe they just activate their pleasure
centers and experience perfect bliss forever.
8:24As time keeps passing and the Noxans keep going
through their cycle of day and night and cooling down,
8:30the universe keeps dying.
8:31After quadrillions of years, the corpses of former stars,
white dwarfs, turn yellow, then orange, then red, then black.
8:40Trillions of trillions of years later:
All galaxies have dissolved like dandelions.
8:46Decillions of decillions of years later: The first black
holes evaporate in bursts of light like sad fireworks.
8:54And the Noxans? They are still around.
8:57At a chilling 10 quintillionths degrees above zero.
9:01They’ve become so slow that a
simple thought takes a trillion years.
9:05They spend 99.999999999999999997%
of the time hibernating.
9:17But for them, nothing has changed.
9:19Their conscious experience is just
as fluid and vibrant as on the first day.
9:24From the outside they live in slow motion.
9:27As they got colder and colder
their thoughts got slower and slower.
9:31But if you and the world around you slow
down at the same pace, you don’t notice anything.
9:36Your conversations, thoughts, adventures
and experiences feel exactly the same as before.
9:41And while the cosmic nights are
now a quattuordecillion years long,
9:45it doesn’t matter to them, because during the
nights the Noxans don’t experience anything.
9:50So no matter how long the
nights are, they pass in an instant.
9:54The Noxans experience a
perfectly fluid existence.
9:57Only that with each night they
use up even less energy than before.
10:02At this point, they have lived, felt and experienced
the equivalent of 4,000 trillion trillion years.
10:09 Their battery has only a tiny
fraction of its original charge,
10:12but the Noxans now need so little energy
that it seems larger than ever before.
10:17True eternity has just begun. Or has it?
10:21Can The Noxans Actually Live Forever?
10:24Whether Dyson's Cold Thoughts can
make you live forever depends on one thing:
10:29can you keep cooling forever, or does
the universe force you to hit a true limit?
10:34There are a few problems – dark energy might
eventually make the universe hit a temperature limit
10:38of one nonillionth degrees above absolute zero.
10:42The Noxans will cool to that
level after a googol years,
10:45but then they can’t cool any further
and their battery will begin to run out.
10:49And after this much time, the universe will
make going on impossible in other weird ways.
10:54Quantum noise might just destroy their brains.
10:57All matter may decay into iron
or proton decay may destroy all atoms.
11:02We don’t know. Forever is a long time.
11:05But even if the Noxans don’t get a true forever – if Dyson's
Cold Thoughts work, then within these googol years,
11:12their consciousness would experience
the equivalent of two trillion, trillion, trillion years.
11:19This may all seem far-fetched and hard to imagine.
11:21But the amazing thing about it is that, for all we
know, the laws of physics don’t forbid life to adapt
11:27 even to a completely dead universe.
11:30And it would mean that life and consciousness
aren’t a brief accident in cosmic history,
11:35but the final chapter of existence itself –
giving the universe meaning, purpose and hope.
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