So what have we learned so far from Crash
Course Big History? Well, the universe is big, it's really big,
and it started from nothing. And now, a whole lot of nothing surrounds
tiny pockets of something, and one day the entire universe will return to almost nothing. Our universe may be one of many, just a tiny
hole in a block of Swiss cheese that forms a multiverse with many other holes entirely
beyond our sight, with constants and dimensions, and physical laws stretching away from the mental
comprehension of humanity's most brilliant minds. But in our tiny cosmic bubble forming as if
by accident, the physical laws of the universe and the unequal distribution of energy arrange
themselves in such a way that in the cosmic blink of 13.8 billion years, in a still fairly
young cosmos, we have emerged. Us! with all of our fighting, and reproduction,
and consumption. We have been cobbled together from the ashes of dead stars. We have been
forged on Earth, despite the chaos of a molten planet bombarded from above by every rock
in the nearby solar system. And we have survived and evolved by the slimmest of margins, our
existence perpetually balanced on the edge of a knife. I mean, a couple times already we've almost
gone extinct. Some of our obstacles have been physical and some have been of our own making,
but from here, many transformations still await us. Now I guess from our perspective, some of
these transformations may be good. Some of them will definitely be bad, like, you know,
ceasing to exist. But really, it all depends on your perspective. I mean, no outcome is
absolutely good or bad in the eyes of the universe. The universe is blind. The universe
doesn't see, it just is. Aah- I forgot the into. Hi. I'm John Green.
Welcome to Crash Course Big History. Today we're talking about the deep future of life,
the universe, and everything. [Theme Music] So today, we're talking about the future. Actually, we're talking about several
potential futures falling on a spectrum. First, there's the projected future. This
is the business as usual, where variables on the Earth and the universe play out as
our current knowledge of them suggests they will play out. I predict that the sun will rise tomorrow,
and that I will skip breakfast and go to work. Second, there's the probable future, where
our current knowledge illuminates several possible futures that could happen, though
variables may play out in a different way in the actual event. For instance, it could
happen that tomorrow morning I will find time to eat breakfast, and I will discover
that it energizes me and improves my productivity, and really is the most important meal of the
day. Unlikely, but it could happen according to our current knowledge of how things work,
in this case, how things work in my kitchen. Third is the possible future where we can
no longer bank on our current knowledge, but rather must anticipate that future discoveries
may alter how we currently think events are gonna play out. For instance, I may find a
pill that provides me with all the calories and nutrients I need for the day, and I never
have to think about eating more food again. In terms of the universe, if we were to gain
knowledge of, like, what dark energy is, and how it works, we may alter the current narrative
of how it will continue to evolve. Fourth, the preposterous future of outlandish
predictions. 150 years ago the idea of flying to the moon would have seemed preposterous,
but one way to test the limits of the possible is by going beyond them into the impossible.
A lot of preposterousness is possible in the next 1,000 years, or 10,000, or 10 million,
or even 100 trillion years. So, what might happen in the next 1,000 years?
Well, last week we discussed how the next century might be pretty rough for us, but
let's say that humanity gets through the 21st century bottleneck and our collective learning
and complexity continues to grow. Well then maybe there could be another great
revolution, like another explosion of complexity as we saw with the dawn of agriculture, or
the advent of industry. In the next 1,000 years we could master hydrogen fusion, the
same process that goes on in the sun. And that would provide us with a tremendous amount of
energy, it would solve most of our energy problems. Another possible great revolution is known
as transhumanism, like your brain is sort of a computer so imagine if you could upload
your consciousness to something plastic or metal like an actual computer. You know, the
thing about human brains is that they kind of rot, so never mind living seventy or eighty
years, try millions of years. Now, some say that both of these revolutions
might be possible within our lifetimes - or at least within your lifetime - and they're actively
being pursued by scientists, but we've been promised a lot of things about the future
over the years. I still don't have a jet-pack, I find that the wi-fi in airplanes is very
slow, and I'm not by nature a complainer, but my amazing virtual reality headset makes
me feel nauseated. But on the timescale of a thousand years,
those revolutions and many others that we haven't thought of are perfectly possible
if human complexity continues to rise. Now, that's a big if, but let's get into bigger
ifs, like what about the next 250,000 years? Well on that timescale, the possibility of
like, a supervolcano eruption like the one at Mount Toba that killed almost all humans
on Earth becomes pretty likely. Then when it comes to asteroids, so-called city-killers
hit on average every 100 years, although most just land in the ocean, and ones big enough
to wipe out most species on Earth like in the extinction of the dinosaurs can potentially
land every few hundred million years. Now it's possible that by this point we could've
colonized some of the moons and planets of the Solar System.
It's also possible that we could have the technology to survive centuries long space
flights out of our Solar System. Especially if we can get some of that transhumanism
because it would remove the need to bring along things like water and food, and also
we wouldn't have to be afraid of the immense amounts of space radiation that destroy humans. Quick question, Stan. How is there not a band
called either "Space Radiation" or "The Transhumans?" Okay, let's zoom out even further and talk
about millions of years. If Homo Sapiens hasn't been wiped out by some
disaster within the next several million years, our species probably won't be around anyway
because we'll have evolved into something else. Like, seven million years is roughly the amount
of time since our species split from our common ancestor with chimpanzees. And while we do
share 98.4% of our DNA with them, a lot of evolutionary change can happen in a few million
years. This is especially true when you consider
that the human capacity for genetic engineering may have developed in a lot of scary and/or awesome
ways, further increasing the pace of change. And when it comes to moving outside of the
Solar System, a few million years is actually a pretty long time, like, presuming that humanity
never finds a way to move faster than the speed of light, physicists estimate that on
the timescale of five to fifty million years, we could colonize almost every star system
in our galaxy. That shows you the precision of predictive
science, by the way, five million years to fifty million years. It's only a 45 million
year difference. But here's a crazy thing to consider - if
we can't move faster than the speed of light, we will never get outside of the Milky Way
because the vast distances between star systems also mean that human populations would be
separated by thousands of light years, and when a species is separated into, you know,
different physical pockets of the universe, it stops being the same species pretty quickly.
I mean, you put turtles on different islands for a few thousand years and you get different
species. I don't think that we're gonna, like, hold on to our shared humanity across hundreds
of thousands of light years. So imagine a distant future where, like, each star system
is seeded by an ancestor and then a few million years later, those cousins look profoundly
different from each other. Wait, like, as different as Americans look
from Canadians or more different? More different, apparently. How can you look more different than I do
from a Canadian? Another thing I'd like you to consider is
humanity's increasing ability to harness energy. From the fire storm of the Big Bang to the
first stars blinking into existence to life's active harvesting of energy to the massive
increase of energy used in the industrial revolution, more energy means higher complexity
and that's our overarching theme in Big History. So life on Earth has gotten pretty good at
harnessing the energy that's like, within Earth and that comes to Earth from the Sun,
right? But maybe a time could come when humanity
or something else like us in the universe could harness the entire power of a different
planet or a chain of several planets or a galaxy. Then we could harness many orders of
magnitude more energy than we can now and we know that is closely associated with rising
complexity. But perhaps I've speculated too much. The
thing about futurism is that the further you look ahead, the more certain things become
again. That's thanks to the beauty of physics, so let's look again at the projected future
based on our current knowledge. So, what will happen in the next billion years? In about a billion years, the Sun will have
begun to exhaust its fuel and will start to inflate. Its luminosity will increase and this
means plants on Earth over the following years will find it harder and harder to do most forms of
photosynthesis and thus sustain complex life on Earth. The beginning of the end. What will happen
in the next three to five billion years? Now the story is starting to get even more tragic.
The Sun will get larger and larger until it boils the surface of the Earth dry. Once we
get to a surface temperature greater than 100 degrees Celsius, we can be pretty sure
that that's it for life on Earth. So if anyone human or human-like is still
around, we'll have to leave our childhood home and move into a dorm room somewhere else
in the galaxy. We won't even be able to come back home for our moms to do our laundry. How about in the next 200 billion years? As dark energy continues to accelerate the
expansion of the universe past the speed of light, we will no longer get to see light
from other galaxies. If we were to lose the knowledge of the Big
Bang cosmology that we were taught at the beginning of this series, our galaxy would
be all we'd see or be aware of. We'd revert to the idea that the universe
had no start date, is static and eternal. The Milky Way would be our entire universe.
That's why a number of scientists refer to the current age where we can see the evidence
for the Big Bang and see other galaxies as "the golden age of astronomy." But you know, a golden age
that lasts hundreds of billions of years is not so bad. What will happen in the next 100 trillion
years? The last, tiny, slow-burning star will have flickered
out and new ones will have ceased to form. No new heavy elements will form, all that will be left
is the residue of heavy elements from long since dead stars, a cosmic graveyard where the remains of
dead stars and planets wander in the darkness. But let's not stop there, what about in the
next trillion trillion trillion years? More accurately 10 to the 40 years. That's
a one with 40 zeros after it. This is an even more incomprehensible stretch of time than a hundred
trillion years and even more incomprehensible things will happen. The most likely scenario
is this: Matter will grow feeble and decay into energy and remember, matter is loosely
speaking just a more congealed form of energy. Eventually, the universe will be an empty
orb of weak cosmic radiation, with the energy spread out like too little butter spread over
too much bread. This, as far as we can tell, is the end of
complexity as we know it. And then, in the next trillion trillion trillion
trillion trillion trillion trillion trillion years or 10 to the 100, even black holes will
evaporate and the universe's grand narrative will have more or less come to an end. After all those transformations into a great amount
of variety and networks of intricate complexity, all will pass away. All that will remain is a universe that
is very old and very tired. It is the specter of heat death. Okay, so for me, one of the most comforting
thoughts about all existence comes from science - the idea from the first law of thermodynamics that
matter and energy are neither created nor destroyed. The building blocks that make up our bodies
have been around since the beginning of the universe, we have merely changed form and after
we die, our bodies will return to that inanimate cosmos from which they sprang. And in that sense,
all life is connected and also, all life is kind of eternal. Now of course, there's still the fear of losing
your particular consciousness depending on your worldview, like, I will cease to be John
Green. And from my perspective, that's not ideal, but we're programmed to have that fear.
If we weren't afraid of ceasing to exist, we wouldn't be a very good species. We would
have gone extinct ages ago and none of us ever would have gotten to be. I don't think
that's either good or bad, it keeps our species going and the universe looks on, free from
any mandate or obligations or programming - completely free. And what a lot of us overlook
is that we are not just observers of the universe, we are the universe. We don't exist outside
of the universe, we are indivisible from it, we are made of the same stuff, and in all
of our transformations over billions of years from star stuff to single cells to students,
to one degree or another, at every stage we've shared in that freedom of transformation to
flow endlessly from one form to another. And maybe we won't survive as individuals, maybe
we won't survive as a species, but we will continue into the deep future. We are a tiny
part of the universe, but we are part of it, and from so simple a beginning in ways most
beautiful and most wonderful, we, the universe, have been and are being evolved. That ability,
in fact necessity to change is your birthright acquired at your original birth 13.8 billion
years ago and it can never be taken away, it can never be destroyed. Thanks for watching Crash Course Big History
and as we say in my hometown: don't forget to be awesome.
How does john leverage his love of science with his religion? He's protestant isn't he?
This made me sad.