Hey, Vsauce. Michael here. I’ve been watching
Bravest Warriors on Cartoon Hangover lately. It’s great, it was created by Pendleton Ward,
and in the show teenagers zip around the universe visiting star systems and planets and here
is my question: When will we do the same? Us humans, in real life. I mean, we’ve managed to put people on the
Moon, and land robots on asteroids, and Mars, and even Titan, a moon of Saturn. Interplanetary travel is scary cool.
But will we ever travel interstellarly? Certainly it will happen, right? I mean, Voyager 1 is
expected to reach interstellar space sometime this year, or maybe in the next year or two.
And it was launched way back in 1977. So, shows like Bravest Warriors are pretty much
just a glimpse of our future, maybe even one within our lifetimes. Right? Well, we’re going to need a DONG for this one. Something you can Do Online Now Guys. The Hayden Planetarium’s digital universe
allows you to explore a 3-dimensional map of our Milky Way. Now, there are about 81
visible stars within just 20 lightyears of our own Sun. The nearest is Proximus Centauri,
which is only 4.3 lightyears away. Getting there? Piece of cake. Piece of difficult
cake, because a lightyear is an incredibly long distance. It’s the distance that light
in a vacuum will travel in an entire year. And in just one second light can travel
so far as to circle the entire Equator of Earth…7 times. Now, a fast bullet can travel at about 1,500 m/s.
And Voyager 1 is traveling at about 17,000 m/s, relative to the Sun. Also relative to
the Sun, our Earth is orbiting at a speed of 29,800 m/s – that’s pretty fast.
But the fastest man-made object ever was the Helios 2 Solar Probe,
which traveled at a maximum speed of 70,220 m/s. Impressive, right? Well, even at that speed,
the fastest speed ever reached by any man made object, crossing this little ol’ gap
and reaching Proximus Centauri would take 19,000 years. But technology in the future is bound to be
improved, along with the maximum speeds we are able to obtain. Even using what we know
now, a solar sail could easily provide the acceleration needed to reach near-lightspeed speeds.
And our current understanding of physics theoretically allows for things like wormholes which, in
theory, could move a spacecraft from one point in space to another faster than light normally could. And who could forget the famous Alcubierre drive?
An idea that fits within most models of our universe, and proposes a way to deliver
a space craft to a distant object faster than light can get there – not by moving the spacecraft,
but, instead, by collapsing and expanding space itself. Things like wormholes and Alcubierre drives
are theoretical, but if they could one day become a reality, how far away might that day be?
It matters. And figuring out exactly when in time we should begin an interstellar
journey is called a Wait Calculation. Leave too soon and before a ship launched today,
full of frozen embryos, ever got to its destination it would be passed by astronauts who left
hundreds, or thousands, of years later, at a point in time when technology was advanced
enough to lap what we have today. Andrew Kennedy calculated that given the
pace of our progress, as far as travel velocity is concerned,
and Earth’s mean annual economic growth, the soonest human civilization might ever
reach Bernard Star, 6 lightyears away, is 1,104 years from today, which isn’t within
any of our lifetimes. It might also be a bit optimistic because it assumes that we not
only solve the problem of speed, but that we also solve problems like “how to survive
interstellar radiation for years?” or “how to avoid collisions with interstellar
material at high speeds?” It also assumes that before we achieve the
technology needed to successfully interstellarly travel, all of human kind isn’t wiped out
by some cataclysmic natural disaster. It may sound unlikely, but we’re not talking about
the near-future, we’re talking about thousands of years from now. Let’s put it this way.
Even given our current, slow means of space travel, it’s estimated that within 5 to 50 million
years, we could theoretically explore and colonize our whole galaxy. That’s a lot of time, though. In fact, statistically
speaking, within the next 500,000 years, it’s very likely that Earth will encounter a meteorite
nearly a kilometer across. Hopefully when that happens we have the prevention abilities
needed to keep ourselves safe. But given all of this information it’s easy to see why
the 2008 Joint Propulsion Conference concluded that it was improbable that humans would ever
explore beyond the solar system. It’s quite depressing to think that scenes
like this one from Shutterstock may be destined to only ever remain that – science fiction. Wait, how quickly is the camera moving in that clip? We’re used to seeing science fiction
scenes like this, but a Nebula tends to be lightyears across, which means that in this
clip we’re traveling at least the speed of light, if not faster.
Would it really look like that? I covered this briefly in my black hole video,
but not completely. If you were to travel at the speed of light, or near the speed of
light, the universe ahead of you wouldn’t look like it usually did. First of all, your
field of view would increase. It would appear as if the universe was receding away from
you as you accelerated. At the same time, all of the light reaching you would be blueshifted
until you were left with this. You may have seen this on Vsauce 2. It’s the cosmic background
radiation blueshifted all-the-way up into the visible range. MIT Game Lab offers a free, downloadable game
that puts you in an environment where the speed of light can be lowered all-the-way
down to typical walking speed. You can experience all of the visual effects I just discussed,
but I wanted to know what it would look like if the speed of light was where it is, and
I took a journey from Earth to the Moon. So, I enlisted my friend Liam from World of
the Orange and New Music to put together a simulation of what it might actually look
like to accelerate to nearly the speed of light and then slow down,
during a trip from Earth to the Moon. Enjoy. Whether or not you should believe that all
the right factors will come together and humans will one day travel that quickly or reach
interstellar destinations largely comes down to whether you want to be an optimist or a
pessimist. But what we’ve accomplished so far is quite amazing considering how weak,
flimsy and vulnerable the human body is in the vacuum of space. Bad Astronomer and SciShow have great videos
discussing this topic. And now, thanks to the brilliant team at Bravest Warriors, I’m
going to go to space. But not while wearing a Vsauce suit, no, no, no, I’ll do it naked.
Whoa. Ok, not that naked. And also maybe some muscles?
Yep, so that’s pretty much what I’d look like. The moment I’m exposed to the vacuum of space
my body would not inflate and explode. Now, the body is a very nicely contained system.
But those parts of me that aren’t well contained…they’ll be the first to go. The air in my lungs and
digestive tract would quickly rush out. Moist, soft tissues would rapidly lose water.
My mouth and lips and eyes would dry out and swell. As water was pulled to the surface
of these things it would vaporize, and the decrease in its pressure would cool my mouth
and eyes to near-freezing. My body would inflate to about twice its normal size as gasses in
my blood came out of solution, slowly evaporating away, cooling the surface of my skin.
Oh, and the blood vessels in my eyes would likely burst, spilling blood into my eyes which,
along with all the other fluid in my eyes, would be rapidly vaporizing on the surface,
freezing and drying them out. Within about 15 seconds I would go unconscious
because oxygen wasn’t reaching my brain. And, as far as I’m concerned, that would be the
end of the entire ordeal. For another 90 seconds or so I would still, technically, be alive,
but I wouldn’t be aware of it or remember any of it. My dead body would remain, internally,
quite warm for a while because in the near vacuum of space there isn’t much matter to
conduct of convect heat away from me. Instead, I would really only lose heat through radiation,
a much less efficient method. It would take hours for me to cool down to the temperature
of space, and by then, I would be nothing but a dried-up piece of slightly bloated and
stretched, dessicated human jerky. If I was exposed to the Sun’s full-on radiation,
not filtered by the usual atmosphere of Earth, I would be a grossly sunburnt piece of jerky. In case that makes you hungry, let me give
you some nutritional facts: 200 pounds of human meat, in outer space, would eventually
become about 120 pounds of freeze-dried jerky. And given what would be left of me that would
be edible as a snack, I’d be worth about 115,000 calories. Maybe humans are the only intelligent life
in the universe. But if you believe that intelligent life could have arisen on other planets,
an interesting idea occurs: The Fermi Paradox. Enrico Fermi calculated that given the number
of planets believed to exist in our galaxy, at least some of them must have been habitable
to life as we know it. And, in many cases, millions and millions of years before life
on Earth even existed. So, if interstellar travel, traveling between
stars and different solar systems, really is possible for intelligent life to do, why
have we not been visited by aliens yet? Well, maybe we have been visited. Maybe they’re
here right now and we just can’t perceive them. Or maybe we haven’t been discovered.
Or maybe we are alone. Or maybe we’re just not worth visiting… So, what are you waiting for? Live your life
in a way that makes traveling lightyears just to hang out with you worth it. And as always, thanks for watching.