Speaker A
The latest limited edition pin is here, now available on the Kurzgesagt shop. You will never leave the solar system.
Humanity faces insurmountable physical and environmental barriers preventing us from leaving the solar system, despite advances in speed and technology.
Ask about this video. Answers come from its transcript only — with the timestamp, so you can check them.
Generated from the transcript and can be wrong — check the timestamp.
Key Takeaways
- Physical and environmental barriers make leaving the solar system with humans onboard currently impossible.
- Even with advanced propulsion, space dust and particles impose a natural speed limit on safe travel.
- Nearby star systems are unlikely to be habitable or worth the decades-long journey for humans.
- Humanity may be confined to the solar system indefinitely, with deep space exploration relying on robotic missions.
- Understanding and overcoming these challenges is essential for any future interstellar ambitions.
What the video covers
- Humanity and possibly all carbon-based life are trapped within the solar system by fundamental physical limits and vast distances.
- Current spacecraft speeds are far too slow to reach even the edge of the solar system within a human lifetime.
- Hypothetical ships traveling at 20% the speed of light could reach nearby stars in decades, but face deadly hazards from space dust and particles.
- Collisions with atoms, dust grains, and small rocks at relativistic speeds cause severe damage to spacecraft, limiting maximum safe travel speed.
- Even the closest star system, Alpha Centauri, is inhospitable and uninhabitable, making interstellar colonization unlikely.
- Most nearby celestial bodies within reach are either extremely hostile or offer no viable habitat for humans.
- Technological solutions like nuclear fusion or antimatter propulsion might allow faster travel, but do not solve environmental dangers or habitat issues.
- The vast emptiness and hostile conditions of space create an invisible barrier that may permanently confine humanity to the solar system.
- Exploration beyond the solar system may rely on AI or robotic probes rather than human crews due to these challenges.
- Space travel remains humanity's greatest challenge, requiring breakthroughs in physics, engineering, and biology.
Chapters
- 00:00Introduction and the Invisible Barrier
- 00:40The Vastness of Space and Speed Limits
- 02:31Current and Hypothetical Spacecraft Speeds
- 04:29The Edge of the Solar System and Travel Times
- 06:12Limits of Faster Travel and Propulsion
- 07:09Sponsor Message: Staying Connected While Traveling
- 08:31Space Dust and Collision Hazards at High Speeds
- 12:34Challenges of Interstellar Travel and Habitable Targets
- 18:59Conclusions and the Future of Space Exploration
- 21:03Closing Remarks and Merchandise
Full Transcript — Download SRT & Markdown
Speaker A
Nobody alive today will. And maybe no human ever. Locked in by an invisible barrier, impossible to overcome for carbon-based animals like us.
Speaker A
And not just us – there may be millions of alien civilizations in the universe, none of them ever able to venture into deep space in a meaningful way.
Speaker A
Okay, but how can this be? We've made countless videos imagining how the exploration of the galaxy and beyond should just be a question of time.
Speaker A
Sort of mandatory for civilizations at a certain point. But there is a catch: we are pushing up against fundamental physics.
Speaker A
What is this barrier, made of dust and nothingness? And why is it so hard to overcome?
Speaker A
You don’t understand how large space is. We don’t either. Conceptualizing the size of space is impossible for our ape brains that evolved to understand distances like “right here” and “over the next hill.”
Speaker A
Space is so absurdly huge that we just check out and just hear “very far.”
Speaker A
“Very far” and “a million times very far” feel the same, but they are not.
Speaker A
To help our brains, let us start with what makes us cross distances: speed. The fastest a human ever traveled in space were astronauts at 40,000 km/h, returning from the Moon in 1969.
Speaker A
Not bad, but way too slow. The fastest thing humans have ever built by far is the Parker Solar Probe, which at this moment uses a physics cheat code, hurling around the gravity well of Venus, accelerating to get closer to the sun.
Speaker A
After seven years of doing this, the probe is shooting through space at a breathtaking 635,000 km/h.
Speaker A
Fast enough to go around the world in 4 minutes or to cover the distance from Earth to the Moon in 36.
Speaker A
So let’s pretend we had a spaceship that fast, with a human crew ready to explore the universe!
Speaker A
Current rockets would need 7-10 months to reach Mars, but our new spaceship covers the distance in just two weeks! Pretty good!
Speaker A
The next stop is Pluto, which we will reach after about a year – okay, much longer, but still okay! It only takes two more years to pass the heliopause and one more to pass Voyager II, which traveled over 50 years to get this far.
Speaker A
Great! The next stop is the end of the Oort cloud, the true edge of the solar system where open space begins! We reach it in… 2,500 years.
Speaker A
Oh. Oh no. Not only did we travel for the amount of time it took to get from the founding of the Roman Republic to the present day, there is NOTHING out here.
Speaker A
This is the invisible barrier. The barrier of nothingness that might trap us in the solar system forever.
Speaker A
Space tends to be like that. There is a place that is very far away but with human ingenuity and billions of dollars we can get there! Then you zoom out one more time and all hope leaves your body.
Speaker A
And the problem is that we have barely started zooming out... Why don’t we just go faster?
Speaker A
Well, we don’t know of a non-magic way to travel faster than light, teleport, or freeze people.
Speaker A
So no warp drive for now. But things like a propulsion system that uses nuclear fusion or antimatter, powerful enough to reach a substantial fraction of the speed of light, are in the realm of the physically possible.
Speaker A
Ignoring the technical details and various problems that these energy sources have, we’ll be very optimistic and make the reasonable assumption that we can get a spaceship to fly at around 20% the speed of light!
Speaker A
Which is extremely fast – 60,000 kilometers per second, 216 million kilometers per hour. Fast enough to reach the edge of the solar system in just 3.5 days and the outer edge of the Oort cloud in eight years.
Speaker A
Alpha Centauri, the closest star system to our own, in 20 years! We can work with that!
Speaker A
There is only one small problem: we don’t have internet! Wait, what? Just kidding – but our sponsor Saily can help YOU with that problem while traveling.
Speaker A
Saily is the eSIM service app from the creators of NordVPN. You can choose from a wide range of affordable eSIM plans for over 200 destinations, so you’ll never be without an internet connection while traveling.
Speaker A
Just download the app, pick a data plan, use the code “kurzgesagt” for a 15% discount on your first data package, and install the eSIM in advance.
Speaker A
It’ll activate automatically when you arrive, and you can start browsing right away. You can also use Saily to feel like a local – it now comes with an app-based phone number for voice calls and SMS that stays the same everywhere.
Speaker A
Perfect for local apps, shops, and travel companions – and to keep your real number private.
Speaker A
With just one app download, you’ve solved your internet problem while traveling once and for all, saving time and expensive roaming fees.
Speaker A
Download Saily and use the code “kurzgesagt” at checkout or go to saily.com/kurzgesagt. All you have to do is pick your next destination – we'll go back to solving our trickier travel problems.
Speaker A
Everything should be sorted out now, right? Well... there is only one small issue: Space hates you: the barrier of dust. Unfortunately, we will run into a few obstacles on the way.
Speaker A
Literally. Because while space is very empty, it is not actually empty. There are energetic particles, gas, dust, and things bigger than dust.
Speaker A
As a lot of unhappy people experience every day, if you are going really fast and smash into something, you have a huge problem.
Speaker A
And at 20% the speed of light, this is true even if the thing you are smashing into is just an atom.
Speaker A
An individual iron atom that hits your spaceship at this speed has enough energy to carve a damage track tenths of a millimeter deep.
Speaker A
Over time, its hull would be riddled with microscopic bullet holes, which is not great.
Speaker A
Of course, our engineers knew this and created a shield for our ship. A sort of protective sail that absorbs or at least slows down most molecules we smash into.
Speaker A
And while this makes the journey much safer, there are things floating around in space that are larger than atoms.
Speaker A
Running into a single grain of dust at 20% the speed of light is like running into a grenade, causing a tiny detonation as the dust explosively evaporates, grinding away our protective shield.
Speaker A
But you can also hit something bigger than a grain of dust. Like a small rock, the size of a golf ball.
Speaker A
Hitting that at 20% the speed of light releases more than double the energy of the nuclear bomb that was dropped over Hiroshima.
Speaker A
We’ll not even talk about anything larger. Atoms, dust, and pebbles are dangerous enough. We might have reached our natural speed limit here – besides the fact that we don’t have a good idea how we could possibly fly any faster,
Speaker A
all of the damaging effects of hitting stuff floating around in the void get much worse fast.
Speaker A
Having said all that, it’s probably fair to assume that with enough shielding, our spaceship should be able to survive traveling through space at roughly 20% the speed of light long enough to get to at least nearby stars in a reasonable amount of time!
Speaker A
Only one more issue to overcome! Almost everything in space that's close is super lame. The first proper target outside the solar system is the Alpha Centauri system.
Speaker A
Which is roughly 10,000 years with our original slow, more realistic ship but only 20 years with our super fast fictional ship!
Speaker A
So let’s cram a few unlucky humans into a tiny box for 20 years and send them on their way and assume they somehow make it without murdering each other!
Speaker A
Four years after their arrival, their message reaches Earth. People around the globe gather together and hold their breath, eager to listen to it: “We arrived! Alpha Centauri and its planets are very pretty up close!
Speaker A
Unfortunately, they are all super deadly and uninhabitable. But we are doing extremely cool astrophysics and are learning a LOT, which is pretty exciting!
Speaker A
We are getting kind of tired of freeze-dried food and desperately need new shows to watch though.
Speaker A
Not sure what we were thinking coming here…” The thing with space is that almost all “close destinations,” if close means something different from what it usually means, a
Speaker A
Not from a scientific perspective of course! It would be an absolute dream to have the privilege to set foot on foreign planets and marvel at the wonders of our universe!
Speaker A
But if 20% of the speed of light might be our speed limit, and we give humans a realistic travel time of say, 40 years, we could reach things that are up to 8 light years away.
Speaker A
None of the targets remotely within this range, within a human lifetime, may be worth traveling dozens of years in a tiny box, through one of the deadliest environments imaginable.
Speaker A
Our solar system is a bit unlucky in that regard, we are in a relatively empty pocket of the galaxy.
Speaker A
This might change in a few million years as we move through the galaxy, and there might be small, localized star spanning civilizations – we discussed this in another video.
Speaker A
Let’s say that we could go much further, to any of the stars within our stellar neighborhood, a sphere about 25 lightyears in diameter.
Speaker A
0.02% of the milky way by the way. This tiny bubble is currently inhabited by 34 stars, and 6 brown dwarfs.
Speaker A
Only three stars in our neighbourhood are similar to the sun. But one of them is actually the sun and another one is Alpha Centauri A.
Speaker A
The other stars close to us are mostly red dwarfs with planets that vary from deadly to super deadly.
Speaker A
There are a few planets in the habitable zones of their stars, where water can be liquid.
Speaker A
But, Mars is also in the habitable zone of the Sun and it is really bad.
Speaker A
Even the planets that we think look most like Earth, like GJ1061 d, come with no guarantees.
Speaker A
Imagine traveling your entire life and then arriving at a Mars. What a brutal letdown that would be.
Speaker A
There are a few stars that would be interesting targets and may have actual habitable planets – planets with oceans and atmospheres that are breathable, which probably would mean that they have some form of microbial life, if not more.
Speaker A
It would be extremely interesting and definitely worth it to check them out! But they could be dozens, if not thousands of light years away.
Speaker A
Which means journeys of hundreds or thousands of years, even at a large fraction of the speed of light.
Speaker A
Of course it is maybe feasible that a future humanity that is technologically way more advanced than us and very motivated could find solutions.
Speaker A
Maybe they have solved biological aging and a travel time of a few hundred years doesn't seem that bad to them.
Speaker A
Maybe they could send AI spaceships with embryos or some version of that into space.
Speaker A
They would probably have way more advanced telescopes to make sure they don’t choose star systems that are deadly and empty.
Speaker A
But it is still hard to imagine without real science fiction technology, how they could build and sustain a connected civilization.
Speaker A
Conclusion The longer you think about deep space, the less it makes sense. The distances are too vast, there is a deadly speed limit and even if we could solve these issues almost all destinations even remotely reachable may not be worth the trip.
Speaker A
Space is the greatest challenge humanity will ever face. Right now we are just not equipped or able to solve it.
Speaker A
Rockets, computers and even nuclear fusion reactors are hopelessly underpowered. We need technology that is overwhelmingly transformative.
Speaker A
Something as wild to us as flying to the moon would have been to a hunter gatherer.
Speaker A
Will we ever get there? We genuinely don’t know. But it is good to remind yourself of something: there are few things that make you look dumber than predicting the future of technology.
Speaker A
In 1903 the New York Times published an editorial, "Flying Machines Which Do Not Fly” that confidently predicted it would take humans one to ten million years to achieve powered flight.
Speaker A
69 days later the first successful flight happened. 66 years later humans landed on the moon.
Speaker A
So we really hope this video will seem as dumb as this article in a hundred years.
Speaker A
And there is another option entirely – maybe our thinking about all this is just completely wrong.
Speaker A
Maybe the future is not out there, but deep down – but we’ll explore that in another video… The latest LTD. Edition Pin is here, continuing the Cosmic Time Collection.
Speaker A
Predicting the future is really hard. But this device offers you a rare glimpse into the end of the Universe.
Speaker A
Spoiler: one by one, all the stars will die, until everything is swallowed by darkness.
Speaker A
Wear this animated, lenticular pin as a reminder that you exist right now, in a brief and extraordinary moment in time when the Universe is still filled with stars and light and there is so much left to discover.
Speaker A
You are exactly where you belong in cosmic time and the Universe. Only 10,000 Vanishing Stars Pins exist, and each one is individually numbered.
Speaker A
Add it to your collection, or start a new one while supplies last. And while humanity may still be confined to a tiny corner of the cosmos, we've already achieved some remarkable things.
Speaker A
To celebrate these milestones, we created our Cosmic Milestones Poster Collection, featuring the first Moon landing, the Mars rover Curiosity, and the Wilson Observatory, all enhanced with shimmering foil details.
Speaker A
Get your favorite, or better, all of them and create a gallery wall that will inspire you every day and remind you of what humanity is capable of.
Speaker A
Head over to our shop, we’ve put together a few deals for you – get your special piece of kurzgesagt and the cosmos now.
Topics:solar systemspace travelinterstellar travelspace dustrelativistic speedsAlpha Centaurispace explorationspace hazardsspace physicsKurzgesagt
