Could We Really Visit Other Stars?

[Intro Music] If you are a fan of science fiction, you have probably read or seen a lot of stories that involve interstellar travel. Like, they are called “Star” Wars and “Star” Trek for reasons. And we might be getting a little closer to making interstellar travel a reality. Just not for humans. Last week, Russian entrepreneur Yuri Milner announced that he was heading a project called a “Breakthrough Starshot”. The plan is to use giant lasers to propel tiny spaceships to Alpha Centauri, our next door star system, and collect a bunch of scientific data. Getting this, right now theoretical, plan to work will take decades of research and probably tens of billions of dollars. But, with some more advanced technology and a lot of problem solving, we might be able to do it. Interstellar travel is hard because space is *big*. Alpha Centauri is the closest star system and it’s about 4.4 light-years away. That’s 41 trillion kilometres. So, to get there from Earth, we would either need to travel for a very long time, or travel very fast. If we tried to go to Alpha Centauri using the technology we currently use in space travel, like rockets powered by propellants, it would take, like, 80,000 years. Which is not super practical. But Milner and the Starshot team want to try the other option and build spaceships that go really fast. Like, a significant fraction of the speed of light, fast. There’s a lot of work that needs to be done to make this happen, but there are a lot of people supporting this endeavour, including physicist Stephen Hawking and laser propulsion expert Philip Lubin. Specifically, the team’s plan is to build very tiny spaceships, about the size of a postage stamp, and then push them through space using a bunch of lasers here on Earth. If the idea of propelling small spaceships with giant lasers sounds familiar, it’s because we talked about it a few weeks ago. It’s called photonic propulsion, and it’s based on the fact that light can have enough pushing power to propel certain kinds of spacecraft. When the laser light (which is made of a concentrated beam of photons) hits a special kind of reflective sail attached to a spaceship, it transfers some of the momentum and pushes the craft forward. The team wants to use this concept to get their tiny spacecraft moving fast enough to shorten the trip to Alpha Centauri to just a couple of decades. So, their grand plan is to build a huge array of lasers here on Earth, which would combine into one big beam. The laser would fire in pulses and accelerate the stamp-sized starship to about 20% the speed of light. Around 20 years later, those starships would get to Alpha Centauri, take measurements as they flew by, with the nanotechnology inside, and then send the data back to Earth. If all goes very well, they might be ready to launch as soon as the 2030s or 2040s, but there are a lot of big challenges here. For one thing, they’re building the laser here on Earth, instead of in space, because it’s a lot cheaper. But when you fire a huge laser through the atmosphere, all of those gas particles weaken and distort the beam, which means that you have to account for less pushing power and potentially slower speeds. They’d also have to be careful to not hit anything in space, that might fly between this incredibly powerful, possibly 100 gigawatt laserbeam, and the spacecraft, like satellites. Plus, their tiny spaceships would have to be able to withstand the beam without melting and stay stable as they’re zooming through space. Not to mention, they have to be able to survive running into interstellar dust at 1/5th the speed of light without being blasted apart. The ships would also need things like a reliable and strong enough power source, as well as an effective way to communicate with Earth from so far away. Technology that we don’t have yet, on that small of a scale. And these are just a few of the issues that need to be solved and the team definitely has their work cut out for them. And a lot of fundraising to do. Milner’s initial $100 million investment is still only a fraction of the billions of dollars necessary to develop this project and all the related technology. It’s a big task, and one that’s going to take a lot of planning, and development, and time, and money. But if we ever want to visit other stars, even just with tiny robotic probes, we have to start at some point. Might as well be now. Thanks for watching this episode of SciShow Space News and thanks especially to all of our patrons on Patreon who help make this show possible. If you want to help us keep making episodes like this, you can go to and don’t forget to go to and subscribe. We’re going to move to a new studio soon, where it’s quieter. That’s loud.

100 Replies to “Could We Really Visit Other Stars?”

  1. I don't see how any non tiny ship would expect to go alllll the way to another galaxy or incredibly far away place in space especially at enormous speeds and not be overwhelmingly paranoid about random space debris that they could collide with before even seeing, or even their trajectories crossing by chance and in both cases, unpredictable and potentially catastrophic damage that could end the mission and all of x y z be wasted

  2. If Flying Saucers are real (which is the case based on mountains of evidence), and they are from another planet, lightyears away. Then we already have the technology present fo this sort of thing, only that it's hidden from the public, and known to a select few.

  3. Even if these spaceships reach Alpha Centauri and send signal back to Earth.. That signal would take 4 years to reach Earth right?

  4. Please stop the visit other stars scam already, we will never have the ability to do it, not even at the end of mankind. Fiction are fiction, you don't see people asking for $$ to find the real Santa Claus at the North Pole.

  5. I always wished I had lived in times when you can just visit another planet to cry after your girlfriend broke up with you.

  6. they got to do better, make bacteria like robot which i consider bacteria probably robot make by alien to terraforming the planet so it more "livable ". the robot will replicate itself once reach a suitable planet and built up bigger machine to communicate with earth.

  7. Man, this will need an international scale of cooperation and funding. I doubt I'll be around when and IF this is even launched…

  8. lets not forget the huge challenge of concentrating laser beams on a postage size object when its gets very far from earth. Is would be worse then shooting a gun from LA and aiming at a pea sized target in japan.

  9. the price of the project is around a trillion dollar but if the price will keep going down like it does right now then in ten years it will only cost 10 billion dollars

  10. a tiny spacecraft the size of a postage stamp … capable of sending data ALLLLL  THE WAAAYYYY BACK to earth … yeah.. sure …. not happening.

    nevermind the fact that this craft would have to be capable of collecting some sort of useful data to send back .. AND resist incredible impacts …. suppose you could build circuits into aerogel … but that'd still be too heavy

  11. that should be extremely difficult to aim right? 'cus it seems to me you won't be able to steer/manoeuvre the craft after you propel it with lasers. Or can you?

  12. This is the reason why it is so important to know the truth about UFOs. If aliens have the technology for interstellar travel then it is possible that someday man could travel to the stars. I believe there are other civilizations throughout the universe but whether one of those have ever visited the earth is a whole other question.

  13. Could they put the lasers on sharks? I don't think they'd have a problem finding funding if they'd just agree to put the lasers on the sharks.

  14. Great news. It's about time, frankly, that people started to put money and research into seriously traversing the stars. We learned a long time ago that rockets are not going to be enough to do this, so it is about time someone embraced the von Neumann model (though these robots will not be as advanced as he envisioned them, but at least it's a first step) and took the idea seriously.

  15. Breaking News: Astronomers say that there will be 7 planets left in our solar system because they are going to destroy Uranus. So, protect Uranus with your life…..

    If you still want Uranus.

  16. Boy, I'm only 13 years old now, that means I'll have plenty of time to see this unfold. I'm incredibly excited, considering that we're likely sending something synthetic into ANOTHER GOD DAMN SOLAR SYSTEM within this century.

  17. So if it launches around 2040 and takes 20 years to get there, we should have the data around 2080? Ugh I don't know if I'm gonna live that long

  18. One problem (I'm probably wrong tho), Since light (lasers) expand when going very far distances, couldn't some spacecraft drift off into even deeper space unintentionally? UNLESS you make the laser extremely concentrated… I assume…?

  19. We could get to other stars by bypassing the speed of light. Supposedly it can't be done by conventional means but that doesn't mean it can't be done.

  20. Is it possible to travel to another galaxy?

    I heard that we have a lot more influence of dark mater within galaxy.
    I mean theoretically – is there some obstacles and danger in space between galaxies?
    Will not our spacecraft decay on molecules, and lost its stability beyond galaxy's boundaries?

  21. Probably someone already commented but (assuming they are making a solar sail style ship to catch the laser) if you're making a giant solar sail, why not actually put the nanotech into the sail – that way the 'postage stamp' isn't actually small, but rather interwoven (with plenty of redundancy) into the material of the solar sail? like long chains of computers and instruments, woven into the sail itself?

  22. ok so I'm guessing the laser will be constantly shooting from earth, why not just make the spaceship shoot the laser and then have a better propulsion system? you would of course have to keep it aimed at earth

  23. If you want this proyect founded quickly, tell the ministry of homeland security and defense that there's terrorists in alpha centaury.

  24. Originally I was afraid that the ugly broad was going to be the reporter for this episode and found out that it was the guy… Phew close call right guys?

  25. We need to do what we can to invest in warp drives. Surely it can happen, right? Not in our lifetime, but still!

  26. I am curious, why not to use focused solar light to propel aircraft. I do not think that lunching mirrors will be more expansive than building a 100GVt laser. However sunlight not as focused as a laser coherent beam, may be this is an issue.

  27. The spaceship reaches Alpha Centauri, and people live there and their scientists blow it up, lots of money wasted + time …..

  28. The one problem that came into my mind was, how are we going to get that info back. It could take centuries considering the distance the data needs to travel. So I thought how about the craft getting back how would that work?

  29. Instead of saying "41 trillion kilometres" you could just say "41 petametres" and save a few syllables. Still, at least you're using metric units. You might want to get into contact with The Metric Maven. He'll be happy to help you come up with a good measurement policy.

  30. How will they overcome time dilation effects of moving that fast? or the redshifted signals we get back? at that speed, wouldn't planet or star look like a massive streak instead of a stationary object?

  31. If only we can build a space elevator, we can cut the project cost in half or more because we can deploy the laser in space easier and we do not need a lot of the emitters when there is not atmosphere that weakens the laser.

  32. So I've always been told that photons are massless particles, so how can particles with no mass have any force at all?

  33. Deceleration ialso an issue. Reaching big speeds one thing. Decelerating is another. Unless you wanna have 2 seconds of data as they zoom past AC

  34. Dear NASA:

    Stop dicking around with Mars and develop good enough technologies so I can at least see an interstellar voyage in my lifetime.

    Love, Callum.

  35. With technology getting faster and cheaper, the project will also be that much closer too. If governments "hopefully cooperative* join and support the project (they will want to be involved for security reasons anyways) that would help it happen even sooner. The team is figuring out great solutions for issues/challenges, and exploring many great ideas that'll improve the nanocraft project. Not too long ago this would of been crazy talk. I doubt the estimated time to finish this will be as long as they say. I'm excited.

  36. MAN CAN NOT ENDURE SPACE FOR 2 Years 3 months. Radiation from deep space equivalent to 4500 full body x-rays a day. @ Hiroshima Victims study.
    Space makes your liver shut down entirely in one years time. @ NASA/JPL Twin Brother experiments.
    Bone loss of 42% bone and muscle loss in one years time.
    Blindness: Space brother is wearing corrective lenses and no flight pay 30% of all astronauts that have spent 6 weeks or longer in space about 600 people thats a very high number and maybe everyone on board.
    Women: absorb 4 times more radiation that a man. They would show signs of aneamia before the men and never survive to make mars.
    We in these frail bodies cant escape our dear life boat earth. We must to survive a titanic wreak of colliding galaxies head on. We will be assimilated, fried by new star formation and millions of degree gas and ripped apart stars. Head on the absolute worst way to hit the core collision will sterilize our galaxy.

  37. If this works, I'll be an old man once we get any information; but I'll still probably be excited about it.

  38. I would love to see this, but I don't see this happening in our lifetime. Hopefully the future generations can figure out the how and financial aspects of it. We're going to miss a lot of amazing moments.

  39. (1) They need to build it in space, (2) We need to discover antimatter so we can send something bigger…. but I guess you have to start somewhere right? (3) It might be helpful to kickstart the probe with normal fuel and then propell it faster with said device. ….. Someday we will have a fully functioning acceleration gate that is far more powerful and will be able to send full sized probes but at the same size… I see this as a small step towards that. Best of luck to them… they are going in the mean time to have to find a way to reduce the price. Perhaps they could use energy from the sun?

  40. It'd help if we sent a probe to a uranium-rich asteroid to construct a giant array of nuclear reactor powered lasers.

  41. So a question on the communicating with the miniature space crafts. Would this be hypothetically achieved if we found a way of utilizing quantum entanglement to communicate?
    I know this is meant to be impossible, but I don't understand why, and aren't there hypothetial ways of getting around those issues?
    For example:
    -Uncertainty can be tackled by diliberated forcing particles into a specific state (see which shows that an electrons spin can be forced).
    -Or how do you detect the spin of the particle without altering its state (see same video where transistors can be used to detect induced electrical current of up spin, without altering the state through shining photons on the particles).
    -If entanglement has been observed on earth, why would communicating technically faster than light be a paradox? Surely it would arrive at the same moment it is sent and not arrive before it was sent?

    I mean what if you were to set up systems where entangled electrons were embedded into seperate devices and then put one literally anywhere else where communication using radiowaves (or other electromagnatic wavelengths) doesn't work because of physical barriers or vast distances? You could potentially have people remote-controlling rovers on Mars, or getting live feed from those tiny, extremely fast space probes Stephen Hawking kis talking about?

  42. My thoughts: Build a large, and I mean LARGE, generational ship in orbit, similar to how the ISS was built. Crew it with no less than 500, carefully screened and selected, volunteers from all corners of the globe and from all walks of life. They can't all be rocket science astronauts, some need to be artist, authors, musicians. We need doctors, farmers, teachers, clergymen. People to create and expand Earth's culture. Social diversity is just as important as genetic diversity.

    Make sure there's ample space for livestock that produces more than one resource. Example: cows give milk, butter, and cheese plus creates offspring that can be killed for its meat. Chickens are another example because of its meat and eggs. Livestock also provide fur and leather so clothes can be made. Make sure there is an equal or greater space for aquaponics, hydroponics, and aeroponics. The very essentials needed for intergalactic travel, sustainable agriculture.

    Then, simply pick a star and go. I know the logistics and funding would be an astronomical* nightmare but it's not impossible. We would just need to simply obtain world peace and create a society where money has no meaning. Completely impracticable and improbable, but not impossible.

    If this is starting to sound familiar, then you've seen Star Trek and more precisely, Star Trek Voyager's episode "The Disease" which has a Varro generational ship. That's why I've always preferred Star Trek over Star Wars. Trek is more about exploring and expanding. The betterment of mankind. Versus Wars which is about conflict and how some guy with a really bad case of asthma is trying to take over the galaxy.

    Well, that's my 2 cents worth. Now, let the battle of War v. Trek commence! Hell, while we're at it, throw a little sub v. dub action in there too. That topic always makes for a great nerdy debate..

    *astronomical, get it? Because it's astro, relating to stars? Oh, never mind…

  43. its almost impossible (i think) cos if you could go to the speed of light it would take a handful of years to travel there (also depending on how far away it is) and by the time you get there it would of felt and took slightly longer than normal, cos of dark matter and gravity pulling it away very very slightly and time dilation doing its thing.

    NOTE:(also im not sure if its scientifically true i just thought of it and searched it up online. and i know this comment litteraly has nothing to do with the video but i put it down anyway because frick it)

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