My understanding with the Voyagers 1 and 2 is (a) they will run out of power before they would ever get far enough to benefit from a relay and (b) they benefited from gravity slingshots due to planetary alignments that happen only once every 175 years.
So building on the Voyager probes is a no-go. But probes sent toward Alpha Centauri that relay signals? Toward the center of the Milky Way? Toward Andromeda? Yes it would take time scales far beyond human lifetimes to build out anything useful, and even at the "closest" scales it's a multi year round trip for information but I think Voyager, among other things, was meant to test our imaginations, our sense of possible and one thing they seem to naturally imply is the possibility of long distance probe relays.
Edit: As others rightly note, the probes would have to communicate with lasers, not with the 1970s radio engineering that powered Voyagers 1 and 2.
Also once you have created the infrastructure of hundreds or thousands of very powerful lasers to accelerate the tiny probes to incredibel speeds, sending many probes instead of a few doesn't add much to the cost anyway.
The Voyager can be overtaken in several years if we to launch today a probe with nuclear reactor powered ionic thruster - all the existing today tech - which can get to 100-200km/s in 2-3 stages (and if we stretch the technology a bit into tomorrow, we can get 10x that).
I found that video very interesting! Especially the second half about apparent superliminal speed
But we already understand the physics and feasibility of "slow" (single-digit fractions of c) interstellar propulsion systems. Nuclear pulse propulsion and fission fragment rockets require no new physics or exotic engineering leaps and could propel a probe to the stars, if one was so inclined. Fusion rockets would do a bit better, although we'd have to crack the fusion problem first. These sorts of things are well out of today's technology, but it's not unforeseeable in a few centuries. You could likewise imagine a generation ship a few centuries after that powered by similar technology.
The prerequisite for interstellar exploration is a substantial exploitation of our solar system's resources: terraform Mars, strip mine the asteroid belt, build giant space habitats like O'Neill cylinders. But if we ever get to that point - and I think it's reasonable to think we will, given enough time - an interstellar mission becomes the logical next step.
Will we ever get to the point where traveling between the stars is commonplace? No, I doubt it. But we may get to the point where once-in-a-century colonization missions are possible, and if that starts, there's no limit to humanity colonizing the Milky Way given a few million years.
Humans evolved to live on earth. Our bodies fare poorly in low gravity, not to mention vacuum. Given sufficiently advanced technology, I'm pretty sure we could evolve some form of intelligence better suited to the environment.
The universe really doesn't want ChatGPT!
It is fair to say, that given space travel tech improves slowly relative to AI, but the distance to be travelled is so great that any rocketry (or other means) improvements will quickly pass previous launches, the first intelligence from Earth that makes it to another system will be superintelligence many orders of magnitude smarter than we can probably imagine.
It's easy until you try to actually build the damn thing. Then you discover it's not easy at all, and there's actually quite a bit of new physics required.
It's not New Physics™ in the warp drive and wormhole sense, but any practical interstellar design is going to need some wild and extreme advances in materials science and manufacturing, never mind politics, psychology, and the design of stable life support ecologies.
The same applies to the rest. Napkin sketches and attractive vintage art from the 70s are a long way from a practical design.
We've all been brainwashed by Hollywood. Unfortunately CGI and balsa models are not reality. Building very large objects that don't deform and break under extremes of radiation, temperature changes, and all kinds of physical stresses is not remotely trivial. And we are nowhere close to approaching it.
A more pragmatic me would point out that the required energy and materials needed would mean we would need breakthroughs in space-based solar capture and mining, but this is still not New Physics.
I think the solution will come from exponentially advancing self-assembling machines in space. These can start small and, given the diminishing cost of getting things to space, some early iterations of the first generation could be mere decades away. There are several interesting avenues for self-assembling machines that are way past napkin-sketch phase. Solar arrays are getting bigger and we have already retrieved the first material from an asteroid.
The quality and reliability of AI agents for processes orchestration and technical reflection is now at a stage where it can begin to self-optimise, so even without (EDIT) a "take-off" scenario, these machines can massively outperform people in manufacturing orchestration, and I would say we are only some years from having tools that are good enough for much larger scale (i.e. planetary) operations.
Putting humans there is a whole other story. We are so fragile and evolved to live on Earth. Unsurprisingly, this biological tether doesn't get much of a look-in here. Just being on the ISS is horrible for a person's physiology and, I am guessing there would be a whole host of space sicknesses that would set in after a few years up there or elsewhere. Unless we find a way to modify our biology enough so we can continually tolerate or cure these ailments, and develop cryo-sleep, we're probably staying local - both of these are much more speculative that everything above, as far as i can tell.
The engineering problem is insurmountable today. But there doesn't seem to be any reason it couldn't be done eventually, given our technological trajectory, unless we believe we are truly on the precipice of severe diminishing returns in most science and engineering fields, and I just don't see that right now.
George Cayley figured out how to build an airplane in 1799, but it wasn't for another century until materials science and high power-to-weight ratio engines made the Wright Flyer possible.
There are plenty of depths to plumb in space systems engineering that we haven't even really had a proper look at yet. A Mars mission with chemical propulsion is hard, but could be made substantially easier with nuclear thermal propulsion - something we know should work, given the successful test fires on the NERVA program back in the 60s. First stage reusability was fantasy 15 years ago, today it's routine.
Obviously, I'm extrapolating a long way out, and maybe at some point we'll run against an unexpected wall. But we'll never know until we get there.
Why Antimatter Engines Could Launch In Your Lifetime https://youtu.be/eA4X9P98ess (3 weeks ago) ... with that T-shirt. ... and the bit about theoretically possible warp drives (4 years ago) https://youtu.be/Vk5bxHetL4s
The furthest a human has been is 250k miles (far side of the moon). The fastest a human has traveled is only 0.0037% the speed of light.
The ISS is about 260 miles from the Earth. At that height, the gravity is actually roughly the same as on the surface, it's only because it is in constant freefall that you experience weightlessness on it.
Mars is 140 million miles away. And not exactly hospitable.
I like how you treat "the fusion problem" with a throwaway, "Yeah, we'd have to solve that" as if we just haven't sufficiently applied ourselves yet.
All of those incredibly difficult things we have not even begun to do are the technical reasons we have not gone interstellar and may be the reason we will never do so.
And even if we solve the issue of accelerating a human being to acceptable speeds to reach another star, the next closest star is 4 light years away. That means light takes 4 years to reach. Even if you could average half the speed of light, that's 8 years, one way. Anything you send is gone.
These enabling technologies are very, very hard. No doubt about it. That's why we can't do this today, or even a century from now.
But the physics show it's possible and suggest a natural evolution of capabilities to get there. We are a curious species that is never happy to keep our present station in life and always pushes our limits. If colonizing the solar system is technically possible, we'll do it, sooner or later, even if it takes hundreds or even thousands of years to get there.
> I like how you treat "the fusion problem" with a throwaway, "Yeah, we'd have to solve that" as if we just haven't sufficiently applied ourselves yet.
If you'd read my comment, you'd see I didn't say that. Fusion rockets would help, but we don't need them. Nuclear pulse propulsion or fission fragment rockets could conceivably get us to the 0.01-0.05c range, and the physics is well understood.
> And even if we solve the issue of accelerating a human being to acceptable speeds to reach another star, the next closest star is 4 light years away. That means light takes 4 years to reach. Even if you could average half the speed of light, that's 8 years, one way. Anything you send is gone.
Getting to 0.5c is essentially impossible without antimatter, and we have no idea how to make it in any useful quantity. Realistically, we're going there at less than 0.1c, probably less then 0.05c. Nobody who leaves is ever coming back, and barring huge leaps in life sciences, they probably aren't going to be alive at the destination either. It'd be robotic probes and subsequent generation ships to establish colonies. But if you get to the point where you are turning the asteroid belt into O'Neill cylinders, a multi-century generation ship starts to sound feasible.
You are talking about massive investments to shoot off into space never to return. Who's paying for that? The only way you do that is if you're so fucked, it's your only option and the profit in it is the leaving.
Not to mention, we need to solve the problems of living in space. Which we haven't yet. According to NASA. The space people.
And it very well could be an insurmountable problem. We do not know. We do know that living in microgravity fucks you up. We know that radiation fucks you up. But we don't even know all the types of radiation one might encounter.
> But if you get to the point where you are turning the asteroid belt into O'Neill cylinders
That right there is an example of "solve this impossibly hard problem and the rest is easy". We are nowhere near doing anything close to that.
What if there was a faith system of ultimatley going to interstellar medium. You have faith, you automatically pay, like the rest of the people and you dont question it. You get tax breaks. It will help you in the end of times or something.
Just decide the ultimate goal to be interstellar medium touching in all directions.
You are a farmer? Well now you continue to farm to feed budding spacers. You are a game dev? Well, people are going to get bored in space, continue developing games for the ultimate goal.
The human compatibility issues with microgravity are well known, as is the solution, which has even been proposed by NASA: centripetal force to create 1G for the astronauts.
As far the the radiation goes, we do indeed know exactly what kinds of radiation they would encounter. And the easiest way to shield humans from it in space is lots of water, or metal. We know this from extensive real work done on earth re: nuclear power plants.
The real issue is money, not technical feasibility. Once the dough rolls in from asteroid mining, it bootstraps the financing issue and pays for itself many times over.
NASA seems less sure than you do. And considering we have to get to the asteroids before we even start to think about mining them, talking about the money from asteroid mining is putting the cart before the horse.
If we do ever reach that distance again it will be even less likely we do it for a third time.
Absent a general decline in the capacity of our civilization the main hurdle I see is that the cost is paid by people who will not live to see the results of it but I don't think that rules it out, I'd certainly contribute to something like that.
What are some of the other factors you are thinking of?
There was simply no incentive to do so yet. But one day we will build faster spacecrafts and then we are going to overtake it quite quickly.
I certainly wouldn't bet against technological progress, and I say that as a complete doomer.
A flyby of both Jupiter and Saturn can be done every two decades or so (the synodic period is 19.6 years)
New Horizons (which has the distinguishing feature of being the fastest human-made object ever launched from earth https://www.scientificamerican.com/blog/life-unbounded/the-f... ) is traveling at 12.6 km/s.
The key part there is that it got multiple gravity assists as part of the Grand Tour https://en.wikipedia.org/wiki/Grand_Tour_program . You can see the heliocentric velocity https://space.stackexchange.com/questions/10346/why-did-voya... https://www.americanscientist.org/article/the-voyagers-odyss...
The conjunction for the Grand Tour is once every 175 years. While you might be able to get a Jupiter and Saturn assist sooner, it is something that would take the right alignment and a mission to study the outer planets (rather than getting captured by Jupiter or Saturn for study of those planets and their moons).
While I would love to see a FOCAL mission https://en.wikipedia.org/wiki/FOCAL_(spacecraft) which would have reason for such a path, I doubt any such telescope would launched... this century.
That alignment will happen many more times in the history of humanity. That is to say, I don't know if a spacecraft to overtake Voyager will be launched on the next alignment or one 10,000 years from now, but it doesn't seem unlikely to happen.
Once we leave the solar system in a self sufficient way I can’t see any event which would cause a species level extinction
IE either what speed Voyager 1 launched at excluding the gravity assists, or what speed New Horizons would have reached if it were launched 175 years after Voyager 1 (to take advantage of the same gravity assists)?
Another part in this is the "the probes are slowing down over time" - and you can see that with the Voyager 1 data that while the velocity after assist is higher than before, its not a line at slope 0 but rather a curve that is slowly going down.
This is further complicated because New Horizons had a launch mass of 478 kg and voyager was a twice as massive at 815 kg.
They also had different mission profiles (Could Voyager 2 taken a redirect from Neptune to Pluto? That trajectory change would have required a perigee inside the radius of Neptune...)
Voyager was done with a Titan III-Centaur rocket (that had a misfire) https://en.wikipedia.org/wiki/Titan_IIIE
> Voyager 1's launch almost failed because Titan's second stage shut down too early, leaving 1,200 pounds (540 kg) of propellant unburned. To compensate, the Centaur's on-board computers ordered a burn that was far longer than planned. At cutoff, the Centaur was only 3.4 seconds from propellant exhaustion. If the same failure had occurred during Voyager 2's launch a few weeks earlier, the Centaur would have run out of propellant before the probe reached the correct trajectory. Jupiter was in a more favorable position vis-à-vis Earth during the launch of Voyager 1 than during the launch of Voyager 2.
Note also in there that a few weeks difference between Voyager 1 and Voyager 2 had different delta V profiles (which is why Voyager 1 is faster)
New Horizons was done with an Atlas https://en.wikipedia.org/wiki/Atlas_V
... and I don't have enough KSP background to do the orbital mechanics for this.
Its not "interstellar speeds" but I'm pretty sure we could get probes further out than Voyager 1 faster if we put the money behind it.
Currently though there’s nothing planned to leave the solar system faster than voyager 1. New horizons will never catch up short of some weird gravity slingshot in millions of years which is probably just as likely to fling musks roadster out into interstellar space
What insight do you have into this issue that would suggest this is true?
... Be responsible for the very longterm torture of billions of intelligent lifeforms who are forced to drift through boring space for 1000s of years.
On earth, the tiny signal from Voyager at this distance is picked up by dish the size of a football field; same with sending of the signal.
What dish size would be required for a “cylindrical/tubular mesh” of probes, say, 1AU apart (ie Earth-Sun distance)? I’m pretty sure that would be manageable, but open to being wrong. (For reference, Voyager 1 is 169AU from Earth, but I have no idea how dish size vs. signal strength works: https://science.nasa.gov/mission/voyager/where-are-voyager-1...)
Much easier just to send probe with large antenna or laser, and make a large antenna at Earth.
Lots of small fishes can resemble a large fish.
And yes, the transmitters will need to be powerful enough be a distinct signal over the background of the star that is in the line of sight of the receiver / beyond the transmitter.
These baby probes could unfold a larger spiderweb antenna the size of a tennis court.
Both parties perform weak measurements on their qubits to extract these subtle signals without collapsing the entanglement, preserving high coherence across the stream. A quantum Maxwell's demon (e.g. many experiments but can be done: https://pubmed.ncbi.nlm.nih.gov/30185956/) then adaptively selects the strongest perturbations from the wave, filters out noise, and feeds them into error correction to reliably decode and amplify the full message.
That's not how quantum physics works. You might be misunderstanding delayed-choice. If you do think it works this way, I encourage you to show a mathematical model: that'll make it easier to point out the flaw in your reasoning.
On the plus side your big probe could push off of the small probe to give itself a further boost, also necessary because otherwise the small probes need thrusters to slow themselves to a stop.
Wasn’t Arecibo used for Voyager?
As I type this, DNS Now is currently receiving data from Voyager 1. https://eyes.nasa.gov/apps/dsn-now/dsn.html
https://imgur.com/a/kXbhRsj for a screen shot of the relevant data.
The antenna data is https://www.mdscc.nasa.gov/index.php/en/dss-63-2/
The logistics would be difficult since it involves catch those flying media, especially if the spacecraft were ejecting them as a form of propulsion, they might not even be flying toward Earth. I was just thinking how early spy satellites would drop physical film, and maybe there are some old ideas like those that are still worth trying today.
You could use this to create a relay in reverse order, but I also wonder if having a 50-100 year old relay would be any better than just using modern tech directly on the newest, fastest probe and then moving on to the next when there are enough improvements.
Plus keeping a probe as active part of a relay is a major power drain, since it will have to be active for a substantial percentage of the whole multi-decade journey and there's basically no accessible energy in interstellar space.
Then again, it's still far from clear to me that sending any signal from a probe only a few grams in size can be received at Earth with any plausible receiver, lasers or not.
Probes I suspect would realistically have to be large enough to send strong signals over long distances, so weightier than a few grams.
I think 99% downtime is an existing paradigm for lots of space stuff, e.g. NASA's DSOC and KRUSTY, so room for optimism there.
Though I think I agree with you that an energy payload as well as general hardware reliability are probably the bottlenecks over long distances. I have more thoughts on this that probably deserve a seperate post (e.g. periodic zipper-style replacements that cascade through the whole relay line) but to keep this on honoring the Voyager, I will say for the Voyager is at least for me huge for opening my imagination for next steps inspired by it.
The problem I see is that lasers are still subject to diffraction, and this is worse the smaller the aperture is relative to wavelength. Due to the small probe mass which you need to split with observation equipment, support systems and presumably some microscale nuclear power supply, you could maybe with a few breakthroughs in engineering manage a wispy affair on the order of a metre at most. It it scales with diameter and mass scales with diameter squared.
So the beam divergence of a visible light laser end with a diameter of over 18 million km over 4 light years. With 100W of transmission power, that's 0.1pW per square kilometer of receiver. Which isn't nothing, but it's not huge either.
I really don't see how the Starwisp type microprobes will actually work on a practical level at any time in the foreseeable future, even if the propulsion works. Not only is the communications a problem, but so is power, computational resources, observation equipment, radiation shielding and everything in between. But anything massier than that requires mindboggling amounts of fuel. And the problem is so much worse if you want to stop at the destination rather than scream past at a modest fraction of c and hope to snap a photo on the way past.
It really seems (sadly, in a way) that building gigantic telescopes will be a lot more instructive than any plausible probe for quite some time. An gravitational lens telescope would be a far better, and probably almost as challenging, project for learning about exoplanets. Not least it would be about 3 times further from Earth than Voyagers.
It might just have to be much too big to be worth it in the next n centuries.
If humans settle Mars it'll probably make sense to build one there for marginal improvement and better coverage with the different orbits of Earth and Mars.
It's faster than probe speed in this age, yeah. But still not enough, if we're talking distances to other specific planets, stars, etc.
Two possible ways to solve this, humans will become immortal or speed of light bypass method will be discovered.
also if this probe network reduces the transmission costs to normal terrestrial levels (and not requiring , say, a 400kw tx dish..) it could drastically increases the utility of the link -- and all of this without discussing how much bandwidth a link network across the stars might possess compared to our current link to Voyager..
(this is all said with the presumption of a reason to have such distance communications channels.. )
As you noted, some of the gains could be signal power, redundancy, the ability to maintain a quality signal over arbitrary distance; but most importantly, seeing the universe from the perspective of the lead probe in the relay, some arbitrary distance away.
Voyager 2 actually launched first, on August 20, 1977, followed by Voyager 1 on September 5, 1977. Because Voyager 1 was on a faster, shorter trajectory (it used a rare alignment to slingshot past both Jupiter and Saturn quicker), it overtook its twin and became the farther, faster probe. As of 2025, Voyager 1 is the most distant human-made object ever, more than 24 billion kilometers away, still whispering data home at 160 bits per second.
Voyager 1 was directed to perform a flyby of Titan, at the cost of being thrown out of the ecliptic and being unable to visit the ice giants like its sister. But this was deemed acceptable due to Titan's high science value.
[1] https://commons.wikimedia.org/wiki/File:Voyager_2_-_velocity...
NASA animation of Voyager 2's trajectory (time in the bottom-left corner): https://youtu.be/l8TA7BU2Bvo
While I'm here: why didn't Voyager 2 continue to slingshot to Pluto? The answer is that its trajectory would have had to bend by about 90° at Neptune, which would have required an apex closer to Neptune's center of mass than the planet's own radius - it would have crashed into the planet instead.
The two Voyager spacecraft are the greatest love letters humanity has ever sent into the void.
Voyager 2 actually launched first, on August 20, 1977, followed by Voyager 1 on September 5, 1977. Because Voyager 1 was on a faster, shorter trajectory (it used a rare alignment to slingshot past both Jupiter and Saturn quicker), it overtook its twin and became the farther, faster probe. As of 2025, Voyager 1 is the most distant human-made object ever, more than 24 billion kilometers away, still whispering data home at 160 bits per second.
Each spacecraft carries an identical 12-inch gold-plated copper phonograph record.
The contents:
- Greetings in 55 human languages.
- A message from UN Secretary-General at the time and one from U.S. President Jimmy Carter.
- 115 analog images encoded in the record’s grooves: how to build the stylus and play the record, the solar system’s location using 14 pulsars as galactic GPS, diagrams of human DNA, photos of a supermarket, a sunset, a fetus, people eating, licking ice cream, and dancing
The record is encased in an aluminum jacket with instructions etched on the cover: a map of the pulsars, the hydrogen atom diagram so aliens can decode the time units, and a tiny sample of uranium-238 so they can carbon-date how old the record is when they find it.
Sagan wanted the record to be a message in a bottle for a billion years. The spacecraft themselves are expected to outlive Earth. In a billion years, when the Sun swells into a red giant and maybe swallows Earth, the Voyagers will still be cruising the Milky Way, silent gold disks carrying blind, naked humans waving hello to a universe that may never wave back.
And it was Sagan who, in 1989, when Voyager 1 was already beyond Neptune and its cameras were scheduled to be turned off forever to save power, begged NASA for one last maneuver. On Valentine’s Day 1990, the spacecraft turned around, took 60 final images, and captured Earth as a single pale blue pixel floating in a scattered beam of sunlight — the photograph that gives the book its name and its soul.
It was the photograph that inspired this famous quote -
"Look again at that dot. That's here. That's home. That's us. On it everyone you love, everyone you know, everyone you ever heard of, every human being who ever was, lived out their lives. The aggregate of our joy and suffering, thousands of confident religions, ideologies, and economic doctrines, every hunter and forager, every hero and coward, every creator and destroyer of civilization, every king and peasant, every young couple in love, every mother and father, hopeful child, inventor and explorer, every teacher of morals, every corrupt politician, every "superstar," every "supreme leader," every saint and sinner in the history of our species lived there-on a mote of dust suspended in a sunbeam.
The Earth is a very small stage in a vast cosmic arena. Think of the endless cruelties visited by the inhabitants of one corner of this pixel on the scarcely distinguishable inhabitants of some other corner, how frequent their misunderstandings, how eager they are to kill one another, how fervent their hatreds. Think of the rivers of blood spilled by all those generals and emperors so that, in glory and triumph, they could become the momentary masters of a fraction of a dot.
Our posturings, our imagined self-importance, the delusion that we have some privileged position in the Universe, are challenged by this point of pale light. Our planet is a lonely speck in the great enveloping cosmic dark. In our obscurity, in all this vastness, there is no hint that help will come from elsewhere to save us from ourselves.
The Earth is the only world known so far to harbor life. There is nowhere else, at least in the near future, to which our species could migrate. Visit, yes. Settle, not yet. Like it or not, for the moment the Earth is where we make our stand.
It has been said that astronomy is a humbling and character-building experience. There is perhaps no better demonstration of the folly of human conceits than this distant image of our tiny world. To me, it underscores our responsibility to deal more kindly with one another, and to preserve and cherish the pale blue dot, the only home we've ever known. "
That picture almost didn’t happen. NASA said it was pointless, the cameras were old, the images would be useless. Sagan argued it would be the first time any human ever saw our world from outside the solar system. He won. The cameras were powered up one last time, the portrait was taken, and then they were shut down forever.
There's also the MESSENGER family portrait https://science.nasa.gov/resource/a-solar-system-family-port...
I think it would be nice for people to take a look at them:
- Aniara (2018)
- High Life (2018)
and maybe in a less artistic view:
- Powers of Ten (1977) yt: https://www.youtube.com/watch?v=0fKBhvDjuy0
Try that to give him a sense of awe. Watch it on a big screen, all the way to the end.
[1]: https://en.wikipedia.org/wiki/Daniel_Suarez_(author)
P.S. Read a lot of his book, great author
This turns entirely on how human biology works in zero versus low gravity. (Same for spin versus natural, or linear, gravity.)
The experiments we need to be doing is building and launching space stations and planetary bases for mice.
Of course, we aren’t anywhere near having the technology for that, and there may not be any suitable planets in that vicinity, but it also doesn’t seem completely impossible.
But we also cannot get complacent thinking that it's future generations problem. We need a breakthrough yesterday.
Basically, reducing costs and tech requirements by going underground (since it is underground we do not need to terraform the planet, and it is less likely to leak oxygen to external environment). Digging dirts and stones is a solvable problem. So optimistically I believe this is just an engineering/cost problem.
--
(§) Something like O'Neill cylinders with fusion as energy source could work
https://m.youtube.com/watch?v=X-3Oq_82XNA
We all Earthlings are extremely lucky to be alive and thriving (or trying to) in such a beautiful bountiful rarest-of-rare ecosystem that somehow survived and thrived despite all the vagaries and vastness of spacetime.
Power of 10: https://www.youtube.com/watch?v=0fKBhvDjuy0
Another relevant video (thanks to user christev for sharing the link): A Brief History of Geologic Time: https://youtu.be/rWp5ZpJAIAE
Absolutely humbling to realise how infinitesimally small and irrelevant our existence is, in the grand scheme of theme. Nature and science are amazing.
(Funny how we say “save the planet” when we really mean “save people/complex life”).
Incentives and goals are very different between the two. We could very much build even more incredible things today; and would argue that we actually do. Just only in the places that seem to matter enough to do that type of special effort for.
Headline is also misleading. It will do so in November 2026, about a year from now.
You often hear about the fatality rate per 100 million or 1 billion passenger miles in transportation statistics, but over the last 15 years, U.S. airlines have averaged less than 1 fatality per passenger light-year traveled
Still, mind blowing. When fact checking this I learned we went over 2 passenger light years worth of airline travel with no fatalities during that time frame. Incredible safety record. Real shame this year has been so terrible for our reputation.
[1] https://www.transit.dot.gov/sites/fta.dot.gov/files/2024-10/...
Some back of the envelope calculations give me roughly ~40,000 deaths per passenger-light-year if you travel by car instead of train.
Good news is that air travel is getting radically safer. If you do the "flight passenger light year" math for 1980-2000, you only make it a few light-hours per fatality, and for the 20 years prior to that, it was about 50 light minutes per fatality. Still safer than cars, on average (although some cars are much safer than others, and a lot of your risk depends on driving habits).
Make the model scale to be 10000000 (10 million). The sun is a chunky 139 meters in diameter. Earth is 15 km (9 miles) away. Pluto is 587 km (365 miles) away. The speed of light is 107 kph (67 mph).
Alpha Centauri is 4.1 million km (2.5 million miles) away... that is 10 times the earth moon distance.
Another comparison... Voyager 1 is moving at 30 light minutes per year. (Andromeda galaxy is approaching the Milky Way at 3.2 light hours per year)
75k years in geological timescales is nothing.
If there are creatures who could live longer than that, perhaps by hibernating or just having really long lifetimes, space exploration is feasible with slow craft.
If you can make that kind of trip the question becomes why bother? You could have used the same technology (actually a much easier version of the tech since you will have access to external resources and don't need to attach enormous engines to get it moving and then stopping at the destination) to use the almost unlimited space in your home solar system instead.
Unless your sun is literally about to explode it is hard to make the argument for the incredibly difficult and long journey to a neighboring solar system.
We can't see it yet, stuck as we are, in the present moment, filled with strife, failure, and disappointment. But the years and centuries to come will see us colonize the solar system, bringing new opportunities for millions, while easing the drain on Earth's ecosystem.
How can I be so sure? Because in the long arc of history that is what we've always done. We went from Africa to Asia to Europe and all the way to the Americas, founding cities and developing technology every step of the way. We launched into the Pacific, exploring island after island, eventually finding a new world in Australia. We have outposts on Antarctica and in low-Earth orbit. And I'm certain that, this decade, humans (Americans, Chinese, or both) will once again walk on the moon.
The people who launched the Voyagers believed that the future would come--they built a machine that would last for decades, knowing that people would benefit from its discoveries. Without that belief, they would have never tried it.
That's my lesson from the Voyagers: we have to believe the future will be better than the past, so that we can build that future. That what we've always done. We are all voyagers, and always have been.
Even if the only goal of colonization is getting resources (which I dispute), some individuals will risk colonization to get resources that they can't obtain at home. Resources are not evenly distributed across a population and, and every piece of land is owned by someone, but not everyone owns land.
The cost of space travel will continue to drop, and at some point it will make sense for people to seek their fortune there.
Moreover, we didn't land on the moon in 1969 to get resources, and we're not going to land in the 2020s for resources. The reasons are complex, and not always logical, but they are definitely not about resources. I don't see any reason why that would change in a hundred years.
That means it will reach a light year in approximately the Earth year 19,860.
These numbers aren't right...Mars is 4 minutes MINIMUM, but could be up to 22-ish minutes at the maximum distance between Earth and Mars. This is also one way, double that for communication and a response.
Also, does anyone know how long communication with the probe is disrupted when the sun is directly between them?
Now I'm presuming they aren't using the actual Earth position, but rather an average Earth position (which is basically just the Sun's position). Since Voyager is ~30 light minutes away from being 1 light-day away, that means this ~16 minute change can affect our 1 light-day mark by up to ~6 months!
My mind understands the numbers, but can't grasp them.
[0] https://www.southampton.ac.uk/news/2018/02/neanderthals-art....
Sometimes I close my eyes and imagine I traveled back in time to the days of the Dinosaurs and just observed how the world was back then.
But I wonder if I'd be able to survive. The atmosphere, environment, microbes, etc, would be drastically different from what we've evolved to handle. Millions of years ago is a very long time!
Edit: Apparently microbes from millions of years ago would be so evolutionary distant that they might not regard me as host.
I'm hoping VR will help with this.
48 years in space and a light-day from Earth? I think it qualifies for "about to" :)
(At this point 1 year is ~2% of total time in space)
Well duh!
I found this a bit silly given the headline: "well duh, that's the theoretical limit barring fancy quantum entaglement nonsense or similar!"
TIL all electromagnetic waves, including radio which Voyager 1 [uses](https://en.wikipedia.org/wiki/Voyager_1#Communication_system), travel at the speed of light. For some reason I always thought we had satellites doing some slower process or needing to somehow "see" light photons coming back from the probe to achieve near-lightspeed communication.
We just need a an engine that accelerates our space ships with 1g constantly. With that, we would reach something like 80% lightspeed after one year. Exactly in the middle between start and destination, we would turn the ship around and start accelerating towards earth again.
A trip to Alpha Centauri could be done in less than 4 years ship-time. Earth-time would be some years longer.
1g constant acceleration would be quite comfy for humans.
The only thing we need for this plan is the constantly running engine. I propose to bend space-time in front (or behind) the ship, for it to keep falling forwards.
But, yeah, I don't think we are ever leaving the Milky Way. Lol
A couple minutes [1].
> we will have to face the problem of time keeping across the galaxy
Not really. Barring relativistic travel, it’s not dissimilar from the problem seagoing voyagers faced on long trade routes. Ship time is set based on the convenience of the passengers and the route.
[1] https://space.stackexchange.com/questions/56055/if-voyager-1...
…because that’s what the math says? Based on Voyager’s relative velocity it’s expected to be about 2 seconds younger than it would have been had it stayed on Earth.
The lesson I see is that absolutely nothing humans do (including “wasteful fighting” and “over-consumption”) matters at all. We could colonize the solar system, or we could die out, and the Pale Blue Dot would remain the same either way.
It seems to me that people are desperately trying to squeeze a distorted message of hope from an image that fundamentally signifies the exact opposite of hope, namely indifference.
> After nearly 50 years in space
I mean, in the future this record will be broken, but right now this is quite epic. Go Voyager 1, go!
Show that the movie a space odyssey was wrong about what's out there.
https://m.youtube.com/watch?v=X-3Oq_82XNA
We all Earthlings are extremely lucky to be alive and thriving (or trying to) in such a beautiful bountiful rarest-of-rare ecosystem that somehow survived and thrived despite all the vagaries and vastness of spacetime.
I've read a ton about immense distances and time, but still get wowed when I read analogies or see visualizations like this.
Crazy stuff, man.
Another relevant video (thanks to user christev for sharing the link): A Brief History of Geologic Time: https://youtu.be/rWp5ZpJAIAE
Absolutely humbling to realise how infinitesimally small and irrelevant our existence is, in the grand scheme of theme. Nature and science are amazing.
Should this happen, we'll see many gigawatts of power in space. A spinoff of this would be large solar-electric spacecraft, or even large lasers for beam powered spacecraft. Either case should allow considerably higher delta-V than chemical rockets.
"On November 2026"
I know it's like a nanosecond in astronomical time, but come on...
voyager ping time 172,800 seconds
1000+ years from now a ship will take off from earth or orbit and pass Voyager in a few hours (assuming the planet is not turned into one huge radioactive, forever-checmical ocean before then)
"From this distant vantage point, the Earth might not seem of any particular interest. But for us, it's different. Consider again that dot. That's here. That's home. That's us. On it everyone you love, everyone you know, everyone you ever heard of, every human being who ever was, lived out their lives. The aggregate of our joy and suffering, thousands of confident religions, ideologies, and economic doctrines, every hunter and forager, every hero and coward, every creator and destroyer of civilization, every king and peasant, every young couple in love, every mother and father, hopeful child, inventor and explorer, every teacher of morals, every corrupt politician, every "superstar", every "supreme leader", every saint and sinner in the history of our species lived there – on a mote of dust suspended in a sunbeam. "
We can't keep our perfect home in working order after so little time but they believe we'll transform dead rocks with no atmospheres in paradise...
> "We bring you Mars", a rendering of a terraformed Mars at SpaceX Headquarters
Any billionaire pointing at space exploration as humanity's salvation is, IMO, either really just craving the attention and glory of conquest (much like Caesar, Napoleon, Alexander, etc) or seeking the conditions of the age of exploration (XV to XIX centuries), when companies were as powerful as governments and expansionism was unfettered.
Consider an alternate reality without food standards and regulations. Things like the melamine incident are commonplace and people regularly suffer due to contaminated food. Someone argues "perhaps the corporations should stop poisoning our food". Then someone else responds "Stop demonizing the executives, their objective is to make a profit, which they get from the consumers. The consumers are the ones buying the contaminated food, the executives aren't. If people don't want to get sick, they should exercise more diligence."
It's easy to offload coordination problems on the people who make imperfect decisions as a consequence, but saying "just don't have coordination problems, then" is rarely useful if one wants to mitigate those problems.
If billionaires were less greedy and paid more, more people could choose environmentally friendly options. If billionaires were less greedy and sold environmental options for cheaper, more people could choose environmentally friendly options. If billionaires cared about the planet, they could use their influence to pass laws for the good of the planet.
Instead you have corporations holding salaries down and squeezing margins from their customers. How's someone making the median salary in Bolivia ($3,631/yr) supposed to buy anything but the cheapest gas-burning car?
You got corporations going full cartoon villain too with disinformation campaigns, lies and bribes/lobbying to impede anything regulation that would cut into their profits. Exxon wants to keep selling gas, and the's a lot they can do (and have done) to keep you without any options but gas [1].
Technically, what we’ve done is almost boringly modest.
~17 km/s
~1 light-day in ~50 years
No realistic way to steer it anywhere meaningful now On cosmic scales it’s… basically still on our doorstep.
Psychologically, it’s still one of the most ambitious things we’ve ever done.
We built something meant to work for decades, knowing the people who launched it would never see the end of the story.
We pointed a metal box into the dark with the assumption that the future would exist and might care.
I keep coming back to this: Voyager isn’t proof that interstellar travel is around the corner. It’s proof that humans will build absurdly long-horizon projects anyway, even when the ROI is almost entirely knowledge and perspective.
Whether we ever leave the solar system in a serious way probably depends less on physics and more on whether we ever build a civilization stable enough to think in centuries without collapsing every few decades.
Voyager is the test run for that mindset more than for the tech.
It is a testament to the ingenuity of the engineers who have worked and are still working on the project that they've managed to keep it to some degree functioning for so much longer than it was intended to last.
Just like Opportunity lasted for 15 years, while its identical twin Spirit only lasted for 6. The Voyager probes could easily have failed long ago, they just didn’t. But not because of planning or foresight. Sometimes things simply work out well.
It makes me wonder when we'll have anything set foot in another star system. I would guess realistically after 2100, but then we went from the Wright brothers to landing on the moon in under 70 years... so I may be proven wrong.
Back of the envelope math - 4.2 light years to the nearest star that's not the sun, current vehicles traveling about 10x the speed of voyager (e.g. 1 light day in 5 years). If something was launched today it would get to the nearest star system in about 7,660 years (assuming that star system also a radius of 1 light day).
100x faster than current (1,000km/s) would still take 76 years.
Definitely not before 2100 and almost certainly so long after that we will seem like a primitive civilization compared to those that do it.
As I understand it, not really. Parker Solar Probe is crazy fast, but only because it has that trajectory, and is unable to just change course and keep that speed in other directions.
If you want to launch something for deep space, the Jupiter-Saturn slingshot is still the most powerful trajectory we know of.
Today's rocket engines would give the probe a higher initial speed, but the final velocity would not differ dramatically. A fair bit higher, but not orders of magnitude.
You are underestimating acceleration. To travel and come to a stop at 4.2 light years, a spaceship with 1g acceleration barely needs 3.5 years in relativistic ship time (~6 years earth time).
The technology to sustain 1g acceleration through 3.5 years is a different story, but very much within our understanding of physics (and not warp drives, etc). 20-50 years of engineering can get us there.
I want to believe, but I think it'll be a lot more than that. The rocket equation is a stone cold bitch in this case.
Sustaining the thrust that accelerates a probe at 1g is very different to sustaining the thrust to move the probe and all the fuel. And it's much worse if you want to stop and not just fly past into deep space.
It might not be. Plenty of hydrogen around everywhere. We just need tech to use it.
Our moon landing missions had a similar ratio, so I assume we can do the engineering to make even a slightly worse ratio work for us a 100 years after it.
In practice it would be better with slingshot maneuvers and picking up mass on the way.
What energy source do you think is merely 20-50 years of engineering effort away from being able to power that kind of journey?
My point is that we are in the realm of just needing new engineering (how to make nuclear reactions, or even antimatter-matter collision work for this goal), not new science (warp drives, something else we don't understand about space or gravity, or mass).
It's maybe too speculative to even matter, but I don't think it's _crazy_ to imagine a handful of AI-fueled advances in materials discovery during the next decade or two. Possibly enough to unlock laser fusion, or something that could be crammed onto a spacecraft.
There is no amount of money in the world that would get me on the ChatGPT rocket
You'd ship embryos and caregiver robots, start breeding/raising people 30 years before you'd arrive.
You are told you are to about make the great achievement humankind has ever made but all you want is a little bit more food and to take a shower.
For machine intelligence, though, it would be easy. Just switch yourself off for a few thousand years.
It's likely that our "children" will go to the stars, not us.
Not saying that other countries won't be able to do stuff like this - probably China is going to take the position that the US used to hold for this kind of exploration. It seems to be a more optimistic culture at this point, but hard to say how long that lasts.
> We built something meant to work for decades, knowing the people who launched it would never see the end of the story.
> We pointed a metal box into the dark with the assumption that the future would exist and might care.
> It’s proof that humans will build absurdly long-horizon projects anyway, even when the ROI is almost entirely knowledge and perspective.
The pyramids, the Bible, governments, or even businesses [0] are all human constructs that last way beyond their creators (and their intention), with and without their creator's intention.
> we ever build a civilization stable enough to think in centuries without collapsing every few decades.
This is a valid point though
[0] - https://en.wikipedia.org/wiki/List_of_oldest_companies
(Examples: "I keep coming back to this:", "Voyager isn't ... It's ...", "the assumption that the future would exist and might care", "on our doorstep", "see the end of the story", "depends less on ... and more on ...", etc.)
"the ROI is almost entirely knowledge and perspective" - this isn't a way I've ever heard an AI talk.
And at a meta-level, accusing someone of being an AI is getting very boring and repetitive (admittedly, I've done it once), and I expect we'll have to get used to that too.
They used to. But these days the people who control the economy and funding for things like this are either politicians interested in 4 year cycles or VCs interested in 5-10 year cycles.
Nobody gives a damn about long horizon stuff anymore. We landed humans on the moon half a century ago, and we still haven't reached Mars. Instead we're building some stupid apps for people who are forced to work 7 days a week in the office on some boring ads optimization algorithm to have someone to walk their dog for them and deliver their groceries for them and monitor their health because they can't get enough exercise (that would solve their health problem the way the body intended) and don't get time to leave the confines of their <strike>jail</strike> office.
I would put good money on a bet that there are more people today who deeply care about the long-term horizon than did in the 60s. I don't think we spent money on long-shots in the 60s because people cared more. I think we did it because it was relatively low-hanging fruit in a gigantic culture war between US-centric Western powers and USSR-centric Eastern powers. We don't have that kind of "most people agree it's an existential threat" level of cultural difference anymore. China? They sell us most of our stuff. We don't hate China, not really. But we hated the Soviets.
Dark forest theory sounds more rational conclusion on long enough timescale than Star trekkish utopias. Although, in next million years, if intercepted it should be trivial to pinpoint where it came from just from trajectory.
Discussing those odds at length would no doubt decrease them.
