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I know enough physics to say no Even inter-Stellar is out of our reach (without generation ship).
We have zero reason to believe in an effective way to build wormhole, jump gates or anything similar. Even high energy cosmic rays have a limited range (due to collision with photons) which is a strong clue that there is no shortcut in space
This is the correct answer.
I think the closest we will come is detecting radio signals from another species. But like obviously 2 way communication would be almost impossible due to sheer distance.
Sadly the universe is filled with enough random radio radiation that its unlikely any coherent signal is going to travel more than a few light years. With our current technology there could be an identical version of earth around the nearest star and we probably couldn't detect it.
The signal isn't destroyed though. So one could argue that isolating it in the noise is doable with enough math.
Obviously the real limit is still distance since we'd need a radio dish like the size of earths orbit or something to pick up a signal weakened from many lightyears away.
the closest we will come is detecting radio signals
But we are talking about intergalactic here.
Radio is only lightspeed, and that is much too slow to cover such distances.
But doesn't the generation ship / cryogenic technology / nuclear technology make intergalactic travel possible (albeit very slow)?
It makes interstellar travel plausible but not intergalactic.
In theory yes... but the oldest frozen specimen of humans we've found is only a few thousand years old. We don't even know if long term cryogenic reanimation is possible.
Assuming the ship travels at 10x our current capabilities we're still looking at ~8,000 years to reach our closest stellar neighbour at only 5 lightyears away.
Then don't do it that way, put a human consciousness into a machine and wait. They said ever, we can get as sci-fi as we want here
We'll still run into the same assumption/problem; shelf life.
Consider how memories work. Every time you remember something, your brain alters that memory slightly. Even looking at how the brain parses the data through several cortex (visual etc) implies that consciousness is potentially inseparable from the components of the brain. In this video about Cockatoo intelligence they speculate that birds brain anatomy causes them to think in ways that seem limited to us.
Basically we don't even know if its possible to preserve human consciousness for that long. Similar to cryogenics we have to question if reanimation is even fundamentally possible after centuries.
It's a simulation of a human consciousness, it can be paused and restarted when certain conditions are met.
Fuck it, let's assume we can build jump gates.
Let's say they're just big enough to send a tiny unmanned drone through.
I hop into my space ship and accelerate with a conventional engine to 86% of light speed.
No violation of physics needed, just shitloads of energy.
I fly to another star, which takes 10 years from earth's point of view.
Due to time dilation at 86% light speed, time in my space ship passes half as fast as on earth.
If someone on earth had a strong enough telescope, they could look at a clock on my ship and see that it ticks half as fast as the clocks on earth.
But in my frame of reference, earth moves away from me at 86% light speed.
So if I look at earth through a telescope, I see that the clocks on earth tick half as fast as mine.
There isn't a universal time. Time is always relative to speed and this is no problem when the reference frames are separated.
I arrive at the star, after 5 years have passed on earth.
I activate a jump gate and send the drone through with a message. It arrives on earth instantly, 5 years after I left.
But from their reference frame, they could see my clock ticking only half as fast as theirs.
After earth's 5 years, only 2.5 years have passed for the space ship they see.
They activate their jump gate and send the drone back with a reply.
It arrives instantly at the star, 7.5 years before my space ship gets there.
This is why FTL travel isn't and will never be possible. Even with tricks like jump gates or wormholes, it creates time paradoxes.
That's not how it works. You're correct when you say that from your point of view it's Earth's clock going half speed and from Earth's point of view it's your clock going half speed while you're traveling away from Earth (or Earth is traveling away from you, both are equally valid), but that's only true as long as the distance between you and Earth continues to increase at 86% of the speed of light. As you decelerate at your destination your reference frame continuously changes until you're back in the same frame as Earth (or nearly so, we can assume the two stars aren't exactly maintaining their relative positions). While you're decelerating, from your perspective Earth's clock speeds up and goes faster than yours, how much is determined by your rate of change in relative velocity. Earth's reference frame isn't changing (ignoring movement around the sun, galactic center, the great attractor, etc.), so the Earth's perspective on your clock doesn't change, the Earth sees your clock gradually speed up as you "slow down" until it's going the same rate, but never faster. So once you're back in the Earth's reference frame both you and the Earth will agree that your clock advanced 5 years while Earth's clock (and your destination's clock, adjusted for any relative movement between it and Earth) advanced 10 years. This assumes a constant 86% light speed and ignores the time accelerating at departure and arrival so let's assume very fast acceleration so it doesn't change more than a couple days.
Edit: this is all completely ignoring gravity based time dilation from the spaceship climbing out of Sol's well and going down the destination's well and only considers velocity based time dilation. It would be more correct if you only considered two spaceships in a void where one accelerates to relativistic speeds and then accelerates back into the reference frame of the other.
Assuming a mechanism exists that changes the universe from being singly connected to multiply connected (i.e., wormholes exist), it is possible to have wormholes permitting faster-than-light travel without time paradoxes, though some additional restrictions may apply.
We have already shown that wormholes connect across both space and time, so that a trip between star systems could take you hundreds of years into the future, and the return trip takes you hundreds of years back in time. And this is even before we throw in how time slips between planets when considering relativistic time dilation due to different speeds and gravitational potentials.
Fortunately, all the weirdness of different time rates and going backward and forward in time can be ignored by the average person. This is because you never need to go from one world to another, or back, across the vast gulfs of interstellar space. You just take the wormhole between them. All you ever need to worry about is the coordinate frame that goes across the wormhole. When considering this reference frame, you're not hopping all over the place in time. If it takes ten minutes to cross the wormhole between the two planets, when you get to your destination world the clocks will read ten minutes later than they did when you left your departure world. By coordinating their time-keeping across the wormhole network, all of the worlds of the network can agree on a common time to coordinate their activities. This is all travelers ever need to worry about, and they can then ignore all the relativistic weirdness. Your network engineers will still need to keep track of relative time drift and how close a given configuration is getting to a time loop. But unless your protagonist is a network engineer, they can just ignore all that stuff. And, as an author, so can you! Assume your engineers are competent, you have good regulatory bodies and standards institutions, and don't worry about any of this "time travel" that doesn't actually let you cause paradoxes.
Strap a solar thruster to the sun, and the Earth and Venus can be used as generational ships. The rest of the solar system will follow the sun. The starlifting array needed to power the thruster will keep the sun "young." There's more than enough Hydrogen and Helium to dump in as fuel.
Venus is a fixer upper, but it just needs several oceans worth of water ice, and some cyanobactera flung at it to cool it down. Maybe we can look into diverting some comets into Venus, I dunno.
Totally.
The Milky Way is on a collision course with Andromeda, so we are already on our way!
Maybe Andromeda is coming to save us. Isn't that what The Andromeda Strain was all about?
That reference was a bit strained.
Humans? Nope. Some kind of actual AGI that doesn’t care about long time scales and can be lashed to a metal rich asteroid and flung out of the solar system? Still probably not, but it could maybe make it to some interesting intra-galactic destinations.
This is basically the foundation for Stanislaw Lem's book The Cyberiad. What if robots built robots that write poetry and fight robotic dragons and travel the stars.
Also the Bobiverse books. Human brain uploaded to a machine and strapped to an engine to sail the stars where stuff happens
Nope
i think we'll destroy ourselves before we get that far
Me, trying not to write a political comment on a non-political question.
I'd guess we're either going to reach futuristic Star Trek communism or a dystopian world-wide techno-feudalism.
Just need to convince the billionaires that there are underage kids to rape on the other side of the galaxy
I was about to pedantically attack the term "underage kids," but then I realized how many juvenile adults there are out there and decided it was valid.
Can't get to the United Federation of Planets without World War III first.
Not for humanity, not as we currently understand ourselves as humans anyway.
I'd argue that it may not happen for individuals. But our DNA? Our culture? Or knowledge? I'm pretty sure these things will travel the stars one day.
Stars yes, voyager is carrying a lot of that info already! But the delta between stars and galaxies is monumental. Andromeda is 2.5 million light years away. The time scales aren't even something we can grasp.
Greg Egan's Diaspora sets out how humanity could explore the galaxy and even the multiverse, which if you can't be bothered reading consists of:
In the here and now the only way to travel to another system with our current tech is via nuclear pulse engines.
Basically you build a large spaceship. Stick it on massive shock absorbers which are in turn connected to a metre plus thick steel plate.
Cut small hole in the middle. Have a door that opens closes.
Eject 1kt explosive device out door. Repeat 500x till you get to orbit.
Basically you could get a spaceship up to very high speed with nuclear pulse engines to turn a multi hundred year journey into less then 100 years.
That said the biggest problem with interstellar journeys is that our material science and manufacturing tolerances are pretty shit. Essentially all of the air will leak out through the metal skin of the spaceship.
I still think carving put an asteroid, sticking engine on it (see nuclear pulse engines) , covering it in ice and water will solve the problems radiation shielding, losing critical gases and provide ample fuel and water for a very long journey.
I suppose it all hinges on what humanity manages to figure out, physics-wise. I like to keep the door open
No, not unless we have made some serious mistakes in our understanding of physics.
I would say it's pretty likely that we have made some serious mistakes but also probably not possible.
Absolutely.
What form it will take is the question. FTL, not likely but long ago we didn't believe in breaking the speed of sound. Generation ships, solar sails, ion drives, folding spacetime, it will happen somehow if we survive as a species.
No, I genuinely don't believe it will. I don't think the human race will ever reach another star, though I do believe it could be possible if we avoided going extinct for a few thousand years.
Another galaxy? No chance, not unless we figure out FTL, which I don't believe is likely. The only FTL I've heard of that might be possible is the Alcubierre drive, but it relies on things that are so exotic, it's likely impossible to create one.
With our current understanding of physics it is impossible. Sucks, I love sci fi but they all rely on inventing some magic machine to make it possible.
There is another layer. You are not only trying to travel through space, but also time.
We know the formula: s^2 = (ct)^2 - d^2
s: spacetime distance/interval (invariant no matter the observer)
c: speed of light
t: time
d: coordinate in 3D space
Now, let’s say we have 2 travelers who need to meet at a certain place. Traveler A is 1 spacetime distance unit away Traveler B is 2 spacetime distance units away.
If they are both at the same age when they started the journey, B would be younger than A even though A is closer to the destination than B! Because B experienced more time dilation, and A needs to either wait at the destination, or travel slower.
So to meet each other at a relatively same age, B needs to travel slower on purpose, or A can take a detour.
Millions of years become meaningless, people who have no spaceships would be a death sentence. They would never see loved ones again. So in a sense, enormous ships that can travel at near the speed of light are a norm for that type of civilization.
We are unfortunately at a very early time of the universe. If we are born later, we could probably see other civilizations travel to us :D
Space travel is weird. Brain hurty.
The kind where one can get to a different galaxy in a single lifetime? I doubt it.
Everyone here saying confidently "no" hasn't kept track of science over the last several thousand years. There have been hundreds/thousands of things that have been "that is impossible" that we simply didn't have the knowledge for to be able to do.
200 years ago you would have been laughed at for thinking man could ever take to the skies, and now flying is a boring tedious thing for us.
75 years ago the idea of carrying a computer in your pocket with thousands of times the sum of the entire compute availability in the world back then would have been scoffed at, and people would have told you it's impossible. Now we use it to post on forums like this like it's nothing.
Both are examples of "it's impossible, the science says so", but that's the neat thing about science. We learn new things every day. Our thoughts change, you don't "believe" in science, you only learn new things.
So is it impossible? I think it's incredibly small-minded and dare I even say arrogant to say it's impossible. How do we know what will be discovered tomorrow, or 100 years from now, or 1000 years from now? We have absolutely no idea what will be possible then. With our current technology? Absolutely not. In 400 years? Who knows someone may be standing in line at security and see a meme making fun of us for thinking it was impossible.
Speed of light limitation. Andromeda is 2.5 million light years away. Even if someone debunks special relativity and finds you could go faster than light, you would be moving so fast relative to cosmic dust particles that it would destroy the ship. So, either way, you cannot practically go faster than the speed of light.
The only way we could have intergalactic travel is a one-way trip that humanity here on earth would be long gone by the time it reached its destination so we could never know if it succeeded or not.
We will just have to let Andromeda come to us.
The big problem is energy. If we had almost infinite energy we could accelerate to a significant fraction of the speed of light at a leasurely 9.81 m/s² in about a year. The travel at almost lightspeed would feel instantaneous for us. Add another year to decelerate at the same rate. We could reach any point in the visible universe in 2 years.
Our destination would just be drastically different from what we observed, depending on how far away it was.
Oh, and apart from the tiny energy problem cosmic radiation will probably destroy our spaceship. I bet at relativistic speeds you'd even get enough neutrino collisions to make them a problem.
It's already possible in a "does it violate the laws of physics or not" sense, the real question is, will anyone that has the requisite resources to do it actually want to.
It would take such an incredibly long time (as in, millions of years or longer for the very closest galaxies) that anyone and any organization sending out such an expedition isn't going to get any meaningful return on their investment, so it would only bring a benefit to whoever was on the "ship" when it arrived. As such, to even have a motive for doing this, you either need a society that does things for the benefit of extremely distant descends, or which is extremely long lived and patient.
As to how you would actually do it, my guess (obviously though, the guess of someone from a society that lacks the technology to do a thing is likely to be wrong about how it later is done) would be that one would use a hypothetical type of structure called a stellar engine These are similar to the "dyson spheres" that science fiction sometimes likes to talk about (usually inaccurately to the actual concept but still), except that they would use the energy emitted by a star, or its mass, to do some particular task, like propel the star in a given direction.
Doing this, your "ship" is actually an entire solar system. Getting that up to speed could take millions of years even for the most efficient designs, and obviously requires an economy capable of building stuff at incredible scales, and having an entire star spare to use for the trip. However, you're going to be taking that kind of time anyway, and so you're probably going to need an entire self contained civilization to have a hope of keeping things running that long, and literal worlds worth of raw materials. There's not much else that even theoretically has enough fuel to move all that to notable fractions of lightspeed. Since there's little point to going to live in another galaxy if there are still unclaimed places to go within your own, a whole star system is probably a relatively small expense for the implied size of civilization that would even want to try to sebd such an expedition. Galaxies contain a huge number of them after all.
While this is all obviously far beyond us now, both in technology and sheer economic scale, there's nothing physically impossible about it, and at least some logical motive (the future resources of a galaxy for one's descendants, if alien life is rare enough for uninhabited galaxies to exist). Given that and just how huge the universe is, I'd actually be willing to bet that somewhere there is someone or something doing this, and that if humans last long enough and keep advancing our technology and infrastructure all the while, some descendant of our species might, though they'd probably seem pretty alien to us by the time it took to reach that point.
Depends how long you have.
I hope we come up with warp drive or something crazy, but technically I don’t see any way this happens.
But if we could, we would ruin wherever we find habitable, and it would be the impetus for us to totally trash the Earth because suddenly it’s disposable and we can just go to Elysium or whatever other place.
We’d find planets and just fill them with toxic waste factories, because who cares, “we” (the rich) don’t have to live there.
We’d take visa scams to the extreme, forcing people into slavery on planets they could never escape from, and quash uprisings with bombs or stranding the people there.
Humans are too greedy and flawed.
I can picture the possibility of a probe visiting our nearest neighbors
But there are so many problems with a generation ship going that far, and no, none of the fun sci fi ways of travel are possible.
Bringing this back to reality, I can definitely see exploring more of the solar system and I can see making use of resources on hand for bulk consumables like fuel, oxygen, water, housing (we’ll have to to make it work). But consider how many things it would take to actually be independent of earth and how large the colony needs to be. Remote bases in our inner solar system can get away with that, but you can’t leave the solar system and expect to rely on any resupplies from earth.
Even if you could achieve the travel time to visit another star system and build a generation ship with enough supplies of everything and that could function that long, how would you survive without a preexisting functional colony of millions of people? Just start with the thousands of types of plastics we use every day and imagine trying to support that for a few people, without oil to drill or other organic chemicals to mine, and without a full scale chemical industry