It's funny how you weren't planning on ever visiting that galaxy 100 billion light years away, but when science says you can't it's suddenly all you've ever wanted. So weird how these limits are still unfathomably huge, but still feel depressingly small when you realize they might be absolute limits of travel for the entirety of forever.
Knowing humanity, just being denied the ability to travel somewhere we can see will just guarantee we do whatever it takes to get there, even doing the previously-thought-impossible like FTL.
Speak for yourself! I was planning to go actually. Until all of this Hubble-bubble-toil-and-trouble brewed up. Oh well. Physicists, astronomers, cosmologists.... who needs 'em?
Accepting challenges and developing genes to surmount that challenges is how life works. Imagine billions of cells in humanity creating emerging drive to conquer space based on those priniciples alone,
100 billion light years? Bro. That's the current size of the observable universe. It shouldn't seem small to you under any circumstance. We cannot begin to even imagine half of half of half of half of half of half of half of half that distance. A *single light year* is 6 TRILLION miles. Do you know how far a trillion miles is? Now multiply that by 100 *billion*. That is not small compared to anything we can understand, and our perspective and size truly is the context here, no other perspective matters. We are the size we are.
One of the biggest things I drew from this episode, that I've never really put much thought into, is that the speed in which we expand from Earth ultimately reduces the amount of communication we can have with it (same for any origin point).
Yes, it's almost a guarantee that if we can't figure out FLT communication then any future civilisations in different star systems and galaxies will be completely independent and not a part of some galactic/universal empire.
Only because we have n’t figured out how to move faster than light. Everything we think is immutable always dissolves. Light speed may be hard to crack but we really don’t know anything at this point. We’ve only be a “technological” civilization for a nano second as far as the universe is concerned. We are a single cell civilization at best
unless we can use Quantum Entanglement for communication in the future, then, regardless of our speed or where the end point user is, we should be able to instantly communicate
@@richardvivian3665I hope you're correct about the _"Everything we think is immutable always dissolves."_ bit. Until relatively (which is just a *blink* before us within _"nano second as far as the universe is concerned"_ period) the humanity has been living as city-states, with the hopes for a given person traveling beyond the visible mountain ranges were slim. In contrast to that, we can finally travel much further than that, now with the currently emerging technologies we'll be able to comfortably travel between the planets in our solar system. Maybe in a few *blinks* from now the humanity+ _(420.69$/mo \s)_ will be actually planning their travels across galaxies.
I love the thought experiment of the Slow Starship, that puts humans in stasis to travel to a distant star system only to awaken and find that future humans have already arrived by a faster starship and evolved both biologically and technologically!
If we were smart we'd send word to said ships that got out sped or even refit them in flight. Would be pretty funny to send out a ship and have it cruising along only to run into an FTL ship from home bringing all the upgrades and resources it needs to get a move on. :)
There's an old DOS game from the 90's called 'Alien Legacy', where Earth sent out a bunch of seed ships, you're the captain of one of these ships, and you emerge from suspended animation to a message informing you that another ship was launched several years after yours, but since it's a more advanced design, it will be arriving a decade sooner, and the other captain is now your boss. Of course, as you explore the system you can't see any signs of the other ship's crew, or habitations, so now you're left with a mystery to solve. (Eventually you do discover what happened to them, it's not pretty.)
@@Commanderziff I remember playing this game for hours and hours in my childhood. It was a great game; a good story and excellent mix of exploration, colony building, resource management, etc
I always thought of space and time being on such unfathomably massive time scales that we could never perceive a change without multigenerational record-keeping. Hearing that every *year* we lose 3 galaxies is so mindboggling.
No way to tell what type of technologies or events which might increase our travels in the universe.... so the PBS space time video is just a theory based on conditions of light speed travel
@@NTJedi Agreed. One can fairly assume that some sort of FTL travel will be available in the far future, which will change how this works. Also, if you travel close to the speed of light, there is relativity as well.
@@michaelvedal1907the more I read into it the more I think locally going faster than light probably is actually impossible. But I do think eventually we’d be able to create a warp drive or even travel through higher dimensions
hey matt, long time watcher and fan. The world is getting scarier as time marches on, but watching space time has consistently been there and given me something I can think about. Thank you for the work you and the rest of space time do. ❤
I feel like this channel is so good at slowly accumulating enough reference knowledge from past videos to bring up new and harder to explain topics. Very good programming.
That's why we need to continue to fund public television (and its progeny like this) so this type of free thinking is accessible to all. Let's not let the MAGAts destroy this, our public libraries, public education, public health and more.
@@mikemccormick6128 Matt has said many time that the channel relies on donations. It has always been its primary source of funding. Also, it is very inadvisable to rely on pubic funding, as that sort of thing always ends on wokeness. Is that what you want? That Matt starts to talk about feminism instead of cosmology?
@@afonsodeportugal All I'm saying is that the original source is PBS. The program originated on PBS. It is absolutely incorrect to say that this video is unconnected to PBS. I have no idea whether or not the channel is connected to PBS and I don't care. This video originally aired on PBS.
PBS Space Time is the perfect combination of huge knowledge and flawless animations, both in an ideal setup to enjoy the content and also learn from it. I've been following it for years and I'm still impressed. I really hope there's content for more years to come, I can't imagine my UA-cam feed without the joy of having a new video.
I think Anton should have a discussion with PBS spacetime regarding the calculation of inhabitable planets at 8:57. ua-cam.com/video/_Tju7EaSfmM/v-deo.html
I'm British and was at the Natural History Museum in NYC last month when I saw a very familiar, albeit beardless, Aussie physicist participating in one of the video exhibits in the space wing of the museum. Never knew you were quite so prolific, Matt!
A followup question I'd like to see explored: assuming we send Von Neumann probes in every direction as fast as possible and as soon as possible, programmed to retrofit every single star in the affectable universe with a stellar engine, and pilot them all toward each other at maximum speed, how much of the affectable universe could we bring together into a gravitationally bound cluster, so as not to be so isolated by the Era of Isolation?
My thoughts exactly. If we are doomed to heat death, exactly how much fuel (matter) can we accumulate before the rest slips beyond our reach? How much time can we buy ourselves through artificial stars or fusion generators or black hole batteries before the end of days? How much time will our science grant us to rage against the dying of the light?
@@Russo-Delenda-Est I'm sure legions of pessimists will immediately pile in here to scream at me about how wrong this is, but since dark energy already violates the *first* law of thermodynamics I'm pretty confident we can in principle exploit that to prevent the heat death of our local part of the cosmos indefinitely. My concern is more about capturing more information, staying in touch with more of the universe that we'd otherwise never be able to hang out with again.
@@Pfhorrest Iirc Issac Arthur had a video on this, "Fleet of Stars" I think it was called. As for avoid heat death, who knows? We can't begin to imagine what discoveries post-human intellects 100,000 years from now will have under their belts, much less the ones billions upon billions of years hence.
@@Pfhorrest 1. I'm not a pessimist. 2. You *are* wrong. Dark energy does not break the first law of thermodynamics. The first law of thermodynamics does not apply, because of the symmetry breaking of spacetime as it expands. (Emily Noethers mathematical theorem on symmetry).
For someone like me who did a first year uni physics course but knows nothing more advanced than that, it's the absolutely perfect level of information to get all the good stuff in there without getting so complicated that I get lost in the equations.
@@bertberw8653 Oh don't get me wrong, it's challenging, but I feel like he doesn't spend nearly as long diving into the complex math of the issue than other creator's I've seen talking at this level. ...plus I kind of skimmed past the string theory stuff lol, those videos were cool, but I couldn't really follow it all past the deeply simplified summary explanations. Maybe one day I'll reach the point where I can follow why exactly we think string theory might be real, but for now I'm just trusting the PhD holders on that one.
@@bertberw8653 that's actually really good to hear. Now I don't feel so stupid for not understanding some of the stuff. Did you see the episode explaining the equations of the standard model lagrangian? Hilarious ... sad ...
@@richardconway6425 Yeah, I just accepted that I'm less intelligent than most people in my major 😂 the good part is that accepting my place made me feel less pressure, and now I know I can just graduate on my own pace and terms
Thank you for posting this video at the exact moment that I was available and able to watch it. These videos always make me so happy... even if they are existentially disturbing.
I can’t shake the massive universe size of FOMO, thinking about the exploration and experiences we are missing out on by being born before we could explore any exoplanet…. It’s devastating.
I like the term "affectable universe". I wonder, if our universe turns out to be informational (or holographic) in origin, if the expansion of the universe could have something to do with affectability and causality in general. The more (complex) interaction the more the universe speeds up. Dark energy may be informational/computational in origin and naturally regulate the density of information and interactions within the universe, maintaining the informational structure in a way that aligns with the expansion. Kind of off-topic, but this episode inspired this idea :)
. . . I think if we ever figure out how to edit whatever the holograph stuff us made of, we can make a bunch of those screwdriver things from Dr. Who and do whatever we want.
@@blizzard1198you never know. 125 years ago we thought it would be impossible for a human to fly, or such an investment that they’d never see it happen. 60 years later they’re sending satellites into space. Laws (or rather our understanding of them) change over time. We find ways to use them to our advantage, or discover new ideas that allow us to circumvent them to a degree (a human on their own can never fly, but we can create machines based off of principles we discovered that do it for us, allowing us to reach the skies). Our 2 biggest enemies for getting off of Earth is time and ourselves. Time in that, how long do we have to get off this planet before a natural disaster wipes us out? Ourselves in that, nuclear war, pollution, over indulgence on resources etc., will stop us in our tracks. Or resigning ourselves to “it’s impossible” and never actually trying, whether we view it as futile or not. Until the day I die, I will believe it possible as we’ve accomplished the “impossible” time and time again.
I wonder if the Great Attractor is an advanced civilization attempting to gravitationally bind a large chunk of the universe before the era of isolation.
People generally fail to understand that the great attractor is just a point we can't observe because it's behind the galactic plane, it's nothing mysterious, and it's almost certainly just a dense region of space with a large cluster.
I got goosebumps when you brought up the great amazing Carl Sagan. "We will one day, venture to the stars." I miss his way of explaining. I think you do a very wonderful job making these videos and explaining as well. Keep up your hard work. That shirt rocks^^) A Glorious Dawn by MELODY SHEEP, go and listen.
Really nice audio editing It was refreshing to have no music during the core concept And even more impactful to have the music come in during the theoretical and story telling section. Thanks for all the videos! 😊
Movies exist to tell a story. It is called science FICTION. Old Science fiction used to imagine new worlds and amazing new things, but modern sci fi is just dystopian nonsense
Thanks for another fantastic video! I do have to say though, "These days there's not much of the Earth left to explore" made me do a spit-take right off the bat... The oceans and the Amazon spring immediately to mind.
I agree, I work as a pilot and often have the chance to overfly beautiful landscapes, but I feel my true experience of nature happens hiking ankles deep in the mud of the lowest valley rather than flying over the highest mountains. I don't think a lifetime is enough to explore the physical Earth, let alone the people, arts, philosophy...
What if we use Stellar Engines to push the star systems we inhabit towards the Milky Way? How many galaxies of stars could we potentially drag back into our Local Group before Isolation?
You would have to have 1 stellar engine per star. You couldn't use a single engine for an entire galaxy by tugging on the black hole. Remember that 80% of the mass of most galaxies is dark matter.
@@tr48092 Even if that's the case, as long as you accelerate a star, it will pull on the dark matter via gravity, just like how the gravity of the dark matter pulls on it. That's essentially the idea behind a gravity tractor, and if you build 1 stellar engine per star, you could accelerate entire galaxies, not quickly mind you, but over time, maybe quickly enough.
Powered by starlight they're too slow. Kurtzkazart's stellar engine however could probably get a fair few back Not much point though when you could just live there instead.
Could entangled quantum bits communicate beyond that horizon if we can escape it? Could one inside it get "magically" pared to one outside it and see influences without being there? Does the heat death date of 10 to the 10 to the 10 to the 56 take into account the era of isolation?
I was thinking about some kind of quantum communicator aswell. If we could entangle the particles ourselves one day we might unlock a way for them to have reasonable communication over some vast distances. Who knows what the future has in store for us
Entangled particles can share information instantaneously, but attempting to manipulate them to send a signal breaks the entanglement. You can't use them to communicate.
Sadly, no. You have to send regular additional information to decypher anything sent through such communicator, and that regular information can't travel faster than light.
Would it be the best plan to maximize resources by sending the colonies farther they can go without losing communication, use the resources from those systems and slowly migrate inward towards Earth as the Isolation Era approaches and engulfs our galaxy cluster? (I think I played to many RTS games)
@@ShadeAKAhayate yeah, what can they even do about it? Send in debt collectors in, like, a billion years? That's a lot of time to prepare a "welcoming party"!
I don't think he was being very honest about communications. Communications would take 10s of millions to 100s of millions of years depending on how far away these galaxies are. I think it is extremely unlikely that we will ever go past our local group. I think it would be highly unlikely that we will get past the Milky Way before life on Earth will be unlivable.
i think I asked this once before, but what is the radius of the non-expanding region of space that contains our galaxy? If I understand correctly, it is the "local cluster" of galaxies, but how big is that? Do we know where the boundary is between space which is expanding and the internal space of our local cluster, which isn't?
Yeah, I have read about this, and the sad answer is that all galactic clusters will eventually move farther and farther from each other. Our cluster is the Local Group, and it is small. It’s possible to travel to other clusters, as this video showed. But the longer you wait to begin going somewhere, the faster you have to go to get there. Descendants of humans might spread to several clusters of galaxies. I hope they will. But the civilizations within the clusters will eventually become permanently isolated from each other.
I personally believe we will have a base on the Moon, and probably at least send people to Mars, though realistically we won't colonize it as it just isn't worth the effort or the cost. I seriously doubt we will go any further than that. It's nice to dream though.
One thing I noticed writing a short story about this scenario: you can use the expansion of spacetime itself to do most of your deceleration for you. This simplifies the colonization process enormously, meaning extra-galactic-cluster colonization may be a great deal simpler than colonizing nearby galaxies. Still, I would question the value of colonizing things at the edge of our Hubble horizon - by the time colonists got there, the target galaxy would consist of nothing but red dwarfs and various types of dead stars. It'd feel rather depressing, I would think.
It doesn’t work that way. You don’t slow down. From your perspective the galaxy speeds up towards you the closer you get lol. Say you’re going half c towards a galaxy 5 billion light years away today. You start at 5 billion light years. Doing the math the galaxy is receding by 104,000 km/s from you. You’re going 150,000 km/s. You are gaining 46000 km/s. Boom; you’re 4 billion now. Galaxy is receding at 83,500 km/s. You’re still moving at half c. There’s been no force acting on you; you’re in an inertial frame. So now you’re gaining on it by 66,500 km/s. Now you’re 1 light year away. You’re gaining on it roughly 150,000 km/s. decelerate fast lmao.
It kind of sounds like every local cluster we visit will have it's own sphere that it can never lose communication with. Might be interesting to know which one of the current clusters we see would be the most optimal one to grow in.
The nearest one, the Virgo Cluster, is huge. Our Local Group is really puny. If our descendants can travel to other clusters, they definitely will travel to Virgo. That cluster alone has more than 1,000 galaxies to explore. The Local Group and the Virgo Cluster are in the Virgo Supercluster. The nearest other supercluster is the Hydra-Centaurus Supercluster, which is closer to the Great Attractor. The Wikipedia article on the Laniakea Supercluster (which is more like a super-supercluster) has some diagrams.
@@foragreenfuture6030Wrong. Locally bound objects remain bound. So the local groups remain bound. Gravity is still strong enough to resist the expansion at that point. If we can get to a large gravitationally bound cluster we’re effectively safe there. Super clusters don’t count. The individual clusters aren’t bound to each other anymore, they’re clustered because the filament structure of the universe emerged early in its history. Space is too big now, only local groups are bound. Tl;dr; gravitationally bound objects remain together. Objects too far apart don’t have enough pull to resist the expansion. Eventually all the galaxies in each locally bound group will merge into one super galaxy.
@@Karlswebb No, you are wrong. foragreenfuture6030 is talking about the Virgo Cluster. Yes we will lose contact with the Virgo Cluster. Why do you need to be so oppositional.
It would be interesting to see, based on these calculations and some assumptions of different points in time, where any alien life might originate from at the furthest.
just imagine in the not too distant future ,if humanity discovers that human civilization on earth is also a causally disconnected region of a far more ancient civilization (premise of Battlestar Galactica)
I would contribute a term of Frogging from the game Frogger. If we jump from log to log and wait for a galaxy to come closer to the “log” galaxy that we land within then we would have to wait for the next galaxy to pass by. This could be “forever” if we have actually understood the movement of galaxies from the observable universe. However being a violent society this may never be realized.
I'd like to see the same graphs showing a ship's communications, while traveling at C, sent and received, with earth not only as you have but also what happens when the ship stops, turns around and heads back. I'm just an old broken truckdriver struggling to grasp a general understanding of as much of everything I can. 🙂
Hey Matt, Awesome job with the channel. If you haven't done one yet can you do a video on what an interstellar spaceship would look like. How to house a population and what energy and food production would be. Thanks
i'm glad you considered speciation and intercommunication. IMO, human decendants can colonize a vast amount of space, but humans won't. speciation will likely happen before we even really leave ths solarsystem.
We already have the tech for 20%, it's just that it's currently banned. But treaties like that don't last forever, no treaty does, really. We've got far longer than humanity has already existed to decide to break the treaty and use the technology we already have, not even to mention invent new tech that's even better. I see no reason why that couldn't be realistic.
@@physics_hacker a trading that even North Korea Iran China follows? Could be I'm truly ignorant and don't know what treaty you are. Are you talking about one of those conspiracies Nazis on the moon, the Nazi Bell, or the Nazi base in Antarctica?
@@physics_hacker If we manage to create permanent settlements on other planets then they won't care about earth treaties. A cultural drift is guaranteed. Over a few thousand years they could even become a new sub species.
@@physics_hackermoreover these speeds are achieved by slingshotting and I have seen an idea using rotating black holes almost along an interstellar highway
Before we attempt this thought experiment, I believe we should discuss how much we would allow ourselves to modify what it meant to be human and still call ourselves human. As this is likely going to be a big part of the future with groups already dedicated to human modification and technology already dramatically enhancing the human experience.
What an odd thing to say. Considering this 'grand scale' is nothing more than a thought in your head, how can it put "life into perspective" for you? Life where you are at it he most important thing there is, as that is your life. What happens 'out there' has no affect on you, except as a metaphor for what occurs out there occurs down here, and what is above, is likewise below
@@pyropulseIXXI I think the simple answer to your question is that this person isn’t you and they have a different perspective and that’s okay lmao Have a good one
You know, the fact they can move through the atmosphere silently is significant. I've seen a vast ship, a disc possibly miles across, travel at several thousand mph across the sky silently before disappearing into thin air. It's also the ability to become invisible l find interesting. Until we humans have such a technology interstellar travel as these guys seem to do will be impossible. But l think it's beyond us as it seems to inhabit a different dimension.
Thinking back on the warp speed episode...if we can overcome those limits somehow to get warp drives, what would the warp factor have to be in order to get past our light cone to what is likely the most distant point? In say 100 or 1000 years
This concept of quintessence, a scalar field seems to be of interest in physics. I do hope dark energy is some sort of fundamental force we can find ways to effect as then perhaps c won't be our limiting factor. It's impossible to travel faster than c as it is the maximum speed but there seems to be more to our understanding of gravity, specifically in cases where it is repulsive rather than attractive. If we can find a way to bring spacetime closer instead of exchanging within it, that would be the way to go. But at the moment that seems to be beyond our understanding. If it is nothing but a dream 3 galaxies gone a year sounds pretty bad.
Communication solution: create a breadcrumb trail of communication satellites that remain in the orbit of each planet we pass. This would create nodes for signal communication to daisy-chain or hop a signal along between each planet (a much shorter distance). Rather than trying to send a direct signal all the way back to Earth and then directly all the way back, you'd just send it to your nearest planetary communication node or satellite to then propagate back and forth. Like we do now with cable/internet/phones but bigger.
A very sensible suggestion for practically achievable interstellar travel was made by Anton Petrov on his UA-cam channel a few days ago. It was rogue planets that travel independent of any star. Occasionally they generate heat enough to be habitable - on themselves or a moon - and also occasionally one such free-ranging vehicle of life might pass close to our solar system. If so then an expedition from humanity could hunker down on such a rogue planet and then just wait. If necessary for millions of years. A planet is a more realistic vehicle for multi-generation travel than any lump of metal and plastic which will always break down eventually. Just saying…
It would be interesting if you could implement time dilation from the perspective of humans on Earth relative to the humans on the spacecraft traveling at near light speeds
If we found some substance that produced the opposite effect of Dark Energy and could use it on a local scale to shrink spacetime in front of a ship while also using Dark Energy behind the ship to expand spacetime, could that be a method of getting past any of the Event Horizons?
What you're describing is called an Alcubierre Drive - or simply Warp Drive And the "substance that produces the opposite effect of Dark Energy" is basically just normal matter; we don't yet know however what Dark Energy is nor do we know whether any other substance exists that creates a negative energy density like Dark Energy
@@Astromath actually, no. The opposite effect of dark energy is just gravity. Ironically, if you want to make a warp drive, then it's dark energy itself that you want to harness, as it has exactly the kind of effects on spacetime that you are looking for- namely, the ability to create expansion or negative pressure. This is precisely why the cosmos is able to expand faster than light, we essentially live within a warp drive. The problem is that first of all, we don't know what dark energy is, so we can't manipulate it like we would want to in order to use it to make warp drives; and second, it appears to be distributed evenly throughout the entire cosmos, while we want to concentrate it in one small bubble of spacetime with a neat arrangement in order to create superluminal velocity. Until we know more about what dark energy is, the alternative is a bizarre thing called negative energy, which sorta does exist in certain conditions in quantum mechanics, but like all quantum effects, trying to make it manifest usefully in the macroscopic world is a pain and may not pan out. Maybe we can make a warp drive, but because of causality related reasons or hawking radiation, the best we can do is travel at exactly C. Which, in fairness, isn't possible any other way. The energy needed would be infinite.
@@formlessone8246 I mean, technically anything is a warp drive, since any massive object (an object with mass) can warp spacetime, just depends on what curvature you're looking for so, both of you are correct
@@formlessone8246 not all warp drive concepts require an expansion out of the back, some just have an extreme energy density in the front to compress spacetime and allow its natural elasticity to settle itself back out the other end. That'd presumably produce a much bigger disturbance of gravitational waves than a controlled re-expansion though.
it depends on a lot of things 1) how much quantum tunneling occurs per population member 2) how far away our colonies our 3) how many people are in our colonies 4) how gravity changes in the area, because mechanics vary an extreme amount based on gravitational forces in the area (I hate using newtonian terms, but I used 'gravity' for conciseness) 5) the decay rates of particles in the colony 6) the changes in the environment of the region, relative to earth calculate for all of the above, and you might have a decent picture if I missed anything, or got anything wrong, then feel free to change my list!
@@JoeWithTheHoesBiden #1 is the OP trying to sound smarter than he is. Also, see #5. #4 is again the OP trying to sound smarter than he is. #5 decay rates are not location dependent. Perhaps for #1 and #5 you meant the ambient ionizing radiation? #6 is just a blanket covering all environmental factors so it makes numbers 4 & 5 redundant.
What we send up is probably not humans of today. We are not very well suited for space travel. If we insist on humans, then an idea would be to terraform planets with ai before growing them
@@AlbertaGeek Yeah I'd be curious to know what effects radiation exposure over long (1000+ year) trips would be. I suppose by the time we can do that though, we will have likely have much better shielding technology.
I see two large assumptions here: 1. the accelerating expansion of the universe will continue at the present rate and never slow down, stop or reverse direction 2. future humanity will never be able to travel or communicate almost instantly using wormholes, or an advanced quantum entanglement device or something similar
There are a lot of unvoiced presuppositions in this video. You assume faster than light travel is impossible, you assume humans would only live on habitable planets(!?), you assume dark energy is real, you assume the universe is expanding. I recommend voicing your assumptions at the beginning of the video next time.
Some people have already mentioned this but it seems like we could have contact with even the most distant colonies so long as we have intermediate colonies (an outpost) to spread the message. I wonder how often you would have to send a colony from earth to still communicate to the most distant colony?
Not really. If outposts are used, then communication will be interrupted at the same time or earlier, between the extreme systems. At a time when space will expand at the speed of light or faster, adding intermediate points on the way does not help. Either the signal does not reach this intermediate station, or it does, but it will never reach the Earth from the intermediate station.
The last signal that we can get from the colony will pass along the border of the cone (12:31). And we will not even dare to answer it, because the signal will not be able to catch up with the world that has gone beyond the boundaries of the cone.
If cellular biology depends on time ticking at a specific rate, all this gets prohibitively difficult. Satellites have to correct for the time difference in orbit, but our cells cannot just up and do that. The longer you're away from home, the more time your body spends putting itself back together slightly out of order.
As a sci fi fan I have to say, based on all the science I can understand, it seems to me we need to crack antigravity and artificial gravity. Gravity is the only thing stronger then light and with an unfathomable amount of energy perhaps we could travel faster then light. We need that Alcubierre Warp drive guys and gals, better get to work!!!
When the series on the fundamentals of the universe resumes, how about covering emergent gravity: Understanding Galaxy Rotation Curves with Verlinde's Emergent Gravity Youngsub Yoon, Jong-Chul Park, Ho Seong Hwang
I still say it's so much simpler than this. Time-dilation alone, explains the "force" of gravity as well as the accelerating expansion of the universe.
Matt mentioned a link to Earth Month playlist will be in the description, but I don’t see a link to a playlist. Themed playlists that include videos from multiple PBS UA-cam channels sounds like a good idea & very interdisciplinaryish
The answer is 0, because the limiting factor will always be gravity, and unless we create artificial gravity through some technology, this will never be overcome. Centrifugal "gravity" is not gravity at all, it doesn't actually simulate it on a fundamental level.
The question on how far humanity could spread depends on the resources available along with how well our understanding of science and how technology can interact with nature. Currently there is no known method for interstellar travel that would not take a multitude of generations before travelers could arrive. I have no doubt that humanity could potentially spread throughout the solar system but how possible interstellar travel could become in the future is something that is very difficult to imagine.
Science and knoledge is lightyears ahead of what we actually do, which sums up to travelling to the Moon 54y ago. We know what to work on to make progress.
I wonder what kind of wild, exotic technology will be possible in the future. Perhaps some exotic warp-like engine will change these figures. I hope so, or the universe feels strangely small for something so unfathomably huge.
but if you can bend space and travel at greater than light speed, then distance is not a problem. Just build the engine to infinite warp and you'll be ok
There are a few assumptions you aren't considering: 1.FTL travel 2.Humanity actually survives to reach a point where they can explore, without either blowing itself up or 3. Humanity is not replaced by General AI or Super-AI.
"so the state of humanity at the moment of launch will form the seed of our cosmic legacy" Trust me, this is a scary thought for everyone who's been watching humanity. Hopefully humans will figure it out sometime within the next billion years.
Earth is home. Always will be. Space is empty for a reason. Drives home the fact that we need to look after home as there's nothing else out there that matches it.
There is actually a lot of Earth we have yet to explore. The oceans cover roughly 70% of Earth's surface and the last figure I heard regarding how much of those oceans we've explored is far less than 20%.
I like to imagine that in the days that we reach for the stars. We will meet our ancestors who went ahead of us before the previous extinction events. Who knows they probably left clues on where they went and a few tech left behind to help us get there faster.
I respect sticking to hard science, but man I do love some conjecture and creativity too. Since this is on PBS I understand you likely have limits on what you can discuss and when. I would love some "What if we could somehow go beyond the speed of light" type conjecture and then compare with this video, for instance. Assuming we had some vehicle to transport us instantly to some other position in our universe, how would that change how we explore? Crazy stuff to consider.
Obviously we are going to need to create either (1) engines that can go faster than Warp 1 i.e. we will need Warp 6 & 7 etc. OR (2) ability to tear the fabric of time & space to appear in another area of space billions of light years away
The whole conjecture would also have to accommodate this fact: Few mammalian species have ever lasted for more than about five million years without differentiating into distinct species. Humans will have evolved into a new species by then.
It's funny how you weren't planning on ever visiting that galaxy 100 billion light years away, but when science says you can't it's suddenly all you've ever wanted. So weird how these limits are still unfathomably huge, but still feel depressingly small when you realize they might be absolute limits of travel for the entirety of forever.
Knowing humanity, just being denied the ability to travel somewhere we can see will just guarantee we do whatever it takes to get there, even doing the previously-thought-impossible like FTL.
Speak for yourself! I was planning to go actually. Until all of this Hubble-bubble-toil-and-trouble brewed up. Oh well. Physicists, astronomers, cosmologists.... who needs 'em?
"... for the entirety of forever"
I like that.
Accepting challenges and developing genes to surmount that challenges is how life works. Imagine billions of cells in humanity creating emerging drive to conquer space based on those priniciples alone,
100 billion light years? Bro. That's the current size of the observable universe.
It shouldn't seem small to you under any circumstance. We cannot begin to even imagine half of half of half of half of half of half of half of half that distance.
A *single light year* is 6 TRILLION miles. Do you know how far a trillion miles is? Now multiply that by 100 *billion*.
That is not small compared to anything we can understand, and our perspective and size truly is the context here, no other perspective matters. We are the size we are.
One of the biggest things I drew from this episode, that I've never really put much thought into, is that the speed in which we expand from Earth ultimately reduces the amount of communication we can have with it (same for any origin point).
Yeah, until Star Trek's subspace is found!
Yes, it's almost a guarantee that if we can't figure out FLT communication then any future civilisations in different star systems and galaxies will be completely independent and not a part of some galactic/universal empire.
Only because we have n’t figured out how to move faster than light.
Everything we think is immutable always dissolves. Light speed may be hard to crack but we really don’t know anything at this point. We’ve only be a “technological” civilization for a nano second as far as the universe is concerned.
We are a single cell civilization at best
unless we can use Quantum Entanglement for communication in the future, then, regardless of our speed or where the end point user is, we should be able to instantly communicate
@@richardvivian3665I hope you're correct about the _"Everything we think is immutable always dissolves."_ bit.
Until relatively (which is just a *blink* before us within _"nano second as far as the universe is concerned"_ period) the humanity has been living as city-states, with the hopes for a given person traveling beyond the visible mountain ranges were slim.
In contrast to that, we can finally travel much further than that, now with the currently emerging technologies we'll be able to comfortably travel between the planets in our solar system.
Maybe in a few *blinks* from now the humanity+ _(420.69$/mo \s)_ will be actually planning their travels across galaxies.
I love the thought experiment of the Slow Starship, that puts humans in stasis to travel to a distant star system only to awaken and find that future humans have already arrived by a faster starship and evolved both biologically and technologically!
Isaac Arthur did an episode on colonizing the galaxy at 1% light speed.
startships are meant to flyyyyyy
If we were smart we'd send word to said ships that got out sped or even refit them in flight. Would be pretty funny to send out a ship and have it cruising along only to run into an FTL ship from home bringing all the upgrades and resources it needs to get a move on. :)
There's an old DOS game from the 90's called 'Alien Legacy', where Earth sent out a bunch of seed ships, you're the captain of one of these ships, and you emerge from suspended animation to a message informing you that another ship was launched several years after yours, but since it's a more advanced design, it will be arriving a decade sooner, and the other captain is now your boss. Of course, as you explore the system you can't see any signs of the other ship's crew, or habitations, so now you're left with a mystery to solve. (Eventually you do discover what happened to them, it's not pretty.)
@@Commanderziff I remember playing this game for hours and hours in my childhood. It was a great game; a good story and excellent mix of exploration, colony building, resource management, etc
I always thought of space and time being on such unfathomably massive time scales that we could never perceive a change without multigenerational record-keeping. Hearing that every *year* we lose 3 galaxies is so mindboggling.
No way to tell what type of technologies or events which might increase our travels in the universe.... so the PBS space time video is just a theory based on conditions of light speed travel
@@NTJedi Agreed. One can fairly assume that some sort of FTL travel will be available in the far future, which will change how this works. Also, if you travel close to the speed of light, there is relativity as well.
@@michaelvedal1907the more I read into it the more I think locally going faster than light probably is actually impossible. But I do think eventually we’d be able to create a warp drive or even travel through higher dimensions
@@bradysmith4405
Travelling through other dimensions is how we will travel faster than light.
@@beringstraitrailway physicists aren’t even sure if there really are higher dimensions though. So that’s iffy too.
hey matt, long time watcher and fan. The world is getting scarier as time marches on, but watching space time has consistently been there and given me something I can think about. Thank you for the work you and the rest of space time do. ❤
For some reason, the phrase “…humanity, or whatever succeeds us…” really caught my attention.
We used to be a different species, we’ll become a new species at some point no matter what happens. It’s just evolution.
Cats
*Chat GPT quietly sitting in the corner*
@@somethinglikethat2176 And the reason suddenly becomes clear…
Brown people with 80iq.
I feel like this channel is so good at slowly accumulating enough reference knowledge from past videos to bring up new and harder to explain topics. Very good programming.
That's why we need to continue to fund public television (and its progeny like this) so this type of free thinking is accessible to all. Let's not let the MAGAts destroy this, our public libraries, public education, public health and more.
@@AndrewPonti This channel has NOTHING to do with public television. It depends on patrons and other donors. It is as private as it can be!
@@afonsodeportugal Not True. This is a PBS show. Look it up.
@@mikemccormick6128 Matt has said many time that the channel relies on donations. It has always been its primary source of funding.
Also, it is very inadvisable to rely on pubic funding, as that sort of thing always ends on wokeness. Is that what you want? That Matt starts to talk about feminism instead of cosmology?
@@afonsodeportugal All I'm saying is that the original source is PBS. The program originated on PBS. It is absolutely incorrect to say that this video is unconnected to PBS. I have no idea whether or not the channel is connected to PBS and I don't care. This video originally aired on PBS.
PBS Space Time is the perfect combination of huge knowledge and flawless animations, both in an ideal setup to enjoy the content and also learn from it. I've been following it for years and I'm still impressed. I really hope there's content for more years to come, I can't imagine my UA-cam feed without the joy of having a new video.
I think Anton should have a discussion with PBS spacetime regarding the calculation of inhabitable planets at 8:57.
ua-cam.com/video/_Tju7EaSfmM/v-deo.html
I'm British and was at the Natural History Museum in NYC last month when I saw a very familiar, albeit beardless, Aussie physicist participating in one of the video exhibits in the space wing of the museum. Never knew you were quite so prolific, Matt!
I am a simple man and i dont understand many of the things touched on in these videos, but i still enjoy them
A followup question I'd like to see explored: assuming we send Von Neumann probes in every direction as fast as possible and as soon as possible, programmed to retrofit every single star in the affectable universe with a stellar engine, and pilot them all toward each other at maximum speed, how much of the affectable universe could we bring together into a gravitationally bound cluster, so as not to be so isolated by the Era of Isolation?
My thoughts exactly. If we are doomed to heat death, exactly how much fuel (matter) can we accumulate before the rest slips beyond our reach? How much time can we buy ourselves through artificial stars or fusion generators or black hole batteries before the end of days? How much time will our science grant us to rage against the dying of the light?
@@Russo-Delenda-Est I'm sure legions of pessimists will immediately pile in here to scream at me about how wrong this is, but since dark energy already violates the *first* law of thermodynamics I'm pretty confident we can in principle exploit that to prevent the heat death of our local part of the cosmos indefinitely. My concern is more about capturing more information, staying in touch with more of the universe that we'd otherwise never be able to hang out with again.
@@Pfhorrest Iirc Issac Arthur had a video on this, "Fleet of Stars" I think it was called. As for avoid heat death, who knows? We can't begin to imagine what discoveries post-human intellects 100,000 years from now will have under their belts, much less the ones billions upon billions of years hence.
@@Russo-Delenda-Est " ... to rage against the dying of the light"
Wow!! That's so poetic .. and ... ragey!! but in a non-agressive way... totally!!
@@Pfhorrest 1. I'm not a pessimist. 2. You *are* wrong.
Dark energy does not break the first law of thermodynamics. The first law of thermodynamics does not apply, because of the symmetry breaking of spacetime as it expands. (Emily Noethers mathematical theorem on symmetry).
This is quickly becoming my favorite astronomy/physics channel on youtube.
For someone like me who did a first year uni physics course but knows nothing more advanced than that, it's the absolutely perfect level of information to get all the good stuff in there without getting so complicated that I get lost in the equations.
@@normalmighty Weird, because I'm in my 3rd year of physics and I still have trouble wrapping my head around some of this stuff sometimes.
@@bertberw8653 Oh don't get me wrong, it's challenging, but I feel like he doesn't spend nearly as long diving into the complex math of the issue than other creator's I've seen talking at this level.
...plus I kind of skimmed past the string theory stuff lol, those videos were cool, but I couldn't really follow it all past the deeply simplified summary explanations. Maybe one day I'll reach the point where I can follow why exactly we think string theory might be real, but for now I'm just trusting the PhD holders on that one.
@@bertberw8653 that's actually really good to hear. Now I don't feel so stupid for not understanding some of the stuff. Did you see the episode explaining the equations of the standard model lagrangian? Hilarious ... sad ...
@@richardconway6425 Yeah, I just accepted that I'm less intelligent than most people in my major 😂 the good part is that accepting my place made me feel less pressure, and now I know I can just graduate on my own pace and terms
Man I love this channel - thank you Matt and the whole PBS ST team!!
These videos are something that keeps my mind going! Space Time is THE best channel on UA-cam!
That light cone and spacetime diagram animations was really neat and made the concept so much easier to follow.
Thank you for posting this video at the exact moment that I was available and able to watch it. These videos always make me so happy... even if they are existentially disturbing.
Plot twist, it was only perfect for you in your version of the universe. In mine, you missed the upload completely.
It's great that PBS is able to work around your schedule
@@rolirolster oh god, the ripple of entanglement hasn't reached you yet, tell me, what is the world like if I didn't get to the video on time?? 👀
You're all in my universe, where I have the top comment.
I can’t shake the massive universe size of FOMO, thinking about the exploration and experiences we are missing out on by being born before we could explore any exoplanet…. It’s devastating.
then support FTL research
@@kanishkchaturvedi1745 absolutely
I like the term "affectable universe". I wonder, if our universe turns out to be informational (or holographic) in origin, if the expansion of the universe could have something to do with affectability and causality in general. The more (complex) interaction the more the universe speeds up. Dark energy may be informational/computational in origin and naturally regulate the density of information and interactions within the universe, maintaining the informational structure in a way that aligns with the expansion.
Kind of off-topic, but this episode inspired this idea :)
. . . I think if we ever figure out how to edit whatever the holograph stuff us made of, we can make a bunch of those screwdriver things from Dr. Who and do whatever we want.
Brilliant episode. Thank you for doing this PBS
"Earth is the cradle of humanity, but one cannot live in a cradle forever." - Konstantin Tsiolkovsky
Unfortunately the laws of the universe disagree,we were born here and we'll die here
@@blizzard1198 so true, a catchy phrase won't bend the harsh reality
@@blizzard1198you never know. 125 years ago we thought it would be impossible for a human to fly, or such an investment that they’d never see it happen. 60 years later they’re sending satellites into space. Laws (or rather our understanding of them) change over time. We find ways to use them to our advantage, or discover new ideas that allow us to circumvent them to a degree (a human on their own can never fly, but we can create machines based off of principles we discovered that do it for us, allowing us to reach the skies). Our 2 biggest enemies for getting off of Earth is time and ourselves. Time in that, how long do we have to get off this planet before a natural disaster wipes us out? Ourselves in that, nuclear war, pollution, over indulgence on resources etc., will stop us in our tracks. Or resigning ourselves to “it’s impossible” and never actually trying, whether we view it as futile or not. Until the day I die, I will believe it possible as we’ve accomplished the “impossible” time and time again.
I disagree we will travel faster then light for sure @@blizzard1198
@@blizzard1198 did u even watch the video above and the last 2 videos?????
Been loving watching this channel. It’s funny how people can get sad on like.. only 20 billion galaxies..:(
Yeah especially when within our life time the most we can hope for is literally making it to the closest planet around, not even the closest star :D
It's called Hybris... or doom.
I wonder if the Great Attractor is an advanced civilization attempting to gravitationally bind a large chunk of the universe before the era of isolation.
It's never aliens.
Until it is.
This is a cool idea for a science fiction story
@@johnducan2487 It's never aliens... until it's aliens
People generally fail to understand that the great attractor is just a point we can't observe because it's behind the galactic plane, it's nothing mysterious, and it's almost certainly just a dense region of space with a large cluster.
I'm still holding out hope for wormhole travel.
Or extra dims
I got goosebumps when you brought up the great amazing Carl Sagan. "We will one day, venture to the stars." I miss his way of explaining. I think you do a very wonderful job making these videos and explaining as well. Keep up your hard work. That shirt rocks^^) A Glorious Dawn by MELODY SHEEP, go and listen.
Fantastic video, as always, Space Time team!
Really nice audio editing
It was refreshing to have no music during the core concept
And even more impactful to have the music come in during the theoretical and story telling section.
Thanks for all the videos! 😊
We always forget these things when we make science fiction movies ... thank you for explaining these ideas in easy to understand formats
scify movies are always full of plot devices. And people take those too seriously.
We also forget that aliens don't speak with a British accent.
@@gabor6259 True, they speak with American accent
Movies exist to tell a story. It is called science FICTION. Old Science fiction used to imagine new worlds and amazing new things, but modern sci fi is just dystopian nonsense
@@martiddy Of course they speak English with an American accent. Why else do you think they always land in the US.
Thanks for another fantastic video! I do have to say though, "These days there's not much of the Earth left to explore" made me do a spit-take right off the bat... The oceans and the Amazon spring immediately to mind.
I agree, I work as a pilot and often have the chance to overfly beautiful landscapes, but I feel my true experience of nature happens hiking ankles deep in the mud of the lowest valley rather than flying over the highest mountains.
I don't think a lifetime is enough to explore the physical Earth, let alone the people, arts, philosophy...
Instant subscription. I love this kind of stuff. Thank you.
“There’s not much left on earth to explore.” That big blue dot? All the blue stuff doesn’t need exploring? Someone call up James Cameron.
What if we use Stellar Engines to push the star systems we inhabit towards the Milky Way? How many galaxies of stars could we potentially drag back into our Local Group before Isolation?
Don’t ask good questions
You would have to have 1 stellar engine per star. You couldn't use a single engine for an entire galaxy by tugging on the black hole. Remember that 80% of the mass of most galaxies is dark matter.
@@tr48092 Even if that's the case, as long as you accelerate a star, it will pull on the dark matter via gravity, just like how the gravity of the dark matter pulls on it. That's essentially the idea behind a gravity tractor, and if you build 1 stellar engine per star, you could accelerate entire galaxies, not quickly mind you, but over time, maybe quickly enough.
I believe Isaac Arthur proposed that as a way to merge galaxies.
Powered by starlight they're too slow. Kurtzkazart's stellar engine however could probably get a fair few back
Not much point though when you could just live there instead.
Could entangled quantum bits communicate beyond that horizon if we can escape it? Could one inside it get "magically" pared to one outside it and see influences without being there? Does the heat death date of 10 to the 10 to the 10 to the 56 take into account the era of isolation?
I was thinking about some kind of quantum communicator aswell. If we could entangle the particles ourselves one day we might unlock a way for them to have reasonable communication over some vast distances. Who knows what the future has in store for us
In theory, it's called an ansible.
Entangled particles, lightyears apart, that allow instant communication. Ender's Game had a good example of it.
Entangled particles can share information instantaneously, but attempting to manipulate them to send a signal breaks the entanglement. You can't use them to communicate.
@@gunslinger2566yeah but impossible.
Sadly, no. You have to send regular additional information to decypher anything sent through such communicator, and that regular information can't travel faster than light.
Would it be the best plan to maximize resources by sending the colonies farther they can go without losing communication, use the resources from those systems and slowly migrate inward towards Earth as the Isolation Era approaches and engulfs our galaxy cluster? (I think I played to many RTS games)
As if colony administrations will gladly and happily send all their resources to the metropoly.
@@ShadeAKAhayate yeah, what can they even do about it? Send in debt collectors in, like, a billion years? That's a lot of time to prepare a "welcoming party"!
@@Darth_Niki4 That's one of the problems inherent to the imperial economy, especially when we talk feudal-like structure.
I don't think he was being very honest about communications. Communications would take 10s of millions to 100s of millions of years depending on how far away these galaxies are. I think it is extremely unlikely that we will ever go past our local group. I think it would be highly unlikely that we will get past the Milky Way before life on Earth will be unlivable.
I hope one day the whole entire universe and the cosmos can all be mapped out
i think I asked this once before, but what is the radius of the non-expanding region of space that contains our galaxy? If I understand correctly, it is the "local cluster" of galaxies, but how big is that? Do we know where the boundary is between space which is expanding and the internal space of our local cluster, which isn't?
Yeah, I have read about this, and the sad answer is that all galactic clusters will eventually move farther and farther from each other. Our cluster is the Local Group, and it is small.
It’s possible to travel to other clusters, as this video showed. But the longer you wait to begin going somewhere, the faster you have to go to get there.
Descendants of humans might spread to several clusters of galaxies. I hope they will. But the civilizations within the clusters will eventually become permanently isolated from each other.
Nice episode and leaves one wondering if humanity has a future beyond Earth.
Not without either changing in some very fundamental ways - or not without losing most of us along the way.
I personally believe we will have a base on the Moon, and probably at least send people to Mars, though realistically we won't colonize it as it just isn't worth the effort or the cost. I seriously doubt we will go any further than that. It's nice to dream though.
One thing I noticed writing a short story about this scenario: you can use the expansion of spacetime itself to do most of your deceleration for you. This simplifies the colonization process enormously, meaning extra-galactic-cluster colonization may be a great deal simpler than colonizing nearby galaxies. Still, I would question the value of colonizing things at the edge of our Hubble horizon - by the time colonists got there, the target galaxy would consist of nothing but red dwarfs and various types of dead stars. It'd feel rather depressing, I would think.
I'm pretty sure it doesn't work like that, you still need to decelerate, you're not slowed by the stretching of space.
@@nadsenoj8719 lol we'd be moving the whole galaxy to the destination at that point. :)
It doesn’t work that way. You don’t slow down. From your perspective the galaxy speeds up towards you the closer you get lol.
Say you’re going half c towards a galaxy 5 billion light years away today.
You start at 5 billion light years. Doing the math the galaxy is receding by 104,000 km/s from you. You’re going 150,000 km/s. You are gaining 46000 km/s.
Boom; you’re 4 billion now. Galaxy is receding at 83,500 km/s. You’re still moving at half c. There’s been no force acting on you; you’re in an inertial frame. So now you’re gaining on it by 66,500 km/s.
Now you’re 1 light year away. You’re gaining on it roughly 150,000 km/s. decelerate fast lmao.
Red dwarves are very very very good locations for colonies, if you have the sort of tech needed for giga-lightyear journeys.
It kind of sounds like every local cluster we visit will have it's own sphere that it can never lose communication with. Might be interesting to know which one of the current clusters we see would be the most optimal one to grow in.
The nearest one, the Virgo Cluster, is huge. Our Local Group is really puny. If our descendants can travel to other clusters, they definitely will travel to Virgo. That cluster alone has more than 1,000 galaxies to explore.
The Local Group and the Virgo Cluster are in the Virgo Supercluster. The nearest other supercluster is the Hydra-Centaurus Supercluster, which is closer to the Great Attractor.
The Wikipedia article on the Laniakea Supercluster (which is more like a super-supercluster) has some diagrams.
But we will eventually lose contact with them, if expansion continues infinitely, we will eventually lose contact with everything.
@@foragreenfuture6030Wrong. Locally bound objects remain bound. So the local groups remain bound. Gravity is still strong enough to resist the expansion at that point. If we can get to a large gravitationally bound cluster we’re effectively safe there.
Super clusters don’t count. The individual clusters aren’t bound to each other anymore, they’re clustered because the filament structure of the universe emerged early in its history. Space is too big now, only local groups are bound.
Tl;dr; gravitationally bound objects remain together. Objects too far apart don’t have enough pull to resist the expansion. Eventually all the galaxies in each locally bound group will merge into one super galaxy.
@@Karlswebb No, you are wrong. foragreenfuture6030 is talking about the Virgo Cluster. Yes we will lose contact with the Virgo Cluster. Why do you need to be so oppositional.
Love this content. Please keep it coming, I share every time
The if in Sagan's 'if we do not destroy ourselves' is doing some very heavy lifting. Good luck all.
It would be interesting to see, based on these calculations and some assumptions of different points in time, where any alien life might originate from at the furthest.
just imagine in the not too distant future ,if humanity discovers that human civilization on earth is also a causally disconnected region of a far more ancient civilization (premise of Battlestar Galactica)
0:10 yes there is… the oceans! we only know less than 10% of the oceans
Lies! We know all the oceans...
I would contribute a term of Frogging from the game Frogger. If we jump from log to log and wait for a galaxy to come closer to the “log” galaxy that we land within then we would have to wait for the next galaxy to pass by. This could be “forever” if we have actually understood the movement of galaxies from the observable universe. However being a violent society this may never be realized.
Great job, man! As always! Great video
I'd like to see the same graphs showing a ship's communications, while traveling at C, sent and received, with earth not only as you have but also what happens when the ship stops, turns around and heads back.
I'm just an old broken truckdriver struggling to grasp a general understanding of as much of everything I can. 🙂
Well I can tell you exactly what they receive, nothing. One second out from earth and nothing can catch up to them 😋
imagine the ship is just the same as information. The ship is traveling as fast as information can travel.
Hey Matt,
Awesome job with the channel.
If you haven't done one yet can you do a video on what an interstellar spaceship would look like.
How to house a population and what energy and food production would be.
Thanks
i'm glad you considered speciation and intercommunication. IMO, human decendants can colonize a vast amount of space, but humans won't. speciation will likely happen before we even really leave ths solarsystem.
"As long liberty spread across the universe"
- Helldiver
I love all of ypur videos and want to watch every single one, but man there's a lot :D keep them coming
I would argue that travelling at 2% lightspeed is more realistic than 20%
We already have the tech for 20%, it's just that it's currently banned. But treaties like that don't last forever, no treaty does, really. We've got far longer than humanity has already existed to decide to break the treaty and use the technology we already have, not even to mention invent new tech that's even better. I see no reason why that couldn't be realistic.
@@physics_hacker a trading that even North Korea Iran China follows? Could be I'm truly ignorant and don't know what treaty you are. Are you talking about one of those conspiracies Nazis on the moon, the Nazi Bell, or the Nazi base in Antarctica?
@@physics_hacker If we manage to create permanent settlements on other planets then they won't care about earth treaties. A cultural drift is guaranteed. Over a few thousand years they could even become a new sub species.
@Ein Kunde because it involves detonating nukes in space
@@physics_hackermoreover these speeds are achieved by slingshotting and I have seen an idea using rotating black holes almost along an interstellar highway
Answer: as far as we can reach wifi
Before we attempt this thought experiment, I believe we should discuss how much we would allow ourselves to modify what it meant to be human and still call ourselves human. As this is likely going to be a big part of the future with groups already dedicated to human modification and technology already dramatically enhancing the human experience.
My brain hurts and that doesn’t happen very often. Wow that was great. Nice journalism man!!
Once robotics and cyborgs has taken over distances, time and the dangers of space will not be such a barrier.
Depends on whether FTL is possible
It is not!!!
@@scottslotterbeck3796 it is!!!!
@@Aiel-Necromancer negative is just a question of reference you can go below 0 Kelvin sort of ;^)
This is one of my favorite episodes. Thinking at this grand a scale really puts life into perspective for me.
What an odd thing to say. Considering this 'grand scale' is nothing more than a thought in your head, how can it put "life into perspective" for you? Life where you are at it he most important thing there is, as that is your life. What happens 'out there' has no affect on you, except as a metaphor for what occurs out there occurs down here, and what is above, is likewise below
@@pyropulseIXXI I think the simple answer to your question is that this person isn’t you and they have a different perspective and that’s okay lmao
Have a good one
@@pyropulseIXXI OK, Obi Wan.
I've always thought "aliens" are actually future former Human hybrids (space traveling humans) travelling time.
You know, the fact they can move through the atmosphere silently is significant. I've seen a vast ship, a disc possibly miles across, travel at several thousand mph across the sky silently before disappearing into thin air. It's also the ability to become invisible l find interesting. Until we humans have such a technology interstellar travel as these guys seem to do will be impossible. But l think it's beyond us as it seems to inhabit a different dimension.
Thinking back on the warp speed episode...if we can overcome those limits somehow to get warp drives, what would the warp factor have to be in order to get past our light cone to what is likely the most distant point? In say 100 or 1000 years
Always an interesting listen Matt, thank you.
This just shows how important FTL travel will be.
If it's possible.
Moving faster than light through space is impossible. However, warping and moving the space itself faster than light is a different thing.
This concept of quintessence, a scalar field seems to be of interest in physics. I do hope dark energy is some sort of fundamental force we can find ways to effect as then perhaps c won't be our limiting factor.
It's impossible to travel faster than c as it is the maximum speed but there seems to be more to our understanding of gravity, specifically in cases where it is repulsive rather than attractive. If we can find a way to bring spacetime closer instead of exchanging within it, that would be the way to go. But at the moment that seems to be beyond our understanding.
If it is nothing but a dream 3 galaxies gone a year sounds pretty bad.
@@martiddy it is a tricky thing, too
No FTL. Sorry!!!
It’s an exciting time to be alive, if we end up becoming a multiplanetary species we are quite literally at the beginning of our species story.
We will not become a multiplanetary species. We are at the end of human history and the last human will gasp his last breath right here on Earth.
@@HawkGTboy I bet you're fun at parties.
@@HawkGTboyshut up.
@@HawkGTboy🌍 💥
@@undercoverbrother67 no youre just scared of the bitter truth
*THE GOD EMPEROR WILLS THAT WE RULE THE GALAXY!*
Communication solution: create a breadcrumb trail of communication satellites that remain in the orbit of each planet we pass. This would create nodes for signal communication to daisy-chain or hop a signal along between each planet (a much shorter distance). Rather than trying to send a direct signal all the way back to Earth and then directly all the way back, you'd just send it to your nearest planetary communication node or satellite to then propagate back and forth. Like we do now with cable/internet/phones but bigger.
A very sensible suggestion for practically achievable interstellar travel was made by Anton Petrov on his UA-cam channel a few days ago. It was rogue planets that travel independent of any star. Occasionally they generate heat enough to be habitable - on themselves or a moon - and also occasionally one such free-ranging vehicle of life might pass close to our solar system. If so then an expedition from humanity could hunker down on such a rogue planet and then just wait. If necessary for millions of years. A planet is a more realistic vehicle for multi-generation travel than any lump of metal and plastic which will always break down eventually. Just saying…
It would be interesting if you could implement time dilation from the perspective of humans on Earth relative to the humans on the spacecraft traveling at near light speeds
Time Dilation is such a kick in the balls >.
@Ein Kunde Not too bright...
@Ein Kunde his content is comprehensive. How do you not get this? Just watch retroactively and take two Tylenol for the pain after you slap yourself.
If we found some substance that produced the opposite effect of Dark Energy and could use it on a local scale to shrink spacetime in front of a ship while also using Dark Energy behind the ship to expand spacetime, could that be a method of getting past any of the Event Horizons?
Faster 👏than 👏light 👏 travel 👏 is 👏equivalent 👏 to 👏time 👏 travel
What you're describing is called an Alcubierre Drive - or simply Warp Drive
And the "substance that produces the opposite effect of Dark Energy" is basically just normal matter; we don't yet know however what Dark Energy is nor do we know whether any other substance exists that creates a negative energy density like Dark Energy
@@Astromath actually, no. The opposite effect of dark energy is just gravity. Ironically, if you want to make a warp drive, then it's dark energy itself that you want to harness, as it has exactly the kind of effects on spacetime that you are looking for- namely, the ability to create expansion or negative pressure. This is precisely why the cosmos is able to expand faster than light, we essentially live within a warp drive. The problem is that first of all, we don't know what dark energy is, so we can't manipulate it like we would want to in order to use it to make warp drives; and second, it appears to be distributed evenly throughout the entire cosmos, while we want to concentrate it in one small bubble of spacetime with a neat arrangement in order to create superluminal velocity. Until we know more about what dark energy is, the alternative is a bizarre thing called negative energy, which sorta does exist in certain conditions in quantum mechanics, but like all quantum effects, trying to make it manifest usefully in the macroscopic world is a pain and may not pan out. Maybe we can make a warp drive, but because of causality related reasons or hawking radiation, the best we can do is travel at exactly C. Which, in fairness, isn't possible any other way. The energy needed would be infinite.
@@formlessone8246 I mean, technically anything is a warp drive, since any massive object (an object with mass) can warp spacetime, just depends on what curvature you're looking for
so, both of you are correct
@@formlessone8246 not all warp drive concepts require an expansion out of the back, some just have an extreme energy density in the front to compress spacetime and allow its natural elasticity to settle itself back out the other end. That'd presumably produce a much bigger disturbance of gravitational waves than a controlled re-expansion though.
Has anyone tried to calculate when the first human spinoff species could emerge, when one of our descendants has evolved into a different species?
Speciation in mammals takes about 4-5 million years naturally. Can also happen much quicker. Much faster if were to do some selective breeding.
it depends on a lot of things
1) how much quantum tunneling occurs per population member
2) how far away our colonies our
3) how many people are in our colonies
4) how gravity changes in the area, because mechanics vary an extreme amount based on gravitational forces in the area (I hate using newtonian terms, but I used 'gravity' for conciseness)
5) the decay rates of particles in the colony
6) the changes in the environment of the region, relative to earth
calculate for all of the above, and you might have a decent picture
if I missed anything, or got anything wrong, then feel free to change my list!
@@JoeWithTheHoesBiden #1 is the OP trying to sound smarter than he is. Also, see #5. #4 is again the OP trying to sound smarter than he is. #5 decay rates are not location dependent. Perhaps for #1 and #5 you meant the ambient ionizing radiation? #6 is just a blanket covering all environmental factors so it makes numbers 4 & 5 redundant.
What we send up is probably not humans of today. We are not very well suited for space travel. If we insist on humans, then an idea would be to terraform planets with ai before growing them
@@AlbertaGeek Yeah I'd be curious to know what effects radiation exposure over long (1000+ year) trips would be. I suppose by the time we can do that though, we will have likely have much better shielding technology.
Pretty optimistic considering most of the Travelers I encounter each day can't figure out the concept of a 4 way stop sign.
I see two large assumptions here:
1. the accelerating expansion of the universe will continue at the present rate and never slow down, stop or reverse direction
2. future humanity will never be able to travel or communicate almost instantly using wormholes, or an advanced quantum entanglement device or something similar
There are a lot of unvoiced presuppositions in this video. You assume faster than light travel is impossible, you assume humans would only live on habitable planets(!?), you assume dark energy is real, you assume the universe is expanding. I recommend voicing your assumptions at the beginning of the video next time.
Some people have already mentioned this but it seems like we could have contact with even the most distant colonies so long as we have intermediate colonies (an outpost) to spread the message. I wonder how often you would have to send a colony from earth to still communicate to the most distant colony?
Not really. If outposts are used, then communication will be interrupted at the same time or earlier, between the extreme systems. At a time when space will expand at the speed of light or faster, adding intermediate points on the way does not help. Either the signal does not reach this intermediate station, or it does, but it will never reach the Earth from the intermediate station.
The last signal that we can get from the colony will pass along the border of the cone (12:31). And we will not even dare to answer it, because the signal will not be able to catch up with the world that has gone beyond the boundaries of the cone.
Hurry Up, Elon! 🚀🌀
The Aliens, Predator movie series already explored theses ideas!😮
If cellular biology depends on time ticking at a specific rate, all this gets prohibitively difficult. Satellites have to correct for the time difference in orbit, but our cells cannot just up and do that. The longer you're away from home, the more time your body spends putting itself back together slightly out of order.
As a sci fi fan I have to say, based on all the science I can understand, it seems to me we need to crack antigravity and artificial gravity. Gravity is the only thing stronger then light and with an unfathomable amount of energy perhaps we could travel faster then light. We need that Alcubierre Warp drive guys and gals, better get to work!!!
When the series on the fundamentals of the universe resumes, how about covering emergent gravity: Understanding Galaxy Rotation Curves with Verlinde's Emergent Gravity
Youngsub Yoon, Jong-Chul Park, Ho Seong Hwang
Without ANOTHER propulsion system currently exist, we can NEVER LEAVE THE MILKY WAY GALAXY
I still say it's so much simpler than this. Time-dilation alone, explains the "force" of gravity as well as the accelerating expansion of the universe.
This is a fantastic argument against UFOs or UAPs.
Que gran video, aguante PBS!!!
Matt mentioned a link to Earth Month playlist will be in the description, but I don’t see a link to a playlist. Themed playlists that include videos from multiple PBS UA-cam channels sounds like a good idea & very interdisciplinaryish
PBS Vitals said the Earth Month playlist is the following:
ua-cam.com/play/PLzkQfVIJun2J5q9CIXPAlL95FSb0tJul7.html
Fascinating and a question that I wanted answered before I die. Thanks for this video. Now let's see what humans do.
The answer is 0, because the limiting factor will always be gravity, and unless we create artificial gravity through some technology, this will never be overcome. Centrifugal "gravity" is not gravity at all, it doesn't actually simulate it on a fundamental level.
I love you, Matt
The question on how far humanity could spread depends on the resources available along with how well our understanding of science and how technology can interact with nature. Currently there is no known method for interstellar travel that would not take a multitude of generations before travelers could arrive. I have no doubt that humanity could potentially spread throughout the solar system but how possible interstellar travel could become in the future is something that is very difficult to imagine.
Science and knoledge is lightyears ahead of what we actually do, which sums up to travelling to the Moon 54y ago. We know what to work on to make progress.
I wonder what kind of wild, exotic technology will be possible in the future. Perhaps some exotic warp-like engine will change these figures. I hope so, or the universe feels strangely small for something so unfathomably huge.
but if you can bend space and travel at greater than light speed, then distance is not a problem. Just build the engine to infinite warp and you'll be ok
Love your videos full of interesting facts and great stuff All the way through .keep making them🤪🤭🧐😇😁👍
There are a few assumptions you aren't considering:
1.FTL travel
2.Humanity actually survives to reach a point where they can explore, without either blowing itself up or
3. Humanity is not replaced by General AI or Super-AI.
"so the state of humanity at the moment of launch will form the seed of our cosmic legacy"
Trust me, this is a scary thought for everyone who's been watching humanity.
Hopefully humans will figure it out sometime within the next billion years.
Earth is home. Always will be. Space is empty for a reason. Drives home the fact that we need to look after home as there's nothing else out there that matches it.
This is a very optimistic question.
There is actually a lot of Earth we have yet to explore. The oceans cover roughly 70% of Earth's surface and the last figure I heard regarding how much of those oceans we've explored is far less than 20%.
I like to imagine that in the days that we reach for the stars. We will meet our ancestors who went ahead of us before the previous extinction events. Who knows they probably left clues on where they went and a few tech left behind to help us get there faster.
I respect sticking to hard science, but man I do love some conjecture and creativity too. Since this is on PBS I understand you likely have limits on what you can discuss and when. I would love some "What if we could somehow go beyond the speed of light" type conjecture and then compare with this video, for instance.
Assuming we had some vehicle to transport us instantly to some other position in our universe, how would that change how we explore? Crazy stuff to consider.
Obviously we are going to need to create either (1) engines that can go faster than Warp 1 i.e. we will need Warp 6 & 7 etc. OR (2) ability to tear the fabric of time & space to appear in another area of space billions of light years away
The whole conjecture would also have to accommodate this fact: Few mammalian species have ever lasted for more than about five million years without differentiating into distinct species.
Humans will have evolved into a new species by then.
Just stay on Earth. The Earth is traveling around the galaxy.
We can really only stay on Earth for another billion years, after that, the Earth will be inhabitable