Will We Ever Reach Another Star?

We hear about discoveries of exoplanets every day. So how long will it take us to find another planet like Earth?

There are two separate parts of your brain I would like to speak with today. First, I want to talk to the part that makes decisions on who to vote for, how much insurance you should put on your car and deals with how not paying taxes sends you to jail. We’ll call this part of your brain “Kevin”.

The rest of your brain can kick back, especially the parts that knows what kind of gas station you prefer, whether Lena Dunham is awesome or “the most awesome”, whether a certain sports team is the winningest, or believes that you can leave a casino with more money than you went in with. We will call this part “Other Kevin”, in honor of Dave Willis.

Okay Kevin, you’re up. I’m going to cut to the gut punch, Kevin. Between you and me, it is my displeasure to inform you that science fiction has ruined “Other Kevin”. Just like comic books have compromised their ability to judge the likelihood of someone acquiring heat vision, science fiction has messed up their sense of scale about interstellar travel.

But you already knew that. Not like “Other Kevin”, you’re the smart one. In the immortal words of Douglas Adams, “space is big”. But when he said that, Douglas was really understating how mind-bogglingly big space really is.

The nearest star is 4 light years away. That means that light, traveling at 300,000 kilometers per second would still need 4 YEARS to reach the nearest star. The fastest spacecraft ever launched by humans would need tens of thousands of years to make that trip.

But science fiction encourages us to think it’s possible. Kirk and Spock zip from world to world with a warp drive violating the Prime Directive right in it’s smug little Roddenberrian face. Han and Chewy can make the Kessel run in only 12 parsecs, which is confusing and requires fan theories to resolve the cognitive space-distance dissonance, and Galactica, The SDF 3, and Guild Navigators all participate in the folding of space.

And science fiction knows everything that’s about to happen, right? Like cellphones. Additionally Kevin, I know what you’re thinking and I’m not going to tear into Lucas on this. It’s too easy, and my ilk do it a little too often. Plus, I’m saving it up for Abrams. Sorry Kevin. Got a little distracted there.

The point is, science fiction is doing colossal hand waving. They’re glossing over key obstacles, like the laws of physics.

Stay with me here.This isn’t like jaywalking bylaws that “probably don’t apply to you at that very moment”, these are the physical laws of the universe that will deliver a complete junk-kicking if you try and pretend they’re not interested in crushing your little atmosphere requiring, century lifespan, conventional propulsion drive dreams.

So let’s say that we wanted to actually send a spacecraft to another star, whilst obeying the laws of physics. We’ll set the bar super low. We’re not talking about massive cruise ships filled with tourists seeking the delights of the super funzone planetoid, Itchy and Scrachylandia Prime.

David Hardy's illustration of the Daedalus Project envisioned by the British Interplanetary Society: a spacecraft to travel to the nearest stars.  (Credit: D. Hardy)
David Hardy’s illustration of the Daedalus Project envisioned by the British Interplanetary Society: a spacecraft to travel to the nearest stars. (Credit: D. Hardy)

I’m not talking about sending a crack team of power armored space marines to defend colonists from xenomorphs, or perhaps take other more thorough measures.

No, I’m talking about getting an operational teeny robotic spacecraft from Earth to Alpha Centauri. The fastest spacecraft we’ve ever launched is New Horizons. It’s currently traveling at 14 kilometres per second. It would take this peppy little probevette 100,000 years to get to the nearest star.

This is mostly due to our lack of reality shattering propulsion. Our best propellant option is an ion engine, used by NASA’s Dawn spacecraft. According to much adored Ian “Handsome” O’Neill from Discovery Space, we’d be looking at 19,000 years to get to Alpha Centauri if we used an ion engine and added a gravitational assist from the Sun.

Just think of what we could do with those 81,000 years we’d be saving! I’m going to learn the dulcimer!
We can start shearing back the reality curtain and throw money and resources to chase nearby speculative propulsion tech. Things like antimatter engines, or even dropping nuclear bombs out the back of a spacecraft

The best idea in the hopper is to use solar sails, like the Planetary Society’s Lightsail.
Use the light from the Sun as well as powerful lasers to accelerate the craft.

Ion Propulsion
Ion Propulsion System Test for Deep Space 1. Image Credit: NASA/JPL

But if we’re going to start down that road, we could also send microscopic lightsail spacecraft which are much easier to accelerate. Once these miniprobes reached their target, they could link up and form a communications relay, or even robotic factories.

Sorry, I think that was my “Other Kevin” talking. So where are we at, fo’ reals?

Harold “Sonny” White, a researcher with NASA announced that they’ve been testing out a futuristic technology called an EM drive. They detected a very slight “thrust” in their equipment that might mean it could be possible to maybe push a spacecraft in space without having to expel propellent like a chemical rocket or an ion drive.

What’s that, Kevin? Yes, you should totally be skeptical. You’re right, that last bit was a salad of weasel words.

Even if this crazy drive actually works, it still needs to obey the laws of physics. You couldn’t go faster than the speed of light and you would need a remarkable source of energy to power the reactor. Also, yes, Kevin, you’re right NASA is working on a warp drive. There’s no need to yell.

NASA is also working on an actual warp drive concept known as an alcubierre drive. It would actually do what science fiction has claimed: to warp space to allow faster than light travel. But by working on it, I mean, they’ve done a lot of fancy math.

But once they get all the math done, they can just go build it right? This concept is so theoretical that physicists are still arguing whether powering an alcubierre drive would take more energy than contained within the entire Universe. Which, I think we can call an obstacle.

Oh, one more thing. “Other Kevin”, thanks for being so patient. Here’s your reward. Unicorns are real, and Kevin has been lying to you this whole time. Go get ‘em tiger. Place your bets. When do you think we’ll send our first probe towards another star? Predict the departure date in the comments below.

33 Replies to “Will We Ever Reach Another Star?”

  1. With current technology, and by admission of your own article, we could launch a probe to Alpha Centauri and have it reach its destination in 19,000 years. Assuming human researchers are still around then and the craft survived and still works on solar power as it closes in on a star four point three light years away, and future scientists have a means of detecting the radio signal from so far away, they’d get their first closeup look at another star system.

    Sorry, folks, it’s the best humans can do today.

    Tomorrow may be another story. I would guess within another generation there will be propulsion technology ten times faster than we have today. 1900 years is better than 19,000, but still not doable for the most part. It will take a good percentage of light speed to make a difference. I don’t think we’ll see that for at least 100 years. Just a guess, of course.

    I also think that half light speed is imminently more achievable than full or near light speed, requiring perhaps only one percent as much energy as full light speed, just as business jets can fly at half the speed of sound on a tiny fraction of the fuel needed for supersonic flight. Still, nearly nine years is a long spaceflight, but at least it would be humanly possible to get there at half the speed of light. It would likely be a one way trip because of the energy needed to stop and turn back, then stop again at Earth another nine years later would simply be too much to carry.

    Admittedly, science may surprise all of us with the next big discovery. Just as powered flight was always possible thousands of years ago, but not available until humans discovered how to do it, light speed I believe, is possible. It’s just that we haven’t yet figured it out. But someday, I’m certain someone will. I doubt I’ll ever see it in my lifetime.

    1. That actually may not be that far far away. One of the problems is obviously propulsion. But say we go one quarter, 1/2, or 3/4ths the speed of light.

      Debris. One little nic becomes a huge blow to it.

      Sending out a sea of mini-probes — super small ones going half the speed of light is an answer. Some may perish of course, but some will run through and make it.

      It’s one concept we overlook when it comes to aliens reaching us. They may be so small, we can’t see them so readily.

  2. And except propulsion problems, there’s the decay problem. Cosmic radiation degradation and loss of fission fuel carried aboard. Even pyramids fall apart during tens of thousands of years, and they are just simply a rock on another rock. Maybe whatever civilization, if any, exists on Earth when the probe signals home its data detected, maybe won’t care or know about that probe and its, for them, strangely formatted radio bitstream.

    A millennia mission needs to somehow consider the society which is supposed to receive the response. (Or maybe not, it’d maybe just be meaningless to try to second guess our distant future anyway? Just go for it and someone will be around clever enough to figure it out)

  3. Okay, playing the devils advocate here – We FACTUALLY do not know if we cannot ‘break the speed of light’ – the ‘math says so’, but hey, math has been known to be wrong more then a few times. . o O (IF we are honest.)

    We do not really know if what will happen at the Speed of Light or FTL. We presume, again if we are honest, that the math is correct … but again, in all honesty, we simply do NOT know 100%.

    Oh, I understand that people who think they are smarter then me, will call me “stupid” – tell me, “Catch up with the times….” and MAYBE you are right … just as maybe, just maybe you are wrong.

    I’ve actually talked with ‘smarter minds then mine’ about this “Speed of Light, so called “law”” … and some have actually said, “Jj, you might just be right. We simply do NOT know, like you said – IF – we are honest….”

    Oh, understand it will be ‘awhile’ before we get to any serious space travel speed, I totally understand that and have my theories on that as well … but for now …. ‘let the flame throwing, begin’ … I can take it. 😉

    1. The speed of light, as any speed, is referenced by a single point in space. Let’s just say we have a spacecraft traveling at light speed as referenced by Earth. If we head for a star that is approaching us, then in reference to that star, we are going faster than light speed.

      OK, another scenario. We are moving at light speed from Earth, when, we open the rear hatch and launch a shuttle. The reaction of that pushes us a few miles an hour faster, so now, we would be going faster than light.

      To make my view on this clear, I don’t believe light speed is the absolute limit. Light speed is only the fastest speed we currently know of.

      Of course, good luck proving or disproving this in any of our lifetimes.

      1. Your initial assumptions are not correct (I will ignore the part about a spacehip travelling at the speed of light) . If a spaceship travelling at speed of light towards a star that is moving towards the spaceship, then the relative velocity of the spaceship towards the star would in fact still be lightspeed. This is the crux of Special Relativity. Let me give you the standard example:

        A spaceship is travelling at, say, 50% of the speed of light towards a star. If you measured the speed of the light that was coming from the star towards the spaceship, what would be the speed that you measure?

        The intuitive answer is: The speed of the beam of light + speed of spaceship, which would be 150% of the speed of light.
        ^This is actually wrong.

        You would in fact measure the speed of the beam of light to be: Exactly the speed of light.
        This is the crux of special relativity: That all observers, regardless of their velocity, will measure the exact same speed of light. You can never catch a beam of light, because a beam of light is ALWAYS moving away from you at the speed of light, even if you are going 99.99999999999999999999999999999999999999999999999999998% of the speed of light. This is what Einstein was pondering when he came up with special relativity: What happens if you were able to travel alongside a beam of light? Since light is a wave, if you could catch up with a beam of light, then would you ‘see’ a standing wave?? This is impossible. Not just a little impossible, or really impossible, but Universe breakingly impossible.

        Now, if at this point, (if you’re still reading) you’re thinking, “but there is no proof of this!”
        There actually is. Maaaany experiments have confirmed this. One of the first experiments was the Michelson-Morley experiment. But there have been so many more. The speed of light is woven into the fabric of the Universe, there is no unravelling it, or cleverly finding a way around it.

      2. I have to disagree with you on that. If you’re moving at light speed, AT light speed, *your* time is going to be instant from point A to point B. Time is not going to elapse. So doing so would be impossible.

        Also, light speed deals with the Construct of the universe itself. It’s not really a speed. It’s basically teleportation, because no time elapses for you. Relative to people on earth, it took “you” 4.x years to get to Alpha Centuri. It didn’t. It took you the time to speed up and slow down from the speed of light. The “highway miles” when going the speed of light took Zero time for you. No time elapsed.

        Matter can’t go the speed of light, nor anything with any considerable mass super close to it really (to get to it in any reasonable timeframe), when we’re talking about “push” and propulsion thru space. This normal “way” of “going”.

        To “go faster than light” could be a possibility, but you’d have to warp/change space itself. Or in other ways, it’d have to be a different Way of moving, where the concept of moving itself changes. THAT is for the far far future.

      3. Okay not to nit pick here.

        But in the example an Alcubierre drive you are staying stationary it’s space-time which is moving around your bubble.

        That is what allows you to travel superluminal distances without actually breaking the speed of light.

        Interestingly if this does work it also avoid the whole time dilation headache where you don’t age but when you return to Earth thousandd of years have passed and everyone you knew is long dead and gone.

        As far as propelling a craft to the speed of light? We know unequivocally that is impossible. The reason for this is found in Einsteins famous equation E=MC2. E is energy, M is Mass, C is the speed of light, the 2 is standing in for squared because the keyboard on my phone won’t do scientific notation.

        So the amount of energy required to move anything with Mass to the speed of light is larger than you could generate if you were to instantly turn all of the matter in the universe to energy all at once you still wouldn’t quite get there. They’d be nowhere to go either but still wouldn’t be traveling at the speed of light.

  4. I don’t think we can realistically reach another star until we can create a drive that can reach a meaningful fraction of the speed of light. Say maybe 1/20th the speed of light. Why? Equipment wears out. The spacecraft will have to travel 1,000’s of years undergoing intense interstellar radiation if traveling considerably slower. Overtime, that will eventually corrupt circuits. And the stars move too. So unless we can catch a star from behind, it really don’t matter. We’ll never get there and be able to slow up. Our little probe will be just a fast fly by.

    1. Going too fast over a long distance, in some conventional space probe will shred the sh!t out of it. The speed in which small debris hits it will be like a MAC Truck slamming into ya. That’s actually a bigger problem than pouring $$ into developing a faster and faster engine to a conventionally-sized probe.

      We won’t be sending People elsewhere, but most likely super-small devices that can get near the speed of light — enough so within a lifetime, it can reach another star. And sending many of them, so at least a few will make it unscathed (such small size), and technology that will allow grain-of-sand sized devices to relay messages back to Earth.

  5. One of the big problems, also, is that the faster you go, the faster all that cosmic dust is going to be impacting a ship. A ship going at even only 10% of the speed of light would be obliterated by tiny bullets firing at 10% of the speed of light. Even a speck of dust would pack an enormous punch. And, if you were to go an even faster fraction of the speed of light, besides the faster projectiles, the ship would probably be vaporized from radiation.

    I don’t think any realistic option would have a ship going at even a fraction of the speed of light.

    I think that the best option in the (distant) future, would be a really advanced probe that spends hundreds or thousands of years in space, reaches a system, and manufactures a huge recieving transmitter of some kind. Then, maybe we could upload our conciousness to this new solar system, and we could do that at the speed of light. We would only need a probe (or many) to make the initial crossing.

    1. The original “Daedalus” study proposed an artificial dust cloud moving 200 kilometres ahead of the main vehicle as a sort of debris shield. Any incoming dust grains would be ionized into a spray of particles and diverted away from the vehicle using a magnetic field. A second system used in conjunction is an X-ray laser or a neutral particle beam firing ahead of the ship to deflect any objects detected in its forward-pointing radar.

      1. That’s interesting, I never heard about that. How would they have accelerated the dust cloud ahead of the ship?

  6. The only practical solution is to warp spacetime. So much discussion is made of using conventional thrust or novel techniques for pushing a spacecraft faster. This is just not practical at all, even for our own stellar neighborhood. The math and even the observations are proven for the warping of spacetime, so this is what we need to focus on. We just have to want to do this, and that’s the problem.

    I have no doubt that it is eventually possible, and that there are some spacefaring species out there using it. However, we are just far too obsessed with spending our resources on competing with each other on ideologies, stockpiling military might against ourselves, and otherwise spending on our own personal entertainment. It will take centuries for us to evolve into a species that can live without these things mentally and emotionally.

    Just imagine right now if a spacecraft arrived from Planet X and aliens introduced themselves (assuming they can communicate with us) and we learned about them. What would you think if they told you that they had hundreds of sub-cultures, nations, dialects, religions, goals, and forms of entertainment all with a relatively short life-span? You’d wonder how they ever accomplished anything, much less got off their planet to visit our ball of dirt. Some astrobiologists believe that the most likely first contact we’d get is from artificial intelligence. This is our naive way of describing an alien species that is mechanical, much more tolerant to environmental conditions, does not have neurological-judgment issues, retains knowledge infinitely better, and has a nearly infinite lifespan. Even if it is a biological that we make contact with first, could you ever imagine them as being inferior to us?

    Whether or not we actually succeed in shifting our global consciousness into one that wants to get off-world is the biggest question – and sadly I really don’t see any indication that we are on our way to that. We need a tipping point. Such as maybe finding signs of civilization such as an alien outpost on Pluto. Or some species sending us a message. Or maybe a visit. In every case, you know our governments will cover it up in order to keep us from falling into global mass hysteria due to the 95% of our population that is fully scientifically retarded or otherwise some kind of zealot.

    I think we’ll get there. Just not now. I’d give it about 19,000 years. Go ahead and send a probe to Alpha Centauri. We’ll get our first warp-jump to meet it when it gets there the old-fashioned way. First step – cancel the Kardashians. Next step, launch that probe.

    1. olfac, do you REALLY believe that *only* 95% of the population is scientifically retarded? You haven’t been reading enough of the comments here.
      hypernova: Thank you for explaining the relativity bit and restating that the speed of light IS an integral part of the fabric of the universe. I *LIKE* that description!! (for its simplicity and its clarity).
      The other writer (to avoid using names) seems to be part of that other 4.99999999999%.

      moozoo, go back to grade school!

      1. That 95% number makes me believe that olfactorycone is living in a American or Muslim society.

  7. What if we used a really long and powerful rail gun to shoot something small (size of a mobile phone)?
    Say get it to 10% the speed of light?
    so it takes ~40 years.

    1. Fastest we.ve launched to date is 0.0001c. 10 folding that basically requires e^10 = 22,000 times more fuel per unit mass. 0.01c would require 10^43 times more fuel per payload mass than New Horizons on the most powerful Atlas V version, which is undoable. Even for a nanogram with all launchers which have ever been built would fall many billion times short. And the trip would still take 450 years.

      A railgun might be a good idea in space or on the Moon. But in an atmosphere it is a bad idea to start with max speed at the surface. It would be much faster than a meteor, and they are vapourized already in at the very thin 100 km altitude.

    2. Then you would have a phone sized probe flying by Alpha Centauri taking phone quality images that will be transmitted a few kilometers to nobody.

      If the phone sized object can withstand 100 G of acceleration for 8,5 hours in a rail gun it would need a 458 000 000 000 meters long rail gun. Thats 100 times the distance to Pluto.

      If we drill a hole through the moon and use the hole as a rail gun the object must withstand an acceleration of 13 million G for 0,23 seconds. Even a solid diamond would disintegrate with that extreme acceleration.

  8. At 2000 times the distance to Pluto it would take a huge antenna and power generator to get a tiny signal back to earth. Probably a 100 meter antenna and tons of fission fuel in a RTG, plus propulsion. Still the new horizons v2.0 Alpha Centauri edition would need thousands of years to reach the target.

    By then someone would have been smart enough to build a v3.0 that is not sent to alpha Centauri, but stays close to Earth and uses the 100 meter antenna as a telescope mirror. Polished and reflective. Saving lots of fuel and no need for a heavy RTG. We would probably know more about alpha Centauri in 100 years then we would get from that spacecraft arriving in thousands of years.

    Save the money and the hassle, build a super gigantic space telescope in stead. Yes, the Alpha Centaury probe would cost magnitudes more then the gigantic space telescope, which probably will cost magnitudes more then the most expensive space telescope yet, Hubble.

    Actually i have an idea for a 100 meter space telescope that will cost less then Hubble, but thats another story.

    1. Wouldn’t a laser communication system and the JWST as a receiver be an option?

      Although how you’d get the things lined up just right would be a challenge.

  9. We have a long, long, long way to go so we might as well put all our energies into our own Solar System and Colonize the Moon and Mars that should take us a thousand years or so (if we survive) and by then we should be ready to start thinking about other Systems to raid with our New Warp Drives… 🙂

    1. For years I’ve entertained the idea that somewhere in some lab or even in a part time inventor’s garage.. a very miraculous and incredible event will occur. That someone will accidentally stumble upon an unknown process or mechanism that opens the door to the galaxy. Let’s say an anti gravity device contributed by a TV repairman?

      1. Over the decades, many great inventions have been born of accidents in garages and labs around the world. I share your thoughts in believing the door to the galaxy might be made to open through just such a discovery. While the theory can undoubtedly work its way out of someone’s garage, the implementation would likely require much more substantial effort. We saw a portrayal of this in one of the Star Trek films. I think that portrayal may not be far off the mark sometime in the distant future.

  10. A lot of good comments above.

    The net effect is that a useful probe is not going to launch within our lifetimes – and probably not for several centuries.

    You have competing design/operational parameters along with sociopolitical issues which have no reasonable solution at this time.

    In order for this all to work you need a robust propulsion system which will work unattended for very long time periods as well as equipment which can run unattended for very long time periods – and then a communications system which can produce a useful signal at immense distances.

    You want to keep the package you are sending very small so that you don’t need energy needs and reaction masses which are, well, astronomically large.

    But if you keep the package small then you won’t be making it sufficiently robust. And when I’m talking robust I’m talking about the need to be able to effectively repair and remanufacture itself while underway since the integrity of the craft could not be ensured even (maybe especially?) if you were able to achieve a very high percentage of the speed of light.

    And don’t forget, to be really worthwhile you’d probably want the craft to decelerate at its destination and to be able to independently assess its new (and likely complex) environment and then adjust its trajectory or orbit to allow for continued integrity of the mission while also getting the most interesting data and then transmitting it.

    It has to be small to get it there. It would have to be huge for it to be able to get there intact and useful. There is no technology on the horizon to do this. May be able to do this some day, but not in the foreseeable future.

    Oh, and that’s just touching a little on the technological aspect. Assuming you were able to build a probe using lightsails which would get there and be functional 1,900 years from now (not likely, but let’s assume)? When it got there would anyone remember it had been launched and still be listening for the signal? Would anyone even care what it sent back? Would the information be simply duplicative by that time due to other technologies having already gotten much of the information and the probes tech being nearly 2,000 years old?

    Even if we were listening and the information was useful, with the data transmission protocols be understood? Seriously, IIRC, there was an attempt to resuscitate a probe a year or two ago and repurpose the thing – they had trouble finding the information needed just to communicate with the thing. They were lucky that the necessary information on the electronics/programming still sort of existed and they were able to communicate, but another decade or two and I doubt they could have made an attempt with any significant chance of success. The challenge with an interstellar probe would be a little different since you would not be trying to command it – but recognizing the signal and deciphering it might be problematic at best.

    Not happening any time soon.

  11. Even if we could get there in 19,000 years, and enter into a useful orbit, would a 30 watt transmitter have enough power to transmit data over such a distance? Also, that would assume NASA or the ESA still existed 19,000 years later and was set up to receive the data. And even if these obstacles are overcome, if the orbit is wrong, it will require 8.6 years to send a course correction and retransmit data. Just The fuel needed to decelerate and do a course correction would require a tremendous amount of extra energy to get it there. Passing along the information about the encounter from generation to generation for 19,000 years will be a challenge. Storing Hydrazine for 19,000 years will be a challenge. I don’t think interstellar travel will ever be possible. We may be able to send something in that direction but after 19,000 years it will be long forgotten and unable to function or transmit data.

    1. The easy answer for the data transmission is to not expect the original probe to push a signal all the way back. A series of probes could relay the signal. Depending on the speeds involved and initial signal power, we’d need to send successive relays every couple of months (I’d guess) whose primary purpose would be to act as a relay. In an ideal situation, we could have these waypoints use emdrive to set up a stationary position, but considering the speeds that may not work. And if we lose one (or more) along the chain, we might lose the signal entirely unless we have enough overlap between their functional zones (which probably doubles the number of relay probes).

      None of this negates the issues brought up previously (multiplied by the number of relays), but it’s the easiest answer for the signal problem.

  12. Propulsion systems and shielding are great impediments to interstellar flight. Currently understood laws of physics, not so much. A 1g spacecraft (i.e. A spacecraft capable of accelerating at 1g = 10 meters per second per second continually) could travel to any point in the universe within a human lifespan (a human on the spacecraft). You can read the technical details in chapter 6 of the textbook “Gravitation” by Misner, Thorne, and Wheeler (My god, the list price is over $400 now).

    This seemingly counter intuitive claim rests on the well established physics of special relativity (time dilation and Lorentz contraction). Also, note that in the ‘rest’ frame of a photon, no time transpires as it travels. We refer to distances as the time for light to travel but that is in our reference frame.

    We may never be able to construct a 1g propulsion system and if we could shielding might be an intractable problem. But the laws of physics say go wherever you wish. Just don’t send me the bill.

  13. Economics rules it out–not actual cost but the opportunity cost of putting money into a probe rather than into better telescopes (I am thinking here of fleets of them in space with observation capacities that make Hubble look like Galileo’s tube). Before 1992 no telescope detected an exoplanet; now they do–the future holds more in that direction than any probe could.

    It might be objected that a probe could gain information not available to telescope observation. But telescopes unlike probes (i) do not have generation long waits, (ii) the questions they investigate can be quickly adapted given new ideas and information, and (ii) any technical problems can be identified — however if a probe that went “silent”, nothing would provide no means of knowing why.

    There is a final cost–there would come a point in the development telescopic sensitivity such that it would make them blinded by the particles emitted back to us (and the telescopes) needed to propel a probe. The cost of not being able to see Alpha Centauri for many generations might be judged too great if that was the price of sending a probe there.

    In short, opportunity costs rule out interstellar exploration.

  14. It is irrelevant whether we can make something travel 10x faster than what we can achieve now. No human made tool can last long enough to reach another star! Solar panels degrade over time, plutonium degrades, batteries wear out, electronics short circuit, etc. There is nothing that can last the 1000’s of years needed and still work. Nothing. Even if we can get a probe to the nearest star in 200 years, it won’t work. If it did work, technology on Earth would have moved past the point of being able to communicate with it because it would be long obsolete by then, just like floppy disks and tapes are obsolete now.

  15. My, my! We are a pessimistic bunch, aren’t we?!!!

    OK, I’m obviously one who is pessimistic so I’m not saying that the pessimism is not realism.

    I will hope for a breakthrough technology but I will not expect it.

  16. I don’t see how it could realistically be doable outside of the Alcubierre drive panning out or if discover negative energy and manage not to wipe ourselves out with it in process.

    I guess if modified our genome enough or learned to digitize and store consiousness the time issue could become moot.

    Although with the latter option I’m not sure what our motivation would be?

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