The odd thing about the universe seems to be that the distances are so vast that it almost doesn't matter if there's other sentient life here or not because it's far too distant to be of any relevance.
Travelling between stars is incredibly expensive (in terms of pure Joules) and time-consuming. I can see the logic in the theory that the most likely outcome for any species reaching sentience is to destroy themselves. either through direct means (eg nuclear or biological war) or indirectly (simply running out of resources)
Calling it irrelevant just because you can't travel there is short-sighted. We could still learn a lot just by watching the broadcasts of another civilization, even if they're already long gone.
The super intelligent life will live forever so distance/time might not be relavant to them as it is to us.
Also, it seems like at this stage of our intelligence we can communicate and find only intelligent life which is at similar stage (which is maybe span of 100K +/- 10K years). That is nothing.
The distances are indeed vast, but the time periods involved are yet more vast. A Von Neumann probe travelling at quite modest speeds should be able to spread over our entire galaxy in mere millions of years; the universe is billions of years old.
So while direct visitation by aliens seems highly improbable, such a probe making contact seems at least a theoretically plausible possibility.
Could we travel by moving the entire solar system with us?
Build a dyson sphere around the sun and harness part of the energy to ever so slowly move our planet and sun towards a nearby suitable star system. Then settle our planet in orbit around the other star.
This way we should have at least some way of sustaining human life past the end of our sun.
I've been watching his "Into the Universe" series, and honestly I have been a bit disappointed. I was hoping for more science -- details about subatomic particles, a discussion of the various interpretations of quantum mechanics, an introduction to M-theory (that doesn't involve violins and floating colors). Instead, one whole episode was devoted to ragging on religion -- a bunch of speculation that doesn't teach any of the interesting science to the show's viewers.
How about an introduction to Hawking radiation, the holographic principle, superpartners? At least an overview of the standard model? Nope. Just reasons "God isn't necessary". I'm not sure why he takes this route for the show. Maybe it gets more viewers and more controversy. It's sadly reminiscient of the history channel. It used to be full of a lot of interesting, objective content about -- believe it or not -- history, but now it's just full of alien speculation and religious prophecies.
It's not a show about science; it's a show about ratings. Popular science gets ratings, which are still less than non-popular-related shows, and which are far higher than any hard-science-related shows could ever get. You'll have to scratch that itch somewhere else... though I totally agree with you!!!
I used to watch the History Channel all the time. I'd keep it on throughout the day while I worked, always enjoying war documentaries or historical pieces. Now it's all reality TV and "Who would win in a fight: Navy SEAL vs. Samurai" nonsense. I guess the "watching television to be informed" target audience is dwindling faster than I thought.
Don't get me wrong, I think Stephen Hawking is a very smart man, and he has definitely done his fair share of work to help people understand science - not to mention that his scientific accomplishments aren't bad, either. That being said, there's just nothing new in this Q&A that he hasn't already said or wasn't already widely known to anyone who bothered to do a quick search on Google (except perhaps the part about his quality of life, but let's face it, that's not important).
I don't think the part about his quality of life is not important.
Lots of people have disabilities, only accounting for spina bifida which is physically less disabling that ALS, or muscle atrophy which leaves cognitive capacity intact, already puts them in the thousands. Someone needs to show them they can achieve many of what they dream about, because most of society only gives them pity and consent. We have Olympic Games for disabled people whose dreams are of being athletes, and we need people like Stephen Hawking to show disabled wannabe scientists and hackers (many of whom I believe read HN and ars) that they can also triumph in their geeky endeavours.
Thats just it though. There are many who WONT go back and re-read what he has said. Some people think that by virtue of him having something to say that he's presenting something new.
You have to remember that in knowing and being familiar with the content being presented that you're in the minority of people who will EVER grasp this knowledge, even on a basic level.
Its important for more people to learn about the frontier in as many ways as possible, as often as they can.
I'm surprised to hear someone of his intellectual caliber resort to ridicule when someone brings up UFOs. UFOs "appearing" to "cranks and weirdos" doesn't really describe the phenomena, as anyone who spent more than 30 minutes on the subject would know.
I'd would have loved to have heard him debate the late John Mack (Harvard Medical School, won a Pulitzer) on the subject. It's incredibly arrogant for him to think that he can ignore the research of other academics (or remain in ignorance of it) and still speak authoritatively on the subject.
I don't expect him to champion the field but since he's asked so frequently about extraterrestrial life and/or UFOs it would be nice if his canned response was a bit more intelligent.
It's incredible to dismiss so much theoretical/speculative physics in the interview and at the same time say that maybe M-Theory will tie up the loose ends in the Standard Model, but then again, maybe it won't and we'll be back to the drawing board. Even though we admittedly don't understand the universe with any degrees of completeness, obviously these popular ideas are false based on our understanding of the universe?
Here's an idea that's been kicking around in my mind for a while: what if it's not that it takes such a tremendous amount of time to travel anywhere interesting in the universe, but that our perception of time is just too fast? Perhaps to an alien race a thousand (or million) years seems like a second. Wikipedia suggests that our perception of time does get (slightly) slower as we age [1], so maybe living significantly longer could do this to us as well. Finally, it seems that our perception of time is largely shaped by the Circadian rhythm; if life evolved somewhere with a much slower "cosmic clock" could that also cause a much slower time perception?
While our perception of time night be subjective, as you suggest, the distances involved are not. Even if it only feels like a few moments, the universe doesn't much care how we feel, or what we perceive.
It is a collection of theories that try to explain why we haven't been contacted yet by aliens.
There is also a very good book on the subject that elaborates further on the theories of the Fermi paradox. In total there are 50 different theories, from life been too young on the universe and thus we're rather alone, to not be able to communicate because they're using superior technology.
http://www.amazon.com/Universe-Aliens-Everybody-Solutions-Ex...
> I have experimental evidence that time travel is not possible. I gave a party for time-travelers, but I didn't send out the invitations until after the party. I sat there a long time, but no one came.
Why would one need to send invitations if the outcome is already known once the party is over? It seems that merely giving a party for time-travelers is a plenty sufficient evidence.
> Another frightening possibility is intelligent life is not only common, but that it destroys itself when it reaches a stage of advanced technology.
Or that it transcends beyond physical 3D realm (as corny as it sounds) and so it's no longer detectable from within it.
Lets be honest, there's obviously other intelligent life in the universe. There's probably tons of it, I don't think it's ever visited earth before, and we'll likely never shake its hand, but its out there. One day we can hopefully communicate with one, it would have to be done with radio signals over generations, but it would be amazing to see it happen.
I've always thought it more likely than the fact that intelligent civilizations destroy themselves is the fact that intelligent civilizations are out there and the really smart ones actually know the Earth exists. Interstellar distance is likely a problem that no one has truly solved but I like to think there's civilization out there that knows the Earth exists and is ripe for life, just they're too far away to do anything about it.
Obviously? Like I go outside and there it is— obvious non-terrestrial intelligent life?
For me it obviously does not exist. It may exist somewhere in the galaxy far away. It might not. We don't know. We will never (by never I mean ~1 billion years) know.
I am amazed to see so much wishful thinking and ignorance regarding physics and astrophysics.
Maybe they like a higher CO2 level and warmer temperatures, and are masquerading as energy company executives. Alienforming a planet is easy if you can get the natives to do it for you.
We will NEVER be visited by extra terrestrial life. The amount of luck required is too great. It's extremely unrealistic and foolish.
1) We need to come to the realization that it is and always will be impossible to travel at the speed of light or anywhere near the speed of light. Doing so would cause radiation particles, micro particles, space dust, and other little things floating around to hit the the crew and ship at extreme speeds and rip the ship apart. A bullet fired from a high powered rifle is only going 1,200 mph and can rip through metal. So imaging your space ship getting pummeled by particles at 670,616,629 mph and the faster you go the more particles you got bombarded with. There are no metals or materials that can sustain this type of damage because these radiation particles are SMALLER than x-ray particles so they'll pass through absolutely everything. And nothing can filter out or block this astronomical amount of radiation that will pummel the crew. We can wish and hope but it's a problem that is out of our control.
2) We need to stop falsely and foolishing assuming that there are aliens far out in the universe that can see us (2012) through a telescope. If you look at the earth right now (2012) from 65 million light years away, to the extra terrestrial, they are just now seeing light from 65 million years ago reach them. So to them there is no intelligent life on earth yet. It won't be another 65 million years until they are finally able to see us humans. By that time WE or THEY will be extinct. Because WE have the same problems THEY have. The vast majority of planets or uninhabitable and we can't travel fast enough to reach a planet, nor evolve or adapt to the bacteria on that planet fast enough to actually live on it.
3) We will most certainly never be able to "move homes" to another planet because the bacteria and organisms on it would be hostile to the point where we can't even safely evolve around it. We can live on Earth because for millions of years our ancesters have built up immunities to all the nasty viruses and plagues and flus that have come and gone. If an extra terrestrial landed here on earth they would not be able to interact with us in ANY way without wearing a bio-suit. They can't breathe our air or drink our water. And you think they're going to travel millions of years to get to a planet they can't even vacation on or enjoy or interact with in any way.
4) Extra terrestrial life that is more advanced than us has no reason to go on a suicide mission to come see us (a bunch of war-mongering primitive hairless baboons)
To any potential aliens who are living millions of years away, we haven't even evolved yet. By the time they see us, we will be gone. By the time they travel millions of light years to finally reach us, both of our species will be dead. Us from extinction and them from getting blasted by radiation. Also, if they are more advanced than us why the hell would they want to come all this way to see us?! That would be like us traveling millions of years on a suicide mission to go see a planet of lemurs.
I love absolutist comments like this. Never is a very very long time. Its possible we already were visited and they've moved on. What most folks don't conceptualize well is that the width of the timeline which constitutes "humans are here" is so damn small on a 4 billion year timeline as to be hard to spot with the naked eye :-).
But lets look at your points:
1) You don't have a good grasp of physics but that's ok. One of the things that happens as you accelerate is that you gp through something called time dilation. Travelling a significant fractions of the speed of light will have time passing much much more slowly on the ship than on Earth. You'll want to work it out so that you approach 'c' at the halfway point, then flip over and decelerate. If you do it that way your crew will easily survive the entire trip. There is the question of energy and reaction mass, real problems and as yet unsolved, but not insoluble. We can and do regularly manufacture anti-matter these days, its a pretty good fuel.
2) You make a number of interesting assumptions here. One is that aliens are 65 million miles away. Consider that we already know that our planet is a death trap, its killed off everything several times already, so we figure out how to leave. Better we create our own environments where all we need do is scoop up interstellar hydrogen for fuel, or perhaps harvest a bit of space junk. The Earth is a spaceship that is gravity locked to the Sun. There is certainly enough material in our solar system to build something that could wander amongst the stars. And if we've figured out cellular biology, and can thus 'fix' any issues that come up, it means we can 'live' in our bodies forever via mechanical repair. If we can do it, so can other species. Imagine a flotilla of 'units' moving in parallel, carrying our alien visitors, from star system to star system. Perhaps seeing a new system every 100 years or so.
3) We can certainly create habitats that don't kill us and that keep things that might kill us out. Further there is a really really interesting change coming when pieces of how people work comes together in a provable way. One good thing, the health care crisis for 'rich' people will be gone. Once we've got the source code, all bets are off.
4) This is just projection ;-) We would go visit a society that was in its early stages of development just to see how they do it. We've been doing that with indigenous island people on the planet, I would be surprised if we had interplanetary capability and we didn't do that.
> these radiation particles are SMALLER than x-ray particles
This indicates you might not understand enough physics to be able to back up your assertions. Firstly, X-rays are in the same category as "radiation particles" (I assume you are referring to electromagnetic radiation). Secondly, radiation "particles" are photons and they don't strictly have a size; they do, however, have a wavelength, which might be what you are alluding to?
(And lastly, if particles "pass through absolutely everything", they do no damage and so aren't problematic.)
> If an extra terrestrial landed here on earth they would not be able to interact with us in ANY way without wearing a bio-suit. They can't breathe our air or drink our water. And you think they're going to travel millions of years to get to a planet they can't even vacation on or enjoy or interact with in any way.
They can vacation on it and enjoy it by wearing a biosuit. And this isn't unreasonable: humans can't breathe water, but we still can enjoy it using a biosuit (SCUBA equipment).
We have found planets that may support life 20 light years away. Recent evidence suggests that most stars around us have planets and a significant percentage of those stars have planets that may support life. It's just that resolving a planet at those distances is hard, let alone radio traffic. So while we have little chance of contacting life 1 million light years from us there is a chance intelligent life with technological civilizations could be within as little as 50 light years of us. And even if they exist we would probably have not noticed them yet.
We might never have physical contact with civilizations a 100 light years from us we could have meaningful if high latency conversations with them at reasonable costs.
PS: It's hard to talk with Voyager 1 a mere (1.8x10^10 km) from us at 50 light years the signal would be 1/700,000,000th the strength. So, the only way your talking out to that distance is with a dish that's pointed in the right direction and even then if the signal was not 1 million times as strong there is no way in hell we would notice it.
Most of your points are sound, but I think you are too pessimistic about them being interested in us. Mightn't they be just as desperate as we are to not be alone?
Perhaps you lack imagination. The first argument has been addressed by many, and in an interesting way by Alastair Reynolds in his Revelation Universe.
Ships apply 1G of acceleration for many years and thus slowly reach speeds close to that of light. The ships are both "aerodynamic" and encased in a thick layer of ice, so that small, rare impacts are survivable. This becomes a plot mechanism in a few of his stories.
While radiation is a serious problem at relativistic velocities, you're a bit too pessimistic:
The most immediate problem is the interstellar gas, which becomes hard radiation at relativistic velocities. However, ~2cm of aluminium shielding are enough to reach 0.3c, and with 1m of water, you can reach 0.5c.
For higher velocities, magnetic shielding coupled with a metallic electron stripper is probably a more pragmatic solution.
I'd say that the chances of us ever coming into contact with intelligent life are worryingly low until well (as in, billions of years) into the future. If we say that "ultimate maturity" of a civilization is to have a technological singularity of some sort, resources wouldn't really be an issue. SETI hasn't picked up anything. Assuming that the universe is infinite in extent, as it currently is hypothesized to be, the only real solution is that life is so spread out as to be almost irrelevantly far away.
[+] [-] cletus|13 years ago|reply
Travelling between stars is incredibly expensive (in terms of pure Joules) and time-consuming. I can see the logic in the theory that the most likely outcome for any species reaching sentience is to destroy themselves. either through direct means (eg nuclear or biological war) or indirectly (simply running out of resources)
[+] [-] Fizzer|13 years ago|reply
[+] [-] tlogan|13 years ago|reply
Also, it seems like at this stage of our intelligence we can communicate and find only intelligent life which is at similar stage (which is maybe span of 100K +/- 10K years). That is nothing.
[+] [-] caf|13 years ago|reply
So while direct visitation by aliens seems highly improbable, such a probe making contact seems at least a theoretically plausible possibility.
[+] [-] bane|13 years ago|reply
http://www.penny-arcade.com/2008/12/1/
Mathematically inaccurate but can be a short and simple way of summarizing costs and complexity.
[+] [-] anonymous|13 years ago|reply
Build a dyson sphere around the sun and harness part of the energy to ever so slowly move our planet and sun towards a nearby suitable star system. Then settle our planet in orbit around the other star.
This way we should have at least some way of sustaining human life past the end of our sun.
[+] [-] Xcelerate|13 years ago|reply
How about an introduction to Hawking radiation, the holographic principle, superpartners? At least an overview of the standard model? Nope. Just reasons "God isn't necessary". I'm not sure why he takes this route for the show. Maybe it gets more viewers and more controversy. It's sadly reminiscient of the history channel. It used to be full of a lot of interesting, objective content about -- believe it or not -- history, but now it's just full of alien speculation and religious prophecies.
[+] [-] rewind|13 years ago|reply
[+] [-] tdfx|13 years ago|reply
[+] [-] vibrunazo|13 years ago|reply
http://xkcd.com/799/
[+] [-] hobin|13 years ago|reply
Don't get me wrong, I think Stephen Hawking is a very smart man, and he has definitely done his fair share of work to help people understand science - not to mention that his scientific accomplishments aren't bad, either. That being said, there's just nothing new in this Q&A that he hasn't already said or wasn't already widely known to anyone who bothered to do a quick search on Google (except perhaps the part about his quality of life, but let's face it, that's not important).
[+] [-] pvarangot|13 years ago|reply
Lots of people have disabilities, only accounting for spina bifida which is physically less disabling that ALS, or muscle atrophy which leaves cognitive capacity intact, already puts them in the thousands. Someone needs to show them they can achieve many of what they dream about, because most of society only gives them pity and consent. We have Olympic Games for disabled people whose dreams are of being athletes, and we need people like Stephen Hawking to show disabled wannabe scientists and hackers (many of whom I believe read HN and ars) that they can also triumph in their geeky endeavours.
[+] [-] BlackNapoleon|13 years ago|reply
You have to remember that in knowing and being familiar with the content being presented that you're in the minority of people who will EVER grasp this knowledge, even on a basic level.
Its important for more people to learn about the frontier in as many ways as possible, as often as they can.
[+] [-] mbenjaminsmith|13 years ago|reply
I'd would have loved to have heard him debate the late John Mack (Harvard Medical School, won a Pulitzer) on the subject. It's incredibly arrogant for him to think that he can ignore the research of other academics (or remain in ignorance of it) and still speak authoritatively on the subject.
I don't expect him to champion the field but since he's asked so frequently about extraterrestrial life and/or UFOs it would be nice if his canned response was a bit more intelligent.
It's incredible to dismiss so much theoretical/speculative physics in the interview and at the same time say that maybe M-Theory will tie up the loose ends in the Standard Model, but then again, maybe it won't and we'll be back to the drawing board. Even though we admittedly don't understand the universe with any degrees of completeness, obviously these popular ideas are false based on our understanding of the universe?
[+] [-] rimantas|13 years ago|reply
[+] [-] fferen|13 years ago|reply
[1]: http://en.wikipedia.org/wiki/Time_perception#Long-term
[+] [-] dr42|13 years ago|reply
[+] [-] elorant|13 years ago|reply
It is a collection of theories that try to explain why we haven't been contacted yet by aliens.
There is also a very good book on the subject that elaborates further on the theories of the Fermi paradox. In total there are 50 different theories, from life been too young on the universe and thus we're rather alone, to not be able to communicate because they're using superior technology. http://www.amazon.com/Universe-Aliens-Everybody-Solutions-Ex...
[+] [-] huhtenberg|13 years ago|reply
Why would one need to send invitations if the outcome is already known once the party is over? It seems that merely giving a party for time-travelers is a plenty sufficient evidence.
> Another frightening possibility is intelligent life is not only common, but that it destroys itself when it reaches a stage of advanced technology.
Or that it transcends beyond physical 3D realm (as corny as it sounds) and so it's no longer detectable from within it.
[+] [-] CJefferson|13 years ago|reply
Well, if you didn't invite anyone, maybe the reason no time-travellers came is that they weren't invited?
[+] [-] verroq|13 years ago|reply
[+] [-] DrewChambersDC|13 years ago|reply
I've always thought it more likely than the fact that intelligent civilizations destroy themselves is the fact that intelligent civilizations are out there and the really smart ones actually know the Earth exists. Interstellar distance is likely a problem that no one has truly solved but I like to think there's civilization out there that knows the Earth exists and is ripe for life, just they're too far away to do anything about it.
[+] [-] rimantas|13 years ago|reply
[+] [-] olalonde|13 years ago|reply
Maybe they like a higher CO2 level and warmer temperatures, and are masquerading as energy company executives. Alienforming a planet is easy if you can get the natives to do it for you.
[+] [-] ChrisNorstrom|13 years ago|reply
1) We need to come to the realization that it is and always will be impossible to travel at the speed of light or anywhere near the speed of light. Doing so would cause radiation particles, micro particles, space dust, and other little things floating around to hit the the crew and ship at extreme speeds and rip the ship apart. A bullet fired from a high powered rifle is only going 1,200 mph and can rip through metal. So imaging your space ship getting pummeled by particles at 670,616,629 mph and the faster you go the more particles you got bombarded with. There are no metals or materials that can sustain this type of damage because these radiation particles are SMALLER than x-ray particles so they'll pass through absolutely everything. And nothing can filter out or block this astronomical amount of radiation that will pummel the crew. We can wish and hope but it's a problem that is out of our control.
2) We need to stop falsely and foolishing assuming that there are aliens far out in the universe that can see us (2012) through a telescope. If you look at the earth right now (2012) from 65 million light years away, to the extra terrestrial, they are just now seeing light from 65 million years ago reach them. So to them there is no intelligent life on earth yet. It won't be another 65 million years until they are finally able to see us humans. By that time WE or THEY will be extinct. Because WE have the same problems THEY have. The vast majority of planets or uninhabitable and we can't travel fast enough to reach a planet, nor evolve or adapt to the bacteria on that planet fast enough to actually live on it.
3) We will most certainly never be able to "move homes" to another planet because the bacteria and organisms on it would be hostile to the point where we can't even safely evolve around it. We can live on Earth because for millions of years our ancesters have built up immunities to all the nasty viruses and plagues and flus that have come and gone. If an extra terrestrial landed here on earth they would not be able to interact with us in ANY way without wearing a bio-suit. They can't breathe our air or drink our water. And you think they're going to travel millions of years to get to a planet they can't even vacation on or enjoy or interact with in any way.
4) Extra terrestrial life that is more advanced than us has no reason to go on a suicide mission to come see us (a bunch of war-mongering primitive hairless baboons)
To any potential aliens who are living millions of years away, we haven't even evolved yet. By the time they see us, we will be gone. By the time they travel millions of light years to finally reach us, both of our species will be dead. Us from extinction and them from getting blasted by radiation. Also, if they are more advanced than us why the hell would they want to come all this way to see us?! That would be like us traveling millions of years on a suicide mission to go see a planet of lemurs.
[+] [-] ChuckMcM|13 years ago|reply
But lets look at your points: 1) You don't have a good grasp of physics but that's ok. One of the things that happens as you accelerate is that you gp through something called time dilation. Travelling a significant fractions of the speed of light will have time passing much much more slowly on the ship than on Earth. You'll want to work it out so that you approach 'c' at the halfway point, then flip over and decelerate. If you do it that way your crew will easily survive the entire trip. There is the question of energy and reaction mass, real problems and as yet unsolved, but not insoluble. We can and do regularly manufacture anti-matter these days, its a pretty good fuel.
2) You make a number of interesting assumptions here. One is that aliens are 65 million miles away. Consider that we already know that our planet is a death trap, its killed off everything several times already, so we figure out how to leave. Better we create our own environments where all we need do is scoop up interstellar hydrogen for fuel, or perhaps harvest a bit of space junk. The Earth is a spaceship that is gravity locked to the Sun. There is certainly enough material in our solar system to build something that could wander amongst the stars. And if we've figured out cellular biology, and can thus 'fix' any issues that come up, it means we can 'live' in our bodies forever via mechanical repair. If we can do it, so can other species. Imagine a flotilla of 'units' moving in parallel, carrying our alien visitors, from star system to star system. Perhaps seeing a new system every 100 years or so.
3) We can certainly create habitats that don't kill us and that keep things that might kill us out. Further there is a really really interesting change coming when pieces of how people work comes together in a provable way. One good thing, the health care crisis for 'rich' people will be gone. Once we've got the source code, all bets are off.
4) This is just projection ;-) We would go visit a society that was in its early stages of development just to see how they do it. We've been doing that with indigenous island people on the planet, I would be surprised if we had interplanetary capability and we didn't do that.
[+] [-] dbaupp|13 years ago|reply
This indicates you might not understand enough physics to be able to back up your assertions. Firstly, X-rays are in the same category as "radiation particles" (I assume you are referring to electromagnetic radiation). Secondly, radiation "particles" are photons and they don't strictly have a size; they do, however, have a wavelength, which might be what you are alluding to?
(And lastly, if particles "pass through absolutely everything", they do no damage and so aren't problematic.)
> If an extra terrestrial landed here on earth they would not be able to interact with us in ANY way without wearing a bio-suit. They can't breathe our air or drink our water. And you think they're going to travel millions of years to get to a planet they can't even vacation on or enjoy or interact with in any way.
They can vacation on it and enjoy it by wearing a biosuit. And this isn't unreasonable: humans can't breathe water, but we still can enjoy it using a biosuit (SCUBA equipment).
[+] [-] _debug_|13 years ago|reply
Just as a microwave oven is practically magic to a caveman, it is reasonable to assume that our tech is caveman-tech to an advanced alien race.
Why travel at the speed of light, for example? Maybe wormholes or teleportation is possible?
[+] [-] Retric|13 years ago|reply
We might never have physical contact with civilizations a 100 light years from us we could have meaningful if high latency conversations with them at reasonable costs.
PS: It's hard to talk with Voyager 1 a mere (1.8x10^10 km) from us at 50 light years the signal would be 1/700,000,000th the strength. So, the only way your talking out to that distance is with a dish that's pointed in the right direction and even then if the signal was not 1 million times as strong there is no way in hell we would notice it.
[+] [-] andrewflnr|13 years ago|reply
[+] [-] lucian1900|13 years ago|reply
Ships apply 1G of acceleration for many years and thus slowly reach speeds close to that of light. The ships are both "aerodynamic" and encased in a thick layer of ice, so that small, rare impacts are survivable. This becomes a plot mechanism in a few of his stories.
[+] [-] aswanson|13 years ago|reply
[+] [-] cygx|13 years ago|reply
The most immediate problem is the interstellar gas, which becomes hard radiation at relativistic velocities. However, ~2cm of aluminium shielding are enough to reach 0.3c, and with 1m of water, you can reach 0.5c.
For higher velocities, magnetic shielding coupled with a metallic electron stripper is probably a more pragmatic solution.
[+] [-] Variance|13 years ago|reply
[+] [-] rimantas|13 years ago|reply
[+] [-] jpeg_hero|13 years ago|reply
[+] [-] nothacker|13 years ago|reply
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