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Author | Topic: Is Faster Than Light travel the wrong question? | |||||||||||||||||||||||
kbertsche Member (Idle past 2121 days) Posts: 1427 From: San Jose, CA, USA Joined: |
quote:This was no doubt a commonly-held conception, and it was certainly a technological challenge. But can you point to a reference where science said this was impossible? quote:String theorists are certainly trying to understand these things in a fundamental, theoretical way. But can you point to any physicists who are actually "working on this sort of thing" with a goal "to make the trip shorter" for human transportation?
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onifre Member (Idle past 2941 days) Posts: 4854 From: Dark Side of the Moon Joined: |
The science at one time said breaking the sound barrier was impossible, so it's also possible (though I would admit unlikely) that the light speed limit is not quite as absolute as we think it is. Agreeing as we always do (on most things) it pains me to have to interject - lol. Actually, the speed of light as a constant is a fact of nature; in fact, one could say a law of physics. I like how a lot of arguments come back to the same line of reasoning; what objective evidence are you using to state that it might not be "absolute," or a constant, as I called it? - Oni
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Michamus Member (Idle past 5147 days) Posts: 230 From: Ft Hood, TX Joined: |
This is kind of a reply to everyone, but I picked Aware Wolf as his was the last post that I felt was in in line with my topic (precisely that is. The side discussion on Technology advancements, change in understanding of Physics, and worm-holes/ space dilation-contraction is fascinating) I do wish there was a type of multi-reply function so everyone I selected would receive a notification e-mail, but alas we are limited to what tools we have.
Aware Wolf writes:
This is how things have been explained to me as well. I do have a few statements in regard to it, that I wish Cavediver were here to discuss.
Picture a meter stick pointing straight up. This represents an object "standing still" in space in a particular FOR.
This statement seems to be true (and I will agree with it) but it is just as you said, from a particular FoR. We understand there to be no Universal FoR, as everything is relative. We also understand there to be no such thing as true rest. With that, from an Earthly FoR, we are at rest, and light is traveling at 300,000km/sec (can't forget the k onifre). Regardless of what direction we point the light beam, it still travels at C, which is why it has that awesome abbreviation for "Constant". Taking that into consideration we must ask ourselves a few questions.1. If we point a light beam forward while traveling .999c, is that light beam going to travel back in time? I'd imagine the answer to be no. 2. If we are traveling .999c away from the Earth... and the Earth is traveling at .002c (I know a stretch) are we now really going 1.001c? I'd say no, we are still going .999c relative to the Earth, but at REST relative to ourselves, and light is still going LS. 3. Does time slow as we experience it? That is, do our internal time-keeping mechanisms suddenly experience time slower from our own FoR if we increase our velocity? Do clocks suddenly start ticking slower than before, as per traveler FoR? I'd say the answer is no, time still apparently drudges forward at the same speed to the traveler, regardless his velocity. So what I see as perplexing is that the meter stick never really changes direction, as you are never really moving (from your FoR). You are constantly at rest (from your FoR), regardless your velocity. With those taken into consideration, what is really keeping us from going from here to Alpha Centauri in one year, or sooner?
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Michamus Member (Idle past 5147 days) Posts: 230 From: Ft Hood, TX Joined: |
I understand what you are saying, and it makes sense. My question kind of assumes that we would be at a Stage of Technological Understanding to where manipulating the energy of stars is about as amazing as plugging in a toaster. (That's not a statement of possibility or probability, just a given necessary to discuss the point further)
kbertsche writes:
I'm not too sure on the precision of your numbers, but I'll take them on good faith. What exactly would be bad about traveling at 1G for 1 year? We experience 1G all the time for many years... In this scenario I would make the space-craft essentially accelerate floor side down, so you would have gravity in space.
An acceleration of 1G for 1 year would give a relative velocity of about 0.7 c, and you would age at about 70% the normal rate.
I'd imagine though that kind of acceleration would require quite a bit of energy to be sustained...
kbertsche writes:
Maybe it is, maybe it isn't. I can't see us as being too qualified as to predicting what the future brings. It does seem like an impossible scenario, with the current questions and solutions we are providing.
The energy expenditure for this would be enormous, of course. That's why sci-fi scenarios of sending people to colonize distant planets are complete fantasy.
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cavediver Member (Idle past 3633 days) Posts: 4129 From: UK Joined: |
that I wish Cavediver were here to discuss. Oh, I'm here Just VAT return time as ever...
what is really keeping us from going from here to Alpha Centauri in one year, or sooner? Nothing - if you can accelerate hard enough and safely enough, you can reach Alpha C as fast as you like - couple of days maybe. Of course, your round trip as measured by someone on Earth will take 8.6 years, but you can do it so to age as little as you choose.
Does time slow as we experience it? I'm not sure what this means. Do you mean, can we see our own watch tick slowly? No, definitely not. You only see those watches that are travelling at speeds relative to your own as ticking slowly (or more quickly in some circumstances)
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Michamus Member (Idle past 5147 days) Posts: 230 From: Ft Hood, TX Joined: |
WOW! You just completely answered all my questions in a couple sentences.
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kbertsche Member (Idle past 2121 days) Posts: 1427 From: San Jose, CA, USA Joined: |
quote:Yes, if we were at such a point technologically, such travel would be simple. quote:They are back-of-the-envelope calculations (literally), and should be accurate to 10% or so. quote:There's nothing wrong with 1G at all for an entire lifetime, of course. But this only gets you to about 0.7 c after a year, where things are just starting to get relativistic. It would be preferable to accelerate at 2G or more to further reduce the time. quote:Exactly. This is the fundamental problem. It puts a very high cost on the process, and this would be true for any society where energy cost is at all significant. These things are fun to speculate about, but they are not realistic in the foreseeable future. They certainly are not realistic until/unless we solve our energy problems. I am frankly surprised at the resistance that such comments meet in this thread. There seems to be a quasi-religious conviction here that mankind will be able to do such things one day. I consider these sci-fi speculations to be in the same vein as (but even less realistic than) global floods or vapor canopies.
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kbertsche Member (Idle past 2121 days) Posts: 1427 From: San Jose, CA, USA Joined: |
quote:Yes, but it's not possible to accelerate hard enough and safely enough to reduce this to a few days. Jet pilots in pressurized suits can endure a few Gs (less than 10?) for very short periods. Even if you could somehow get to 12G's, it would still take a month to get to 0.7 c where things begin to get relativistic. I invite you guys to check my back-of-the-envelope math. Here's a brief explanation of it:1G acceleration is about 10 m/s^2. 1 year is about 3x10^7 seconds. So in a non-relativistic world, 1G for 1 year would take you to a velocity of 3x10^8 m/s. This just happens to be the speed of light, making things convenient. We haven't actually gotten to this velocity, of course, because of relativistic effects which we have ignored. But with a fixed force of acceleration for a year, we HAVE imparted the same momentum as in the non-relativistic case, a momentum equal to c times the rest mass (p = m0c). The total energy is then sqrt(2) times the rest energy, and the velocity is 0.7 c. Edited by kbertsche, : clarified?
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DevilsAdvocate Member (Idle past 3091 days) Posts: 1548 Joined: |
If we have enough energy to push a spacecraft to near c velocities I don't think using some of this energy to counteract g-forces would be much of an issue i.e. utilizing a rotating wheel like in 2001: A Space Odyssey, etc.
Correct me if I am wrong. One of the saddest lessons of history is this: If we've been bamboozled long enough, we tend to reject any evidence of the bamboozle. We're no longer interested in finding out the truth. The bamboozle has captured us. It is simply too painful to acknowledge -- even to ourselves -- that we've been so credulous. - Carl Sagan, The Fine Art of Baloney Detection "You can't convince a believer of anything; for their belief is not based on evidence, it's based on a deep seated need to believe." - Carl Sagan "It is far better to grasp the Universe as it really is than to persist in delusion, however satisfying and reassuring." - Carl Sagan, The Demon-Haunted World
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kbertsche Member (Idle past 2121 days) Posts: 1427 From: San Jose, CA, USA Joined: |
quote:Centrifugal force from a rotating wheel can only add acceleration; it can't reduce it. This only makes things worse.
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Coyote Member (Idle past 2096 days) Posts: 6117 Joined: |
These things are fun to speculate about, but they are not realistic in the foreseeable future. They certainly are not realistic until/unless we solve our energy problems. I am frankly surprised at the resistance that such comments meet in this thread. There seems to be a quasi-religious conviction here that mankind will be able to do such things one day. I consider these sci-fi speculations to be in the same vein as (but even less realistic than) global floods or vapor canopies.
You are correct about the physics; we don't know how to do efficient interplanetary travel, let alone interstellar travel. But in the history of science the safe way to bet has always been that something will turn up. Science fiction embodies that optimism. I think Arthur C. Clarke's three "laws" of prediction would apply here:
Religious belief does not constitute scientific evidence, nor does it convey scientific knowledge.
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DevilsAdvocate Member (Idle past 3091 days) Posts: 1548 Joined: |
What if the people were somehow able stay on the side of the centrifuge in the direction that the spaceship is moving as opposed to away from it, thus subtracting from rather than adding to the g forces produced by the engines. Maybe a centrifuge inside a centrifuge going in opposite directions? Not sure. Also g-dampening may work i.e. liquids, etc. It sounds convaluted by I am sure someone could figure this out.
Edited by DevilsAdvocate, : No reason given. One of the saddest lessons of history is this: If we've been bamboozled long enough, we tend to reject any evidence of the bamboozle. We're no longer interested in finding out the truth. The bamboozle has captured us. It is simply too painful to acknowledge -- even to ourselves -- that we've been so credulous. - Carl Sagan, The Fine Art of Baloney Detection "You can't convince a believer of anything; for their belief is not based on evidence, it's based on a deep seated need to believe." - Carl Sagan "It is far better to grasp the Universe as it really is than to persist in delusion, however satisfying and reassuring." - Carl Sagan, The Demon-Haunted World
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DevilsAdvocate Member (Idle past 3091 days) Posts: 1548 Joined: |
I know this is far fetched but what if there is a cabin inside the centrifuge that spins independently of the centrifuge and maintains a position on the side of the spaceship opposed to the g-forces caused by the accelerating engines. The capsule would still be subject to the negative g-force (in relation to the g-forces towards the engine) of the centrifuge thus helping to damnpen the excessive g-forces towards the engine.
Of course getting this all to work would be incredibly complex and the centrifuge would have to spin at incredibly high speeds. If there were a malfunction God help the crew because if they are accelerating faster than 10-11 g's they probably would not survive. Also this would all need to reverse when the ship began deccelerating. Any thoughts if this could hypothetically work? Edited by DevilsAdvocate, : No reason given. One of the saddest lessons of history is this: If we've been bamboozled long enough, we tend to reject any evidence of the bamboozle. We're no longer interested in finding out the truth. The bamboozle has captured us. It is simply too painful to acknowledge -- even to ourselves -- that we've been so credulous. - Carl Sagan, The Fine Art of Baloney Detection "You can't convince a believer of anything; for their belief is not based on evidence, it's based on a deep seated need to believe." - Carl Sagan "It is far better to grasp the Universe as it really is than to persist in delusion, however satisfying and reassuring." - Carl Sagan, The Demon-Haunted World
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lyx2no Member (Idle past 4706 days) Posts: 1277 From: A vast, undifferentiated plane. Joined: |
Any thoughts if this could hypothetically work? Draw a box around your ship. Everything within that box must have the same average acceleration or it would not long stay within the box. Now, for a second or ten we could accelerate something aft reducing it's immediate G but we'll pay for it in spades when we get to the stern. Edited by lyx2no, : Style. It's not the man that knows the most that has the most to say. Anon
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Taz Member (Idle past 3281 days) Posts: 5069 From: Zerus Joined: |
kbertsche writes:
There you go again, trapped in 16th century way of thinking. After all, people from the age of sail never thought using fossil fuel in a certain way in combination of aerodynamics would allow people to travel from Europe to America in a day. Transporting -->matter --> at relativistic velocities requires -->energy. --> Transporting matter is the topic of the OP and the thread. Basically, instead of allowing room for new innovations and discoveries on space-time travel that doesn't require the energy of an entire star, you insist on a closed minded approach that everything other than the standard model of projectile motion through space the way we currently understand physics is a fantasy.
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