Ramjet and light sail are the two most feasible options. Wikipedia has a cursory survey.
While improvements in propulsion would be great, the biggest thing getting us to the far stars will be incremental improvements in keeping small groups of people alive for generations with access to basically no resources but what they bring with them and the energy they can harvest from starlight (and to the near stars, there would be considerable light the whole way, initially from the sun, later from both, and finally from the target).
We could probably fly a generation ship to Alpha Centauri, with people on board, in something like 400 or 500 years (less on board, though not a huge amount). That's a heck of a long time, but I feel doable. Early groups of humans often migrated over similar time frames, almost as alone.
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quote:Originally posted by fugu13: We could probably fly a generation ship to Alpha Centauri, with people on board, in something like 400 or 500 years (less on board, though not a huge amount). That's a heck of a long time, but I feel doable. Early groups of humans often migrated over similar time frames, almost as alone.
There'd be no reason to go to Alpha Centauri though, since it doesn't have any habitable worlds. We could always terraform, I suppose, but are there even any planets in that buffer "life" zone?
I say we just do what they did in that old video game from Bungie, the makers of Halo (I think the older game was called Marathon), and hollow out one of Mars' moons and turn it into a spaceship! Then we can just send it off to some distant world and forget about it for 300 years. Completely silly and non-sensical...or best idea ever? I think we all know the answer to that.
Now hurry up and get your drills! I'll meet you in space, Bruce Willis style.
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The odds of finding any actually habitable worlds around even a planet with possibly habitable worlds is very low, and basically zero for any system within striking distance. While I think it'd be great if we could find habitable worlds, in the "short term" (the next few thousand years), I think the best bet is developing the technology and aiming for space colonies in nearby, resource rich systems (which Alpha Centauri is likely to be).
Terraforming as a practical endeavor, at least with the materiel that could be brought interstellar (within our solar system's a bit different) and the time frames we'd like (less than thousands of years), is far further out scientifically than traveling to other star systems is.
Stone_Wolf: yep, generation ships have been a common theme in science fiction many times.
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Blayne Bradley
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Actually there's been quite some evidence I've read that NASA might be rethinking how rare habitable worlds might be. They might be alot more common than we gave credit for.
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And understandably so, we can only make an educated guess on the matter. A constantly updating educated guess it may be, but we can never make a declaration of fact until we put hardware on the ground and retrieve the information.
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quote:Actually there's been quite some evidence I've read that NASA might be rethinking how rare habitable worlds might be. They might be alot more common than we gave credit for.
Quite a bit more common, definitely. However, the definition of being habitable in that case isn't the same as "habitable by people who arrived in a generation ship using what they've brought and can create with what's on hand". Also, quite a bit more common is a long, long way from "above a tiny tiny percentage chance for any world in feasible range".
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Why do they think they're more common? I mean, in order to make that kind of hypothesis, wouldn't there have to be other habitable worlds to use for comparison, instead of just this one? I have to wonder about how this convorsation went at NASA when they figured this out...
Scientist 1 (henceforth known as Bob): Man, so we've been at this for a while now and still haven't found any new Earths.
Scientist 2 (henceforth known as Pac-Man): Yeah that sucks.
Bob: Hey, I have an idea! What if there are more habitable planets than we first thought? Think about it! It would be like Star Trek. We could both get hot green girlfriends!
Pac-Man: Or maybe other Earths are just super rare. You know, like what the evidence points to.
Bob: That's stupid. You're stupid!
Pac-Man: But what about the Drake Equation?
Bob: Equation? Drake? This isn't Uncharted! I beat that game last night! Besides, we're scientists, not math teachers. Don't you know anything?
Pac-Man: My God, you're right!
Bob: Hells yeah I am! There's a reason they put me in charge of the department, you know. I make shit happen.
quote:Actually seeing as how NASA gets barely any money and a much larger amount of our taxes go into the military and foreign affairs, I seriously doubt the validity of what you're saying.
I don't see what that has to do with what I said, which is that that there's no way we could have afforded to keep spending money on the space program for the last fifty years like we did during the Apollo program.
The Apollo program, as far as I have gathered, was a *profitable* venture, when the value of technological advances related to the project are factored in. The economic benefit of the investment (roughly $25 billion), has been staggering over the past 5 decades. There is virtually no industry that has developed in the last half century that doesn't owe at least part of its growth to NASA spending.
Critics of NASA are so often short sighted critics of (admittedly real) wasteful spending, who refuse to see the full picture of what state sponsored R&D can do. Because there is no other sector of the economy, no private enterprise, prepared to invest a hundred billion dollars in a venture that has no profit motive.
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Even if there's no other gain, I tend to think the continued survival and propagation of our species is a pretty profitable venture. When did we as a people lose the ability to aim for long term results? I wonder what our generation's response would be to, say, the Marshall Plan.
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quote:Originally posted by Juxtapose: I vote that Jeff gets to stay.
I second that!
quote:Even if there's no other gain, I tend to think the continued survival and propagation of our species is a pretty profitable venture. When did we as a people lose the ability to aim for long term results? I wonder what our generation's response would be to, say, the Marshall Plan
Funny you mention this line of thought, because I've noticed that America doesn't really think long term at all. It's actually a bit of a foreign concept for us. We make investments and expect results in under 5 years.
Japan is a great example of the total opposite. Many companies over there plan things out and make investments that affect future generations rather than just the current one. It's a completely different way of viewing the world and the way business is done.
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quote:Japan is a great example of the total opposite. Many companies over there plan things out and make investments that affect future generations rather than just the current one. It's a completely different way of viewing the world and the way business is done.
Japan's debt is 2.5 to 4 times the US as a percentage of GDP (depending on counting methodology) -- and they don't have being a world superpower involved in multiple wars as an excuse. They pour huge amounts into wasteful construction projects to buy out political constituencies. If Japan has much of an aptitude at planning for the future, they're doing an awfully good job of hiding it.
And there are plenty of US companies looking far more than five years out. There are multiple US based aerospace (emphasis on space) companies basing their business on space launches anticipated decades in the future. US companies sink huge amounts of money into future research programs that only pay out after over a decade or more of work. Venture capital firms frequently sink hundreds of millions into companies that aren't expected to even turn a small profit until more than five years in the future.
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Now fugu, that is just depressing. 4 times our debt? Are you sure about that? I mean, we have 15 trillion dollars of it, and even double it's still hard to imagine. Of course, if your numbers are recent and reflect the insane natural disaster they recently experienced (and the nuclear facility that was directly affected), I can imagine it being possible. Still, that's a lot of money.
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I actually get somewhat scared when I think of this question due to the likely possibility that, as gigantic as the universe is, we will always be limited to this planet due to the laws of the universe. That is, it'll always be unfeasible to visit other star systems or to even establish human life elsewhere in this solar system. This planet is all we might ever know and we're screwing it up.
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It's not impossible, Sa'eed, just improbable that we'll do it in the near future. Humanity is just too limited right now to acheive that kind of travel, but they used to say the same thing about going to the moon, as well as a whole slew of other things we eventually acheived. Just give it a few more centuries Posts: 1324 | Registered: Feb 2011
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I think interstellar travel is possible. I do not think it will necessarily ever be an economically useful way to deal with the limited resources on our planet (in particular, ones that make it a nicer place to live than a sealed biodome)
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On paper, the technology already exists for relatively cheap interplanetary travel and possibly even to get up to low relativistic speeds. In fact, it has been around since about 1947. Just one problem, it's illegal. Check out Project Orion and nuclear pulse propulsion.
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Yeah! I remember that concept. Nuclear powered propulsion. The only reason it's illegal is because the UN decided against detonating nukes in the atmosphere, which it technically does...
They are supposedly working on a new way to use this technology that would get around this law. I don't know the details though.
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No need to detonate nukes in atmosphere, just launch from space. And Project Orion is probably infeasible as primary propulsion for anything beyond travel in the solar system (though it'd be great for that), because even with its extreme efficiency, the amount of fuel to be carried is just too huge.
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I believe one of the SALT treaties also banned space based nuclear weapons, banning one being built and launched in orbit as well.
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And it's not as shortsighted as you might think. The speeds that one of these vehicles could achieve could cause it to wipe out all life on Earth if it were turned against the planet.
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I never said it was shortsighted. Merely pointing out that we had the technology decades ago, but just weren't allowed to use it.
Being in the racing business, I run across this sort of thing all the time. People like to say things like "we put a man on the moon but can't make brakes that last a race at Martinsville." The truth is, we CAN. The technology exists but is banned by the organizing body. We all have rules to follow, even NASA.
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Blayne Bradley
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I think FTL Travel will one day be possible, obviously in a way consistent with our current understanding of physics.
I think magnetic plasmic propulsion is pretty feasible for interplanetary space travel a few generations later, fusion engines according to the calculations I have access to can reach 1-2g acceleration and make a 2 day trip to mars with only fuel taking up 5% of the mass of the ship.
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quote:obviously in a way consistent with our current understanding of physics.
Less than obviously, because there aren't any feasible ways for that to happen that I'm aware of absent the expenditure of amounts of energy on scales like the total output of the sun for a long period.
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Even that would only, what, get us close to the speed of light? I mean, you can't just brute force it, after all.
Heck, in a location where the speed of light is lower than it is in a vacuum, going faster than that speed only causes you to bleed energy until you go slower than that place's speed of light, from what I've read...
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quote:Even that would only, what, get us close to the speed of light? I mean, you can't just brute force it, after all.
That's for holding open a wormhole.
quote:Heck, in a location where the speed of light is lower than it is in a vacuum, going faster than that speed only causes you to bleed energy until you go slower than that place's speed of light, from what I've read...
Yes, it's called friction . The speed of light is slower in various materials because the light is being absorbed and then emitted from atom to atom.
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All we have to do is open a trans-dimensional gateway so that we can "slide" into an alternate reality where this other universe is actually smaller. Then we just spend a few hours in there heading to wherever we're going, and the "slide" right back out. Then viola! We've just traveled 23000 light years in two hours. No explanation required!
Or
We do the KAPAX solution. Just wait for a beam of light and "catch" it and hold onto it until we get to our destination. Light would become the new public transportation system! I'd like a ticket for 1, please.
Or
We do the Event Horizon solution. Bend space like a piece of paper so that we can just pop up on the other side. Because going in a straight line is boring and for losers.
Or
We create a giant system of "Gates" we can use to travel through wormholes from system to system. Since we probably won't have the tech to build them anytime soon, we'll have to randomly discover them in Egypt. I'm sure nothing bad will come of this.
Or
We just ignore the laws of physics and do it anyway. Because laws were made to be broken, and screw physics and all that other crap. Star Trek had the right idea all along.
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Blayne Bradley
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quote:Originally posted by 0Megabyte: "I think FTL Travel will one day be possible, obviously in a way consistent with our current understanding of physics."
I'm curious which way that would be...
Miguelle Alcubieres Warp Drive is actually an example of ftl travel being possible under our current understanding of physics but engineeringly prohibitive, its obviously the case that ANY revolutionary breakthrough that would allow for FTL travel would have to still conform to our current understanding of physics that has been experimentally proven to be true.
Luckily we're not limited to traveling faster I'll paraphrase Asimov.
quote: Suppose you are a traveller trying to reach point B from point A through a valley of dense foliage and that this trip will take no shorter than three days. That is three days of travel no matter how much effort or energy one puts into traveling through this valley [analogy to the lightspeed limit - Blayne].
However, what if we are clever? And instead of traveling on foot which we know to be impossible to ever travel to the other side of the valley in under three days decide to undertake the same journey in an hot air balloon? We are still under the same rules as before, but through our "shortcut" have found an ingenius solution to the "speed limit" we can travel to traverse the valley.
Essentially the solution is obviously not traveling via acceleration but to find a shortcut, a loophole, that allows for something akin to Ftl travel while not breaking the laws of physics.
Now I'm not saying Alcubierres drive is the solution, even further refinements to it haven't really made the issue any more insourmountable to our current understanding of engineering the principle is clear. There ARE ways to travel FTL, we just need to keep searching.
When I say "travel faster" I do not say accelerate, which physics say is impossible, I mean "find a shortcut".
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Blayne, did you even read my post? I gave you like five examples of shortcuts. I mean, honestly, if none of those work for you then you are just asking the impossible.
quote:Originally posted by Blayne Bradley: Miguelle Alcubieres Warp Drive is actually an example of ftl travel being possible under our current understanding of physics
No more accurate than the last time you claimed this.
Does the word "speculative" mean anything to you?
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quote:Miguelle Alcubieres Warp Drive is actually an example of ftl travel being possible under our current understanding of physics but engineeringly prohibitive, its obviously the case that ANY revolutionary breakthrough that would allow for FTL travel would have to still conform to our current understanding of physics that has been experimentally proven to be true.
Except for all the parts that, as far as we know, aren't possible. Like entering and leaving the bubble, which is the most essential part (assuming we can find one within range, since creating one is even far out of the range of possibility with current theories).
quote:Essentially the solution is obviously not traveling via acceleration but to find a shortcut, a loophole, that allows for something akin to Ftl travel while not breaking the laws of physics.
Take a look at the estimates of the energy involved, then take a look at my post again.
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Blayne Bradley
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quote:Originally posted by Jeff C.: Blayne, did you even read my post? I gave you like five examples of shortcuts. I mean, honestly, if none of those work for you then you are just asking the impossible.
Find me some physics papers that explicitly say they're possible.
quote: Take a look at the estimates of the energy involved, then take a look at my post again.
You miss the point, the point is FTL travel in theory is plausible, we just need to find something convenient.
quote: No more accurate than the last time you claimed this.
Does the word "speculative" mean anything to you?
I'm going to go with the theoretical physicist on this on instead of random forum poster.
Also we're Kardeshev 0 on the scale of civilization advancement, go up a few levels and we might meet the energy requirements.
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quote:You miss the point, the point is FTL travel in theory is plausible, we just need to find something convenient.
But all the theoretically plausible methods are necessarily inconvenient, and extremely so. That it would be theoretically possible to make an unbroken human chain around the world touching hands, including in the oceans, does not mean it can ever happen, and that is orders of magnitude more easy than FTL travel under our current physical understanding.
Physics might definitely come up with some means of practical FTL travel eventually; I hope so. But it will be new physics.
quote:I'm going to go with the theoretical physicist on this on instead of random forum poster.
I'm fairly certain you're not reading the theoretical physicist right. I bet you the theoretical physicist is talking about something that gets around some of the biggest restrictions in physics (reaching the speed of light in a vacuum), but is still not possible in our current understanding of physics. That's called speculation about possible future advances in physics, not outlining a situation that's theoretically possible today.
quote:Also we're Kardeshev 0 on the scale of civilization advancement, go up a few levels and we might meet the energy requirements.
I don't think you understand the scales of energy being discussed. To even have a chance of harnessing the amounts of energy under consideration, we'd need something like a Dyson sphere.
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Look, All you have to do is make yourself BIGGER. E.g., the time it takes for an ant to cross a football field vs. a 18 year-old running back pumped full of steroids.
If the ant were BIGGER, say as big as the entire field, then its relative speed (in terms of getting from some point (a) to point (b) would be, well, instantaneous--seeing as its already everywhere (relative to the football field)etc.
Now, extrapolate this notion of "change of scale" to our most human of conditions...and you can imagine (I hope) that it is, in fact, the "scale" of this very imagination (in question) that is the important variable. The trip across the universe is an imaginative act, both in the lab and under the covers.
I've seen some of you, if ever so briefly, standing there on the 23rd moon of Alpha Centuri. The ships will get there,
quote:Find me some physics papers that explicitly say they're possible.
*smacks forehead*
It was a joke, Blayne. All of them were.
Except for the one where I said we'd have to find stargates in the middle of Egypt and use them to travel throughout the Galaxy. That one was totally real!
quote:Originally posted by Blayne Bradley: I'm going to go with the theoretical physicist on this on instead of random forum poster.
Seriously.
I've decided this (well some variation on it) will be my default post whenever I reach an impass with Blayne on China/Communism/Russia/US/Anime/etc.
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. The speed of light is slower in various materials because the light is being absorbed and then emitted from atom to atom.
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