My opinion is that<br />1) FTL is impossible<br />2) Slower than light interstellar travel may be possible, with a vast generation ship, for example, but it will be such a waste of resources, with no concievable material returns, that it will never ever be done.<br />3) The same math would apply on alien worlds with alien spiecies.<br /><br />What do you think?
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I think Von Neumann machines will make the trip and possibly generation ships as well. After all Humans have lived on some very small islands for many generations. <br /><br />Once at a sutable destination the Von Neumann machine would first make a habitat and then an ecosystem (including humans) from memory.
Technically speaking, it will only become possible if we (Humanity) are given a reason to make it so. How it would come about is anyones guess, whether its Von Neuman machines, the Bussard ramjet, or other ideas.<br /><br />No doubt interstellar travel is challenging, but if this is as far as humanity can go, think of the other limitations that implies. Is there a limit to how far we can go in medicine? Air travel? Construction, including safer buildings, cars etc. Where will humanity be say, a millinia from now, same as us?<br /><br />Has humanity already reached its limit? I suspect not and most likely if and when interstellar travel comes about, it will do so with machines not yet imagined and reasons that are possible to imagine such as simply finding a reasonably Earthlike world.<br /><br />On your point 2, generational ships would likely travel to earthlike worlds that can be colonized and most likely never return to this Earth and in doing so, develop a Von Neumann like scenario of exploiting the planets resources and populating it with infrastructure necessary for the human populations to follow. <div class="Discussion_UserSignature"> <p><strong>My borrowed quote for the time being:</strong></p><p><em>There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened.</em></p> </div>
And therein lies the problem, we as a society are having trouble deciding on budgets for just going to the moon in what are currently proposed Apollo tech craft.<br /><br />Orion technology has drawbacks as well:<br /><br />Number of nuclear bombs required to power Orion:<br />3,000,000 to 300,000,000!<br /><br />The arms race produced some fifty-thousand nuclear<br />bombs in fifty plus years between two Countries at a cost (U.S.) measuring in the hundreds of billions of dollars.<br /><br />Not exactly something our current political climate would support. In addition, we have never demonstrated the ability to supply food, water, to crews of any ship that would require decades or longer to reach their destination stars.<br /><br />Harnessing fusion would be a safer bet to me but we still have to regenerate food water, breathing air.<br /><br />Orion data source:<br />page 66 of "The Starflight Handbook". <div class="Discussion_UserSignature"> <p><strong>My borrowed quote for the time being:</strong></p><p><em>There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened.</em></p> </div>
Of course, interstellar space travel is physically possible.<br /><br />But that isn't the question.<br /><br />Its physically possible to build a stairway to orbital altitudes. But it will never happen, because it would be incredibly wasteful in financial and material resources, and would have little or no benefet for the people paying the bill.<br /><br />Similarly, any concievable method of getting to the stars will not benefit those who have to pay the enormous costs, ever, at all.<br /><br />It will never ever happen.<br /><br />
Sooner or later natural resources on Earth will be depleted.<br />Whoever manages to hold on to them will win.<br />Maybe not in 100 years but in 200, 500 ? Who knows.<br />And once cheap access is established to Solar Systems then its not long before somebody will have a reason to leave it- out of political, economical, religious, ideological reasons etc.
If you want to travel to another star within a reasonable fraction of your lifetime, there are two ways of achieving it:<br /><br />1. Go very very fast<br /><br />2. Live a very long time<br /><br />I am convinced that aging will be defeated and immortality will become reality long before practical interstellar travel. And for beings who do not age, a 10,000 year long trip at leisurly 0.5% c might not be such a big deal. Pack a lot of VR entertainment.
<font color="yellow">Q: Will interstellar travel ever occur?</font><br /><br />I am assuming you mean <i>manned</i> interstellar space travel.<br /><br />My answer:<br />1. Such a trip is remotely possible with a lot of technoogical imagination.<br />2. I really, really doubt any inhabitant of earth in the next 25M years will ever travel successfully to another star simply because the planetary resource requirements are way too great to make the global commitment to make this huge gamble on a spacetrip with such an uncertain outcome. And since it will take another 25M years until fossil fuels renew themselves sufficiently for another great civilization after humankind to arise to a state of advanced industrialization (and even then the prime metal ore deposits will be expended), I really doubt any other species will get there either. <div class="Discussion_UserSignature"> <div class="Discussion_UserSignature" align="center"><em><font color="#0000ff">- - - - - - - - - - - - - - - - - - - - - -</font></em> </div><div class="Discussion_UserSignature" align="center"><font color="#0000ff"><em>I really, really, really miss the "first unread post" function.</em></font> </div> </div>
What makes you think humans (or their descendants) will be limited to <b>planetary</b> resources? I think it is a given that the resources of the entire Solar System (which utterly dwarf Earth's resources) will have to be mastered before interstellar travel is attempted. I also have not doubt said resources WILL be mastered.
I think despite what you see in scifi books, that it is unlikely that the solar system will be colonized, for the same economic reasons.<br /><br />It can't be made profitable for the people paying the bills.<br /><br />As resources on Earth get tighter, the bills will get even more unreasonable. The needed spacecraft will be more and more expensive.<br /><br />Even if the system were colonized, the people doing it will be perpetually short of resources. The cost of extracting resources will always be huge.<br /><br /><br />Look at the early white colonists of north america- they mostly died out from starvation in a land of plenty. Imagine those problems amplified by a factor of a thousand, and the cost of getting them there and supplying them amplified buy a million. And even if they do well, it will never pay to send resources back to earth, the people who paid for it in the first place. <br /><br />
<font color="yellow">What makes you think humans (or their descendants) will be limited to planetary resources? I think it is a given that the resources of the entire Solar System (which utterly dwarf Earth's resources) will have to be mastered before interstellar travel is attempted. I also have not doubt said resources WILL be mastered. </font><br /><br />From the information I have read and consider valid, and the opinion I have come to, I do think that the planetary resources (and asteroids and moons) are too expensive to mine profitably. I don't think these resources will be mined before the earth is depleted (and afterwards it will be too late), because it simply costs too much to bring the masses out of planetary gravitational wells and transport it to the needed location. You read too much science fiction. <br /><br />I realize my opinion will not be popular amongst many of you - but since you asked the question which started this thread, I gave it. I fervently love astronomy, space travel, chemistry, science and science fiction; but I am also a realist and I will not be blinded by my dreams. <div class="Discussion_UserSignature"> <div class="Discussion_UserSignature" align="center"><em><font color="#0000ff">- - - - - - - - - - - - - - - - - - - - - -</font></em> </div><div class="Discussion_UserSignature" align="center"><font color="#0000ff"><em>I really, really, really miss the "first unread post" function.</em></font> </div> </div>
People make statements about the Earth's resources being depleted, but the ones that really matter - the metals - will never be depleted. We live on a 12,000km wide ball of metals, and to date we've literally only scratched the surface. Same thing goes for energy: sure we're burning up all the easily accessible petroleum, but there are other games in town besides oil.
It will happen. Especially if we discover worlds similar to our own. First with probes, then...<br />About FTL...anything is possible. It's been "only" 100 years since manmade objects ever soared threw the sky, and we're already discussing the possibility of FTL. Even that is something to admire. <br />Even if we never discover means to travel at FTL speeds, i would be quite ready(if asked) and willing to go on a one way trip, even if it takes me 50 yers to get there. 
I'm guessing there's even more individuals who would be considering the same, especially if we're talking about generation ships.
I'm guessing there's even more individuals who would be considering the same, especially if we're talking about generation ships.i think space travel will be revolutionized, in an indeterminant time in the distant future, to utilize light itself as a means of transport. don't ask me specifically how, but as long as information can ride a light beam, there will be innovation upon that basic idea.
I think many of the posts in this thread show a failure of imagination. In the last 200 years, the maximum speed a person could travel at has gone from about 20 m.p.h., on a sailing ship, to about 45,000 m.p.h. on New Horizons (after Jupiter's gravity assist, and yes I know it is unmanned, but we could have made a manned ship to do the same thing, although the astronauts might have had a short life expectancy), an increase of over 2000 times maximum speed. If we had the same percent increase over the next 250 years, we would be making space ships capable of going 2.8 Billion mph which is about 4c. Now, I am not a member of the woo-woo crowd, and don't believe anything can go faster than c, but I do believe that we could eventually get to significant fractions of c, perhaps as much as .3c. At. .3c the closest star is 12 years away and many stars are within 60 years. We will send probes to stars when it only takes 12 to 60 years to get there, and if there is anything interesting at those stars, humans will some day follow.
The problem would be collisions-IIRC around .2 c is fastest speed before you encounter serious problems with shielding.
<font color="yellow">We will send probes to stars when it only takes 12 to 60 years to get there, and if there is anything interesting at those stars, humans will some day follow.</font><br /><br />If humanity doesn`t leave the Solar System in about 5 billion years , it will mosl likely die out. Long time frame I know, but I believe; or at least I hope that we`ll still be around at that time. <div class="Discussion_UserSignature"> </div>
I think it's more than a bit presumptuous to say that interstellar travel will <b> never </b> occur.<br /><br />I'll agree that if we make the assumption that Orion will always be the best we can do, interstellar spaceflight isn't <b> probable </b> in the next several centuries.<br /><br />But there are too many variables. If scientists discovered that a "planet killing" body was going to impact Earth in 150 years, neccessary resources to build a few Orions would probably take priority over most everything else.<br /><br />If you <b> know </b> your planet is terminal, I would think that any taken risk is preferrable to the known alternative. <br /><br />We would at least attempt to move a viable number of the population to Mars, I would think, if we had enough time to do it.<br /><br /> <div class="Discussion_UserSignature"> <em>"2012.. Year of the Dragon!! Get on the Dragon Wagon!".</em> </div>
<b> I don't think these resources will be mined before the earth is depleted (and afterwards it will be too late)</b><br /><br />That's the statement I disagree with. What exactly do you mean by "earth is depleted"? Many people glibly talk about "earth resources running out," but except for fossil fuels all "earth resources" are <b>reusable</b>. Do you know that US does not mine iron any more? It is all recycled. Most of the iron in your car was originally mined for WWII. Likewise with copper, tin, silver, and pretty much any large-scale use metal. Modern civilization needs LESS of these metals, not MORE -- and what it does need has already been mined out, smelted, scrapped, and only needs to be re-melted. Platinum, gold, and other precious metals are being mined because demand for them remains high, but it will be VERY long time before they are really "depleted" -- and by that time extracting them from asteroids will become more attractive.<br /><br />The only things we truly <i>use up</i> are non-reusable energy sources -- fossil fuels and uranium. But those (the former, anyway) have many viable alternatives, and will soon have to be phased out anyway. And (solar) energy is exactly one thing which IS profitable to bring from space -- or soon will be.<br /><br />So before you toss out phrases like "earth resources will be depleted," think: Which resources? And are they really getting depleted, or just reused over and over?<br /><br />I suppose I was unclear in my previous post. The only "resource" truly beyond Earth capabilities which is necessary for interstellar travel is ENERGY. And while I do not ever expect anyone to export iron or magnesium from asteroids to Earth, ENERGY is one thing I do expect to be so exported. Think of a solar panel 1000 km on the side, orbiting Sun as close as Mercury. THAT could power a starship -- and long before such use is needed, could power the increasingly energy-hungry Earth.
Also, keep in mind that new technology creates new resources and makes old resources obsolete. 120 years ago whale oil was a running-out resource. 150 years ago gasoline was a dangerous waste byproduct of lamp oil. And 200 years ago oil was just smelly black mud. Which is why statements like "Two thirds of Earth's resources have been used up!" (an actual headline I once saw) are absurd. For all I know, in 50 years carbon nanotubes will make iron and copper obsolete. And even if they don't, it does not really matter that "Earth is a 12,000 km ball of metal" -- what matters is <i>once used, metals do not disappear, but are used again and again</i>.
i haven't seen anyone mention wormholes, warped space, or<br /> folded space.<br /><br />It's quite possiable that at some point in time we may learn<br />how to make such a distace jump without needing FTL travel.<br />afterall, if string theory is correct (which i doubt) then we are<br />going to have our first artifical (and awful small) black hole <br />soon.
I'm dissapointed of all the naysayers in this discussion. Simply stating we can't or never will do something because there isn't a conceivable way YET really doesn't accomplish anything. Qso makes an excellent point in that we shouldn't assume man won't progress in technology in space travel like we wouldn't with other areas of life, medicine, etc. I think when we have more of a reason to, we eventually will continue to improve until we do have a way at some point. After all, the old world didn't have much of a reason to 'sail off the edge of the world'. Curiosity won out until they eventually tried it. We may eventually discover it isn't as hard as we think until we look at the problem the right way. Mankind supposedly never would fly....and now we can fly, or break the sound barrier, or go to the moon. You get the point....Maybe one of the Voyager space probes will start accelerating once it leaves our solar system or something as simple as that could lead to a new discovery, you never know!
Think of it using the Kardashev Scale http://en.wikipedia.org/wiki/Kardashev_scale <br /><br />In that case its way in the future when we essentially have become minor deities.
The metals won't disappear, you are correct in this respect.<br /><br />But the metals will be scattered and corroded into ions. At this point, the metals will effectively disappear from commerce and usage unless one is willing to expend a huge amount of energy to extract them.<br /><br />You are right that conservation and recycling will delay this dire prediction. I agree! I am not predicting the shortages of metals now, or in the next century. But I do think some metals will be highly depleted in less than a millenia from now, and maybe sooner (yes, we will still have lots of Fe and Al).<br /><br />By the way, a recent study is predicting the depletion of Cu, Pt, Rh, Au and Pd rather sooner than that, especially as China and India fully modernize and start consuming at levels equal to Americans.<br /><br />And even though the core of the earth is metallic, it is surrounded by a hugely thick layer of silicate mantle and crust. We need to conserve and wisely use the rick ore deposits we now have.<br /><br />A millenia or two from now all the fossil fuels including coal will be depleted too. At this point we will have to rely on renewable energy and maybe nuclear breeders. Perhaps if we are very lucky (and don't count on it!) fusion will become commercially viable. <div class="Discussion_UserSignature"> <div class="Discussion_UserSignature" align="center"><em><font color="#0000ff">- - - - - - - - - - - - - - - - - - - - - -</font></em> </div><div class="Discussion_UserSignature" align="center"><font color="#0000ff"><em>I really, really, really miss the "first unread post" function.</em></font> </div> </div>
<b>the metals will be scattered and corroded into ions. At this point, the metals will effectively disappear from commerce and usage unless one is willing to expend a huge amount of energy to extract them. <br /><br />You are right that conservation and recycling will delay this dire prediction. I agree! I am not predicting the shortages of metals now, or in the next century. But I do think some metals will be highly depleted in less than a millenia from now, and maybe sooner (yes, we will still have lots of Fe and Al). </b><br /><br />If we do not have fusion or orbital solar power "less than a millenia from now" then we <i>deserve</i> to die out! And if we do, then extracting these metals from asteroids will not be a big deal. (Which, BTW, does not require COLONIZATION. Nobody LIVES on oil rigs.)<br /><br />However, where there is demand, a supply appears, and I expect that Earth's demand for energy will exceed what can be satisfied by fossil fuels, fission AND renewables in less than a century. At which point either fusion or orbital solar will become a necessity -- and will be built. Without any colonization.
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