I beg to differ. For as much as we love our home, it's a galactic question of whether we should put all our eggs in one basket. Yes, we may become more efficient, but what stops us from being more efficient everywhere? Your notion of money is actually irrelevant in the view of humanity, as money is merely our way of putting a value of things. I believe if we somehow encounter aliens, they'd be bamboozled with our concept of money.


This post has been edited by ThanatosSwiftfire: Jun 15 2009, 06:41 PM

Converting it into electricity not because we need the energy. It's just to convert the energy to a less harmful form. But then again, if we are able to harvest energy from gamma rays efficiently, wouldn't it generate a lot of energy, since gamma rays are high energy rays?

This post has been edited by Thinkingfox: Jun 15 2009, 06:48 PM

Yes that's the first step towards any useful spaceship, but the issues with radiation in space have not been solved yet by any means. Propulsion is the next problem, we have nothing that's remotely efficient when it comes to propulsion (ion ones are nice and everything but they're slow...... not much acceleration at all, and you can dream on when it comes to antimatter, we only make less than a nanogram of antimatter each year, and nothing much's going to change on that front either)

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Added on June 15, 2009, 6:49 pmBloody hell. I'm saying that it is highly unlikely methods will be found to convert it due to their penetrating power, and that their main mode of losing energy is from ionisation, which is extremely, extremely hard to actually get any useful energy out of.

We're going to have to get to much more exotic forms of materials before it'll even be possible.

This post has been edited by bgeh: Jun 15 2009, 06:49 PM

Blame me for being a madmen, but honestly, if we actually had a population problem, i'd send these peoples out on space travel anyway regardless of the radiation issues. If they make it, we get a new colony. If they don't, we get rid of some people on our planet.

On a side note.

Also, if we could build a big enough spaceship, whether it's slow or not would be irrelevant, because in a big enough spaceship where we can develop a self-sustaining ecosystem, with corresponding birth rates to meet the death rates in space, mankind will reach where they are meant to reach anyway. Though the people who reach our said potential colony won't be the same as the person we send up, but so long as somebody gets there, humankind gets a point.

if we could, i'd probably sent all the prisoners there

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Added on June 15, 2009, 6:53 pmwho knows, they use money too?

This post has been edited by IcyDarling: Jun 15 2009, 06:53 PM

hahaha, if they do, i'd be damned as hell interested. Honestly, had we encountered a peaceful alien civilization and initiated trading systems, and IF we ever go as far as integrating our financial systems, I'd think that in itself would be a very interesting problem to solve.

No, at the timescales, and extremely slow velocities we're talking about, it'll be in the millions of years before a spaceship even reaches anything close. And here's a question if you think propulsion isn't important: How exactly do you stop your spaceship from zooming past if you find a habitable planet?

I would assume that 'bloody hell' is something you use frequently. I did not say it's feasible, I just say it would be useful if we could do that. It might seem unlikely now, but maybe not in future, just like how humans in the 19th century could not imagine what computing and the internet can do for us today.

Good point. Maybe we'd crash into it. Or send drop-pods like in C&C.

Perhaps something like the sort of a solar parachute? (i've read about some concepts about using sails to slow down spaceships, as space, whilst gravity-less, has some stray atoms and other stuffs that may provide some 'friction') Space isn't exactly.. a void of nothing. There's something there, just very much less of anything. So a big sail could be used?

Too frequently in fact.

Yes, but that's the realm of science fiction, assume some miraculous solution to fix problem xyz. There's none right now, unless some exotic form of matter is found, and what is the range of this converter? Can it take in 10^20eV rays or will it just let it through? Does it fix the cosmic ray issue?

And at the same time, would it really generate enough useful energy? Doubtful. The shielding's there to prevent us from getting fried, but you'd be surprised at how little energy in total is really needed to irradiate us.


Any crash would kill everyone in the spaceship, and the drop pods have the same problem that they have the same velocity of that mothership and you still need to fix that propulsion problem, because the drop pod's not going to be able to communicate ever again with the mothership.

And if we are to even approach interstellar travel speeds, solar parachutes will not be good enough to slow us down at all.


addendum: Look, I don't mean to rain on your parade. It's a nice idea, but we're really that far behind technologically speaking before we even have a remote chance of getting a useful working spaceship that is self sustaining and can provide enough shielding from the high radiation especially in the timescales we're talking about. There is a place for science fiction, but as of right now, and afaik, for quite a while more (decades perhaps), it simply isn't possible, unless some really big breakthrough occurs.

This post has been edited by bgeh: Jun 15 2009, 07:24 PM

10^20eV is just 16J. Anyway, I get your point that there's tremendous energy from gamma radiation. I do not have much knowledge of nuclear fission but since fission produces a great amount of energy through chain reaction , wouldn't there a method of reversing the process ie. reverse chain reaction?

If we know how to accelerate to that speed, can't we use the same type of propulsion in the reverse direction to brake?

Thinkingfox: Try that, but from a single proton (and yes, they have been observed - cosmic rays of that energy). For comparison's sakes, 1 gram of protons [rest mass] with that energy would have approximately 10^25J. Anything above 1MeV is usually deemed as dangerous to us, so yeah imagine 10^20eV

No the concept wouldn't work for reverse propulsion unfortunately (afaik)

Accelerating to that speed isn't much of a problem because we have plenty of millennia to accelerate. It's a question of how to actually slow down if we see something promising, in say a matter of a century or less? And even that's highly inefficient because plenty of energy is lost and you need to accelerate again, and also a quick deceleration might impose strains on the spaceship's body, so that's again another engineering problem

This post has been edited by bgeh: Jun 15 2009, 07:46 PM

Why will reverse propulsion not work?

Note, so actually, what is the question we are asking about space travel right here?

A general discussion of the idea on colonising other planets

Erm, I was merely thinking about colonizing as far as erm.. mars. LOL. I actually didn't go as far as other solar systems yet, or maybe, just as far as pluto, and having mining networks across the asteroids to fuel our greed, which I think would be the short term goal, aka -moon-mars-mining colonies across the solar system.

This in itself would probably take 100 years, by which hopefully, travel to further star systems would come into consideration.

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Do any of you think we're racing against the clock?

Each passing day our resources diminish, which I would feel equates to less available for scientific pursuits to colonize say... mars.

Sorry, included it in the edit above.

Also I confused your above post. Well, I thought you were trying to apply some idea of reverse chain reaction to reverse propulsion, which was a mistake I made. Sorry about that. Well my question would be what would reverse chain reaction do then?

And yes, I do think that this topic isn't really suited to this forum, because it sounds more fictional than real applied science?

Thanatos: Read the above posts on why terraforming Mars will be a much tougher adventure than any of us care to think

My personal POV: Frankly, as a wannabe scientist, I can't be bothered about human exploration in space, I'm more interested in robotic exploration because they're much cheaper, and thus more missions can be sent to gather more information than sending one hugely expensive human mission. I understand it helps to stir the human imagination, and it helps with funding too, but I honestly wish it was spent more on robotic explorations until there is the available technology for humans to explore cheaply.

This post has been edited by bgeh: Jun 15 2009, 08:03 PM

I think this is a very interesting thread albeit full of fictional theories.
At least, we share what we thought about it.

For myself, I think spare travel/exploration could happen someday.
As it is a century ago when everyone thought going to the moon is something impossible.
With the never-ending R&D our scientists are doing, someday, it could very well happen.

And I'm thinking of Star Trek or maybe Star Wars. =D

Yes, I apologise for introducing a lot of strange ideas to this forum. Well, as I said, I am not very well versed on the topic of nuclear fission, so I do not know. I was just wondering if it's possible.

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Added on June 15, 2009, 8:25 pmWhen we see something promising, we could stop the thing at the same magnitude with acceleration. Then we can move to the site at a much lower speed. The ship could surely be designed to take the same magnitude deceleration as acceleration. On inefficiency, I was just addressing the problem of whether it is possible to brake as stated in your post (quoted below). Energy lost due to acceleration and deceleration is unavoidable, in my opinion, because it happens even in normal jet and rocket travel.



This post has been edited by Thinkingfox: Jun 15 2009, 08:27 PM

Yes but if you take hundreds to thousands of years to accelerate to anything resembling the speed of light (which will be needed if we're to do any useful interstellar travels, let alone intergalactic ones), you'd need an equally long time assuming the same deceleration rate to do it, i.e. you need to know long in advance, and by that I mean very very long in advance. And what about the fuel issue? There's no more refuelling once you leave the Earth. And even then, we're supposing space is empty. How do you avoid objects in your path, if you travel at say 0.01c, given that we clearly cannot see them until we're relatively close? One collision and there goes the spaceship.

Currently for planet - planet transitions (Earth - Mars, Earth Venus), we rely very strongly on atmospheric braking to land on the planet. This will not be possible at the speeds we're talking about for interstellar travel, and heck landing's probably not even an option, just plain old orbiting