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Gliese 581 d and e. Recent discovery indicates we should send in Kevin Costner

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Posts

  • DarkCrawlerDarkCrawler Registered User regular
    edited April 2009
    Yeah. I'd rather die in space then underwater if something horrible happens. Drowning is just awful.

    Besides, what is a better way to go then die in space?

    DarkCrawler on
  • fjafjanfjafjan Registered User
    edited April 2009
    Yeah. I'd rather die in space then underwater if something horrible happens. Drowning is just awful.

    Besides, what is a better way to go then die in space?

    Then your final thought could be "at least none of my ancestors went like this!"

    fjafjan on
    Yepp, THE Fjafjan (who's THE fjafjan?)
    - "Proving once again the deadliest animal of all ... is the Zoo Keeper" - Philip J Fry
  • FendallFendall Registered User
    edited April 2009
    Don't worry, getting crushed by a kilometre of water above you would be a lot quicker than dying of simultaniously freezing,boiling and asphyxiating.

    Fendall on
  • electricitylikesmeelectricitylikesme Registered User regular
    edited April 2009
    Fendall wrote: »
    Don't worry, getting crushed by a kilometre of water above you would be a lot quicker than dying of simultaniously freezing,boiling and asphyxiating.
    Space has a feeling of exploration to it, whereas submarines are difficult to make interesting. If they could make submarines with big glass cockpits that I could fly around in like in Aqua Nox I'd be down for that too.

    electricitylikesme on
  • Gabriel_PittGabriel_Pitt (effective against the Irish) Registered User regular
    edited April 2009
    Yeah. I'd rather die in space then underwater if something horrible happens. Drowning is just awful.

    Besides, what is a better way to go then die in space?
    To die quietly in bed in your moon house?

    Gabriel_Pitt on
    squigsig_zpsyo1fqhao.jpg
  • FarseerBaradasFarseerBaradas Registered User
    edited April 2009
    Yeah. I'd rather die in space then underwater if something horrible happens. Drowning is just awful.

    Besides, what is a better way to go then die in space?
    To die quietly in bed in your moon house?

    Nah, that's boring.

    You have to die in space while setting off the nuke that destroys the asteroid.

    That's the best way.

    FarseerBaradas on
    sigeb2.png
  • HonkHonk Honk is this poster. Registered User, __BANNED USERS regular
    edited April 2009
    Fendall wrote: »
    Don't worry, getting crushed by a kilometre of water above you would be a lot quicker than dying of simultaniously freezing,boiling and asphyxiating.

    Fun fact: Freezing wouldn't play a part in it at all. As in space you can only loose temperature due to it radiating away (slowly), as there is no matter (basically) to absorb the temperature from your body via contact.

    Honk on
  • electricitylikesmeelectricitylikesme Registered User regular
    edited April 2009
    Honk wrote: »
    Fendall wrote: »
    Don't worry, getting crushed by a kilometre of water above you would be a lot quicker than dying of simultaniously freezing,boiling and asphyxiating.

    Fun fact: Freezing wouldn't play a part in it at all. As in space you can only loose temperature due to it radiating away (slowly), as there is no matter (basically) to absorb the temperature from your body via contact.
    However all the gases in your body and many of the liquids would be spontaneously taken from +1 atmosphere to 0, and the resultant attempt to reestablish a vapor pressure would freeze you.

    It's like how if you put a vacuum on the headspace of a body of water, it'll freeze.

    electricitylikesme on
  • fjafjanfjafjan Registered User
    edited April 2009
    It's like how if you put a vacuum on the headspace of a body of water, it'll freeze.
    Well, a large portion of it will boil, the rest will freeze

    fjafjan on
    Yepp, THE Fjafjan (who's THE fjafjan?)
    - "Proving once again the deadliest animal of all ... is the Zoo Keeper" - Philip J Fry
  • tbloxhamtbloxham Registered User regular
    edited April 2009
    Hurrah, I've figured it out. Thanks to Cyclone ranger for making me think about it a bit clearer. I had neglected to consider the enormous effect the changing mass of the ship has on the effectiveness of its drive system. A specific ship and fuel type does indeed have a maximum speed, however a specific fuel type does not, since you get the same push from each piece of fuel and each subsequent piece of fuel operates on a less massive remaining ship. So if you have a ship made of kg bricks of fuel, and a 1kg package to accelerate burning the first package gives 1/100 of its energy to the payload, whereas burning the last gives 1/2 of its energy to the ship. This is innacurate of course, but if you change from summation to integration you can solve to get...

    Maximum Attainable KE density of ship = ln(total mass/final mass) * engine efficiency * energy density of fuel
    KE density to travel at V = KE = (c^2)/(1-v^2/c^2)^0.5 - c^2

    The changing mass of the ship really makes a surprisingly huge and helpful difference. I think my confusion was that all the rocket equations you provided where to do with rockets with conventional exhausts in classical reference frames, which isn't what we have with any of these super ships. Most of them are effectively being accelerated by collisions with gamma rays on the pusher plate in the same direction as them.

    This system doesn't work for a ship which can somehow operate without a mass loss, such as a bussard ramscoop. I'm fairly confident that it has to obey my previous equation since you effectively won't get any extra energy once it takes the same amount of energy to grab a particle from the vacuum and speed it up as that particle can liberate in energy.

    Adding this factor for a reasonable ship (90% fuel) effectively bumps the KE up by a factor of 2.3, which doesn't help much for our antimatter super ship, but means fission or fusion drives get to a better speed.

    tbloxham on
    Your puny weapons are useless against me
  • DarkCrawlerDarkCrawler Registered User regular
    edited April 2009
    Yeah. I'd rather die in space then underwater if something horrible happens. Drowning is just awful.

    Besides, what is a better way to go then die in space?
    To die quietly in bed in your moon house?

    Nah, that's boring.

    You have to die in space while setting off the nuke that destroys the asteroid.

    That's the best way.

    No way, riding your spaceship into a Sun is a better way.

    Or a black hole.

    DarkCrawler on
  • Der Waffle MousDer Waffle Mous three times snugglier New Yark, New Yark.Registered User regular
    edited April 2009
    Yeah. I'd rather die in space then underwater if something horrible happens. Drowning is just awful.

    Besides, what is a better way to go then die in space?
    To die quietly in bed in your moon house?

    Nah, that's boring.

    You have to die in space while setting off the nuke that destroys the asteroid.

    That's the best way.

    No way, riding your spaceship into a Sun is a better way.

    Or a black hole.
    Into the mouth of the giant space monster is the best.

    STDoomsDay.jpg

    Der Waffle Mous on
    zaku.png
    Steam PSN: DerWaffleMous Origin: DerWaffleMous Bnet: DerWaffle#1682
  • HonkHonk Honk is this poster. Registered User, __BANNED USERS regular
    edited April 2009
    fjafjan wrote: »
    It's like how if you put a vacuum on the headspace of a body of water, it'll freeze.
    Well, a large portion of it will boil, the rest will freeze

    We'll just have to test this then so we'll know for sure what'll happen.

    Any volunteers?

    Honk on
  • MolotovCockatooMolotovCockatoo Registered User regular
    edited April 2009
    Quick, everyone keep debating tbloxham's equations - at this rate we'll have tricked him into constructing a fully functional prototype rocket in about 3 weeks!

    MolotovCockatoo on
    Killjoy wrote: »
    No jeez Orik why do you assume the worst about people?

    Because he moderates an internet forum

    http://lexiconmegatherium.tumblr.com/
  • zakkielzakkiel Registered User regular
    edited April 2009
    tbloxham wrote: »

    The changing mass of the ship really makes a surprisingly huge and helpful difference. I think my confusion was that all the rocket equations you provided where to do with rockets with conventional exhausts in classical reference frames, which isn't what we have with any of these super ships. Most of them are effectively being accelerated by collisions with gamma rays on the pusher plate in the same direction as them.

    All rockets are powered by collisions with a pusher plate. Super ships will still obey the rocket equation in a classical frame, which is the kind of frame we're discussing. Just thought you should know.

    zakkiel on
    Account not recoverable. So long.
  • fjafjanfjafjan Registered User
    edited April 2009
    Honk wrote: »
    fjafjan wrote: »
    It's like how if you put a vacuum on the headspace of a body of water, it'll freeze.
    Well, a large portion of it will boil, the rest will freeze

    We'll just have to test this then so we'll know for sure what'll happen.

    Any volunteers?

    Not really, I've seen this done (well, low pressure, not vacuum). Thing is in water the molecules have different speeds, so the faster ones, as pressure decreases, can 'get away', ie boil, meanwhile the slower ones will stay, untill that they freeze.

    fjafjan on
    Yepp, THE Fjafjan (who's THE fjafjan?)
    - "Proving once again the deadliest animal of all ... is the Zoo Keeper" - Philip J Fry
  • electricitylikesmeelectricitylikesme Registered User regular
    edited April 2009
    fjafjan wrote: »
    Honk wrote: »
    fjafjan wrote: »
    It's like how if you put a vacuum on the headspace of a body of water, it'll freeze.
    Well, a large portion of it will boil, the rest will freeze

    We'll just have to test this then so we'll know for sure what'll happen.

    Any volunteers?

    Not really, I've seen this done (well, low pressure, not vacuum). Thing is in water the molecules have different speeds, so the faster ones, as pressure decreases, can 'get away', ie boil, meanwhile the slower ones will stay, untill that they freeze.
    Well they don't stay until they freeze - it's a Boltzmann distribution. If you remove the high energy elements then slowly the distribution re-asserts itself with a lower mean. Keep upping the vacuum and eventually you've removed so much energy that there isn't much left.

    electricitylikesme on
  • KageraKagera Imitating the worst people. Since 2004Registered User regular
    edited April 2009
    It sucks not being able to travel space. All that shit there is to see and the best we get are enhanced photos and CG.

    I mean, I WANT to see a black hole up close, that shit is just infinitely interesting to me.

    Kagera on
    My neck, my back, my FUPA and my crack.
  • OremLKOremLK Registered User regular
    edited April 2009
    An interesting essay on this subject by science fiction writer (it's not what you think) Charles Stross. Warning, it's long. And kind of a downer.
    The High Frontier, Redux

    (I am currently suffering from a bad cold, and it's screwing with my ability to think straight. So rather than risk damaging my real work in progress, I decided to tidy up some thoughts I've been kicking around for a while, and bolt together this essay. Which will, I hope, begin to highlight the problems I face in trying to write believable science fiction about space colonization.)

    I write SF for a living. Possibly because of this, folks seem to think I ought to be an enthusiastic proponent of space exploration and space colonization. Space exploration? Yep, that's a fair cop — I'm all in favour of advancing the scientific enterprise. But actual space colonisation is another matter entirely, and those of a sensitive (or optimistic) disposition might want to stop reading right now ...

    I'm going to take it as read that the idea of space colonization isn't unfamiliar; domed cities on Mars, orbiting cylindrical space habitats a la J. D. Bernal or Gerard K. O'Neill, that sort of thing. Generation ships that take hundreds of years to ferry colonists out to other star systems where — as we are now discovering — there are profusions of planets to explore.

    And I don't want to spend much time talking about the unspoken ideological underpinnings of the urge to space colonization, other than to point out that they're there, that the case for space colonization isn't usually presented as an economic enterprise so much as a quasi-religious one. "We can't afford to keep all our eggs in one basket" isn't so much a justification as an appeal to sentimentality, for in the hypothetical case of a planet-trashing catastrophe, we (who currently inhabit the surface of the Earth) are dead anyway. The future extinction of the human species cannot affect you if you are already dead: strictly speaking, it should be of no personal concern.

    Historically, crossing oceans and setting up farmsteads on new lands conveniently stripped of indigenous inhabitants by disease has been a cost-effective proposition. But the scale factor involved in space travel is strongly counter-intuitive.

    Here's a handy metaphor: let's approximate one astronomical unit — the distance between the Earth and the sun, roughly 150 million kilometres, or 600 times the distance from the Earth to the Moon — to one centimetre. Got that? 1AU = 1cm. (You may want to get hold of a ruler to follow through with this one.)

    The solar system is conveniently small. Neptune, the outermost planet in our solar system, orbits the sun at a distance of almost exactly 30AU, or 30 centimetres — one foot (in imperial units). Giant Jupiter is 5.46 AU out from the sun, almost exactly two inches (in old money).

    We've sent space probes to Jupiter; they take two and a half years to get there if we send them on a straight Hohmann transfer orbit, but we can get there a bit faster using some fancy orbital mechanics. Neptune is still a stretch — only one spacecraft, Voyager 2, has made it out there so far. Its journey time was 12 years, and it wasn't stopping. (It's now on its way out into interstellar space, having passed the heliopause some years ago.)

    The Kuiper belt, domain of icy wandering dwarf planets like Pluto and Eris, extends perhaps another 30AU, before merging into the much more tenuous Hills cloud and Oort cloud, domain of loosely coupled long-period comets.

    Now for the first scale shock: using our handy metaphor the Kuiper belt is perhaps a metre in diameter. The Oort cloud, in contrast, is as much as 50,000 AU in radius — its outer edge lies half a kilometre away.

    Got that? Our planetary solar system is 30 centimetres, roughly a foot, in radius. But to get to the edge of the Oort cloud, you have to go half a kilometre, roughly a third of a mile.

    Next on our tour is Proxima Centauri, our nearest star. (There might be a brown dwarf or two lurking unseen in the icy depths beyond the Oort cloud, but if we've spotted one, I'm unaware of it.) Proxima Centauri is 4.22 light years away.A light year is 63.2 x 103 AU, or 9.46 x 1012 Km. So Proxima Centauri, at 267,000 AU, is just under two and a third kilometres, or two miles (in old money) away from us.

    But Proxima Centauri is a poor choice, if we're looking for habitable real estate. While exoplanets are apparently common as muck, terrestrial planets are harder to find; Gliese 581c, the first such to be detected (and it looks like a pretty weird one, at that), is roughly 20.4 light years away, or using our metaphor, about ten miles.

    Try to get a handle on this: it takes us 2-5 years to travel two inches. But the proponents of interstellar travel are talking about journeys of ten miles. That's the first point I want to get across: that if the distances involved in interplanetary travel are enormous, and the travel times fit to rival the first Australian settlers, then the distances and times involved in interstellar travel are mind-numbing.

    This is not to say that interstellar travel is impossible; quite the contrary. But to do so effectively you need either (a) outrageous amounts of cheap energy, or (b) highly efficient robot probes, or (c) a magic wand. And in the absence of (c) you're not going to get any news back from the other end in less than decades. Even if (a) is achievable, or by means of (b) we can send self-replicating factories and have them turn distant solar systems into hives of industry, and more speculatively find some way to transmit human beings there, they are going to have zero net economic impact on our circumstances (except insofar as sending them out costs us money).

    What do I mean by outrageous amounts of cheap energy?

    Let's postulate that in the future, it will be possible to wave a magic wand and construct a camping kit that encapsulates all the necessary technologies and information to rebuild a human civilization capable of eventually sending out interstellar colonization missions — a bunch of self-replicating, self-repairing robotic hardware, and a downloadable copy of the sum total of human knowledge to date. Let's also be generous and throw in a closed-circuit life support system capable of keeping a human occupant alive indefinitely, for many years at a stretch, with zero failures and losses, and capable where necessary of providing medical intervention. Let's throw in a willing astronaut (the fool!) and stick them inside this assembly. It's going to be pretty boring in there, but I think we can conceive of our minimal manned interstellar mission as being about the size and mass of a Mercury capsule. And I'm going to nail a target to the barn door and call it 2000kg in total.

    (Of course we can cut corners, but I've already invoked self-replicating robotic factories and closed-cycle life support systems, and those are close enough to magic wands as it is. I'm going to deliberately ignore more speculative technologies such as starwisps, mind transfer, or AIs sufficiently powerful to operate autonomously — although I used them shamelessly in my novel Accelerando. What I'm trying to do here is come up with a useful metaphor for the energy budget realistically required for interstellar flight.)

    Incidentally, a probe massing 1-2 tons with an astronaut on top is a bit implausible, but a 1-2 ton probe could conceivably carry enough robotic instrumentation to do useful research, plus a laser powerful enough to punch a signal home, and maybe even that shrink-wrapped military/industrial complex in a tin can that would allow it to build something useful at the other end. Anything much smaller, though, isn't going to be able to transmit its findings to us — at least, not without some breakthroughs in communication technology that haven't shown up so far.

    Now, let's say we want to deliver our canned monkey to Proxima Centauri within its own lifetime. We're sending them on a one-way trip, so a 42 year flight time isn't unreasonable. (Their job is to supervise the machinery as it unpacks itself and begins to brew up a bunch of new colonists using an artificial uterus. Okay?) This means they need to achieve a mean cruise speed of 10% of the speed of light. They then need to decelerate at the other end. At 10% of c relativistic effects are minor — there's going to be time dilation, but it'll be on the order of hours or days over the duration of the 42-year voyage. So we need to accelerate our astronaut to 30,000,000 metres per second, and decelerate them at the other end. Cheating and using Newton's laws of motion, the kinetic energy acquired by acceleration is 9 x 1017 Joules, so we can call it 2 x 1018 Joules in round numbers for the entire trip. NB: This assumes that the propulsion system in use is 100% efficient at converting energy into momentum, that there are no losses from friction with the interstellar medium, and that the propulsion source is external — that is, there's no need to take reaction mass along en route. So this is a lower bound on the energy cost of transporting our Mercury-capsule sized expedition to Proxima Centauri in less than a lifetime.

    To put this figure in perspective, the total conversion of one kilogram of mass into energy yields 9 x 1016 Joules. (Which one of my sources informs me, is about equivalent to 21.6 megatons in thermonuclear explosive yield). So we require the equivalent energy output to 400 megatons of nuclear armageddon in order to move a capsule of about the gross weight of a fully loaded Volvo V70 automobile to Proxima Centauri in less than a human lifetime. That's the same as the yield of the entire US Minuteman III ICBM force.

    For a less explosive reference point, our entire planetary economy runs on roughly 4 terawatts of electricity (4 x 1012 watts). So it would take our total planetary electricity production for a period of half a million seconds — roughly 5 days — to supply the necessary va-va-voom.

    But to bring this back to earth with a bump, let me just remind you that this probe is so implausibly efficient that it's veering back into "magic wand" territory. I've tap-danced past a 100% efficient power transmission system capable of operating across interstellar distances with pinpoint precision and no conversion losses, and that allows the spacecraft on the receiving end to convert power directly into momentum. This is not exactly like any power transmission system that anyone's built to this date, and I'm not sure I can see where it's coming from.

    Our one astronaut, 10% of c mission approximates well to an unmanned flight, but what about longer-term expeditions? Generation ships are a staple of SF; they're slow (probably under 1% of c) and they carry a self-sufficient city-state. The crew who set off won't live to see their destination (the flight time to Proxima Centauri at 1% of c is about 420 years), but the vague hope is that someone will. Leaving aside our lack of a proven track record at building social institutions that are stable across time periods greatly in excess of a human lifespan, using a generation ship probably doesn't do much for our energy budget problem either. A society of human beings are likely to need more space and raw material to do stuff with while in flight; sticking a solitary explorer in a tin can for forty-something years is merely cruel and unusual, but doing it to an entire city for several centuries probably qualifies as a crime against humanity. We therefore need to relax the mass constraint. Assuming the same super-efficient life support as our solitary explorer, we might postulate that each colonist requires ten tons of structural mass to move around in. (About the same as a large trailer home. For life.) We've cut the peak velocity by an order of magnitude, but we've increased the payload requirement by an order of magnitude per passenger — and we need enough passengers to make a stable society fly. I'd guess a sensible lower number would be on the order of 200 people, the size of a prehistoric primate troupe. (Genetic diversity? I'm going to assume we can hand-wave around that by packing some deep-frozen sperm and ova, or frozen embryos, for later reuse.) By the time we work up to a minimal generation ship (and how minimal can we get, confining 200 human beings in an object weighing aout 2000 tons, for roughly the same period of time that has elapsed since the Plymouth colony landed in what was later to become Massachusetts?) we're actually requiring much more energy than our solitary high-speed explorer.

    And remember, this is only what it takes to go to Proxima Centauri our nearest neighbour. Gliese 581c is five times as far away. Planets that are already habitable insofar as they orbit inside the habitable zone of their star, possess free oxygen in their atmosphere, and have a mass, surface gravity and escape velocity that are not too forbidding, are likely to be somewhat rarer. (And if there is free oxygen in the atmosphere on a planet, that implies something else — the presence of pre-existing photosynthetic life, a carbon cycle, and a bunch of other stuff that could well unleash a big can of whoop-ass on an unprimed human immune system. The question of how we might interact with alien biologies is an order of magnitude bigger and more complex than the question of how we might get there — and the preliminary outlook is rather forbidding.)

    The long and the short of what I'm trying to get across is quite simply that, in the absence of technology indistinguishable from magic — magic tech that, furthermore, does things that from today's perspective appear to play fast and loose with the laws of physics — interstellar travel for human beings is near-as-dammit a non-starter. And while I won't rule out the possibility of such seemingly-magical technology appearing at some time in the future, the conclusion I draw as a science fiction writer is that if interstellar colonization ever happens, it will not follow the pattern of historical colonization drives that are followed by mass emigration and trade between the colonies and the old home soil.

    What about our own solar system?

    After contemplating the vastness of interstellar space, our own solar system looks almost comfortingly accessible at first. Exploring our own solar system is a no-brainer: we can do it, we are doing it, and interplanetary exploration is probably going to be seen as one of the great scientific undertakings of the late 20th and early 21st century, when the history books get written.

    But when we start examining the prospects for interplanetary colonization things turn gloomy again.

    Bluntly, we're not going to get there by rocket ship.

    Optimistic projects suggest that it should be possible, with the low cost rockets currently under development, to maintain a Lunar presence for a transportation cost of roughly $15,000 per kilogram. Some extreme projections suggest that if the cost can be cut to roughly triple the cost of fuel and oxidizer (meaning, the spacecraft concerned will be both largely reusable and very cheap) then we might even get as low as $165/kilogram to the lunar surface. At that price, sending a 100Kg astronaut to Moon Base One looks as if it ought to cost not much more than a first-class return air fare from the UK to New Zealand ... except that such a price estimate is hogwash. We primates have certain failure modes, and one of them that must not be underestimated is our tendency to irreversibly malfunction when exposed to climactic extremes of temperature, pressure, and partial pressure of oxygen. While the amount of oxygen, water, and food a human consumes per day doesn't sound all that serious — it probably totals roughly ten kilograms, if you economize and recycle the washing-up water — the amount of parasitic weight you need to keep the monkey from blowing out is measured in tons. A Russian Orlan-M space suit (which, some would say, is better than anything NASA has come up with over the years — take heed of the pre-breathe time requirements!) weighs 112 kilograms, which pretty much puts a floor on our infrastructure requirements. An actual habitat would need to mass a whole lot more. Even at $165/kilogram, that's going to add up to a very hefty excess baggage charge on that notional first class air fare to New Zealand — and I think the $165/kg figure is in any case highly unrealistic; even the authors of the article I cited thought $2000/kg was a bit more reasonable.

    Whichever way you cut it, sending a single tourist to the moon is going to cost not less than $50,000 — and a more realistic figure, for a mature reusable, cheap, rocket-based lunar transport cycle is more like $1M. And that's before you factor in the price of bringing them back ...

    The moon is about 1.3 light seconds away. If we want to go panning the (metaphorical) rivers for gold, we'd do better to send teleoperator-controlled robots; it's close enough that we can control them directly, and far enough away that the cost of transporting food and creature comforts for human explorers is astronomical. There probably are niches for human workers on a moon base, but only until our robot technologies are somewhat more mature than they are today; Mission Control would be a lot happier with a pair of hands and a high-def camera that doesn't talk back and doesn't need to go to the toilet or take naps.

    When we look at the rest of the solar system, the picture is even bleaker. Mars is ... well, the phrase "tourist resort" springs to mind, and is promptly filed in the same corner as "Gobi desert". As Bruce Sterling has puts it: "I'll believe in people settling Mars at about the same time I see people settling the Gobi Desert. The Gobi Desert is about a thousand times as hospitable as Mars and five hundred times cheaper and easier to reach. Nobody ever writes "Gobi Desert Opera" because, well, it's just kind of plonkingly obvious that there's no good reason to go there and live. It's ugly, it's inhospitable and there's no way to make it pay. Mars is just the same, really. We just romanticize it because it's so hard to reach." In other words, going there to explore is fine and dandy — our robots are all over it already. But as a desirable residential neighbourhood it has some shortcomings, starting with the slight lack of breathable air and the sub-Antarctic nighttime temperatures and the Mach 0.5 dust storms, and working down from there.

    Actually, there probably is a good reason for sending human explorers to Mars. And that's the distance: at up to 30 minutes, the speed of light delay means that remote control of robots on the Martian surface is extremely tedious. Either we need autonomous roots that can be assigned tasks and carry them out without direct human supervision, or we need astronauts in orbit or on the ground to boss the robot work gangs around.

    On the other hand, Mars is a good way further away than the moon, and has a deeper gravity well. All of which drive up the cost per kilogram delivered to the Martian surface. Maybe FedEx could cut it as low as $20,000 per kilogram, but I'm not holding my breath.

    Let me repeat myself: we are not going there with rockets. At least, not the conventional kind — and while there may be a role for nuclear propulsion in deep space, in general there's a trade-off between instantaneous thrust and efficiency; the more efficient your motor, the lower the actual thrust it provides. Some technologies such as the variable specific impulse magnetoplasma rocket show a good degree of flexibility, but in general they're not suitable for getting us from Earth's surface into orbit — they're only useful for trucking things around from low earth orbit on out.

    Again, as with interstellar colonization, there are other options. Space elevators, if we build them, will invalidate a lot of what I just said. Some analyses of the energy costs of space elevators suggest that a marginal cost of $350/kilogram to geosynchronous orbit should be achievable without waving any magic wands (other than the enormous practical materials and structural engineering problems of building the thing in the first place). So we probably can look forward to zero-gee vacations in orbit, at a price. And space elevators are attractive because they're a scalable technology; you can use one to haul into space the material to build more. So, long term, space elevators may give us not-unreasonably priced access to space, including jaunts to the lunar surface for a price equivalent to less than $100,000 in today's money. At which point, settlement would begin to look economically feasible, except ...

    We're human beings. We evolved to flourish in a very specific environment that covers perhaps 10% of our home planet's surface area. (Earth is 70% ocean, and while we can survive, with assistance, in extremely inhospitable terrain, be it arctic or desert or mountain, we aren't well-adapted to thriving there.) Space itself is a very poor environment for humans to live in. A simple pressure failure can kill a spaceship crew in minutes. And that's not the only threat. Cosmic radiation poses a serious risk to long duration interplanetary missions, and unlike solar radiation and radiation from coronal mass ejections the energies of the particles responsible make shielding astronauts extremely difficult. And finally, there's the travel time. Two and a half years to Jupiter system; six months to Mars.

    Now, these problems are subject to a variety of approaches — including medical ones: does it matter if cosmic radiation causes long-term cumulative radiation exposure leading to cancers if we have advanced side-effect-free cancer treatments? Better still, if hydrogen sulphide-induced hibernation turns out to be a practical technique in human beings, we may be able to sleep through the trip. But even so, when you get down to it, there's not really any economically viable activity on the horizon for people to engage in that would require them to settle on a planet or asteroid and live there for the rest of their lives. In general, when we need to extract resources from a hostile environment we tend to build infrastructure to exploit them (such as oil platforms) but we don't exactly scurry to move our families there. Rather, crews go out to work a long shift, then return home to take their leave. After all, there's no there there — just a howling wilderness of north Atlantic gales and frigid water that will kill you within five minutes of exposure. And that, I submit, is the closest metaphor we'll find for interplanetary colonization. Most of the heavy lifting more than a million kilometres from Earth will be done by robots, overseen by human supervisors who will be itching to get home and spend their hardship pay. And closer to home, the commercialization of space will be incremental and slow, driven by our increasing dependence on near-earth space for communications, positioning, weather forecasting, and (still in its embryonic stages) tourism. But the domed city on Mars is going to have to wait for a magic wand or two to do something about the climate, or reinvent a kind of human being who can thrive in an airless, inhospitable environment.

    Colonize the Gobi desert, colonise the North Atlantic in winter — then get back to me about the rest of the solar system!

    http://www.antipope.org/charlie/blog-static/2007/06/the_high_frontier_redux.html

    OremLK on
  • SkutSkutSkutSkut Registered User regular
    edited April 2009
    So would a perputual motion device help, maybe a micro blackhole engine or something? I'm waiting in patience for the LHC to kick science in the junk.

    SkutSkut on
  • fjafjanfjafjan Registered User
    edited April 2009
    Fucking I'll write it again.
    STOP AGAIN (probably way easier than building 0.9x c rocket engines) ==> Space travel of 100-200 years IS NOT A HUGE PROBLEM. So we can get to the other planets, we just need to stop our cells from dying, there are other cells that do this (or close enough anyhow), so we just need to copy, we don't need to invent the wheel.

    fjafjan on
    Yepp, THE Fjafjan (who's THE fjafjan?)
    - "Proving once again the deadliest animal of all ... is the Zoo Keeper" - Philip J Fry
  • OremLKOremLK Registered User regular
    edited April 2009
    If we come up with a way to allow effective immortality within my lifetime, I'll eat a sock. You know, on my death bed. But then I'll get my immortality treatment, so that will be cool.

    Of course, if we do come up with that technology, extra-terrestrial colonization will immediately become much more important.

    OremLK on
  • fjafjanfjafjan Registered User
    edited April 2009
    OremLK wrote: »
    If we come up with a way to allow effective immortality within my lifetime, I'll eat a sock. You know, on my death bed. But then I'll get my immortality treatment, so that will be cool.

    Of course, if we do come up with that technology, extra-terrestrial colonization will immediately become much more important.
    It's far far easier than the dreamed up shit people are talking about here. You know, building space ships big enough, and more importantly, fast enough to get to another solar system. Like, it's crazy hard. How would we even communicate? Each signal takes 20 years! and it needs to be incredibly strong to reach them in a comprehensible manner.
    And I'm not talking immortality, I am talking stopping aging. Aging is really only a few processes that our cells go through that causes them to die, and us to grow old. Stopping that means living untill a couple hundred won't be too hard, and that means space travel will be way way easier, since we don't need super magical engines or energy sources, since we don't need to get there in less than 50 years, suddenly a 200 year trip is reasonable and we can go at speeds we've already managed (though for smaller ships).

    fjafjan on
    Yepp, THE Fjafjan (who's THE fjafjan?)
    - "Proving once again the deadliest animal of all ... is the Zoo Keeper" - Philip J Fry
  • electricitylikesmeelectricitylikesme Registered User regular
    edited April 2009
    I'd just be content if we could start launching some interstellar probes sometime soon. I figure you'd send a stream of them at regular intervals so they could act as relays for each other to report back (as well as be multiply redundant for the mission).

    It'd blow my mind if we could get fly by images of planets in another star system. Blow my mind even more if we could get a probe which could decelerate and establish orbit. Even more if we could send landers.

    I mean, seriously - taking images of planets in other star systems. That right there would be an AMAZING accomplishment.

    electricitylikesme on
  • geckahngeckahn Registered User regular
    edited April 2009
    fjafjan wrote: »
    I am talking stopping aging. Aging is really only a few processes that our cells go through that causes them to die, and us to grow old. Stopping that means living untill a couple hundred won't be too hard

    Its really not that simple. You stop cells from aging quickly and you know what happens? they all start getting cancer. So its like the reverse of what you actually want to happen. Long life will be attained when we can figure out how to stop our bodies repair mechanisms from breaking down.

    geckahn on
  • tbloxhamtbloxham Registered User regular
    edited April 2009
    SkutSkut wrote: »
    So would a perputual motion device help, maybe a micro blackhole engine or something? I'm waiting in patience for the LHC to kick science in the junk.

    Micro blackhole engine (ie an engine which is a blackhole somehow suspended behind the ship which evaporates at the exact rate you put fuel into it) would be just as as good as an antimatter engine, and allow us to simply use normal matter rather than antimatter + matter. The black hole itself would have a tiny mass, but you'd still face a maximum speed set by your fuel energy density and the fuel/ship ratio of your ship.

    A 90% fuel antimatter/black hole ship still tops out at 0.77 c. A 99 % fuel ship can make it up to a scorching 0.88 c. A dynamically evaporating black hole drive is both safer (even if you dropped it in the earth it wouldn't suck in mass fast enough, this thing would be tuned to need to be fed like a bastard. The lighter the hole, the faster you need to feed it to stay stable, and we would want to feed it fast for high accelerations) and 'easier' than an antimatter drive. However we have no idea really how to make either. Black hole energy at least allows us to do direct matter to energy conversion, but at least we have a basic idea how to make anti matter.

    tbloxham on
    Your puny weapons are useless against me
  • zakkielzakkiel Registered User regular
    edited April 2009
    tbloxham wrote: »
    SkutSkut wrote: »
    So would a perputual motion device help, maybe a micro blackhole engine or something? I'm waiting in patience for the LHC to kick science in the junk.

    Micro blackhole engine (ie an engine which is a blackhole somehow suspended behind the ship which evaporates at the exact rate you put fuel into it) would be just as as good as an antimatter engine, and allow us to simply use normal matter rather than antimatter + matter. The black hole itself would have a tiny mass, but you'd still face a maximum speed set by your fuel energy density and the fuel/ship ratio of your ship.

    A 90% fuel antimatter/black hole ship still tops out at 0.77 c. A 99 % fuel ship can make it up to a scorching 0.88 c. A dynamically evaporating black hole drive is both safer (even if you dropped it in the earth it wouldn't suck in mass fast enough, this thing would be tuned to need to be fed like a bastard. The lighter the hole, the faster you need to feed it to stay stable, and we would want to feed it fast for high accelerations) and 'easier' than an antimatter drive. However we have no idea really how to make either. Black hole energy at least allows us to do direct matter to energy conversion, but at least we have a basic idea how to make anti matter.

    How would you drag the hole behind you?

    zakkiel on
    Account not recoverable. So long.
  • electricitylikesmeelectricitylikesme Registered User regular
    edited April 2009
    zakkiel wrote: »
    tbloxham wrote: »
    SkutSkut wrote: »
    So would a perputual motion device help, maybe a micro blackhole engine or something? I'm waiting in patience for the LHC to kick science in the junk.

    Micro blackhole engine (ie an engine which is a blackhole somehow suspended behind the ship which evaporates at the exact rate you put fuel into it) would be just as as good as an antimatter engine, and allow us to simply use normal matter rather than antimatter + matter. The black hole itself would have a tiny mass, but you'd still face a maximum speed set by your fuel energy density and the fuel/ship ratio of your ship.

    A 90% fuel antimatter/black hole ship still tops out at 0.77 c. A 99 % fuel ship can make it up to a scorching 0.88 c. A dynamically evaporating black hole drive is both safer (even if you dropped it in the earth it wouldn't suck in mass fast enough, this thing would be tuned to need to be fed like a bastard. The lighter the hole, the faster you need to feed it to stay stable, and we would want to feed it fast for high accelerations) and 'easier' than an antimatter drive. However we have no idea really how to make either. Black hole energy at least allows us to do direct matter to energy conversion, but at least we have a basic idea how to make anti matter.

    How would you drag the hole behind you?
    Black hole pulls on the mass of the ship while pushing on the ship with the energy it's releasing (as well as itself since it's omnidirectionally doing it).

    electricitylikesme on
  • YannYann Registered User regular
    edited April 2009
    This is the fastest space craft we've ever made according to wikipedia.

    Another source.

    Yann on
  • tbloxhamtbloxham Registered User regular
    edited April 2009
    zakkiel wrote: »
    tbloxham wrote: »
    SkutSkut wrote: »
    So would a perputual motion device help, maybe a micro blackhole engine or something? I'm waiting in patience for the LHC to kick science in the junk.

    Micro blackhole engine (ie an engine which is a blackhole somehow suspended behind the ship which evaporates at the exact rate you put fuel into it) would be just as as good as an antimatter engine, and allow us to simply use normal matter rather than antimatter + matter. The black hole itself would have a tiny mass, but you'd still face a maximum speed set by your fuel energy density and the fuel/ship ratio of your ship.

    A 90% fuel antimatter/black hole ship still tops out at 0.77 c. A 99 % fuel ship can make it up to a scorching 0.88 c. A dynamically evaporating black hole drive is both safer (even if you dropped it in the earth it wouldn't suck in mass fast enough, this thing would be tuned to need to be fed like a bastard. The lighter the hole, the faster you need to feed it to stay stable, and we would want to feed it fast for high accelerations) and 'easier' than an antimatter drive. However we have no idea really how to make either. Black hole energy at least allows us to do direct matter to energy conversion, but at least we have a basic idea how to make anti matter.

    How would you drag the hole behind you?

    Well, err, wizards. I mean, just making and maintaining the black hole would be an act of near insane technology. I guess you could somehow charge the black hole by injecting a net negative charge, and set up an electric field to precisely match the acceleration force of the ship. Another option might be to inject the matter with a slight asymmetry, so the hole continually accelerated forward towards the ship while the radiation would be ejected uniformly, causing the same acceleration on hole and ship. The momentum asymetry needed to accelerate the tiny hole by the same as the massive ship would be insignificant and wouldn't really slow the ship that much.

    I mean, its kinda like asking how the warp drive can be cooled due to the heat it creates. Or how we would address the manufacturing problems with making Flemitronioum Core elements en masse. We don't even know anything about how to practically create and tune the mass of a black hole, let alone transport and move one. The only thing we do know is that it would be an eminently useful power source if we could build one.

    tbloxham on
    Your puny weapons are useless against me
  • tbloxhamtbloxham Registered User regular
    edited April 2009
    zakkiel wrote: »
    tbloxham wrote: »
    SkutSkut wrote: »
    So would a perputual motion device help, maybe a micro blackhole engine or something? I'm waiting in patience for the LHC to kick science in the junk.

    Micro blackhole engine (ie an engine which is a blackhole somehow suspended behind the ship which evaporates at the exact rate you put fuel into it) would be just as as good as an antimatter engine, and allow us to simply use normal matter rather than antimatter + matter. The black hole itself would have a tiny mass, but you'd still face a maximum speed set by your fuel energy density and the fuel/ship ratio of your ship.

    A 90% fuel antimatter/black hole ship still tops out at 0.77 c. A 99 % fuel ship can make it up to a scorching 0.88 c. A dynamically evaporating black hole drive is both safer (even if you dropped it in the earth it wouldn't suck in mass fast enough, this thing would be tuned to need to be fed like a bastard. The lighter the hole, the faster you need to feed it to stay stable, and we would want to feed it fast for high accelerations) and 'easier' than an antimatter drive. However we have no idea really how to make either. Black hole energy at least allows us to do direct matter to energy conversion, but at least we have a basic idea how to make anti matter.

    How would you drag the hole behind you?
    Black hole pulls on the mass of the ship while pushing on the ship with the energy it's releasing (as well as itself since it's omnidirectionally doing it).

    That would work too, although the hole would need to be enormous. The pull on the ship of the hole and vice versa goes up with mass, the power output of the hole goes down with mass, you'd need to pick the crossover point and it might mean a very low acceleration.

    Although, now I do the calculations our black hole ship faces another problem. To achieve a low enough conversion rate, say a few kg per second of mass means the black hole needs to weigh a few hundred tonnes. It actually means we want our ship to be titanically huge so we can use an enormous mass of fuel each second and get our black hole mass low.

    tbloxham on
    Your puny weapons are useless against me
  • electricitylikesmeelectricitylikesme Registered User regular
    edited April 2009
    tbloxham wrote: »
    zakkiel wrote: »
    tbloxham wrote: »
    SkutSkut wrote: »
    So would a perputual motion device help, maybe a micro blackhole engine or something? I'm waiting in patience for the LHC to kick science in the junk.

    Micro blackhole engine (ie an engine which is a blackhole somehow suspended behind the ship which evaporates at the exact rate you put fuel into it) would be just as as good as an antimatter engine, and allow us to simply use normal matter rather than antimatter + matter. The black hole itself would have a tiny mass, but you'd still face a maximum speed set by your fuel energy density and the fuel/ship ratio of your ship.

    A 90% fuel antimatter/black hole ship still tops out at 0.77 c. A 99 % fuel ship can make it up to a scorching 0.88 c. A dynamically evaporating black hole drive is both safer (even if you dropped it in the earth it wouldn't suck in mass fast enough, this thing would be tuned to need to be fed like a bastard. The lighter the hole, the faster you need to feed it to stay stable, and we would want to feed it fast for high accelerations) and 'easier' than an antimatter drive. However we have no idea really how to make either. Black hole energy at least allows us to do direct matter to energy conversion, but at least we have a basic idea how to make anti matter.

    How would you drag the hole behind you?
    Black hole pulls on the mass of the ship while pushing on the ship with the energy it's releasing (as well as itself since it's omnidirectionally doing it).

    That would work too, although the hole would need to be enormous. The pull on the ship of the hole and vice versa goes up with mass, the power output of the hole goes down with mass, you'd need to pick the crossover point and it might mean a very low acceleration.
    Well if we're deriving power from the blackhole by it's Hawking radiation, then strictly speaking any mass going in is being omnidirectionally emitted as energy. If we're reflecting most of it off the ship, then since the mass of the black hole is so small I don't think it's completely impossible to presume that we could design a ship with a reaction chamber such that we can reflect some of it's own energy back at it to accelerate the black hole as well. The ship would slow down in doing so, but the ship would be many many times more massive then the black hole so we could keep it moving in the same direction as the ship.

    electricitylikesme on
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