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This is a great headline-grabber but I still see landing a man on Mars as being an awful long way off. I heard Jerry Pournelle talking about this and he said s

by cletus 16y ago

This is a great headline-grabber but I still see landing a man on Mars as being an awful long way off. I heard Jerry Pournelle talking about this and he said something like landing a man on the Moon and establishing a lunar colony is an engineering problem. Landing a man on Mars is a science problem. The difference? We can already do the former. it's simply a question of money and the will to do it. The problems are basically solved. Landing a man on Mars has far bigger problems. The round trip (or even one way) journey with current propulsion technology will take an incredibly long time (upwards of 2 years). How do you keep someone alive that long? What about the psychology of isolation? Sustained radiation exposure is a real problem. Personally I see manned spaceflight, particularly to other planets, as being largely a propaganda exercise until: 1. The cost of lifting into orbit (per kg) goes down. Way down. Like 2 or even 3 orders of magnitude; and 2. We have a much faster means of propulsion to make journey lengths manageable. (1) is probably the easiest to solve. SpaceX's launch prices are actually quite low (but those are fairly low orbits; launching to another planet is more expensive). Virgin Galactic and other private suborbital efforts will (hopefully) lead to a dramatic cost reduction of getting into orbit. (2) is a fundamentally hard problem. Ideas such as solar sails and the like are far from being practical (plus with a solar sail, how do you get back?). Magnetic fields as solar sails is an interesting idea but has a whole bunch of other problems. Otherwise you need to eject mass to give you velocity. That mass is something you have to carry. The more mass (fuel) you carry, the less effective each gram is (in delta-V terms). What I think will probably drive this is the coming earthbound resource shortages (inevitable unless we drastically reduce population; it's simply a question of when) that will drive a permanent presence in space. Once you have a huge industrial manufacturing capacity in space, the economics completely change. EDIT: I agree with other comments in that a one-way (colonization) mission makes far more sense but I'm still unconvinced this will happen anytime soon, probably not in my lifetime. Mars does have some interesting properties though if a colony can become self-sustaining: 1. Lower gravity. This actually makes the idea of a space elevator far more feasible [1]; and 2. Mars has features that extend beyond the atmosphere. The atmosphere is ~11km thick. Olympus Mons is 25km high. I've read seemingly informed speculation that if we (the human race) had evolved on Mars, we'd already be heavily spacebound since it would be far, far easier. This is what might justify colonizing Mars. Not that that is an easy problem. [1]: http://www.physicsforums.com/showthread.php?t=95924 http://www.physicsforums.com/showthread.php?t=95924

drm237 16y ago
I'm not sure we need to dramatically reduce the population in order for the Earth to sustain us, we just can't let it continue to grow unchecked forever. According to the FAO, the earth could feed up to 12 billion people: http://en.wikipedia.org/wiki/Hunger#World_statistics http://en.wikipedia.org/wiki/Hunger#World_statistics
- cletus 16y ago
  Food is the least of our problems. Energy is a bigger problem. While we can make energy from renewable sources it is far more expensive (which has ramifications for our entire way of life) and not yet established that we could provide it on the scale necessary to replace our non-renewable sources. But the biggest problem is resources. Metals, rare earth elements and the like. These are largely irreplaceable in the sense that we can produce so much of them by (typically) digging fairly shallow holes in the ground. We're already going to some fairly inhospitable places to meet our insatiable demand (eg the Arctic in northern Canada and Europe, the Andes). If we're not careful we may well find our own answer to the Fermi paradox.
  - cheez 16y ago
    Nuke-u-ler.
  - evgen 16y ago
    Actually, food is the only problem when it comes to whether or not a population is sustainable. Enery and resource usage determine if a particular lifestyle is sustainable for a given population. Given sufficient energy other resource problems tend to go away (e.g. the amount of various minerals that are in solution within the oceans is mind-boggling but it takes energy to get them out). In the end the lifestyle any particular population can sustain will come down to an energy production/capture and management problem.
    - cletus 16y ago
      > Energy and resource usage determine if a particular lifestyle is sustainable for a given population And maintaining a particular lifestyle tends to be a strong catalyst for war as a means of solving population problems. The problem is we're now at a point where such a thing could be truly devastating. While the threat of mutually-assured destruction has kept the specter of nuclear war at bay, I believe you'll see the means of destruction migrate to more fine-grained methods, most notably genetic engineering and nanotechnology, both of which will become increasingly accessible on a scale nuclear technology never has. > Given sufficient energy other resource problems tend to go away I agree but all the energy replacements in the foreseeable future will make energy more expensive not cheaper. Fission-based energy has the same fuel problem fossil fuelds do (the unfulfilled promises of thorium reactors notwithstanding). Fusion-based energy has huge problems, some of which are fairly fundamental and not likely to be solved anytime soon. The most obvious problem (containment of plasma) is probably solvable with magnetism. The bigger problem is neutrons. You currently can't leave a fusion reactor on for very long before it starts destroying its container. He-3 (Helium-3) is one possibly solution to this but that stuff is incredibly rare and may well present the same fuel problems as any other energy source. Interestingly there's a supply of it on the Moon due to billions of years of solar wind on an atmosphere-less body. > In the end the lifestyle any particular population can sustain will come down to an energy production/capture and management problem. With some fairly nasty corrections that may have undesirable consequences for the rest of us. Anyway, that's why I say food is the least of our problems. We can already produce enough food for the present population. It's unclear how much longer we can support the lifestyle of that same population. Energy factors in here too as we're now fairly distant from our food (given how urbanized the developed world generally is) but population redistribution will occur naturally as the energy equation changes.

by cletus 16y ago

drm237 16y ago

I'm not sure we need to dramatically reduce the population in order for the Earth to sustain us, we just can't let it continue to grow unchecked forever. According to the FAO, the earth could feed up to 12 billion people: http://en.wikipedia.org/wiki/Hunger#World_statistics http://en.wikipedia.org/wiki/Hunger#World_statistics

cletus 16y ago
Food is the least of our problems. Energy is a bigger problem. While we can make energy from renewable sources it is far more expensive (which has ramifications for our entire way of life) and not yet established that we could provide it on the scale necessary to replace our non-renewable sources. But the biggest problem is resources. Metals, rare earth elements and the like. These are largely irreplaceable in the sense that we can produce so much of them by (typically) digging fairly shallow holes in the ground. We're already going to some fairly inhospitable places to meet our insatiable demand (eg the Arctic in northern Canada and Europe, the Andes). If we're not careful we may well find our own answer to the Fermi paradox.
- cheez 16y ago
  Nuke-u-ler.
- evgen 16y ago
  Actually, food is the only problem when it comes to whether or not a population is sustainable. Enery and resource usage determine if a particular lifestyle is sustainable for a given population. Given sufficient energy other resource problems tend to go away (e.g. the amount of various minerals that are in solution within the oceans is mind-boggling but it takes energy to get them out). In the end the lifestyle any particular population can sustain will come down to an energy production/capture and management problem.
  - cletus 16y ago
    > Energy and resource usage determine if a particular lifestyle is sustainable for a given population And maintaining a particular lifestyle tends to be a strong catalyst for war as a means of solving population problems. The problem is we're now at a point where such a thing could be truly devastating. While the threat of mutually-assured destruction has kept the specter of nuclear war at bay, I believe you'll see the means of destruction migrate to more fine-grained methods, most notably genetic engineering and nanotechnology, both of which will become increasingly accessible on a scale nuclear technology never has. > Given sufficient energy other resource problems tend to go away I agree but all the energy replacements in the foreseeable future will make energy more expensive not cheaper. Fission-based energy has the same fuel problem fossil fuelds do (the unfulfilled promises of thorium reactors notwithstanding). Fusion-based energy has huge problems, some of which are fairly fundamental and not likely to be solved anytime soon. The most obvious problem (containment of plasma) is probably solvable with magnetism. The bigger problem is neutrons. You currently can't leave a fusion reactor on for very long before it starts destroying its container. He-3 (Helium-3) is one possibly solution to this but that stuff is incredibly rare and may well present the same fuel problems as any other energy source. Interestingly there's a supply of it on the Moon due to billions of years of solar wind on an atmosphere-less body. > In the end the lifestyle any particular population can sustain will come down to an energy production/capture and management problem. With some fairly nasty corrections that may have undesirable consequences for the rest of us. Anyway, that's why I say food is the least of our problems. We can already produce enough food for the present population. It's unclear how much longer we can support the lifestyle of that same population. Energy factors in here too as we're now fairly distant from our food (given how urbanized the developed world generally is) but population redistribution will occur naturally as the energy equation changes.