4 ms·

We are not confined to Earth. Currently something like 99.9999999% of the energy radiated by the sun is emitted into empty space, where it is completely wasted.

We are not confined to Earth. Currently something like 99.9999999% of the energy radiated by the sun is emitted into empty space, where it is completely wasted. That can all be harvested. To put that into perspective, our civilization could use 20 trillion times more energy than it does now if it harvested the sun's entire output.

lostlogin 2y ago
> We are not confined to Earth. A couple of humans can go to space in that they can go up for short stints. The rest of us are confined to earth for the foreseeable future. Even if we weren’t, I’d like the place kept nice.
- ETH_start 2y ago
  The energy harvesting infrastructure can extend beyond Earth while we live here. With advanced launch capabilities we can also build much more livable habitats beyond Earth than the ISS. And yes, we should keep Earth nice, but we don't need to limit economic development to do that.
  - henearkr 2y ago
    There is a right order in which to do these things: 1) enable space harvesting of energy and minerals, 2) unleash growth. Doing 2) first as we are is just planetary-scale suicide. We should even first concentrate on 0) figure out how to preserve the biosphere liveability, and stick to these rules.
    - ETH_start 2y ago
      I respectfully disagree. There are vast opportunities, even on Earth, to expand energy generation without overloading the environment — such as utilizing arid lands for large-scale solar farms and expanding nuclear power, among other solutions. That said, I believe a robust space economy is imminent, not some distant uncertainty. Starship has already had partially successful test launches, and if it follows the same trajectory as the reusable Falcon 9, we will soon have a fully reusable vehicle capable of delivering 150 tons to low-Earth orbit per launch. If Musk follows through on his ambition to develop a fleet large enough to transport the materials needed for a self-sustaining Martian civilization, we could see an explosion in lift capacity within the next decade or two, radically transforming the scale of human expansion into space.
      - gf000 2y ago
        Even a post-ww3 nuclear wasteland Earth with climate catastrophe is orderS of more habitable than anything else in the Solar system. Musk is a scammer and is dumb as a rock on any technological question. Also, energy is useless if it's not where you actually want to use it, and transporting it is expensive/lossy. The cheapest energy is one which doesn't have to be used up to begin with, and we could optimize the existing workflow much more, over some child-dream Martian scam.
        ETH_start 2y ago
        That is simply not true. A post-World War III nuclear wasteland would be subject to attack and pillaging by roving human bands, whereas a deep space colony would not be. And energy transportation being lossy is not a deal breaker when you can generate massive amounts of energy out in space. Even if you lose 90% of it, 10% of an enormous number is still an enormous number.
        gf000 2y ago
        Did you account for the maintainance of any equipment out in space? Just because we can produce space junk faster doesn't make the rest any cheaper. Also, getting robbed is a luxury compared to not having air to breathe.
        ETH_start 2y ago
        It will get more affordable as the amount of infrastructure that is outside of Earth's gravity well — and any other steep gravity well — increases. The thing with the Starship is it allows us to expand that infrastructure rapidly, so we can soon have a sizable industrial base that can access low-gravity resources like asteroids and moon regolith.
        ben_w 2y ago
        Anywhere we can get to at the scale necessary to make significant power, there's not much stopping humans, or at least automated robots, from also going there to attack and pillage. -- The most habitable place in the solar system, outside of Earth, is Mars. Mars has 50% of the sunlight that Earth. Owing to the lower sunlight level, it is colder than Antarctica. The atmosphere is equivalent to taking ours, then systematically deleting every molecule that isn't carbon dioxide without replacing it with anything else. Owing to the combination of low partial pressure and low temperature, half the atmosphere condenses into the polar caps each Martian winter. The ground is more toxic than an actual, literal, superfund cleanup site. It is drier than the actual, literal Sahara. The lack of oxygen in the atmosphere means there's no ozone layer. The lack of ozone layer, the thin remaining atmosphere, and the lack of magnetosphere, means it's a high-radiation environment. PV there also gets regularly covered in dust. Our moon is even less hospitable, owing to no atmosphere at all and being tidally locked with Earth. Venus has an atmosphere so dense that it has gone beyond the critical point where gas and liquid cease to be distinguishable, so you could reasonably also describe it as an ocean. An ocean of 465°C supercritical CO2 in which lead occasionally condenses onto mountaintops. -- There's three currently achievable ways to transport power through space at scale. Optical, microwave, or kinetic. Optical is either a bunch of mirrors or a laser on the sending side, with a normal PV system on the receiving side. Usual caveats apply, Earth spins so it has a relative night, doesn't work through clouds, maximum power density before PV systems overheat etc. All EM systems, microwave and optical, share a constraint about focussing: minimal size of target depends on the size of the antenna and the wavelength used. Because microwaves are so much longer (no much freedom to choose a different wavelength as there's a limited atmospheric window), the normal suggestion for ground stations is a 10 km diameter receiving rectenna — that's contiguous, you don't get PV's advantage of being able to split it up. Kinetic currently means an RFG — launch it e.g. electromagnetically towards a similar coil on the ground that decelerates it to extract the energy. This is theoretically possible and would totally work, but to be clear: it's shooting a bullet into the barrel of another gun, and this is not something we have a lot of experience doing, certainly not at scale or for the purposes of power generation.
  - 1propionyl 2y ago
    > livable habitats beyond Earth Fetuses do not properly develop in the womb outside of Earth gravity. Sorry. End of the road for that sci-fi pipe dream.
    - ETH_start 2y ago
      Artificial gravity can easily be created through centrifugal force.
notfed 2y ago
> That can all be harvested. Can it? How?
aqueueaqueue 2y ago
We don't have tech to do that and I cannot see it happening this century
- ETH_start 2y ago
  Starship will reduce the cost to send a kilogram of mass into orbit by ten to a hundredfold, meaning the cost will come down to something in the order of $100 or even down to $20 per kilogram, from its current cost of $1,500. This is not science fiction, this is totally feasible in the foreseeable future.
  - gf000 2y ago
    And then what, you put up a cable to it able to withstand the whole atmosphere? Also, what about space debris hitting it, rotating the panels? Each one will be able to align properly or do they need a way to self-align? Do you think any of that will be able to compete with... A dumb panel here on Earth that itself continues to be cheaper each year, or more efficient production lines requiring less power to begin with?
  - aqueueaqueue 2y ago
    We don't need to do this. Just put the panels on this planet. And fix the politicians brain worms / fear of other politicians with brain worms. If we can't get a solar panel on our roofs I can't see the impetus to get them up past the moon.
- ben_w 2y ago
  I can see it happening, compounding growth has a way of doing that. But, given how we keep rushing into predictable disasters, I now expect to live to experience personally, first hand, a K2-level Kessler cascade from the inside. When people figure out the missing parts of VN replicators, that all happens over a handful of decades.
lodovic 2y ago
Don't discount the energy and materials required to build that Dyson sphere

lostlogin 2y ago

> We are not confined to Earth. A couple of humans can go to space in that they can go up for short stints. The rest of us are confined to earth for the foreseeable future. Even if we weren’t, I’d like the place kept nice.

ETH_start 2y ago
The energy harvesting infrastructure can extend beyond Earth while we live here. With advanced launch capabilities we can also build much more livable habitats beyond Earth than the ISS. And yes, we should keep Earth nice, but we don't need to limit economic development to do that.
- henearkr 2y ago
  There is a right order in which to do these things: 1) enable space harvesting of energy and minerals, 2) unleash growth. Doing 2) first as we are is just planetary-scale suicide. We should even first concentrate on 0) figure out how to preserve the biosphere liveability, and stick to these rules.
  - ETH_start 2y ago
    I respectfully disagree. There are vast opportunities, even on Earth, to expand energy generation without overloading the environment — such as utilizing arid lands for large-scale solar farms and expanding nuclear power, among other solutions. That said, I believe a robust space economy is imminent, not some distant uncertainty. Starship has already had partially successful test launches, and if it follows the same trajectory as the reusable Falcon 9, we will soon have a fully reusable vehicle capable of delivering 150 tons to low-Earth orbit per launch. If Musk follows through on his ambition to develop a fleet large enough to transport the materials needed for a self-sustaining Martian civilization, we could see an explosion in lift capacity within the next decade or two, radically transforming the scale of human expansion into space.
    - gf000 2y ago
      Even a post-ww3 nuclear wasteland Earth with climate catastrophe is orderS of more habitable than anything else in the Solar system. Musk is a scammer and is dumb as a rock on any technological question. Also, energy is useless if it's not where you actually want to use it, and transporting it is expensive/lossy. The cheapest energy is one which doesn't have to be used up to begin with, and we could optimize the existing workflow much more, over some child-dream Martian scam.
      - ETH_start 2y ago
        That is simply not true. A post-World War III nuclear wasteland would be subject to attack and pillaging by roving human bands, whereas a deep space colony would not be. And energy transportation being lossy is not a deal breaker when you can generate massive amounts of energy out in space. Even if you lose 90% of it, 10% of an enormous number is still an enormous number.
        gf000 2y ago
        Did you account for the maintainance of any equipment out in space? Just because we can produce space junk faster doesn't make the rest any cheaper. Also, getting robbed is a luxury compared to not having air to breathe.
        ETH_start 2y ago
        It will get more affordable as the amount of infrastructure that is outside of Earth's gravity well — and any other steep gravity well — increases. The thing with the Starship is it allows us to expand that infrastructure rapidly, so we can soon have a sizable industrial base that can access low-gravity resources like asteroids and moon regolith.
        ben_w 2y ago
        Anywhere we can get to at the scale necessary to make significant power, there's not much stopping humans, or at least automated robots, from also going there to attack and pillage. -- The most habitable place in the solar system, outside of Earth, is Mars. Mars has 50% of the sunlight that Earth. Owing to the lower sunlight level, it is colder than Antarctica. The atmosphere is equivalent to taking ours, then systematically deleting every molecule that isn't carbon dioxide without replacing it with anything else. Owing to the combination of low partial pressure and low temperature, half the atmosphere condenses into the polar caps each Martian winter. The ground is more toxic than an actual, literal, superfund cleanup site. It is drier than the actual, literal Sahara. The lack of oxygen in the atmosphere means there's no ozone layer. The lack of ozone layer, the thin remaining atmosphere, and the lack of magnetosphere, means it's a high-radiation environment. PV there also gets regularly covered in dust. Our moon is even less hospitable, owing to no atmosphere at all and being tidally locked with Earth. Venus has an atmosphere so dense that it has gone beyond the critical point where gas and liquid cease to be distinguishable, so you could reasonably also describe it as an ocean. An ocean of 465°C supercritical CO2 in which lead occasionally condenses onto mountaintops. -- There's three currently achievable ways to transport power through space at scale. Optical, microwave, or kinetic. Optical is either a bunch of mirrors or a laser on the sending side, with a normal PV system on the receiving side. Usual caveats apply, Earth spins so it has a relative night, doesn't work through clouds, maximum power density before PV systems overheat etc. All EM systems, microwave and optical, share a constraint about focussing: minimal size of target depends on the size of the antenna and the wavelength used. Because microwaves are so much longer (no much freedom to choose a different wavelength as there's a limited atmospheric window), the normal suggestion for ground stations is a 10 km diameter receiving rectenna — that's contiguous, you don't get PV's advantage of being able to split it up. Kinetic currently means an RFG — launch it e.g. electromagnetically towards a similar coil on the ground that decelerates it to extract the energy. This is theoretically possible and would totally work, but to be clear: it's shooting a bullet into the barrel of another gun, and this is not something we have a lot of experience doing, certainly not at scale or for the purposes of power generation.
- 1propionyl 2y ago
  > livable habitats beyond Earth Fetuses do not properly develop in the womb outside of Earth gravity. Sorry. End of the road for that sci-fi pipe dream.
  - ETH_start 2y ago
    Artificial gravity can easily be created through centrifugal force.

notfed 2y ago

> That can all be harvested. Can it? How?

aqueueaqueue 2y ago

We don't have tech to do that and I cannot see it happening this century

ETH_start 2y ago
Starship will reduce the cost to send a kilogram of mass into orbit by ten to a hundredfold, meaning the cost will come down to something in the order of $100 or even down to $20 per kilogram, from its current cost of $1,500. This is not science fiction, this is totally feasible in the foreseeable future.
- gf000 2y ago
  And then what, you put up a cable to it able to withstand the whole atmosphere? Also, what about space debris hitting it, rotating the panels? Each one will be able to align properly or do they need a way to self-align? Do you think any of that will be able to compete with... A dumb panel here on Earth that itself continues to be cheaper each year, or more efficient production lines requiring less power to begin with?
- aqueueaqueue 2y ago
  We don't need to do this. Just put the panels on this planet. And fix the politicians brain worms / fear of other politicians with brain worms. If we can't get a solar panel on our roofs I can't see the impetus to get them up past the moon.
ben_w 2y ago
I can see it happening, compounding growth has a way of doing that. But, given how we keep rushing into predictable disasters, I now expect to live to experience personally, first hand, a K2-level Kessler cascade from the inside. When people figure out the missing parts of VN replicators, that all happens over a handful of decades.

lodovic 2y ago

Don't discount the energy and materials required to build that Dyson sphere