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Wouldn't you just use earthlight and normal solar panels? The internet says moonlight is 1/345th the power of sunlight but once you factor in Earth's larger rad

Wouldn't you just use earthlight and normal solar panels? The internet says moonlight is 1/345th the power of sunlight but once you factor in Earth's larger radius and larger albedo you get 1/9th the power of sunlight. IE you just use 10 times as many solar panels to get you through the night.

jhgb 5y ago
> The internet says moonlight is 1/345th the power of sunlight but once you factor in Earth's larger radius and larger albedo you get 1/9th the power of sunlight. That sounds weird. As per Wikipedia, Sun's apparent magnitude is around -26.7, full Moon's is -12.7, so the Sun is 400000 times brighter than the Moon under the best circumstances. Earth being larger can't correct this by three orders of magnitude.
lovemenot 5y ago
Even if you are off by orders of magnitude, there may still be a useful thought in here. Find a large symmetrical crater pointing directly at Earth. Silver its surface with very cheap to transport BoPET (Mylar). Once installed, there's no need to worry about the sheets flying off or dust blowing over since there is no wind. Place a solar / thermal collector at the crater's focal point. Reap power from earth-light. If you choose a large crater, an MVP system can go live with just a small collector and small portion of the crater silvered. It can subsequently scale as your growing operations demand more power. It can do double-duty in broadcast communications too.
- shkkmo 5y ago
  You won't ever be able to concentrate eartlight enough to start a fire... I doubt that you can get any real power generation from such a system.
  - lovemenot 5y ago
    We don't need the heat for fire. Maybe for comfort though. The moon gets mighty cold at night. Its temperature range is about 80 to 370 Kelvin. You could use the same kit to radiate away some of that intense daytime heat too. Spread it across all of Earth. Now as to solar PV, in principle it might be doable I guess. But I am not able to make the necessary calculations. How large would the crater need to be for 10MW say? Even as a heat engine, you might get useful power out. If you could achieve say 150 - 200 celsius difference between your concentrator and night time temperature of the surrounding rocks. Which rocks serve as both the engine's heat-sink and a relatively comfy foundation for your habitat.
    - lovemenot 5y ago
      Finally, how cool it would be for someone on Earth to look at that crater with a telescope. Especially when an astronaut turns up at its focal point.
shkkmo 5y ago
> moonlight is 1/345th the power of sunlight I'm pretty sure you are off by several orders of magnitude here as all sources I find list the sun as ~400,000 times brighter than the moon. https://what-if.xkcd.com/145/ https://what-if.xkcd.com/145/

jhgb 5y ago

> The internet says moonlight is 1/345th the power of sunlight but once you factor in Earth's larger radius and larger albedo you get 1/9th the power of sunlight. That sounds weird. As per Wikipedia, Sun's apparent magnitude is around -26.7, full Moon's is -12.7, so the Sun is 400000 times brighter than the Moon under the best circumstances. Earth being larger can't correct this by three orders of magnitude.

lovemenot 5y ago

Even if you are off by orders of magnitude, there may still be a useful thought in here. Find a large symmetrical crater pointing directly at Earth. Silver its surface with very cheap to transport BoPET (Mylar). Once installed, there's no need to worry about the sheets flying off or dust blowing over since there is no wind. Place a solar / thermal collector at the crater's focal point. Reap power from earth-light. If you choose a large crater, an MVP system can go live with just a small collector and small portion of the crater silvered. It can subsequently scale as your growing operations demand more power. It can do double-duty in broadcast communications too.

shkkmo 5y ago
You won't ever be able to concentrate eartlight enough to start a fire... I doubt that you can get any real power generation from such a system.
- lovemenot 5y ago
  We don't need the heat for fire. Maybe for comfort though. The moon gets mighty cold at night. Its temperature range is about 80 to 370 Kelvin. You could use the same kit to radiate away some of that intense daytime heat too. Spread it across all of Earth. Now as to solar PV, in principle it might be doable I guess. But I am not able to make the necessary calculations. How large would the crater need to be for 10MW say? Even as a heat engine, you might get useful power out. If you could achieve say 150 - 200 celsius difference between your concentrator and night time temperature of the surrounding rocks. Which rocks serve as both the engine's heat-sink and a relatively comfy foundation for your habitat.
  - lovemenot 5y ago
    Finally, how cool it would be for someone on Earth to look at that crater with a telescope. Especially when an astronaut turns up at its focal point.

shkkmo 5y ago

> moonlight is 1/345th the power of sunlight I'm pretty sure you are off by several orders of magnitude here as all sources I find list the sun as ~400,000 times brighter than the moon. https://what-if.xkcd.com/145/ https://what-if.xkcd.com/145/