Skip Navigation
InitialsDiceBear„Initials” ( by „DiceBear”, licensed under „CC0 1.0” (
Posts 2
Comments 171
How large would a city/base on the moon have to be in order to be visible with the unaided human eye from earth?
  • Someone's already given an answer for a non-illuminated structure, but the necessary brightness of a light to be visible is also an interesting question.

    We'll assume the light is located on the dark portion of the Moon. From experience, the dimmest stars clearly visible with the naked eye when right next to the Moon are around magnitude 1, which is about 3.6x10^9 photons/sec/m^2.

    If we focus the light on the near hemisphere of the Earth (which has an area of 2.5x10^14 m^2) we need to produce 9x10^23 photons/sec. A green photon has an energy of around 3.7x10^-19 joules, so the total power output is 9x10^23 x 3.7x10^-19 = 333 kW.

    For reference, this is roughly comparable to the wattage of the fastest electric car chargers. It's a lot of power, but well within the capability of a small lunar solar farm.

  • PSA: GoDaddy gated their own API. DDNS users warned
  • If you're looking for a new registrar, I've had only good experiences with NameSilo. They're not the cheapest, but they're generally cheaper than GoDaddy, don't paywall arbitrary things like APIs or WHOIS privacy, and have good support.

  • A cool guide about Rain on different worlds
  • The source for that seems to be this. This is what it says:

    Intriguingly, the temperature of OGLE-TR-56b's upper atmosphere is theoretically just right to form clouds, not of water vapor, but of iron atoms. Earlier this year, astronomers reported evidence for iron rain on brown dwarfs. However, such storms only occur over a short portion of a brown dwarf's lifetime, while the newly discovered 4 billion year-old OGLE-TR-56b should still be experiencing this exotic weather, thanks to strong heating from the nearby star.

  • One of my shots of the eclipse.


    A wind turbine during sunset