Let’s say the roofs are all red, how big does it have to be to be visible as a little red dot?
http://www.waloszek.de/astro_mond_0_e.php
tl;dr: between 120 and 350 kilometres depending on how good your eyes are.
Paris is around 15km Tokyo is 90km
Whew. Don’t have to worry about them ruining the view in my lifetime!
That’s if they don’t put a giant ad on the moon. Just need a little bit of paint!
Since the Moon is tidally locked, being on the opposite side of the Moon would mean you could never see it.
Right now there might be a massive base manufacturing… Astronaut ice cream and we would never know
I was about to reply that op didn’t ask about the other side of the moon… Then you went to making astronaut ice cream!
Well played…
Or a nazi base
What movie is this from?
Iron Sky, one from the “so bad it’s good” shelf.
Thanks!
So that’s what China was doing back there! Their “sample return” must’ve just been a shipment of astronaut ice cream.
Depends on how bright the lights are, and the phase.
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.
