Mars at Sunset


    • Not our moon, I think. Closest distance to Mars is about 30 million miles, which is 120 times the distance to our moon. Imagine the triangle this forms. You’d need binoculars or sharp eyes on the surface of Mars to see the two objects as separate.

      • It’s our Moon. It would be clearly visible to the naked eye on Mars. This is a significant though not pivotal plot point in my famous as-yet-unwritten Mars trilogy.

        No other moons are naked eye visible from Earth; if they had been solar system astronomy may have progressed more rapidly.

  1. It also depends which way up the picture is. I’m guessing the Rover in somewhere near the Mars equator, so the Earth/Moon ecliptic plane is at 90 deg to where we’d expect it to be, so it’s probably our Moon. If the Moon was either fully ahead or fully behind Earth, on either of its quarters as seen from us, then it would be about 1 degree of arc shifted from the Earth either “up” or “down” in the picture. The Moon otherwise might be “full” as seen from us in which case seen from Mars it would be invisible, or else it would be a “New Moon” seen from Earth in which case it would also be invisible from Mars. I’m assuming Mars is somewhere more or less “behind” Earth relative to the Sun in these pictures. If Mars was a bit ahead or behind the Earth in orbital terms, then partial monnphases would be visible from Mars at various brightnesses and angular separations.

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