4 ms·

Wouldn't at most they just have to move a quarter across the moon? Just thinking out loud.

• malnourish 11y ago
  I think at most is incorrect, they could travel in the wrong direction.
  • Jtsummers 11y ago
    The furthest they could be is a point exactly center of the far side of the moon. If they travel along a great circle, they'd only have to travel a distance equal to one quarter to the moon's circumference to be able to see the Earth.
    • klodolph 11y ago
      But they'd have to know which direction is the correct direction, and they wouldn't know which direction is correct until they knew where the Earth was.
    • avmich 11y ago
      If they live not at the center of the far side - and if they choose the wrong direction (because how should they know?) - they can travel more than a quarter of the moon great circle.
      • Jtsummers 11y ago
        Ah, good point. So really the at most is `0.5*circumference - epsilon` (starting just on the far side). In the worst case, if they manage to stay on a great circle.
        • emiliobumachar 11y ago
          From the article: "Owing to various view angles from different parts of the Earth, the most ambitious jet-setting astronomer could have seen a maximum of 59 percent of the surface of our planetary companion. " If we take into account that fact that Earth is not a point, then epsilon is not so tiny after all, it's around 0.045 times circunference. This would make the final result 0.455 times circunference.