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We tend to discuss (understandably) how we don't see the far side of the Moon, discuss the difficulty of the "radio shadow", and are delighted to occasionally s
by ctdonath 11y ago
We tend to discuss (understandably) how we don't see the far side of the Moon, discuss the difficulty of the "radio shadow", and are delighted to occasionally see pictures thereof.
Consider the reverse: someone (yes, hypothetically) living their life on the far side of the Moon would be completely unaware their quiet home is just 1.3 light-seconds away from a brilliantly reflective orb teeming with life.
- mediumdeviation 11y agoWell, all Moonies have to do to see the Earth is to travel to the opposite side of it, whereas to do the opposite from Earth requires launching a vehicle out of the planet's atmosphere, across the orbit of the Moon, and back to Earth again. Granted, it wasn't until several hundred years ago that Earthlings began to circumnavigate the globe, but the technology to travel long (cross-continental) distances have existed since ancient times.
- TomSawyer 11y agoMoonies is not the preferred nomenclature — Mooninites, please.
- bottlerocket 11y agoOn the moon nerds get their pants pulled down and they are spanked with moon rocks.
- the-dude 11y agoYou're not wrong...
- Rotten194 11y agoMoonmen, please.
- ewams 11y agoWouldn't at most they just have to move a quarter across the moon? Just thinking out loud.
- malnourish 11y agoI think at most is incorrect, they could travel in the wrong direction.
- Jtsummers 11y agoThe 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 agoBut 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 agoIf 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 agoAh, 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 agoFrom 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.
- david-given 11y agoAt one point there was a theory that there was another Earth, in the same orbit as ours, but diametrically opposite so that it was always hidden by the Sun. There may actually be one. I'm not aware of anyone who has wasted expensive spacecraft time, energy and bandwidth to point an instrument in that direction to look.
- breadbox 11y agoIf there was anything of any size there, we would be able to measure its effect on the rest of the planetary orbits. Also, it would not be in a stable orbit, and would eventually either get ejected from the solar system, move into a different, stable orbit, or intersect with us (as Theia presumably did).