On the Motion of the Moon in the Margaret Wise Brown Classic "Goodnight Moon"
Please observe the following composite image, taken from several different exposures of the moon.
It is clear from the non-linear motion of the moon across the sky that the orbit of the moon is not a simple ellipse. This is probably because the planet inhabited by the race of sentient bunny-like aliens (henceforth: Planet Bun) is probably in a non-stable multi-body system. It likely involves multiple other moons, planets, and potentially stars, although we can clearly see from the view out this window that the stars must all be opposite Planet Bun from the observer. The intense gravitational forces from the other unseen bodies of the system must steer the moon in a strange path, and not in an elliptical orbit around Planet Bun.
Also, based on the fact that the pattern of the background stars changes so rapidly between each exposure, we can conclude that Planet Bun itself must be orbiting or rotating at a very high velocity. In fact, the "moon" may not be a satellite of Planet Bun at all. It could very well be a double planet or, judging by the lack of surface features, a white dwarf star that Planet Bun itself is orbiting. In fact, judging by just how quickly Planet Bun's view of the background stars changes, it may be quite likely that the "moon" is in fact a neutron star, which Planet Bun orbits in hours or minutes. The orbital distance is likely quite close in order for a small star to have such a high angular diameter.
Note also how the apparent motion of the "moon"-like neutron star speeds up between the fixed-interval exposures. This is likely because Planet Bun is in a highly-elliptical orbit and it is approaching perigee, causing the vast orbital speed increase.
One more nostalgic piece of childhood goes THBPPTH.
ReplyDeleteAssuming the "moon" is actually a neutron star, and Planet Bun is approximately earth-sized, then the distance from the window to the star is only 9,000km. Planet Bun would orbit the star every 12.64 seconds at 1.5% the speed of light in a circular orbit.
ReplyDeleteThis could explain the apparently non-linear motion of the stars and sun if the views out the window are at random intervals of time - Planet Bun could be anywhere in its orbit in the time it takes to speak a few sentences.
However, at this distance an earth-sized planet would be tidally locked by the approximately 2.6 million Gs of tidal acceleration, with the same side continuously facing the Bun Sun, so from any point on Planet Bun the sun would not normally move in the sky.
Also note that assuming the planet miraculously was not somehow ripped apart by those forces, the only place you could survive without being yanked right off the surface would be at the day/night terminator, which would place the star at or near the horizon, which is consistent with the illustrations.
If we assume a slightly elliptical orbit, then the tidal locking would only occur near perihelion, and the planet would rotate slightly near aphelion, moving the star through the sky slightly on each orbit, although this would require a mobile habitat to stay near the terminator where the G forces balance out. If the Bun Sun moves across the Planet Bun sky about as fast as our moon, stars, and sun, then this habitat would have to travel approximately 1,000 mph on the surface.
Perhaps it runs on a circumplanetary maglev rail system, which should be able to maintain those speeds since there would be no drag due to an atmosphere (sucked off the planet by the G forces). Slight deviations in the track from perfectly circular could account for any additional anomalous movement of the Bun Sun in the sky.
On the other hand, a small rabbit-operated spaceship in orbit around the neutron star would be perhaps a more plausible scenario.
Of course another perfectly logical explanation could be: that's no moon... it's a space station.
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