Would a moon in geosynchronous orbit have phases? (more)?

Question

How would it affect tidal patterns? what other effects would it have on the host planet? What about eclipses?

Im in the process of writing a Sci-Fi book and want the Sci portion to be in the very least believable if not factual as we today understand science and the universe

Answer 1

The most obvious effect would be that it would not be visible from all parts of the planet. Only half the hemisphere would be able to see it and that it would be in always at the same ploint in the sky. Phases sould be there. Now how they would be ... hmmm you need to run a simulation to check it out.

The fact that it would be in geosynchronous orbit and the same mass proportion between earth and moon stand it means that it would probably had been much further away than the current earth moon distance and the gravitational effects like tidal effects would have been a lot less. I will calculate this distance when I and edit this answer later.

One other thing i could think is that the side of the earth that never gets the moon might have been a bit more valnuareble to meteors. So you would get much more meteor showers there. Also the animal life would be acting different.

Answer 2

The only way a geosynchronous orbit stays in one position in the sky is if the orbit is in the rotational plane of the planet. If the planet has an axial tilt, the plane of the geosynchronous orbit will be different than the orbit of the planet around the sun. In this case, there will only be 2 eclilpses a year - during the spring and summer equinoxes. During the other times, if you sketch out the orbits, the moon's orbital path will never come directly between the sun and the planet.

As someone mentioned earlier about tides, there would be no tides, just a bulge. However, the bulge would be pretty big - in Earth's case, the geosynchronous altitude is 1/10 the distance to the moon, meaning the gravity exerted by the moon on the Earth would be 100x greater! If you wanted to be creative, you could even argue that given a moon of enough mass compared to the planet, the area under the moon would have less gravity.

Hope some of this helps and good luck with your book.

Answer 3

Well if you lived on the part of the planet directly below the moon you would have a full moon every night at midnight and possibly an eclpise every day at noon(if it was in perfect line with the sun and earth). People living in the opposite hemispere would of course never see the moon.

In response to Sparodic, actually the moon would have to be much closer in order to achieve geosynchronous orbit.(1/28th the distance?)


BTW if the moon still has the same side always facing earth (like it does now) then a lunar day would be the same length as an earth day.

ECLIPSE UPDATE: Even though the moon would be moving through the sky 28 times faster it would also be 28 times larger
making the eclipse duration the same.

Answer 4

A moon in geosynchronous orbit would indeed have phases. The greatest difference from the natural moon is that it would pass through all its phases in 24 hours. It would be full at midnight (if it was not in the planet's shadow) and new at noon.

The tidal effects would depend on its mass and high tide would always be over the same spot of the ground, as well as the antipodes (the opposite side of the planet).

Eclipses would depend on its apparent diameter and the inclination of its orbit.

Answer 5

Such a Moon would have phases, but it would go from new to full and back to new once a day instead of once a month.

It would cause no tides. It would cause a bulge on the Earth, just as our real Moon does, but that bulge would not move around the Earth, it would stay in one place and so sea levels would never change because of it.

Also, there would be places on Earth were it never appeared in the sky. Anything in geostationary orbit stays over one spot on the ground and on the other side of the globe from that spot it would never be above the horizon.

There could be eclipses if it was the right size, but they would be really short, 28 times shorter than the real Moon causes, because it would be moving 28 times as fast as it passed the Sun in the sky.

Answer 6

If you lived dierctly below the moon I would think that it would go through all of it's phases over the course of a single day cycle.
If you lived at an angle from the moon it would go though the appropriate amount of phases. For instance, someone who lived at about a 45 degree angle from the moon may see the new moon, wax to full moon, and see an accelerated waning.
There would be a solar and lunar ecclipse guaranteed twice a year, assuming the world would "wobble" like the Earth does.

Answer 7

ACCORDING TO ME IT WOULD NOT AFFECT TIDAL PATTERNS
NO MOON IN GEOSYNCHRONOUS ORBIT MIGHT HAVE FACES BECAUSE IT DOES NOT DEPEND ON THE POSITION OF THE SATELLITE BUT THE DAYS TAKEN BY MOON FOR ITS ROTATION OR REVOLUTION