Quote:
Originally posted by mika
Earth has one moon.
I guess there are all kind of theories:
THE moon is actually slowly moving away from the Earth - eventually this could cause it to break free from Earth's gravity -> we have 0 permanent moons
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The moon is slowing moving away, but slowing down. It will eventually stop. This is because the moon is slowing the rotation of the earth from tidal forces, as the earth successfully occomplished on the moon. It has a tidal lock on the moon - the forces of gravity on the near side are greater than the forces of gravity on the far side. The process of this lost energy of rotation is translated into distance of angular momentum. When the rotation slows and stops, so will the increased radius of the moon's orbit. The only way we'd lose the moon is if it moved far enough away that another planet grabbed it away... it can never escape earth's gravity any other way. Even if there was an explosion on the moon, like in some movies, we wouldnt lose the moon unless it accelerated at escape velocity (11 km/sec), or unless it got far enough away that another planet's gravity was stronger than earth's and took it away.
Besides, it wasnt meant as a trick question - the moon is there, it's real, it's at least 1 moon, so i shouldnt have put the option of '0 moons' - my apologies. it must have made people think it wasnt serious, so that was dumb.
Quote:
Originally posted by mika
On the other hand -> thousands of satellites do orbit earth. Are they permanent? yes, some are as permanent as the moon. Are they as big? No. But define big ENOUGH.
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Definition:
moon (mn)
n.
A
natural satellite revolving around a planet.