Why isn't the moon considered a planet?

Answer 1

While we don't yet have a good definition of a planet, a planet is considered to be something that orbits the Sun on it's own, while a moon is something that orbits something that orbits the Sun. Asteroids can (and do) have moons, to my knowledge there are no moons with their own moons.

Actually, some space scientists think that Earth and the Moon should be considered a double planet system, since they are so similar in size (compared to, say, Jupiter and any of its moons). But since they didn't form at the same time (the Moon formed due to a huge collision with Earth) this idea probably will never catch on.

Answer 2

This is actually a very good question, especially in light of the numerous answers that have been dead wrong.

If you want to do a little math exercise, you should use Newton's Law of Gravity and calculate the gravitational attraction between the moon and the sun and compare it to the attraction between the moon and the earth.

You will find that the moon is more strongly attracted to the sun than it is to the earth! That is right, if the earth and the sun were to part ways, the moon would stay with the sun (assuming it survived the tidal forces).

If you plot the moon's orbit out on paper, you will find that at no time does the moon's orbit every convex away from the sun. At all points, the moon is concave towards the sun.
On the other hand, during a new moon, the moon's orbit is convex away from the earth.
The moon's orbit looks very much like a dodecagon (a 12 sided polygon) where the angles are wher the moon is at the full moon stage and the earth and sun are pulling in the same direction, and the flat sides are at the new moon stage and the earth and sun oppose one another.

One of the other answers has it mostly right in that the moon and the earth are technically coorbiatal bodies and (also technically) the moon qualifies as a planet. But can you imagine how problematic it would be to change everyone's minds on that matter?

In the end it will all get down to what is the definition of a planet. And at this point in time, based on current criteria, the moon is a planet, albeit a coorbital planet that is tidally locked to a sibiling.
But 99.99% of the people do not know this bit of trivia, and so the label of satellite remains.

Answer 3

Planets are near spherical objects that orbit a star. Although the moon indirectly orbits the sun (our star), it only does so because it directly orbits a planet (the Earth). Objects that obtain a regular orbit around a planet (and are smaller than planets) are satellites.

Official definition for a planet: "A nonluminous celestial body larger than an asteroid or comet, illuminated by light from a star, such as the sun, around which it revolves."

The latter part of that definition seperates what we call a planet (i.e. Earth) and a satellite (i.e. The Moon).

Answer 4

What Is Considered A Planet

Answer 5

A planet is generally considered to be a relatively large mass of accreted matter in orbit around a star. The moon orbits the Earth.

Answer 6

A satellite is an accrued mass that revolves around the planet due to the gravitational pull (G) of the planet being applied on the considerably smaller mass, satellite..

There are basically two types of satellites. Natural and Artificial. Moon is the natural satellite of earth that revolves around the earth.

A planet, however, is an accrued mass that revolves around the Sun due to the universal gravitational pull acting on the planet. The Sun's gravitational pull acts on all the 10 planets.

Answer 7

The moon orbits us, we orbit the sun. Also the moon lacks the arbitrary minimum size requirements for a planet.

Answer 8

Because the moon orbits another celsestial body besides the sun. if it were to be considered a planet it would have to have its own orbit independant of earth.

Answer 9

it was said that long ago when the formation of the planets began a massive rock collided with earth thus taking pieces of earth and slowly stopping the gigantic rock. And was stopped by gravity and formed into a sphere.Something like that i know it seems fake but i am a big fan of the science ch not sure if u know it but it explaines everything about the moon how it was made and how it formed.

Answer 10

there are over a hundred moons in the solar system some much larger than the earth's.The reason they are called moons or sattelites is because the orbit around a planet.The planets orbit the sun.That is the distinction.