the great planet debate ?

Question

-for me planet something that have a round shape and rounding the sun..
what is the definition of a planet in your oppinion ?

Answer 1

General question. What makes a planet a planet? Is it the mass? Diameter? Orbit? Distance from the sun?

I would say that the following are minimum characteristics of planets.

1 & 2 below are arbitrary, you may prefer other variables.

1. Minimum Mass. 10^20 Kg. (about 1/100th the mass of Pluto).
2. Minimum Diameter. 1,500 Km (about 900 miles)
3. Orbit. Must be in orbit around a sun, and not a planet (therefore, Luna is not a planet, even though it's larger than Pluto).
4. Distance from sun. Not relevant, as long as it is clearly in orbit around the sun. Therefore, a massive sun may have planets dozen's of light-years away.
5. Is not itself a sun. That would be a binary or higher system.
6. Must not be in interstellar space, not associated with a sun or suns.
7. Not in a field of other bodies with the same approximate orbit. That would leave out anything in the Asteroid Belt and Oort Cloud.


Now, how about "Xena" (aka, 2003 UB313)? To Hades (Greek God of the underworld) with conventions for naming planets. Xena is perfect. And Gabrielle for the moon.

Answer 2

When the sun forms there will be a huge disk of mateiral which all planets are made of surronding it. That material will eventuall form the REAL planets.

The remaining material will become either asteroids, comets or become the Oort Cloud. The great planet debate is about Pluto.
Now Pluto orbits in the kuiper belt, which makes it a 'kuiper belt object'. Now pluto might be a planet, but it might be a rather large circular rock which is sopposedly a kuiper belt object.

Outside the kuiper belt is another planet, Redna, which is said to be much bigger than pluto.

PLANET:
A planet is generally considered to be a relatively large mass of accreted matter in orbit around a star. A mass that becomes massive enough to undergo nuclear reactions is considered a star, not a planet. Based on historical consensus, the International Astronomical Union (IAU) lists nine planets in our solar system. However, since the term "planet" has no precise scientific definition, many astronomers contest that figure. Some say it should be lowered to eight by removing Pluto from the list, while others claim it should be raised to ten or even higher depending on how planets are categorized.

Answer 3

Does Pluto have gravity? Does it have a moon? Is it relatively round? Is it imagined that it was formed in the same way as Mars, Jupiter, etc? Does it have an atmosphere? Are they calling some objects in space planets when they are not in orbit around a star? Geeze.

Isn't this a form of descrimination? Do we need to keep an eye on these guys who obviously have latent superior attitudes?

Little people unite. Some are trying to say you not people because you are little when you have all of the characteristics of people.

If the sun expanded to the point where the only place the few remaining people could get too to live was Pluto, would they turn it down?

Does anyone want to pay scientists to sit around and argue about this? Tell them to get back to the work of saving mankind.

Who is man to decide what planets the sun wants to maintain in its orbit?

Answer 4

I like the idea that anything that has enough gravity to make itself round, and that orbits the sun instead of another planet, is a planet. Short and simple.

Of course, this creates a few oddities in that some moons of Jupiter or Saturn might be larger than some planets (like Pluto), but who cares?

Answer 5

There IS a planet debate: should we declassify Pluto to be a planet?
The recent discovery of Xena has put de debate on the table once more.
If scientists cannot find an exact definition of a planet, who are we to try to answer?
Nevertheless, I would say that any relatively big object orbiting a star would be a planet, and any relatively big object orbiting a planet is a moon, but then you would tell me that hubble telescope (relatively big), orbiting the Earth (orbiting a planet) is then a moon!!!

Answer 6

My definition for a planet is:
A Planet is a heavenly body which moves around a star. It can be rocky, icy, only air or probably full of living things! However, a planet isn't perfectly round like it's orbit.

Answer 7

I think it should be the size(mass) and how it moves around the sun. The Kuiper belt has 15 "planets" and it starts after our 8th planet. I think it should say the belt has "dwarf planets" in it. Xena is bigger than Pluto, but both are smaller than the moon.

Answer 8

I like the idea of sub-dividing our solar system into separate classes, so we would have something like (in order of distance from our sun):

- Rocky planets (Mercury, Venus, Earth, Mars)
- Asteroids (Ceres, Pallas, Vesta etc)
- Gas Giants (Jupiter, Saturn, Uranus, Neptune)
- Kupier Belt object ("Xena", Pluto, Sedna, Quaoar etc)

This is not without precedence. When Ceres, the biggest of the asteroids, was discovered it was named as a planet. It was later reclassified as an asteroid when more and more of them were discovered.

Answer 9

Anything that blots out the sun ie my Womans Behind its the size of a planet.

Answer 10

a planet is a body in space that circles a star sometimes they are round but sometimes they are other shapes