There are 8 Planets now. What are the basis for inclusion or exclusion of a heavenly body in the planet list?

Answer 1

some consider pluto and charon to be a binary system, but two small bodies orbit this system. they are called nix and hydra. this does not change anything about the solar system or pluto. it just corrects the mistake of classifying pluto as a planet initially.

http://www.iau.org/fileadmin/content/pdfs/Resolution_GA26-5-6.pdf
http://en.wikipedia.org/wiki/Pluto

pluto orbits the sun, is round, does not have an isolated orbit (a bunch of other similar bodies have similar orbits.), and is not a satellite so it is a dwarf planet.

this same thing has happened before. beginning in 1800, astronomers found a few bodies orbiting between the orbits of mars and jupiter, and they finally stopped calling them planets after the fourth discovery. astronomers then added numerals to the names, and pluto recently got its numeral. 150 years from now, no one will think of "134340 pluto" as a planet. very few will even know we classified it as a planet. "1 ceres" and "136199 eris" are other dwarf planets.

i have been waiting for this since i was about twelve. i feel somewhat satisfied. i knew that pluto didn't fit the pattern set by the major bodies in the solar system so it was an anomaly. it just felt illogical and "out of place". this was the right thing to do, believe me. i don't understand why so many are having such a problem with this.

i don't know how long this will drag on tho. many planetary scientists are not satisfied that the definition is rigorous enough.

Answer 2

The Rose Center says there is no universal definition of a planet and instead divides the solar system into the Sun and five families of objects.

"The majority of astronomers have said that unless there is definitive evidence to the contrary, Pluto stays a major planet."
"There is no scientific insight to be gained by counting planets,'' says Neil de Grasse Tyson, director of the Hayden Planetarium, the centerpiece of the Rose Center. "Eight or nine, the numbers don't matter

Answer 3

The International Astronomical Union (IAU), the official scientific body for astronomical nomenclature, currently defines "planet" as a celestial body that, within the Solar System,

(a) is in orbit around the Sun;
(b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape; and
(c) has cleared the neighbourhood around its orbit;

or within another system,

(i) is in orbit around a star or stellar remnants;
(ii) has a mass below the limiting mass for thermonuclear fusion of deuterium; and
(iii) is above the minimum mass/size requirement for planetary status in our solar system.

For easy understanding criterea that makes a heavely body a planet and they include,
a. They should not emit their own light but relfect light emited from another light source.
b. They should move in a eleptical path around the sun(the light source)Heavenly objects that go a round a light reflecting body is called a sattelite.

c. Their paths should be in the sameplane as the other planets.
d. Enough mass.

The reasons why they stripped pluto of teh planet status is because it was too small to be a planet and it had a different path around the sun. Pluto's path was not in the same plane as that of other planets.

Answer 4

9 planets. Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, Pluto. A planet must have a regulated surface. Pluto may not be a planet, just an asteroid. They still think about that

Answer 5

THE FOLLOWING ARE THE REASONS FOR NOT CONSIDERED AS PLANET:

1.PLUTO IS TINY IN SIZE
2.OFF BEAT ORBIT
3.ORBIT IS NOT LIKE PLANETS
4.PLANET STATUS NOT GIVEN AS ON 24/08/2006

Answer 6

its true but acc to sceintistthere are 8 planets and acc to astrologers there are still 9 planets and dont know the reason sorry

Answer 7

Size matters!

Answer 8

Who cares? Like, it makes a difference in my life - in anybody's life?

Answer 9

it has its own orbit around a sun

Answer 10

exclusion