2006-09-13 11:40:23 · 17 answers · asked by Anonymous in Science & Mathematics ➔ Astronomy & Space
They are all planets?? They all orbit around the sun?? there are loads of possibilities..
2006-09-13 11:42:19 · answer #1 · answered by Anonymous · 1⤊ 0⤋
There are only eight planets, according to the definition put forth by the International Astrophysical Union. Pluto is now a "dwarf planet".
They all have in common that they
1. Orbit the Sun (but the Hipparcos space probe, which orbits the Sun, is not a planet)
2. Do not orbit another planet (so the Moon and Ganymede are not planets, even though Ganymede is almost as big as Mercury)
3. Are larger than the total of everything else in its orbit's vicinity combined.
To me what they have in common is that their mass is between 200 exatons and 13 Jupiter masses (about 26 yottatons - where by "ton" I mean metric ton). This type of definition would be usable for extrasolar planets.
2006-09-13 12:55:33 · answer #2 · answered by alnitaka 4 · 2⤊ 0⤋
Well, There are eight planets now unfortunally .. Sorry to disappoint you, but pluto has been downgraded to dwarf planet.
Three things the 8 planets have in common:
1) The orbit the sun
2) They have cleared thier orbits from other objects.
3) They have enough mass to be spherical under it's own gravity.
Other things
1) They have moons like Earth, Mars, Jupiter, Saturn, Uranus.
2) Some are rocky, some are gassy, and some are icy.
3) All of them do not support life, except Earth :)
Hope that helps ;)
2006-09-13 12:05:05 · answer #3 · answered by Duda .. 3 · 2⤊ 0⤋
Things About Planets
2016-12-16 10:45:13 · answer #4 · answered by deibert 4 · 0⤊ 0⤋
The 8 (not 9) planets have the following in common:
1. All are in orbit around the sun.
2. Its mass is so that gravity forces it to assume hydrostatic equilibrium (spherical shape).
3. Has cleared its neighborhood around its path, excluding natural (moons and minor asteroids) and man-made satellites.
Other things that SOME planets have in common with each other:
1. 6 of the 8 planets have atleast 1 moon (Mercury and Venus have none).
2. 4 planets are considered "terrestrial" planets (Mercury, Venus, Earth, and Mars).
3. 4 planets are considered "gas giants" (Jupiter, Saturn, Uranus, and Neptune).
2006-09-13 12:01:45 · answer #5 · answered by T F 3 · 1⤊ 0⤋
Mercury, Venus, Earth and Mars are rocky planets. Jupiter and Saturn are Gas Giants. Neptune and Uranus are Ice planets (as was Pluto when it was considered a planet) It can't be their makeup. Most but not all have satellites (moons), Saturn and Pluto have rings, Pluto's rings are tipped up sideways. They each have a different orbit and orbital period. Pluto and Neptune eventually cross paths so that Pluto is not always the most distant body (can't call it a planet any more). Gee; I don't know. Perhaps they were born of the same stuff that makes up our entire solar system maybe?!
Let me know when you figure this one out.
2006-09-13 11:52:57 · answer #6 · answered by tercir2006 7 · 1⤊ 1⤋
Defition of planet.
1) Orbits the sun
2) Is large enough to be spherical under the force of its own gravity
3) It has cleared its orbit of other objects.
Pluto failed on the last count.
2006-09-13 11:51:02 · answer #7 · answered by Dr GH 2 · 2⤊ 0⤋
There alre only 8 planets. Pluto is not cosiderd a planet anymore.
2006-09-13 11:42:30 · answer #8 · answered by Anonymous · 1⤊ 1⤋
(1) All eight of them are approximately spherical in shape
(2) None of the eight are sufficiently massive to start deuterium fusion in their core (ie they are not brown dwarf stars)
(3) They all eight rotate round a star or a stellar remnant
(4) Since, they were formed, all eight of them have swept their path clear of other objedts and debris
The above 4 points qualify them as planets under the latest IAU definition of a planet agreed on 24th August in Prague.
In addition
(5) they all rotate and spin on their axes
(6) seven of them have a "year" that is longer than their "day" (the exception is Venus)
(7) the axes arounf which they spin of seven of them have a small angle of inclination (the exception is Uranus)
(8) seven of them have names based on Greek or Roman deities (the exception is the Earth)
(9) six of them have been known since antiquity ((the exceptions are Uranus and Neptune)
(10) six of them have one or more moons (the exceptions are Mercury and Venus)
(11) three of them have a ring system around them (Saturn, Uranus and Neptune)
(12) their orbits are co-planar and none of them is markedly eccentic.
2006-09-13 12:15:27 · answer #9 · answered by Not_many_people_know_this_but 3 · 2⤊ 0⤋
We only have 8 planets now.
They all orbit the sun, they each cleared their orbit, they're big enough to have a gravatational influence, they're big enough so that their gravity made them into a sphearical shape.
2006-09-13 12:11:31 · answer #10 · answered by Anonymous · 0⤊ 0⤋