2006-09-20 12:02:24 · 15 answers · asked by Alan R 1 in Science & Mathematics ➔ Astronomy & Space
PLANETS IN OUR SOLAR SYSTEM: six known since antiquity. Uranus discovered 1781. Neptune discovered 1846. Eight in all.
The first 4 asteroids discovered (1 Ceres, 2 Pallas, 3 Juno and 4 Vesta) were all regarded as planets from their discovery (1801-7) till the 1860s when that status was withdrawn from them. For a while we therefore we had 12 planets.
Pluto, discovered 1930, was regarded as a planet till 24th August 2006 when it too had that status withdrawn from it and was demoted to being a dwarf planet.
DWARF PLANETS IN OUR SOLAR SYSTEM: three objects are now categorised this way: Pluto, the asteroid 1 Ceres (discovered 1801) and the object 2003 UB 313, temporarily nicknamed Xena which has now in recent days been given the permanent name Eris (after the Greek goddess of Strife and Discord) by the IAU (as has its moon Dysnomia, the daughter of Eris in the Greek myth).
Eris (diameter 2400±100 km) is a little bigger than Pluto (diameter 2306±20 km) and orbits to twice as far away at aphelion (97 AU as compared to Pluto's 49 AU). It is a Scattered Disk Object where Pluto is a Kuiper Belt Object.
There are 12 more candidates for the status of dwarf planet; six of these have names (Sedna, Orcus, Ixion, Charon, Quaoar and Varuna) two have nicknames (Easterbunny and Santa) and four just have year-and-number designations.
Sedna is perhaps the most interesting of these as its highly eccentric orbit extends to ten times as far from the sun as Eris does (975 AU at aphelion as compared to Eris' 97 AU). Sedna is variously regarded as an Inner Oort Cloud Object or an Extended Scattered Disk Object. It traverses both regions of the Solar System.
SMALL SOLAR SYSTEM BODIES IN OUR SOLAR SYSTEM: we now know of 1000 or more Trans-Neptunian Objects, (80% of these in the Kuiper Belt) discovered since 1992 (that is about 70 a year). We now know of some 338,000 asteroids, and are discovering them at a rate of 5,000 a month, Some 13,000 of these have names. It is estimated there may be somewhere between 1.1 and 1.9 million such asteroids of more than 1 kilometre in diameter.
So the Solar System is now both "getting bigger" and "filling up"!
EXTRA-SOLAR PLANETS IN OTHER STAR SYSTEMS: we now know of 200+ such planets orbiting 170+ stars and are finding them at the rate of about 20 a year. Two stars have 4 such planets, four have 3 and fourteen have 2.
The most recently discovered exoplanet is 450 light years away. The nearest is 10 light years away and the farthest is 21,500 light years away.
These are not given names, just designations. eg the 3 planets Gliese 876 b c and d orbit the red dwarf star Gliese 876 a, 15 light years away,
ASTEROID AND KUIPER BELTS AROUND OTHER STARS: in the last two years we have found a belt of such objects around the star Tau Ceti, 11 light years away (10 times as massive as our own asteroid belt) and around the star HD 69830 (25 times as massive as our own asteroid belt) which is 41 light years away, which also has 3 Neptune-sized planets in its habitable zone.
2006-09-20 14:11:47 · answer #1 · answered by Anonymous · 11⤊ 0⤋
Planet X
2016-03-26 23:39:19 · answer #2 · answered by Anonymous · 0⤊ 0⤋
Mercury Venus Earth Mars Jupiter Saturn Uranus Neptune
2006-09-20 12:37:48 · answer #3 · answered by Anonymous · 1⤊ 0⤋
this question has been answered in a ton of ways and all give the same answer. YES there are 8 planets in OUR solar system. however these aren't the only planets, in fact there are MANY planets in our galaxy... new ones just keep getting found all the time.
2006-09-20 13:33:51 · answer #4 · answered by david p-p-preut 1 · 0⤊ 0⤋
to answer ur question, right now science does not have the power or technology to do so. coz when u look into the sky and u see our sun the sun is a star, so now when u look up at the sky during night how many stars do u see? these are all suns to other solar system. the closest star next to earth is like 1,000 light years away (light years is the measurement used to measure lenght in space) having told u dis understand that we as humans do not possess the know how or technology right now to know how many planets there are in space. keep in mind, there might be many others planet like earth out there somewhere that we do not know coz space is never ending. hope dis help and informed u.
2006-09-20 12:23:12 · answer #5 · answered by Maria 2 · 0⤊ 0⤋
The planets of our solar system in order from the sun are:
Mercury
Venus
Earth
Mars
Jupiter
Saturn
Uranus
and Neptune
Recently, a panel of scientists demoted Pluto. It is no longer a planet, but a dwarf planet.
2006-09-20 14:01:10 · answer #6 · answered by Yippy 1 · 0⤊ 0⤋
There are eight planets and three dwarf planets in our solar system. Here they are in order from the sun. Dwarf planets are denoted by a "D" in parenthesis.
Mercury
Venus
Earth
Mars
Ceres (D)
Jupiter
Saturn
Uranus
Neptune
Pluto and Charon (D)
2003 UB313 {a.k.a. Xena} (D)
If we would have kept Pluto as a planet, then Xena, and Ceres, and Charon would have became planets giving us a 12-planet solar system.
2006-09-20 12:17:47 · answer #7 · answered by johnj1017 2 · 0⤊ 1⤋
There are eight planets and millions of sub-planets undiscovered the planets are:
Mercury
Venus
Earth
Mars
Jupiter
Saturn
Uranus
Neptune
Sub-planets:
Pluto
Ceres
Xena
Sedna
Ixion
Quaoar
2202Ux25
Varuna
2002tx300
2002AW197
2004 Dw
ETC,ETC,ETC,
yet to be discovered...
2006-09-20 14:05:54 · answer #8 · answered by Paul L 2 · 0⤊ 0⤋
Officially, the count is 8. Pluto and UB313 are classified as Kuyper Belt Objects.
2006-09-20 12:18:28 · answer #9 · answered by Anonymous · 1⤊ 0⤋
NINE:
Mercury, Venus, Earth, Mars, Saturn, Jupiter, Uranus, Neptune, (Pluto would go here but is no longer a planet), and Zena.
Zena was formerly UB313. Zena has a moon, and yes it's called Gabrielle.
2006-09-20 12:13:06 · answer #10 · answered by cyanne2ak 7 · 0⤊ 2⤋