what is the latest news about the number of accepted planets?Is pluto out?Is sedna in?

Answer 1

The latest news about the number of planets accepted is 8.Yes Pluto is out but sedna is not yet accepted.

Answer 2

the planets are mercury, venus, earth, mars, jupiter, saturn, uranus, and neptune.

http://www.iau.org/fileadmin/content/pdfs/Resolution_GA26-5-6.pdf

pluto is not a planet. pluto and charon are considered 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.

the international astronomical union never considered classifying "90377 sedna" as a planet. before the 24 august 2006 vote, the iau committee assigned to draft the definition for the word "planet" seems to have considered classifying "1 ceres", "136199 eris", and charon as planets, but the the general convention preferred a definition that excluded them and "134340 pluto".

http://en.wikipedia.org/wiki/Pluto
http://en.wikipedia.org/wiki/90377_Sedna

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 several discoveries. 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 3

According to my sons science teacher there are only 8 at the moment, which is also what was on the science channel 2 days ago. Pluto has been demoted to "Dwarf Planet" and Sedna is under discussion but not accepted as of yet.

Answer 4

It isnt the first time that a solar system body has been declassified as a planet.

In antiquity the Sun and Moon were thought of as planets but lost their status. with the acceptance of the Copernican sun-centered Solar System (and the earth gained that status) (16th Century).

Since then only 2 other bodies have gained that status and kept it: Uranus )1781) and Neptune (1846).

But 25 others have gained and lost it if we include 9 bodies that were written about as planets by their discovers (Io, Callisto, Europa, Ganymede, Titan, Rhea and Iapeter) (17th Century) or the newspapers (Xena and Sedna) (21st Century) although not officially regarded as such.

The first seven became known as moons, as more were discovered. 15 bodies between Mars and Jupiter were classed as planets on discovery but later demoted to asteroids) (19th Century) as more were discovered. Pluto and Xena became demoted to dwarf planets as more objects beyond Neptune were discovered.

Sedna is classed as an extended scattered disk object as its orbit takes it out to 975 AU at aphelion, but may yet be accepted as a dwarf planet when they have checked it for roundness (one of the new criteria).

In total 30 objects gained or had planetary status in the last 500 years and 27 of them have lost it again, which added to Mercury, Venus, Mars, Jupiter and Saturn which have been planets sincve antiquity, makes 8 planets now. It dipped to 6 in 1543, climbed steadily to 23 in 1851, fell to 8 again, rose to 9 in 1930 when Pluto was added and fell back to 8 again when Pluto was dropped in 2006,

Expect another dozen or so dwarf planets to be declared as such in the next few years but for more planets, look to other stars for these, We have found over 200 already.

Answer 5

Pluto is no longer a planet. Sedna is not considered an official planet yet. So 8.

Nasa described Sedna this way: " a mysterious planet-like body orbiting our Sun"

Answer 6

Pluto (officially designated 134340 Pluto) is the second-largest known dwarf planet in the solar system.

Sedna and Pluto are both now grouped as Kuiper Belt objects.

Answer 7

Not only have we found stars with planets around them, some nearby stars have now been found to have an asteroid belt around them, and much more massive than our own asteroid and Kuiper belts, it is, too. So an exercise in distinguishing planets from dwarf planets may well be need as regards the objects in those extra-solar asteroid belts, as well as in our own, when we glean more information about them.

As a first step the IAU has decded that to be a planet in another star system, a body shall be at least the size that a planet has to be in our solar system (but they haven't defined what that lower limit is, yet!) But at a goess, they mean a lower limit of bigger than Pluto and smaller than Mercury.

Watch this space!

Answer 8

No Pluto has been replaced by Goofy

Answer 9

there are 8 planet :Mercury ,Venus ,Earth,Mars ,Jupiter
,Saturn ,Uranus ,Neptune .

but I miss pluto

Answer 10

only pluto is out