Why is Pluto no longer a planet?

Question

im nin science and i need answers

Answer 1

Pluto, a planet since 1930, got the boot because it didn't meet the new rules, which say a planet not only must orbit the sun and be large enough to assume a nearly round shape, but must “clear the neighborhood around its orbit.” That disqualifies Pluto, whose oblong orbit overlaps Neptune's, downsizing the solar system to eight planets from the traditional nine.

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Pluto no longer a planet

Aug. 24, 2006
Special to World Science
Updated Aug. 25

As­tronomers from across the globe meet­ing in Prague adopt­ed a new def­i­ni­tion of “plan­et” Thurs­day. But the word­ing ex­clud­ed Plu­to, a mem­ber of the club of So­lar Sys­tem plan­ets since its dis­cov­er­y in 1930. And some re­searchers crit­i­cized the def­i­ni­tion as vague.

The de­ci­sion fol­lows years of grow­ing frus­tra­tion among sci­en­tists over the lack of a de­fi­ni­tion. New find­ings have made it in­creas­ingly ob­vious that tra­di­tion­al notions of “plan­et”—usu­ally de­scribed as a large, round bod­y or­bit­ing a star—are too fuzzy to be of much use.

Some as­ter­oids are al­most as large and round as plan­ets. And some plan­ets are al­most large and hot enough to be con­sid­ered a type of star called a brown dwarf.

Af­ter tu­mul­tu­ous de­bate in Prague, the pres­tig­ious In­ter­na­tion­al As­tro­nom­i­cal Un­ion voted to de­fine a plan­et as a ce­les­tial body that or­bits the sun; is mass­ive enough for its self-grav­i­ty to pull it into a ball shape; and “has cleared the neigh­bour­hood around its or­bit.”

Advocates of the wording argued that a planet must be the dominant object in its neighborhood.

This de­fi­ni­tion leaves eight plan­ets in our So­lar Sys­tem, as­tronomers said: Mer­cu­ry, Ve­nus, Earth, Mars, Ju­pi­ter, Sat­urn, ura­nus and Nep­tune. Plu­to is out be­cause its ob­long or­bit over­laps with that of larg­er Nep­tune.

The de­ci­sion at a con­fer­ence of 2,500 as­tronomers was a stark shift from a week ago, when the or­ga­ni­za­tion lead­ers floated a pro­pos­al that would have reaf­firmed Plu­to’s plan­etary sta­tus and made plan­ets of its larg­est moon and two oth­er ob­jects. That plan proved un­pop­u­lar.

The guide­lines ul­ti­mate­ly adopt­ed al­so did­n’t sit well with re­searchers who still hold that Plu­to is a plan­et. But they of­fered some sol­ace by cre­at­ing a cat­e­go­ry of “d­warf plan­et,” which in­cludes Plu­to. This clas­si­fi­ca­tion is sim­i­lar to the plan­et cat­e­go­ry but com­prises those ob­jects that have not cleared their or­bital neigh­bor­hood.

The dwarf cat­e­go­ry is to in­clude al­so the as­ter­oid Ce­res, con­sid­ered a plan­et in the 1800s be­fore it got de­mot­ed; and 2003 UB313, nick­named Xena, an icy ob­ject slight­ly larg­er than Plu­to.

“The clas­si­fi­ca­tion does­n’t mat­ter. Plu­to—and all So­lar Sys­tem ob­jects—are mys­te­ri­ous and ex­cit­ing new worlds that need to be ex­plored and bet­ter un­der­stood,” Lou­is Fried­man, ex­ec­u­tive di­rec­tor of the Plan­e­tar­y So­ci­e­ty in Pas­a­de­na, Cal­i­for­nia, told the BBC News.

The de­ci­sion set­tles a con­tro­ver­sy over wheth­er Xena would rise to plan­etary sta­tus, said Mike Brown of Cal­i­for­nia In­sti­tute of Tech­nol­o­gy. Brown and col­leagues an­nounced Xe­na’s dis­cov­er­y last year. “I’m of course dis­ap­point­ed that Xena will not be the tenth plan­et, but I def­i­nite­ly sup­port the IAU in this dif­fi­cult and cou­ra­geous de­ci­sion,” said Brown. “It is sci­en­tif­i­cally the right thing to do.”

Not all as­tronomers agreed. Be­sides those who in­sist Plu­to is a plan­et, oth­ers com­plain that the new def­i­ni­tion is still mud­dled.

“What ex­act­ly is meant by a plan­et ‘clear­ing its neigh­bor­hood?’ said Hal Weav­er of Johns Hop­kins uni­ver­si­ty in Mary­land. De­bate may al­so con­tin­ue be­cause, al­though the new def­i­ni­tion is meant to dis­tin­guish plan­ets from smaller bod­ies, it did­n’t take on the ques­tion of how to sep­a­rate super-large plan­ets and stars. That ques­tion does­n’t af­fect the clas­si­fi­ca­tion of plan­ets in our So­lar Sys­tem, but will be rel­e­vant to some oth­ers.

Answer 2

The distant, ice-covered world is no longer a true planet, according to a new definition of the term voted on by scientists today.




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"Whoa! Pluto's dead," said astronomer Mike Brown, of the California Institute of Technology in Pasadena, as he watched a Webcast of the vote. "There are finally, officially, eight planets in the solar system."

In a move that's already generating controversy and will force textbooks to be rewritten, Pluto will now be dubbed a dwarf planet.

But it's no longer part of an exclusive club, since there are more than 40 of these dwarfs, including the large asteroid Ceres and 2003 UB313, nicknamed Xena—a distant object slightly larger than Pluto discovered by Brown last year.

"We know of 44" dwarf planets so far, Brown said. "We will find hundreds. It's a very huge category."

A clear majority of researchers voted for the new definition at a meeting of the International Astronomical Union (IAU) in Prague, in the Czech Republic. The IAU decides the official names of all celestial bodies.

The tough decision comes after a multiyear search for a scientific definition of the word "planet." The term never had an official meaning before.

What Is a Planet Today?

According to the new definition, a full-fledged planet is an object that orbits the sun and is large enough to have become round due to the force of its own gravity. In addition, a planet has to dominate the neighborhood around its orbit.

Pluto has been demoted because it does not dominate its neighborhood. Charon, its large "moon," is only about half the size of Pluto, while all the true planets are far larger than their moons.

In addition, bodies that dominate their neighborhoods, "sweep up" asteroids, comets, and other debris, clearing a path along their orbits. By contrast, Pluto's orbit is somewhat untidy.

Answer 3

The International Astronomical Union decided that Pluto was no longer a planet. The reason is that while Pluto is round, orbits the sun, and has three moons, it has not cleared (via gravity) its own orbit of debris. Instead, they decided to classify it as a "dwarf planet".

See the details below.

RESOLUTION 5A
The IAU therefore resolves that "planets" and other bodies in our Solar System, except satellites, be defined into three distinct categories in the following way:

(1) A "planet" [footnote 1] is a celestial body that (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.

(2) A "dwarf planet" is a celestial body that (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 [footnote 2] , (c) has not cleared the neighbourhood around its orbit, and (d) is not a satellite.

(3) All other objects [footnote 3] except satellites orbiting the Sun shall be referred to collectively as "Small Solar-System Bodies".


Footnote 1: The eight "planets" are: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune.

Footnote 2: An IAU process will be established to assign borderline objects into either dwarf planet and other categories.

Footnote 3: These currently include most of the Solar System asteroids, most Trans-Neptunian Objects (TNOs), comets, and other small bodies.

RESOLUTION 6A
The IAU further resolves:

Pluto is a "dwarf planet" by the above definition and is recognized as the prototype of a new category of trans-Neptunian objects.

Answer 4

The Bible doesn't even aspect out different planets. till very those days, there had in no way been an attepmt to furnish a reliable definition as to what a planet is. the in problem-free words element that replaced into required to be a planet replaced into that it replaced right into a celestial body that orbited a favourite individual or human being gadget of stars (like binary stars) the project is that all the junk contained in the asteriod belt would qualify as planets, then, besides as arguably moons that orbit planets which orbit stars. various of skills were proposed. finally, the only which replaced into extensively huge-spread (even with the reality that no longer thoroughly) that disqualified Pluto replaced into that it ought to orbit round a favourite individual and in no way something else. Pluto's moon, Charon, is close adequate in length to Pluto itself that the moon does no longer orbit round Pluto. particularly, both easily one of them orbit round a level in area between them (in the route of Pluto, yet no longer everywhere interior Pluto). As such, Pluto and Charon both orbit that aspect which orbits the solar, particularly than Pluto itself orbitting the solar.

Answer 5

Astronomers felt that it was too small to be considered a planet, even though it's own satellite Charon is half of Pluto's size.

Answer 6

It is still a planet but excluded at our solar system,it is called the dwarf

Answer 7

Cause apparently pluto was originally wrongly identified to be one by some dumbass.

Answer 8

It's too small...so now its an asteroid called 134340