Dwarf Planet

Two years ago, in August 2006, Pluto, which is more than 70 years was considered the ninth planet of our solar system, has lost that status. The few hundred astronomers, who in recent days by the General Assembly of the International Astronomical Union (IAU) in Prague has not gone home and not scattered all over a beer city, by majority vote adopted a resolution to define what a planet. Pluto is the requirements of the resolution and did not meet him, along with two other bodies of the solar system, attributed to a dwarf planet.

To sweeten the pill "fans" of Pluto, the researchers then tried to call after him all the dwarf planets, moving beyond Neptune's orbit. However, the two terms are proposed to describe such objects, found no support. "Plutonovye objects" astronomers seemed too heavy, and "plutons", as it turned out, was already occupied - as geologists call the big rocks that solidify in magma even before you turn on the surface. It should be noted that, in English and other languages ​​written in the former planet Pluto, as Pluto, without the n at the end, but because the term "pluton» - pluton was different from the name of the planet a few notable than just a change in capital letters on the lowercase, writes sunhome.ru

Plutoid - dwarf planet semi-major axis of the orbit is greater than the semi-major axis of the orbit of Neptune. It is assumed that all of the new dwarf planets, which will be open in the future will belong to the class.

In early summer, by the way, the official name of the dwarf planets, moving beyond Neptune's orbit, yet been established. They were called Plutoid. As explained by the President of the Shore Institute of Applied Astronomy, St.-Petersburg - Russia's only member who took the decision unit MAC, the term "Plutoid" came on purpose.

So astronomers have not only perpetuated the former ninth planet, but also emphasized the similarity of the current situation with the situation astronomers 200 years ago. Then opened the first objects in the main asteroid belt. And if the very first of them - Ceres first began to call the eighth planet (today the eighth planet - Neptune - the astronomers did not know), then with the discovery of Pallas, Juno and Vesta became clear that these small bodies should be given a different name. They became the "asteroids" or simply "minor planets."

Surprisingly, the astronomers, who seems to be better than others need to understand the emptiness of the whole dispute about the name and status of a celestial body, still fiercely debate on this matter.

At the weekend at the Center for the Alexander Kosyakova American University, Johns Hopkins University in Maryland over the whole conference "dissent" with the decision of the MAC, which in the debate with his opponents tried to defend the planetary status of Pluto, and simultaneously to determine what is a planet. Ended the conference, in general, to no avail. Of course, the decision to change the MAC, scientists still have not been able to, but no reasonable alternatives, which all would agree, they could not be found.

The central event of the three-day meeting was the public "Large planetary debate" between the two parties that have expressed, in fact, all the arguments of proponents and opponents of the new definition of planet. The first was represented by Neil Degrassi Tyson - American planetary scientist and popularizer of astronomy. Pluto's planetary status defended Mark Sykes - still better known planetary scientist, speaking more and organizer of the Maryland meeting.

Present in the hall, and probably the most fierce opponent of the MAC address Alan Stern, who flatly refused to accept the term "Plutoid", saying that for him that Plutoid that hemorrhoids (in English these words are in tune) - almost the same thing. Stern can understand - that for years he supervised the preparation of the American space mission to Pluto, New Horizons, which launched in early 2006 and now with an unprecedented man-made spacecraft to speeds close to the main purpose of his trip. If you spend most of his life to the study of one planet, its demotion to "neplanety" probably really perceived as a bad hemorrhoids.

Neil Tyson is the difference between hemorrhoids and Plutoid understand. Back in 2001, five years before the controversial IAU resolution, he took this decision for himself. As director of the New York Planetarium, Tyson simply threw Pluto from the exposition dedicated to the planets of our solar system than incurred the wrath of the American public. By the way, semi-handicraft case studies that provided the astronomers of different countries, showed that Americans are concerned about the status of Pluto is much stronger than people in other countries. Why is difficult to answer - perhaps out of love for Disney dog ​​of the same name, perhaps because of Pluto - the only planet discovered American (Clyde Tombaugh).

Tyson recalled the definition of a planet, which invented the International Astronomical Union two years ago. In applying for this status of a celestial body must have three main properties.

First, it must revolve around the sun.

Secondly - to be in hydrostatic equilibrium, which inevitably means a round or spheroidal (for rapidly rotating bodies) form, as well as geological and tectonic activity, even though at some stage of its existence. To fulfill the second requirement, the planet must be massive enough to pull the power out of its own parts could exceed the strength of the reaction of solid rock. By the way, why the mountains on the moon or Mars might be substantially higher than the earth - the earth when they grow up to certain limits, they immediately melted soles.

Thirdly, this planet should be the sole master of its orbit and its environs - for billions of years of the solar system, it should clean up these areas from all other large bodies.

That's just not satisfy the third requirement Pluto, which moves in the downtrodden similar objects Rohe, called the Kuiper belt.

Objects that perform only the first two conditions, the MAC two years ago decided to be called dwarf planets.

The third was named Plutoid Makemake. The International Astronomical Union officially assigned facility, formerly known as the Polynesian god 2005FY9 name Makemake - the creator of humanity and god of fertility in the culture.

Apart from Pluto to carry him now his companions in the Kuiper belt and Eris and the asteroid Ceres, Makemake. Eris is more massive than Pluto, and, and that's what astronomers convinced of the need to deprive Pluto status. If he left the planet, then this will give the same status, and many other bodies - an estimated Tyson's still about 4-5 dozen such objects Eris and Pluto are waiting to be discovered. However, Pluto, Eris and Makemake and form now known population Plutoid. The only dwarf planet, which is not Plutoid - is Ceres, from the main asteroid belt, all other asteroids are massive enough even to take a rounded shape.

Sykes, in turn, says "fatal," the third requirement of the domination of the planet around its orbit - an artificial and illogical.

"It turns out that the same object may or may not be a planet, depending on where it is located" - lamented Sykes. Even the Earth - the largest of the terrestrial planets, planetary counted so far not been able to clear its neighborhood of other objects, if the 4.5 billion years ago, she would not have been formed at its present orbit, and in the asteroid belt. Accordingly, it would not be in this case and the planet, while four smaller-sized moon, if it magically appeared in its current orbit, the hostess, was considered a planet.

Sykes and his colleagues believe that a purely physical definition of a planet - more than reasonable. However, many of them offer to give up the first requirement - of revolution around the Sun. Under the current definition, none of the extrasolar planets circling around distant stars, the planet is not. However, the proposed definition, it will be full-fledged planets not only Pluto and Ceres, and the moon, and the major satellites of giant planets, even Pluto - Charon, which is only half of his "master."

The criterion of belonging to the planets, according to Sykes, must be the condition of hydrostatic equilibrium - count, round shape. The only caveat - the mass of the planets should still be so large that their centers were nuclear reactions, such objects are already known stars.

However, the scientists would not be scientists, if they do not use meaningless, in general, the debate about the status of Pluto for a meaningful and far-reaching generalizations.

As noted by Neil Tyson, the science has reached a level which is unwise to mix within a term such dissimilar bodies, like the terrestrial planets, giant planets, dwarf planets or Plutoid. The physical characteristics of these objects are very different, and attempts to call them all planets only confuse. In this sense, the selection of dwarf planets - a step in the right direction, as well as the Department of Plutoid Ceres.


However, following his logic, the category of planets should be abolished altogether by selecting a class of objects in the terrestrial planets - Mercury, Venus, Earth and Mars, and the other - the giant planets - Jupiter, Saturn, Uranus and Neptune. True, they just want to take the next step, after Jupiter and Saturn are also not similar to Uranus and Neptune, Venus and Earth - on Mercury.


Would the astronomical community to reject the word "planet" as a defined term at all? It is unlikely - at least, even disagree with the decision of the MAC two years ago and have not come to any single solution on how to behave on.


In any event, this event showed one important thing. Science - not a frozen set of dogmas, and changing, living world. For the sake of this tutorial conference in Maryland, probably worth to pursue.