Recently, with the improvement in the resolution of telescopes, new bodies have begun to be discovered on the far fringes of the solar system. The properties of some of these celestial bodies match the properties of known planets - what then should be done? Expand the solar system family? Or maybe change the settings?
It's not every day that such a storm occurs in astronomer circles: What is a planet? Is Pluto a planet? And what about new bodies being discovered around our sun and around other suns? A committee of astronomers is trying to give new names to the bodies circling the Earth, but agreement is still far away.
Recently, with the improvement in the resolution of telescopes, new bodies have begun to be discovered on the far fringes of the solar system. The properties of some of these celestial bodies match the properties of known planets - what then should be done? Expand the solar system family? Or maybe change the settings? This is the crux of the debate going on these days in the astronomer community. The situation became even more complicated, when planets orbiting other suns also began to be discovered, some of them so large that "our" largest planet - Jupiter - dwarfs them.
Most astronomers agree that the name 'planet', or in dialect 'planet', cannot encompass in its definition bodies so different from each other. Therefore, one of the almost certain results will be that the famous sentence saying that nine planets revolve around our sun will be deleted from the textbooks, reports the prestigious journal nature.
At the center of the controversy is Pluto, the farthest body from the Sun that is considered a planet. Many astronomers believe that this small, cold and distant body does not meet the definition of a planet. In previous discussions, Pluto was saved from expulsion from the solar system, but the problem became acute when astronomer Mike Brown from the California Institute of Technology, Caltech, and other astronomers announced in July 2005 the discovery of a celestial object larger than Pluto, known today by the affectionate name 2003 UB313, in an orbit even further from Pluto's orbit. [Journalist Steve Mirsky suggested in his humorous column in Scientific American that the "new planet" should be called Goofy, a suggestion that the Walt Disney Studios would certainly welcome.]
If Pluto is a planet, says Brown, then 2003 UB313 must also be called that - it is larger and orbits the same
In the same neighborhood: a comparison between the orbit of Pluto and the orbit of the new "planet".
region of the solar system. Others continued and argued that if we put 2003 UB313 into the family of planets, what would happen to the round objects, which were also recently discovered, and are only slightly smaller than Pluto? On the other hand, others say that neither Pluto nor 2003 UB313 deserve to be called planets. In their opinion, these bodies are nothing more than rounded pieces belonging to the Kuiper belt - a large collection of icy or rocky bodies that orbits the edge of the solar system.
According to the article in Nature, a committee of 19 astronomers, members of the International Astronomical Organization (IAU), suggests attaching a title to the noun 'planet' and thus dividing them into groups that would include all round bodies (non-round bodies are defined as asteroids or comets). According to the proposal, Pluto and 2003 UB313 would be called trans-Neptunian planets, because their orbits lie beyond the orbit of the giant planet Neptune. The other titles will be based on the properties of the planets, the Earth for example will be called a terrestrial planet, as well as Mercury, Venus and Mars. The planets Jupiter, Saturn, Uranus and Neptune will officially be called: gas giants planets. Critics of the proposal argue that the method must be consistent and that all planets must be named according to their properties. They suggest calling Pluto and its companions, such as 2003 UB313, the pictorial name ice dwarf planets.
The members of the committee are having difficulty reaching an agreement, but they may submit their recommendations in two weeks - we will update.
for further reading
An article on the space.com website about the ongoing debate
An article on the website of Mike Brown who discovered 2003 UB313 describing the discovery
The best site about the planets called nine planets - pay attention to the title of the site
to the Hamada site
