Six years ago, Michael E. Brown, a professor of planetary astronomy at the California Institute of Technology, he saw a faint dot in some slabs that depicted the most remote areas of our planetary system. Quell'esiguo point had moved a few millimeters on the starry background than previous observations had concealed a tiny star. Brown did not know what he could discern was distraught and made an uproar in the scientific community. And the effects of his discovery are still alive.
who are more experienced will have realized by now that we are talking about the discovery of Eris, a dwarf planet and the so-called object transneptunian. It was undoubtedly farther than Pluto, and undoubtedly the largest. Soon all the world's telescopes were pointed towards the location of the "newcomer." And no one objected when scientists spread the news that Eris was larger than Pluto: all had been able to verify for themselves. Eris was the tenth planet?
At 15:03 of August 24, 2006 was the fateful beheading of Pluto, greek god of the underworld: the scientific community had issued the its verdict. That verdict removed the charge of "planet" Pluto. In Washington, the National Air and Space Museum, was adorned the display panel of Pluto as a sign of mourning, in Pasadena, California astronomers Institute of Technology si camuffarono da pianeti e hanno simbolicamente seppellito il loro compagno. La American Dialect Society ha scelto il verbo «to pluto» per rappresentare l'azione di sminuire o degradare qualcuno o qualcosa.
Eris aveva sconfitto il nemico, ma non aveva vinto la battaglia: non divenne il nono pianeta. La dea della discordia si era distratta. Ma Eris rimaneva comunque più grande, seppur di 100 chilometri, di Plutone.
«E' chiaramente più piccolo» dice, oggi, Alain Maury, testimone diretto della scoperta di Eris. E, in un suo studio pubblicato sull'insigne rivista Nature, afferma che la più piccola Reproduction of Pluto would still be larger than the largest reproduction of Eris (it's easier to say in English, believe me). According to the verdict of the International Astronomical Union, Pluto - although bigger than Eris - not always meet all the requirements to qualify as a planet in its own right.
But at this point, there arises a legitimate question: if we had noticed at once that Eris is actually smaller than Pluto, it was not necessary to degrade it, and then the verdict would not have taken place, and consequently the system Solar would be was that? "Maybe," is the response of Brown, although in his book "How I killed Pluto" declares that the Union has done the right thing. For decades, Pluto was a planet that magically shrank from day to day. It departed from a land size of the celestial body, then drops to a dwarf with a diameter less than half that of departure. In 1980, Professor Alexander J. Dessler, jokingly calculated that - according to the rate at which Pluto "narrowed" from month to month - would finally died in 1984.
But the story did not end well, -182 degrees Celsius because that characterize the surface of Pluto can still allow evaporation of molecules of nitrogen and methane ice, which form un'irrisoria and subtle atmosphere that envelops the planet. Well, the atmosphere is likely to deflect the light. So the surface is twilight and the dimensions seem to vary because the light 'wobbles' literally. Eris is 97 times farther from the Sun than Earth, with freezing temperatures that do not allow the formation of any atmosphere. Then the light comes more regularly and evenly, allowing scientists to calculate very carefully the physical findings of Eris.
Surveys more accurate will come in 2015 thanks to the New Horizons probe, which takes on board the ashes of the discoverer of Pluto - Clyde Tombaugh - and, curiously, is powered by plutonium.
We conclude that the outer solar system is much richer and varied than we expected: the dwarf planet Haumea, where a day lasts four hours, trans-Neptunian object Sedna, on which lasts for one year about 11,487 years on Earth. We hope to hear more and more.
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