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New solar system(?)

The echoes of the decision made last Thursday, in the matter of taking the title "planet" from Pluto, are still echoing, and there are already calls for its return to its previous status

Pluto. Photograph from the Hubble Space Telescope
Pluto. Photograph from the Hubble Space Telescope

The echoes of the decision made last Thursday, in the matter of taking the title "planet" from Pluto, are still echoing, and there are already calls for its return to its previous status.

In recent years, there have been occasional reports in the astronomical world that "Pluto's position is being considered". The general attitude towards those news was mostly as a joke and nothing more. However, last Thursday, at a conference of the IAU - the World Astronomical Organization - it was decided that Pluto will lose its prestige and will henceforth be included in a separate group of "dwarf planets".

"But what is there? To confirm a lily is called,
His smell is pleasant even if his name is different."
(Romeo and Juliet - William Shakespeare translated by Reuven Avinoam).

Even if all astronomy experts vote "against" unanimously, Pluto will not stop orbiting the sun, its orbit will not change and "even tomorrow the sun will rise". Of course, on Pluto the sunrise is much colder than here on Earth, the average temperature on its surface is minus 223 degrees Celsius and the intensity of light from the Sun is almost 2,000 times smaller than that felt on Earth. Pluto, which has long been considered the smallest of the planets (currently Mercury is the smallest), is now associated with a new group called "dwarf planets", which besides Pluto also includes its moon Charon.

The reason that precisely now, 76 years, almost, since the discovery of Pluto, it was so important for the IAU to update the status of Pluto, lies in the fact that in 2003 an object cataloged as UB313 was discovered and named by its discoverers "Xena", and that ice block, as it turned out, is large Even more than Pluto! The reason it was decided not to include "Zina" in the group of planets is because it is not known how many more "Zinas" are lurking in vast distances and waiting to be discovered. That is why the IAU is required to determine the rules that will allow the objects visible in the sky to be classified into categories.

The currently accepted way of division is:
• Star - stars are suns, our sun is the closest star to the earth.
• Planets - in the solar system there are 8 planets: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune - closed list (*currently)
• Dwarf planets - the new category, for now, includes Pluto (former planet), Charon (Pluto's moon), Ceres (asteroid) as well as UB313
• Minor planets - include comets and asteroids, (so far, Keres has been classified in this category)

Where did Pluto come from?

Since prehistoric times, six planets have been known (although until the 16th century the Earth was not considered a planet, but the center of the universe). A person who observes the sky from a dark place will be able to notice that the position of the planets between the Saturn stars changes over time, Hema can appear and disappear from the evening sky in just a month, while the movement of Saturn is barely noticeable during several months. The ancients noticed these movements and therefore credited the moving points of light with the name "planet" - nomad. In 1781, William Herschel, a British astronomer, discovered Uranus, and in 1846, Johann Galle (Galle) discovered Neptune, two rather distant planets that are not visible to the naked eye, and discoveries were made possible thanks to Newton's theory of gravity and were a tremendous proof of its scientific validity.

Abnormal vagabonds

After the discovery of Neptune, two anomalies remained in the movement of the planets - Neptune's movement showed a certain deviation from the calculations, as did Hema. It was hypothesized that there was another planet beyond the orbit of Neptune, called "Planet X", as well as an inner planet called "Vulcan". Of course, many scientists all over the world wanted to be among the discoverers. Viewing these two planets should have been quite difficult. The hypotheses were that Vulcan is very close to the Sun, orbits it rapidly and is never seen beyond the twilight range. Planet X, on the other hand, was supposed to be a huge distance away.

Initially, the search for Planet X was based on calculations of Neptune's orbital deviation, but after many years of scanning the skies, Planet X remained elusive. Vulcan, as it turned out at the beginning of the 20th century, does not exist. One of the proofs of Einstein's theory of general relativity is the deviation in the orbit of the planet Mercury. It is not an inner planet that does this, but the warping of space by the mass of the Sun.

The searches were not only done in university observatories but also in private research centers, the most important of which is the telescope established by Percival Lowell in Flagstaff, Arizona. Although it was established with the aim of observing the Martian canals, on the night of February 18, 1930, 14 years after Lowell's death, Clyde Tombaugh discovered Planet X. The name given to the planet, perpetuated the observatory's initials PL, And so also in the monogram that constitutes the astronomical symbol

The name "Pluto" was suggested by a British girl, 11-year-old Venetia Borney at the time. The name "Pluto" was preferred over names like "Zeus" "Minerva" and "Lowell".

In the 70s, the Vijar spacecraft reached Uranus and Neptune and measured their mass, and then it turned out that the measurements and calculations that led to the start of the search for Planet X were wrong: an incorrect mass estimate caused a mistake in calculating their orbit. A spacecraft called New Horizons is now on its way to Pluto and it is not expected that its course will be changed due to the decision, even though one of the main reasons for launching the spacecraft was that Pluto is the only planet that has not yet been reached by a spacecraft.

Meanwhile, the main uproar over Pluto's demotion is among the astrological community, where they are unsure how a decision, made by some 400 astronomers, will affect their predictions. I would advise them to worry more about Tam's question, namely, how did Pluto infiltrate the astrological predictions in the first place? And in this context, what about Uranus and Neptune, which have only been known for a few hundred years?

S, for a special issue that dealt with planets outside the solar system: "Only the ability to maintain the atmosphere is important, not the atmosphere itself, therefore Mercury, even though its atmosphere is borderline, will maintain its planetary status.
One thing is certain after today's vote - the solar system will not look the same.

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