Researchers and astrobiologists David Greenspoon (David Grinspoon) and researcher Alan Stern (Alan Stern) expressed their opinion that their research confirmed suspicions about the fact that Pluto is a planet. Recall that in August 2006, participants in the Congress of the
International Astronomical Union of 2.5 thousand people voted for the decision to exclude Pluto from the list of planets in the Solar System. This led to many changes in educational publications, scientific works and maps of the starry sky.
Congress participants were convinced that in order to be called the planet of the Solar System, Pluto does not have a strong enough gravitational field to clear its orbit from other celestial bodies. And because of the lack of mass, the planet could not be so called.
However, according to David Greenspoon and his colleagues, any celestial body with individual geography and climate, including satellites of large planets, can be called a planet. In addition, they claim that the planet necessarily has a spherical shape and consists of gas, ice or solid rocks, which distinguishes it from other celestial bodies such as asteroids.
Scientists are convinced that by reviewing the parameters with which the planets must conform, the participants of the International Astronomical Union questioned the fact that the Earth is also a planet. Indeed, in the first 500 million years of its existence, it also did not meet the criteria established in 2006, like many exoplanets.
Greenspoon and Stern are confident that the definition of a planet should not be based on the orbital characteristics of a celestial body, but on its geophysical parameters. According to them, Pluto is a full-fledged dwarf planet, just like the Sun is a dwarf star.
New Horizons - NASA automatic interplanetary station, launched under the program of the New Frontiers and designed to study Pluto and its natural satellite Charon. The launch was carried out on January 19, 2006, the device performed the passage of Jupiter (with a gravitational maneuver in its field) in 2007 and a
scientific program for studying Pluto in 2015 , at the beginning of 2019 it is planned to study Kuiper belt objects. The full research program of New Horizons is designed for 15-17 years.