A US research team calls for the dwarf planet Pluto to be redefined as a planet soon. The team argues with knowledge that is centuries old.
USA / Kassel – The decision of the International Astronomical Union (IAU) to downgrade Pluto to a dwarf planet in 2006 led to great differences between astronomers. The reason for the downgrade was a new definition of planets. A celestial body has been considered a planet since 2006 that meets the following criteria:
- It has to move in an orbit around the sun.
- It must have enough mass to be approximately spherical.
- And it must dominate its orbit – that means that the planet must have “cleared” its orbit of other objects over time.
However, Pluto is influenced by Neptune. In addition, it shares the orbit with other chunks, so it is excluded from the new definition.
According to the Süddeutsche Zeitung, US astronomers are now presenting new arguments why Pluto should be considered a planet again. Researchers led by Philip Metzger from the University of Central Florida have published a paper on the taxonomy around the concept of planets. According to the online portal Digital Pioniers, a five-year literature search led her to the conclusion that the definition of planets had changed over the centuries due to pragmatic rather than scientific influences.
Pluto a planet again soon? The definition used is based in part on “popular concepts”
The definition adopted by the IAU is also based in part on the “popular” concepts. According to the researchers, this should be vehemently rejected. From a scientific point of view, a geological taxonomy is much more appropriate. According to the online portal Digital Pioniers, this would assess planets not according to their environment, but according to their own intrinsic properties (structure and characteristics such as water and atmosphere).
This view is centuries old and was represented, for example, by Galileo Galilei. In 1632 he referred to moons as planets because he had recognized geological structures on the lunar surface that resembled those of the earth. The scientists have already put forward a proposal to reformulate the definition.
US researchers suggest: According to the new definition, Pluto would soon be a planet again
Accordingly, a planet would be a “body with substellar mass that has never undergone a nuclear fusion” and has a hydrostatic equilibrium. According to the new definition, the list of planets would be many times longer. According to Metzger, around 150 objects would then be included, including numerous moons – and also Pluto.
Researchers at the University of Cambridge only recently discovered a new type of habitable planet in space. The search for life in space is currently investigating what role penguins could play in this. (Luisa Ebbrecht)