There are five official dwarf planets in the solar system, and the largest of them is Eris, although Pluto is still the best known.
Eris is almost one and a half times farther from the Sun than Pluto, and unlike Pluto, no space probe has yet come close to it. So not much is known about Eris yet.
Now, however, two American scientists, Francis Nimmo of the University of California, Santa Cruz and Michael Brown of the California Institute of Technology have come to new conclusions on the internal structure of Eris on the basis of unpublished observational results and write about it in the journal Science Advances.
The results of the observations indicate that Eris’ companion, or the moon, called Dysnomia, always faces Eris from the same side, and Eris always faces Dysnomia from the same side.
This is because the celestial bodies have slowed down each other’s rotation over time with their tidal forces.
Another important information that emerged from the observations is that the mass of Dysnomia must remain below a certain value.
This is an important result because until now scientists had no clear idea of Dysnomia’s mass.
The bilateral one-sidedness of the dwarf planet and its companion and the upper limit of the possible mass of the companion were the two grains of information on the basis of which Nimmo and Brown made effective new calculations.
The main result, which surprised the scientists themselves a bit, was the fact that Eris’s thick ice layer is suddenly dissipative, or dissipative in scientific terms.
In this it differs from Pluto’s thick ice crust, which is hard and immobile, but probably covers an ocean of liquid water, which in turn extends over Pluto’s solid core.
According to Nimmo and Brown, Eris’s structure is a bit simpler: the occasionally floating plume of ice, or ice soup, or ice slurry, rests directly on the solid core. The ice is likely prevented from freezing hard by the heat generated by the decay of radioactive elements in Eris’ core.
The researchers hope to make even more precise observations in the future and to test, among other things, whether the mass limit for Dysnomia could be even more stringent. If this were the case, one might conclude that the Eris ice is even more sulphurous.
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2023-12-04 13:20:00
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