Joel Kontinen
How could a dwarf planet (or in this case, two of them) be geologcally active for 4.5 billion years?
The answer is not even blowin' in the wind. It is beginning the resemble the epicycles that were used to keep alive a geocentric solar system before the days of Copernicus and Galileo.
Erin and Makemake orbit the sun in the Kuiper belt beyond Neptune.
New Scientist spells out the problem:
”Both worlds seem much too small and cold to have the sort of inner planetary activity that can lead to volcanism.”
But they are nonetheless geologically active.
New Scientist discusses a paper Will Grundy at Lowell Observatory and Orkan M. Umurhan at the SETI Institute presented at the American Astronomical Society meeting on 17th October:
”But Grundy and Umuhan reason Eris and Makemake must have some inner activity. The proof is in their ices. When we measure reflection from the surface of both worlds, we see strong spectral lines associated with frozen methane. When this evaporates, it creates a reddish aerosol “gunk” called tholin on the tiny worlds’ surfaces. Grundy and Umurhan calculate that this gunk makes up about 10 per cent of the total ice on Eris, but more on Makemake.
Judging by the amount of methane, we would expect tholin to be a big part of the surface, making the worlds appear darker. Instead, they appear bright white, more like the regions of Pluto covered in nitrogen ice. So Grundy and Umurhan reason the dwarf planets must have volcanoes spewing nitrogen ice to cover the tholins.”
A more logical approach would be to question the assumed age of the solar system. It would make the epicycle type tricks superflous.
Source:
Wenz, John. 2017. Volcanoes that spew stretchy ice could make dwarf planets bright. New Scientist (20 October).
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