• Study suggest Pluto had a “hot start” when it formed

    • NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute/Alex Parker
    Date:23 June 2020 Author: Leila Stein

    A new study has suggested how Pluto, which sits so far from the Sun, could have liquid oceans that sit beneath its surface.

    In a new theory on the formation of the planet which sits in the far reaches of the freezing Kuiper Belt, scientists have proposed that Pluto could have generated enough heat during its formation to keep the subsurface oceans liquid for billions of years after the cold crust froze over.

    “For a long time people have thought about the thermal evolution of Pluto and the ability of an ocean to survive to the present day,” said co-author Francis Nimmo, professor of Earth and planetary sciences at UC Santa Cruz in a statement. “Now that we have images of Pluto’s surface from NASA’s New Horizons mission, we can compare what we see with the predictions of different thermal evolution models.”

    NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute/Alex Parker

    Since water expands when it freezes and contracts when it melts, the hot-start and cold-start scenarios have different implications for the tectonics and resulting surface features of Pluto, explained first author and UCSC graduate student Carver Bierson.

    “If it started cold and the ice melted internally, Pluto would have contracted and we should see compression features on its surface, whereas if it started hot it should have expanded as the ocean froze and we should see extension features on the surface,” Bierson said. “We see lots of evidence of expansion, but we don’t see any evidence of compression, so the observations are more consistent with Pluto starting with a liquid ocean.”

    These new findings imply that other large objects in the Kuiper belt probably formed in a similar manner, starting out hot and therefore could have had early oceans as well.

    Image: NASA



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