Pluto’s twin dwarf planet Eris is surprisingly soft cheese like

Stargazer Daily
4 Min Read

18 years ago, scientists identified a diminutive, glacial celestial body named Eris, situated billions kms beyond Neptune. In stark contrast to its planetary kin Pluto elevated to a vibrant, kinetic world post-New Horizons’ exploration in 2015, Eris remains untouched by robotic envoys. Its remoteness from Earth is such that in observations, it manifests merely as a solitary pixel of luminosity.

Eris was discovered on Jan. 5, 2005, from data obtained on Oct. 21, 2003, during a Palomar Observatory survey of the outer solar system by Mike Brown, a professor of planetary astronomy at the California Institute of Technology; Chad Trujillo of the Gemini Observatory; and David Rabinowitz of Yale University.

In essence, our knowledge regarding Eris remains scant.

What we comprehend is that Eris possesses an atmosphere, wherein congelation and precipitation occur on the surface beneath. This atmospheric phenomenon is attributed to its location near the periphery of the Solar System, being approximately 68 times distant from the sun compared to Earth.

Fresh models, derived from data collected by an array of radio telescopes in Chile, have unveiled additional facets of Eris. Residual warmth from the dwarf planet’s genesis appears to seep out, inducing a gradual undulation of its icy expanse.

This process metamorphoses Eris into a semblance less of a solid, stony orb and more akin to a pliable substance, comparable to, as study co-author Francis Nimmo of the University of California Santa Cruz eloquently puts it, “a soft cheese or something like that.” It exhibits a proclivity to flow to some extent.

dwarf planet eris

Despite Eris maintaining an aura of mystery, it is deemed an “almost perfect” sibling to Pluto—both dwarf planets nearly identical in size. Initially appearing marginally larger than Pluto when first identified in 2005, a scientific dispute ensued.

This disagreement led the International Astronomical Union (IAU) in 2006 to reclassify Pluto as a dwarf planet and christen the newfound celestial body Eris, after the Greek goddess of discord, spurred by the contention within the scientific community.

In the recent examination, Nimmo and collaborator Mike Brown, a Caltech astronomer renowned for discovering Eris in 2005 and gaining notoriety as the individual who dethroned Pluto, approximated the mass of Eris’ diminutive satellite, Dysnomia.

Eris and its moon share a mutual tidal lock, signifying that both perpetually face each other. Scientists posit this is a consequence of the minute moon inducing tides on Eris, instigating the dwarf planet’s deceleration over a span exceeding 4.5 billion years.

Current revelations propose that Eris likely harbors a rocky nucleus enveloped by a convective icy casing.

“The rock contains radioactive elements, and those produce heat. And then that heat has to get out somehow,” elucidates Nimmo. “So as the heat escapes, it propels this gradual undulation in the ice.”

Nimmo and Brown postulate that Eris’ surface is anticipated to be relatively smooth, with any distinctive features likely obliterated by the flow of ice.

“It would be advantageous to obtain measurements of Eris’ shape because if it deviates significantly from regularity, that would contradict our model.”

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