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Dwarf Planet Eris Is More Massive Than Pluto

Date:
June 18, 2007
Source:
NASA
Summary:
Aptly named after the Greek goddess of conflict, the icy dwarf planet, Eris, has rattled the general model of our solar system. The object was discovered by astronomer Mike Brown of Caltech in the outer reaches of the Kuiper belt in 2005. Adding insult to injury for the former ninth planet, Brown has now determined that Eris is also more massive than Pluto.
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Dwarf Planet Eris and satellite Dysnomia
Credit: NASA, ESA, and Mike Brown, (California Institute Of Technology)

Aptly named after the Greek goddess of conflict, the icy dwarf planet, Eris, has rattled the general model of our solar system. The object was discovered by astronomer Mike Brown of Caltech in the outer reaches of the Kuiper belt in 2005.

Its detection provoked debate about Pluto’s classification as a planet. Eris is slightly larger than Pluto.

So if Pluto qualified as a full-fledged planet, then Eris certainly should too. Astronomers attending the International Astronomical Union meeting in 2006 worked to settle this dilemma. In the end, we lost a planet rather than gaining one. Pluto was demoted and reclassified as a dwarf planet along with Eris and the asteroid Ceres, the most massive member of the asteroid belt.

Adding insult to injury for the former ninth planet, Brown has now determined that Eris is also more massive than Pluto. This new detail was determined by observations of Eris’ tiny moon Dysnomia. The Hubble Space Telescope and Keck Observatory took images of the moon’s movement, from which Brown precisely calculated Eris to be 27 percent more massive than Pluto. In fact, if you scooped up all the asteroids in the asteroid belt they would fit inside Eris, with a lot of room to spare.

Currently, Eris is more than three times farther from the Sun than Pluto. It is so cold out there that the dwarf planet’s atmosphere has frozen onto the surface as a frosty glaze. The coating gleams brightly, reflecting as much sunlight as fresh fallen snow. The path Eris takes around the Sun is shaped like an oval rather than a circle. In about 290 years, Eris will move close enough to the Sun to partially thaw. Its icy veneer will melt away revealing a rocky, speckled landscape similar to Pluto’s.


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The above post is reprinted from materials provided by NASA. Note: Materials may be edited for content and length.


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NASA. "Dwarf Planet Eris Is More Massive Than Pluto." ScienceDaily. ScienceDaily, 18 June 2007. <www.sciencedaily.com/releases/2007/06/070617130655.htm>.
NASA. (2007, June 18). Dwarf Planet Eris Is More Massive Than Pluto. ScienceDaily. Retrieved July 7, 2015 from www.sciencedaily.com/releases/2007/06/070617130655.htm
NASA. "Dwarf Planet Eris Is More Massive Than Pluto." ScienceDaily. www.sciencedaily.com/releases/2007/06/070617130655.htm (accessed July 7, 2015).

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