Is Pluto Bigger Than Mercury

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The controversy betwixt Pluto and Eris regarding their status as "largest dwarf planet" continues. During a articulation meeting of the American Astronomical Guild Division for Planetary Sciences and the European Planetary Scientific discipline Congress final week in Nantes, France, new data was presented that may help settle the fence. The new findings regarding this size of Eris may be a surprise to some, and to others a confirmation of what was believed to exist true.

How were astronomers able to make the new measurements of Eris, and what implications will these new measurements take on the Pluto / Eris debate?

Using a angelic alignment known as an occultation, Bruno Sicardy of the Paris Observatory (University of Pierre and Marie Curie, French republic) and his team were able summate the diameter of Eris in 2010. The occultation was caused by Eris moving past a groundwork star, which blocked the star's light and cast a small shadow on World. When Sicardy and his team compared the shadow's size at two unlike sites in Chile, the calculations provided a bore of 2,326 kilometers for Eris. A previous study by Sicardy in 2009 placed Pluto'due south diameter to exist at to the lowest degree 2,338 kilometers.

Nonetheless, the showtime estimates of Eris' size that were made soon after its discovery put the diameter at 3,000 km, plus or minus 400 km. Just a later approximate from observations with the Hubble Space Telescope said Eris might be ii,400 km in diameter, plus or minus 100 km.

If Sicardy's data calculations hold true, this places Pluto and Eris at virtually the exact same diameter. What has continued to not be up for debate, however, is that Eris is far more massive than Pluto. Given a nearly identical diameter for Eris and Pluto, Eris's extra mass makes it the denser of the two dwarf planets. According to Sicardy and his team the increased density of Eris, "indicates that Eris is mainly composed of rocky fabric, with a relatively thin ice drapery." Since Pluto's density indicates it comprised of about equal parts ice and rock, Eris'south extra mass would appear to validate Sicardy'south assertion.

The Co-discoverer of Eris, and noted "Plutokiller" Mike Brownish (Caltech) offers an interesting thought regarding the Pluto / Eris Debate:

"Scientifically, knowing which one is bigger will teach us…. admittedly naught. The fact that they are nearly identical in size is scientifically interesting; which one is a few kilometers bigger than the other matters non one fleck." Brown too added, "Only, all the same, I will admit to having a flake of an emotional attachment to Eris, so, deep down within, I want to believe it will plough out to be a little bigger.

You tin can read a brief synopsis of Sicardy's findings at: http://meetingorganizer.copernicus.org/EPSC-DPS2011/EPSC-DPS2011-137-eight.pdf

If you'd like to learn more about the Pluto / Eris debate, Brown has some great thoughts regarding the debate on his blog at: http://www.mikebrownsplanets.com/2010/11/how-big-is-pluto-anyhow.html