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Weirdest Object in the Solar System? July 16, 2009

Posted by stcescience in Astronomy, planets.
Tags: , , ,

Matt Bulman has his blog at:    http://stcescience.wordpress.com/

Taken From newscientist.com

Astronomers have recently discovered one of the strangest objects, to date, in our solar system.  This dwarf planet has virtually the same diameter as Pluto but is only about 1/3 its mass – meaning it actually looks more like a flattened cigar or pancake.  Read more at:  http://www.space.com/news/080919-fifth-dwarf-planet.html

The question then becomes how does such an object form?  It is no coincidence that nearly all planets and stars are spherical in shape.  Objects tend to assimilate to the lowest energy state possible, or in the case of celestial bodies – spheres.  This is because the planets and stars have a very large gravitation force pulling inward from all directions; creating a “ceiling” or “roof” that is the same height in all directions (a sphere).  But how then do anomalies such as these exist?

According to the article “The new dwarf planet has the same diameter as Pluto, but is much thinner, and contains about 32 percent of Pluto’s mass. Scientists suggest Haumea’s long, narrow shape arose from its rapid spin — it rotates about once every four hours.”  In other words there are forces on this object other than just its gravitational pull.  This is true of all celestial bodies; however it becomes much more apparent as objects begin to rotate very quickly.

Think of it much like building a clay pot.  As you rapidly spin the clay in a circle the clay begins to flatten and elongate.  This is due to the centripetal acceleration of the mass.  As the mass continues to spin faster and faster it begins to accelerate outward and is either shot outward and off the remaining mass or causes the clay pot to elongate and squish together.

Haumea’s formation would be much like that of a clay pot.  While the dwarf planet has a gravitational force pulling inward in all directions, it is also spinning incredibly fast on its axis.  So you could imagine that the mass is being pulled in and pushed out by two competing forces.  However this gives rise to an even bigger question – why then is such a large body spinning so incredibly fast?

What’s even more interesting is the object’s name.  According to the original article, “The object previously known as 2003 EL61 is now named Haumea, after the goddess of childbirth and fertility in Hawaiian mythology.”

Taken from: NASA, ESA, and A. Feild (STScI)

Haumea is one of the largest members of the relatively newly coined “Kuiper Belt”.  The Kuiper Belt is basically a large gathering of ice structures extending out further than Neptune’s orbit.  Through the analysis of this region in space astronomers have pretty much been able to demote Pluto from full planet to simply the largest member of this region in space.  It is a lot like the asteroid belt only it is much larger and all of the substances are made primarily of ice rather than rock.  Astronomers are discovering more and more Kuiper Belt members through closer analysis of our solar system.

Institute for Astronomy at the University of Hawaii faculty member David Jewitt is one such astronomer.  Jewitt believes, “the Kuiper Belt holds significance for the study of the planetary system on at least two levels. First, it is likely that the Kuiper Belt objects are extremely primitive remnants from the early accretional phases of the solar system. The inner, dense parts of the pre-planetary disk condensed into the major planets, probably within a few millions to tens of millions of years. The outer parts were less dense, and accretion progressed slowly. Evidently, a great many small objects were formed. Second, it is widely believed that the Kuiper Belt is the source of the short-period comets. It acts as a reservoir for these bodies in the same way that the Oort Cloud acts as a reservoir for the long-period comets.”



1. Laurel Kornfeld - July 16, 2009

It is not correct to say that “Through the analysis of this region in space astronomers have pretty much been able to demote Pluto from full planet to simply the largest member of this region in space.”

Pluto is still a planet, and so is Haumea. Only four percent of the IAU voted on the controversial demotion, and most are not planetary scientists. Their decision was immediately opposed in a formal petition by hundreds of professional astronomers led by Dr. Alan Stern, Principal Investigator of NASA’s New Horizons mission to Pluto. One reason the IAU definition makes no sense is it says dwarf planets are not planets at all! That is like saying a grizzly bear is not a bear, and it is inconsistent with the use of the term “dwarf” in astronomy, where dwarf stars are still stars, and dwarf galaxies are still galaxies. Also, the IAU definition classifies objects solely by where they are while ignoring what they are. If Earth were in Pluto’s orbit, according to the IAU definition, it would not be a planet either. A definition that takes the same object and makes it a planet in one location and not a planet in another is essentially useless. Pluto is a planet because it is spherical, meaning it is large enough to be pulled into a round shape by its own gravity–a state known as hydrostatic equilibrium and characteristic of planets, not of shapeless asteroids held together by chemical bonds. These reasons are why many astronomers, lay people, and educators are either ignoring the demotion entirely or working to get it overturned.

2. Ryan S - February 6, 2013

do you teach at stce

jcconwell - February 10, 2013

No, I’m at Eastern Illinois University.

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