There were so many "planets" that the International Astronomcal Union (IAU) came up with a new definition in August 24, 2006. What is an object that orbits around the sun, has enough mass for its self-gravity that it assumes a nearly round shape, has not cleared the neighborhood around its orbit, and is not a satellite ? For many years, new objects were being discovered and there was not really a definition for planet. The word planet came about in the ancient time meaning "wanderer." In the Solar System, there are objects that looks like a planet but is not, and these objects are call Dwarf Planet (pluto-like).

An object bigger than Pluto, the biggest so far, was discovered in an reanalysis in 2005. This caused a big crisis and a heated subject that made astronomers think "what is a planet." Due to Eris discovery, all pluto-like objects are called plutiod or dwarf planet. Eris recieved her name from a greek goddes, who is of discord and strife. "Eris caused strife and discord by causing quarrels among people and that's what this one has done too," said Mike Brown "| quote cited She was discovered by Michael Brown of the California Institute of Technology, Chad Trujillo of Gemini Observatory, and David Rabinowitz of Yale University.



Eris symbol

can be located at R.A. 01h 39m 24s.34 and Dec. -05° 10' 11".0. Eris is a member of the | Kuiper Belt, a swam of icy bodies beyond Neptune in orbit around the sun. It is the fourth brightest kuiper belt object. The KBO orbit 2.8 to 4.6 billion miles (30-50 AU) from the sun. There are different kinds of KBO. Plutinos (mini-Plutos) are those that has similar orbits like Pluto's. Cubewanos are those with orbits that are more like circles. Not only is Eris is a member of the KBO but it is also considered a Scattered Disk Objects (SDO), which is bodies that orbit out of the main plane of the solar system and form part of the population of trans-Neptunian objects (TNOs) that exist at the outer edge of the solar system beyond Neptune. SDO orbit is very eccentric and the distance to the sun varies enomously and can reach billions of km.

Eris is 27% more massive, and 5% larger than Pluto. It is 10 billion miles away from the sun, making it the most distant object ever seen in oribit around the sun. It takes 557 yers to orbit around the sun, which takes more than twice as long than Pluto. Just like Pluto, it is made of half rock and half ice. However, Eris's methane is more yellowish compare to Pluto's reddish methane, and it reflects about 86% of the sunlight compare to 60% for Pluto. Eris like other planets also has a moon name Dysnomia.

Dysnomia is the daughter of Eris who is a mythological demon spirit of lawlessness. Dysnomia is about 60x fainter than Eris with a diameter estimated to be approximately 8x smaller. The moon orbital period is thought to be about two weeks, half of Earth's moon. Dysnomia appears to be similar to the moon of 2003 EL61, code name Santa, with satellite name Rudolph.with nothing but frozen water. Eris's moon possibaly may has a darker surface than Eris's very frosty highly reflictive surface.

Another minor planet that was discovered in November 2003 but not announced until March 2004 is Sedna. It was named after the Inuit goddess Sedna who created the sea creatures of the Arctic Ocean. It is the coldest most distant place known in the solar system. She has a high albedo and very red-Reddish object after mars. The temperature never rises above -240 celsius (-400 degrees Fahrenheit). Just like Eris it was discovered by Dr. Mike Brown, Drs. Chad Trujillo , and David Rabinowitz.

Sedna is suggested to be formed near the sun, in region between Jupiter and Neptune. It may have an gravitational encounters with other bodies causing it to launched in its current orbit. However, the trouble is that she never comes closer than about twice the distance of Pluto. It could be related to the hypothesized Oort cloud, but its 10x closer than the predicted distance of the Oort cloud. The Oort cloud is an immense spherical cloud surrounding the planetary system and extending approximately 3 light years, about 30 trillion kilometers from the Sun. This vast distance is considered the edge of the Sun's orb of physical, gravitational, or dynamical influence.| More info " Brown speculated that this "inner Oort cloud" might have been formed billions of years ago when a rogue star passed by the sun, nudging some of the comet-like bodies inward." | quote

Sedna (2003 VB12) diameter is 800 - 1100 miles, less than 1,700 km ( about 1,00 miles). It's mass is unknown and the bulk density is also unknown, probably about 2 grams per cubic centimeter making it roughly half rock and half ice. Its orbit is highly elliptical with an orbital period of 11,249 years. The average orbital radius is 525.6 AU ( semi-major axis), orbital eccentricity is 0.855, and orbital inclination is 11.9 degrees - 12 degrees, less Pluto's. The rotational period of Sedna is about 20 days or so, but no longer than 50 days. Sedna's Axial period is 10 hours, Perihelion is 76.0 AU, and Aphelion is 928 AU.

Sedna had our astronomers baffled with its mystery self. Sedna rotates slowly, which causes astronomers like Mike Brown to think it has a moon. However, with NASA's Hubble Space Telescope, it shows that Sedna stands alone with only faint background of the stars around it. "I'm completely baffled at the absence of a moon," Brown said. "This is outside the realm of expectation and makes Sedna even more interesting. But I simply don't know what it means."| Quote There are four possibilities for why we can not see Sedna's moon. The first reason is that the moon may be behind Sedna and we could not see it. The chances of this happening is 1 in a 100 chances, but it can not be ruled out yet. Second reason is perhaps the moon is fainter than what we exspected. Third reason is perhaps there is no moon. It is possible that there was once a moon, but it may have gotten knocked out by another passing object or it's time just ran out. The last possibable reason is that perhaps our evidence is misleading us. Either the brightening and dimming that we think we see are not real or the measurement is real, but we are being fooled. Before we can determine if Sedna really have a moon or not, We need to careful look at the rotation of Sedna next year.

A new dwarf planet, 2005 FY9, was discovered on March 31, 2005, by a team led by Mike Brown of the California Institute of Technology. It became the fourth dwarf planet and third plutiod officially in July 2008. Makemake was named after a Polynesian creator of humanity and god of fertility. Mike Brown choose this name because of its Easter Island, also known as Rapa Nui. Before it was named Makemake pronounced "maki-maki", it was called Easterbunny among astronomers that were observing it because it was discovered a few days after Easter in 2005. It was one of the celestial bodies, along with Eris and 2003EL61, that caused the question "what is a planet."

Makemake diameter is 1,300 and 1,900 km about 808 to 1,181 miles with an orbit of 310 years. Its temperature is - 240° C (-406° F), close to Sedna's. It is the second brightest trans-neptunian object known after Pluto. It can be seen using high-end amateur telescope since Makemake has an magnitude of 16.5. It is currently lies at 52 AU, and can be seen in the constellation Coma Berenices. It's surface is reddish like Sedna, surface cloaked in large amounts of nearly pure frozen methane, and smaller than both Pluto and Eris. Makemake is currently near its aphelion at a distance of 4.8 billion miles. It will reach true aphelion in 2033. Makemake has no moon.

Another recent dwarf planet that been recently named in 2008 is Haumea, discovered by José Oritiz and Micheal Brown on 28th December 2004. It was nicknamed Santa because it was found just prior to Christmas. Haumea was named after goddess of fertility and childbirth in Hawaiian mythology. It rotates once every four hours, because of this its shaped like a squashed rugby football. It may have collided with another larger object a long time ago. If this is so, it may explain why its in an odd shape.

Haumea orbits the Sun once every 285.31 years, averaging 43.34 AU or 6.50 billion kilometres away. Haumea aphelion is 59.73 A.U., preihelion is 43.34 A.U., and semi-major axis is 43.335 AU. Perihelion last occurred in February 1991, with the next perihelion expected sometime in October 2135. Its orbital period is 104.234 days with an average orbital speed at 4.48km per second. It's inclination is 28.19 degree with an longitude of ascending node of 121.90 degrees. Haumea sidereal rotation is 0.1631 hour or 3.912 hours, mean sidereal rotation is 3.9154 hours (2006), max magnitude is 15.8, and min magnitude is 175. Pluto's diameter is similar to Haumea longest axis but her other two axes are shorter; its mass is about 3rd of Pluto's. Unlike Pluto, she only has two moons.

It was discovered in 2005 that Haumea has moons now call Hi'iaka and Namaka. They nicknamed it Rudolph and Blitzen since Haumea was nicknamed Santa. Astronomers think that the moons may have been part of Haumea when she collided with a larger object. Hi'iaka and Namaka are the daughter of Haumea who is believed to be born by springing from part of the body of thier mother. Hi'iaka ( Rudolph ) was named after Hi'iaka who was the goddess of hula dancers. She has a diameter about 310 km, and orbits her mother every 49 days at a distance of 49,500 km. Namaka was a goddess of water spirit. She has a diameter of roughly 170 km and orbits her mother every 34.7 days at a distance of 39,300 km.


:Pluto -Tiffany- :Ceres -Fielding- :Eris -Check- Makemake -Check- :Haumea -check-

Sedna -Check-
2003 EL61,
^ [2]

Scientists estimate there may be 70 dwarf planets amongst outer solar system objects that have been discovered already.

The first members of the dwarf planet category are Ceres[3], Pluto[4] and Eris. largest dwaft planet and largest found object since discovery of neptune and its moon.

- Eris is the biggest out of the three



Eris (2003 UB313 / Xena ) < picture < oort cloud


Sedna ( 2003 VB12) < why it rotates slow

Just some interestign Found this picture to be amusing and sad. Its pluto being taken out of the planet category. Earth is the leader.[5]