Dwarf Planet | Observations in Astronomy

According to the International Astronomical Union (IAU), there are eight planets. These planets include Mercury, Venus, Mars, Neptune, Jupiter, Saturn, Uranus and Earth. Are you wondering what happened to Pluto?

Pluto is considered a dwarf planet. There are five dwarf planets, including Ceres, Haumea, Makemake, Eris and Pluto. This was clarified in August 2006. These five planets were potentially going to be considered IAU planets, but the definition of a planet was clarified with a formal defined by the IAU.

The IAU determined that a planet must have three qualifications in order to be considered a planet in the Solar System. First, it must orbit around the sun. Secondly, it must be big enough to be gravitationally dominant in it’s own orbit, so that no other large bodies are in the “neighborhood.” Thirdly, the planet must be large enough to be round (or, at least, almost round). If the planet does not meet all three of these qualifications, it’s considered a dwarf planet.

Not everyone agrees with this classification, of course. Some say that not all of the planets have actually cleared their own neighborhoods, for example. Many astronomers refuse to follow the classification. Also, scientists like Mike Brown say there are actually lots and lots of “dwarf planets” out there, soon to be discovered.

Naturally, many people in the non-scientific community have had trouble letting go of Pluto as a planet. Remember grade school? Or, perhaps the 1930′s discovery. Also, when Eris was first discovered it was called the “tenth planet” which has lead to much media attention and some confusion. Still, at this point, there are officially nine planets.

Pluto No More

One of the most exciting astronomical decisions made in our lifetime is the decision to reclassify Pluto from the status of a planet, to the status of a dwarf planet. This has been a highly contested decision, and many astronomers do not necessarily agree with the decision. This landmark event comes after the definition of a planet is fully explained, and therefore Pluto does not fit the bill.
A planet is defined as a large star that is round in shape due to its own spinning and force. It also must be in control of the area near the planet. This would mean that any moons would have to be under the force of the spin of the planet of the orbit it shares. The original definition was that a large being had to have a moon within its orbit. The moon must also be somewhat smaller than the plant it orbits. In the case of Pluto, its moon is only half its size, and not necessarily under Plutos control.
The problem lies in that in order to be a planet, it is a rare claim. In fact, without Pluto, there are only eight planets in our solar system. With Pluto being added to the list of dwarf planet status, it joins a club of over 40 planets that are close by, and hundreds more that are known in our galaxy. The reclassification will bring about major changes on how the solar system is taught, how textbooks are written, and how the solar system is appears for school children.
All in all, what this means, is that there is a change within out galaxy, and that there will probably be many more to come. This is merely one instance of things that could affect the world we know in the future.

How Many Planets Are There?

Pluto No More

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