Why Is Pluto Not A Planet Anymore?
How Many Planets In The Solar System
Growing up, I completed many school projects, and one I recall most favourable was a project on our solar system. Using styrofoam balls, sticks and coloured paints, I constructed a unique-looking solar system with all 9 planets. Why 9 planets? Well that is how many planets there were when I was growing up.
Yes, 9 planets in the solar system.
Each with their own defining features, size and distance from the sun.
You would have been correct in any trivia contest if you said the planets were Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune and Pluto.
However, give this answer today and you would be wrong. Wrong? How can that be? Well, put simply, it is because Pluto is not considered a planet anymore.
Believe it or not!
Education for Kids
History of Pluto
Pluto was discovered in 1930 by an astronomer from the United States of America, and was identified as the smallest planet in our solar system and the 9th planet from the sun.
According to NASA, Pluto is:
- located more than 5.8 billion kilometres from the sun.
- Approximately 40 times as far from the sun as Earth is.
- A huge 2.300 kilometres wide.
- Very cold - temperature on Pluto ranges from 375 - 400 degrees below zero.
Pluto orbits the sun following an oval path, taking 248 years per cycle, and sometimes is closer to the sun than at other times. One day on Pluto is about 6.5 days on Earth.
A mission to Pluto is underway.
NASA launched its first mission to Pluto in 2006 under the name of 'New Horizons' which is scheduled to arrive in 2015. A 9 year journey. The New Horizon's spacecraft is about the size of a piano and is expected to spend at least 5 months investigating its new surroundings.
The spacecraft is fitted with cameras to take photos of Pluto which will be sent back to the astronomers so that they can learn far more about Pluto, the dwarf planet, than ever before.
Why Pluto Is Not A Planet Anymore
On August 24th 2006, an organisation of professional astronomers passed a resolution which revoked Pluto's status as a planet.
Pluto is not considered a planet anymore
Pluto is now categorised as a dwarf planet.
Nothing else has changed though. It still orbits the sun like before, it is still the same size as it was before, it still looks the same however because of its size and because it cannot clear other objects out of its way, it is considered dwarf and therefore is no longer one of the 9 planets in our solar system.
So now there are not 9 planets, but 8. How bizarre!
What is a dwarf planet?
NASA state that there are many criteria that help to correctly define and explain exactly what a dwarf planet is. The International Astronomical Union (IAU) defines a dwarf planet as ‘… is a celestial body orbiting a star.. large enough to be rounded by its own gravity...and is not a satellite..."
With the newest inclusion of Pluto there are five dwarf planets: Pluto, Eris, Makemake, Haumea and Ceres.
Here's a comical view associated with Pluto no longer being a planet
Remember this for your school projects, trivia competitions or keep it under your hat and be the smart one out of your friends.
Pluto is not a planet. Pluto is a dwarf planet.
Don't forget that there are now only 8 planets in our solar system.
Time to re-write history!
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