- "I feel sorry for Pluto"
- "I'm sad Pluto is gone"
- "What happened to Pluto?"
First a Few Facts About Pluto:
- Discovered in 1930 by a US astronomer. It was originally classified as a planet. Pluto was the smallest planet in our solar system and the 9th planet from the sun.
- It exists in the Kuiper Belt (an asteroid belt) and is mostly made of rock and ice.
- Pluto's orbit is oval, so at times its closer to the sun than other times. On average, Pluto is 3.6 million miles from the sun. That is 40 times further from the sun than Earth.
- Pluto is only 1,400 miles wide...that's about half the width of the United States...so Pluto is actually slightly small than Earth's moon.
- It takes 248 years for Pluto to orbit the sun and one day on Pluto is about 6 1/2 Earth days.
- Pluto has three moons, it's largest is Charon. The other two moons are Nix and Hydra.
- Conditions on Pluto are very cold. Temperatures range from 375-400 degrees below zero. It is believed that Pluto is covered in ice.
- Pluto gravity is only 1/15 of that on Earth. A person who weighs 100 pounds on Earth would only weight 7 pounds on Pluto.
What Happened To Pluto:
In 2003, an astronomer found a new object beyond Pluto. Thinking this new object was a planet, it was named Eris. The discovery of Eris was the start of Pluto's downfall as a planet. Eris caused other astronomers to discuss the topic...what makes a planet a "planet".
In 2006, the International Astronomical Union (IAU) formally defined what a planet is. This new definition excluded Pluto and reclassified it as a member of the dwarf planets.
The IAU defined three conditions for a planet to be consider a "planet":
- The object must be in orbit around the Sun.
- The object must be massive enough to be a sphere by its own gravitational force.
- It must have cleared the neighborhood around its orbit.
In 2006, NASA launched the first mission to Pluto, called New Horizons (pictured above). New Horizons is a spacecraft about the size of a piano, that is going to the edge of our solar system. It will take about 9 years to reach Pluto. So in 2015, New Horizons will arrive at Pluto and spend more than 5 months studying Pluto and its moons. New Horizon will then study other objects in the Kuiper Belt.
Thank you for visiting,