Sucks to be Pluto

The moment I finished the space odyssey, I began getting grief about not including Pluto. Sorry friends, but Pluto is not a planet. Sure it used to be, but it was downgraded. Like most other scientists I have to agree that it doesn’t deserve to be in the same class as bodies like Jupiter and Saturn.

The International Astronomical Union (IAU) is who started the drama around Pluto. They are the big shot organization that controls how we think about space. They are also the ones with the authority to name heavenly objects.

The drama started in January 2005 when Eris (official name: Eris 136199) was discovered. Eris was found orbiting out past Pluto in the Kuiper Belt. It was determined to be 27% more massive than Pluto. NASA started calling Eris the tenth planet and got excited about the high probability of finding more planets, but the IAU had something to say about that.

In August 2006, the IAU held a meeting in Prague and passed Resolution 5A. This resolution established guidelines to determine if something is a planet or a dwarf planet.

To be a planet, an object must:
1. Orbit the sun
2. Be large enough to produce enough gravity to make itself (mostly) round
3. Clear the neighborhood around its orbit

To be a dwarf planet, an object must:
1. Orbit the sun
2. Be large enough to produce enough gravity to make itself (mostly) round
3. Not have cleared the neighborhood of its orbit
4. Not be a satellite (moon)

All other objects (i.e. comets, asteroids, etc) are classified collectively as “Small Solar System Bodies”.

Pluto is tiny (only about 70% the size of our moon), but it is able to meet requirements one and two of being a planet. The problem lies in requirement three. Pluto orbits in the Kuiper Belt (basically the same thing as the asteroid belt, just a little larger. It starts right outside the orbit of Neptune). A true planet would have cleared the belt out of its orbit, but Pluto did not.

Picture from http://www.mathiaspedersen.com/

Just like that, Pluto got its planet card revoked. Our solar system only contains 8 planets (Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune). In Resolution 6A, Pluto was officially named a dwarf planet as well as the prototype for a new variety of trans-Neptunian objects, which (according to Resolution 6B) will be called “Plutonian Objects”.

Now Pluto gets to hang out with the other dwarfs, like Ceres and Eris.

Whatever, I would rather hang out with them anyway!

Robert’s Out of This World Space Odyssey: Venus, Earth’s Sweltering Sister

The odyssey continues with Venus! Holding the title of Earth’s twin, no other planet is more similar to Earth then Venus. Named after the Ancient Roman goddess of love and beauty (because of its beautiful and bright appearance in the night sky), Venus is similar to Earth in size, mass, magnetism and composition. It is also the closest planet to the Earth. At its closest, Venus is only 23.7 million miles (38.2 million kilometers) away from you.

Orbiting the sun in almost a perfect circle (remember that the planets orbit in an elliptical shape), a year on Venus lasts 225 Earth Days. The ancient Mayans tracked Venus’ orbit and used it to create their calendar. One day (one rotation) on Venus takes approximately 243 Earth days. Combine those two numbers with some fancy-pants physics and math and you will figure out that one lunar day (sunrise to sunset) on Venus is about 117 Earth days long. To make that long day a little more fun, Venus decided to switch it up a little and rotate on its axis retrograde (east to west). Earth rotates prograde (west to east). That means on Venus, the sun rises in the west and sets in the east. If Earth did that, I wonder if they would change TV show times and make the Eastern Standard Time an hour earlier.

Above all else, the trait Venus is most known for is how hot this sassy little siren is! Venus has a thick atmosphere (actually, the densest in the universe) mostly comprised of carbon dioxide and clouds of sulfuric acid. Doesn’t that sound lovely? Heat from the sun gets trapped inside the atmosphere causing surface temperatures on Venus to soar well above 470°C (880°F). Venus is a great place to study global warming due to green house gasses. And what better to add to temperatures hot enough to melt iron then hurricane force winds and acid rain?

Giant clouds containing sulfuric acid whirl around the outer atmosphere of Venus at 360 kilometers (224 miles) per hour. The lower the clouds, the slower the wind. One the surface, wind speeds are estimated to be gentle breezes. In addition to the clouds pouring down sulfuric acid rain, they also produce lots of lightning.

If you can get past the intense weather, the surface of Venus is mostly large, flat, smooth plains. The plains are dotted with thousands of volcanoes. There are also 6 mountain ranges on the planet and a few impact creators.


If you want to see Venus, just look into the night sky – it will be the brightest thing you see. Like Mercury, it will creep across the face of the sun (a transit) twice within roughly a century. The transits occur close together and the next one will be June 6, 2012.