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!

A Little Hump Day Treat

I’m putting up another post in a few, but I wanted to share this website…

Just in case you ever wanted to know how much you would weigh on other planets

Robert’s Out of This World Space Odyssey: Neptune, The Final Planet

Neptune is the 8th and outermost planet in our solar system (Pluto is no longer a planet and we will talk about that another time), orbiting 2.8 billion miles (4.5 billion kilometers) away from the sun. That makes Neptune far enough away for people on Earth not to be able to see it without a telescope. Even then it just looks like a fixed star. If you remember an older post, you will know that since Neptune is hard to see from Earth (impossible without a telescope), it is actually the first planet discovered using math. Two astronomers working in the mid-nineteenth century, John Couch Adams and Urbain Le Verrie, both realized that the orbit of Uranus was not as predicted – something with a large gravitational force must be altering it. It must be another planet. On September 23, 1846, Neptune was discovered and named after the Roman god of the sea (the international community of astronomers didn’t like naming the planet after Le Verrie).

Neptune is roughly 4 times bigger than Earth and is comprised mostly of hydrogen, helium, water and silicates (the stuff you make rocks out of). Like its sister ice giant, Uranus, Neptune has an inner rocky core (about the size of Earth), surrounded by a liquid layer that blends into layers of thick clouds. These clouds whip around the planet, sometimes at speeds greater than the winds on Jupiter. The clouds contain methane, which provides the planet’s brilliant blue color.

Being the farthest from the sun also means taking the most time to complete an orbit. One full year (a complete orbit around the sun) on Neptune takes 165 Earth years. One day on Neptune (full rotation around its axis) lasts 16 hours 7 minutes.

Neptune has 6 thin, hard to notice and non-uniform rings. It also has 13 identified moons. Triton is the largest moon and is the only major moon in the universe to orbit a planet in the opposite direction the planet rotates. It is believed that Triton started life as a comet orbiting the sun. One day it got a little too close to Neptune and before it realized what was happening; it got sucked into orbit by Neptune’s gravity and became a moon. The surface of Triton is the coldest known place in our solar system, coming in at a bone chilling -390°F (-235°C).

And that’s it. You have now learned a little something about all of the planets in our solar system. I hope you enjoyed our lovely little space odyssey!

Robert’s Out of This World Space Odyssey: Uranus, Haha, You Said Uranus

You better grab a parka and some hot chocolate, because we have arrived at the ice giants.

At a distance of 1,784,860,000 miles (2,872,460,000 kilometers) from the sun (a distance that takes light almost 3 hours to travel), Uranus is orbiting though the suburbs of our galaxy. Discovered by astronomer William Herschel in 1781, Uranus is the first planet discovered since ancient times.

When you talk about the orbit of Uranus around the sun, you are starting to really talk about a distance to travel. One year on Uranus (a full orbit around the sun) takes 30,685 Earth days or a little more than 84 Earth years. Most people don’t even live that long. One day on Uranus is a little faster than an Earth day, only taking 17 hours 14 minutes. What is fun about the rotation of Uranus around its axis is that this plant basically rotates on its side. Scientists believe during formation something about the size of Earth smacked into Uranus and knocked it onto its side. Being tipped on the side means that for the majority of the Uranian year only the poles receive light and leave the rest of the planet in the dark. To make the rotation even better, like Venus, Uranus rotates retrograde (east to west) – you know, just to be different.

Uranus is a ball of gas and liquid about four times the size of Earth. Due to its distance from us, there is a lot of speculation about the composition of Uranus. It may have a solid rocky core, about the size of Earth, surrounded by a liquid sea full of dissolved ammonia. Above this sea would be layers of thick water clouds stocked full of frozen ammonia crystals. Topping the atmosphere off are blue-green clouds comprised of frozen methane crystals. Similar to the other gas giants, Uranus is probably a planet covered in high winds and violent storms.

William Shakespeare wrote in a Midsummer Night’s Dream, “Sweet Moon, I thank thee for thy sunny beams; I thank thee, Moon, for shining now so bright.” Astronomers liked that line, so they decided to name the moons of Uranus after Shakespeare’s characters. All of the moons orbit the planet in the same way it rotates (the orbits look like they go up and over then back under the planet, versus around it like our moon). Oberon and Titania are the largest moons (they are also the king and queen of the fairies). Miranda is the smallest and innermost moon and is also the most unique moon in the galaxy. It has a cavern 12 times deeper than the Grand Canyon. Uranus has 27 identified moons and more are expected to be found.


We know there should be more moons because something needs to explain the extra gravity being provided to help hold together Uranus’ rings. Yup, Uranus has rings too. An inner ring system found in 1977 and an outer ring system found in 2003. In 2007 it was observed that the outer rings are really brightly colored. See, look, 2007 – that is not long ago. There is still so much to learn about the planets!

Robert’s Out of This World Space Odyssey: Saturn, The Diva

When Galileo was just sitting on his balcony, having a lovely glass of limoncello, nibbling on a cannoli and looking into the havens through his telescope, he saw the 6th planet from the sun. This is the last planet anyone on Earth will be able to see with a naked eye. As Galileo sketched the planet, he noted two spheres on either side of the main body. He drew them on as handles attached to the planet and assumed this planet must be a triple-bodied system. Not until Dutch astronomer Christiaan Huygens came along in 1659 did the world realize that this planet was actually surrounded by thin rings. Now Saturn and her rings is the most recognizable planet in our solar system.

Saturn (named after the Roman god of agriculture) is the second largest planet in the Milky Way. Much like Jupiter, Saturn is a gas giant comprised mostly of hydrogen and helium, with a possibility it may have a solid rocky core. Saturn has earned the title of least dense planet. It is 1/10 the density of Earth and 2/3 the density of water. If you could put Saturn in a giant bucket of water, it would float.

This ball of gas can whip around the sun once every 10,759 Earth days. That means one year on Saturn is equal to 29.5 Earth years. One day on Saturn (a full rotation around its axis) takes 10 hours 39 minutes – just a little slower than Jupiter.

The weather on Saturn is also comparable to Jupiter. Saturn has layers of various gasses at different temperatures that give the presence of colorful cloud bands covering the planet. High winds keep the clouds moving.

Everyone knows Saturn because of her rings. Rather than one giant ring, Saturn has a system of rings that rotate around the equator and never touch the planet. Narrow ringlets of ice and rock particles (ranging in size from a grain of sand to the size of a house) come together to form the 7 major rings of Saturn. The particles are believed to come from asteroids, comets and pieces broken off of Saturn’s moons. The rings rotate at various speeds and can reach widths of almost 180,000 miles (300,000 kilometers) across. They may be wide, but they are not thick – they vary from 660 to 9,800 feet (200 to 3,000 meters). In some places the rings may only be as thick as a tall person. There are also several gaps in the rings, with the largest (the Cassini Divide) being 4,800 kilometers (3,000 miles) wide. This gap is caused by the gravitational force of one of Saturn’s moons, Mimas.

Saturn has 53 naturally orbiting moons. The moons are all uber interesting – some actually orbit right in the middle of the rings creating gaps. The largest of all the moons is Titan. Titan is the second largest moon in the galaxy (it’s bigger than mercury). It has a strong gravitational force and alters the orbit of some of Saturn’s other moons. Titan is the only moon in our solar system with an atmosphere. What makes its atmosphere even more interesting is that it is 95% nitrogen – the same as Earth’s early atmosphere. Studying Titan could teach scientists how the Earth formed billions of years ago.

Robert’s Out of This World Space Odyssey: Jupiter, The Big Boy

Bring on the gas giants! And what better one to start with than the biggest planet in our solar system, Jupiter.


Jupiter is a big boy. In fact, it is so big that it Jupiter and its moons are basically a mini solar system within our own. When I say big, I mean big (compared to the other planets). It would take over 1,000 Earths to make something the size of Jupiter. Being so big makes it easy to see from Earth with the naked eye. Jupiter will be the second brightest planet in the sky (second to Venus). Because of its size, the ancient Romans named this planet after the king of their gods, Jupiter (the Greeks called it Zeus).

There is very little (if any) solid material on Jupiter – it is a giant ball of gas and liquid. It is comprised mostly of hydrogen and helium (more similar to the sun than the Earth), but there may be a very small solid metal core. If Jupiter was 80 times larger, it actually would have become a star and not a planet. Being so large also means it is the most massive (heaviest) planet, but since this weight is primarily Hydrogen and Helium (the two lightest elements), it is not very dense.

It takes this ball of gas 4,333 Earth days (about 12 years) to orbit around the sun. Jupiter can make one full rotation on its axis in 9 hours 56 minutes. That is faster than any other planet. Spinning so fast makes the center of Jupiter bulge out such that the diameter of the planet 7% larger at the equator than at the poles.

The average temperature of Jupiter (taken at the level we would consider ground level and also where any life would be, if there is any) is 70°F (21°C) – that is room temperature on Earth. Other than pleasant temperatures, the weather forecast on Jupiter calls for clouds and wind. The clouds are made of different chemicals that provide Jupiter with its fun colors. The high clouds of frozen ammonia are white and the darker blue clouds are found below them. The Great Red Spot is this planets most distinguishable beauty mark. It is a swirling spot of gas that is big enough for three Earths to fit inside of it. It really doesn’t move much and can shift colors from opaque to deep red (the color comes from small amounts of sulfur and phosphorous mixed with the ammonia crystals).

No giant planet wants to travel alone and Jupiter is no exception. This planetary rockstar has picked up a bunch of moons – 62 to be exact. The largest four, the Galilean moons (they were discovered by Galileo) are Io, Europa, Ganymede and Callisto. Jupiter is so big that it even has enough gravity to hold a comet in orbit.

A little known fact to most people is that Jupiter also has rings. That’s right, take that Saturn, you’re not the only one! Discovered in a picture taken by Voyager 1, the rings of Jupiter encircle the planet right around the equator. Jupiter has 3 faint rings that are made of tiny partials (similar to the size of particles in cigarette smoke). The main ring is around 20 miles (30 kilometers) thick and has an outer edge approximately 80,000 miles (129,000 kilometers) from the center of the planet.

Robert’s Out of This World Space Odyssey: Mars, Who Earth Would Borrow a Cup of Sugar From

Wave to Earth as we pass by on our way to the next planet: Mars!

On a dark night, with a good idea where to look, you can see Mars from Earth. It will look like a bright red dot in the night sky. The ancient Romans named this planet after their god of war and destruction because of its blood red color.

Mars is Earth’s closest neighbor – only 33,900,000 miles (54,500,000 kilometers) away at its closest. Although not the smallest, Mars is no giant. It is about half the size of Earth. The planet does have a very thin atmosphere that is thick enough to have some clouds and weather patterns. The average temperature on Mars is -80°F (-60°C), but can range from -195°F (-125°C) at the poles to around 70°F (20°C) at the equator. Mars has a similar solar day to Earth that lasts 24 hours 39 minutes 35 seconds long. A year on Mars lasts 687 Earth days and is complete with seasons (thanks to a lovely tilt on the axis).

Just like all of the other rocky planets, Mars is covered with volcanoes, valleys, large continents, rocks, blah, blah, blah. Mars is famous for its color, which it gets from its dirt. The soil on Mars contains lots of iron-rich minerals which provide the lovely rust color. Unlike the other rocky planets, Mars does not have a magnetic field. So if you ever get lost there, don’t bother with a compass.

Accompanying Mars through its cosmic voyage are its two moons (satellites): Phobos and Deimos. Named after the two sons of the god Aries (the Greek version of the god Mars), these two moons are not exactly what you think of when you think of a moon. They are very small (Phobos is the largest with a diameter of 17 miles and then Deimos with a diameter of 9 miles) and irregularly shaped. In space, things become round because gravity pulls of them. These two moons are too small to have their own significant gravitational force. Although still debated, it is believed that these moons were actually asteroids that came a little too close to Mars and got stuck in orbit around the planet.

I would hope that all of you have at least heard about the missions to Mars. The world is very interested in studying our closest neighbor. Finding water on the surface of Mars was a huge deal and hints that life may be possible on this planet.

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.

Robert’s Out of This World Space Odyssey: Mercury, the Littlest Planet

Let the exploration of the Milky Way Galaxy commence! I posted about stars a few weeks ago, so now let’s talk about the planets! I heart all of the planets equally so we'll just talk about them in order, starting with Mercury...

Mercury is the small planet right next to the sun. It is the smallest planet in our solar system (about the size of Earth’s moon), but is the second (to Earth) most dense planet. Being dense basically means it is really heavy for its size (science people are cringing at this definition, but it works, so back off!). Mercury is the closest planet the sun. At its closest it is only 28,580,000 miles (46,000,000 kilometers) away from the sun’s surface. Being so close to the sun means daytime temperatures on the surface of this tiny planet reach a sweltering 430°C (800°F). Mercury does not have an atmosphere (atmospheres are like a big blanket - they can hold in warmth and keep out space trash) so a night on Mercury usually plummets to around -180°C (-290°F). Imagine dressing to go out for dinner.

Mercury is named after the Ancient Roman god, Mercury. Mercury (the god) was the FedEx god who could get places the fastest with his super-fly winged shoes. The name is fitting since the planet Mercury orbits the sun faster than any other planet. One year (a full rotation around the sun) takes Mercury 88 Earth days. A day on Mercury (one full rotation around the axis – an imaginary line running through the center of the planet) is 59 Earth days long. Since it is going around the sun so quickly, but rotating so slowly, it takes 176 Earth days to have 1 solar day (to go from sunrise to sunset). Isn’t that kind of bizarre?

Being so small and close to the sun makes seeing Mercury a little difficult. Thirteen times a century, Mercury will pass in front of the sun and people on Earth will be able to see the planet (this is called a transit). The next time we can do this is May 9, 2016.

In 1974-1975 the US space probe, Mariner 10, did flybys of Mercury and provided people on Earth with the first up close images of the planet. Basically, it looks like our moon – it’s full of craters and mountains created by comet and meteor impacts. Radar imaging done in 1991 shows that despite being so hot, the poles (which stay cold) may contain frozen water. NASA has the Messenger probe aimed at Mercury now. The probe did flyby pictures in 2008 and 2009. Messenger will settle into orbit around Mercury in 2011 and study the planet’s composition and magnetic field for a year.

He got big ego, such a huge ego...

A dear friend of mine (who is also about to become a year older) found these pictures for me. I'm a visual kind of guy so obvi I love them!

The first couple images are straight forward...






Sirius (a fairly close star) is the brightest star in Earth’s night sky. Pollux is 34 light years away and is the brightest star in the Gemini constellation. Arcturus is the second brightest star visible from the northern hemisphere (3rd brightest overall) and is the brightest in the constilation Boötes.


Rigel is a blue supergiant that is the sixth brightest star in the sky. It is the brightest star in the constellation Orion. Aldebaran is an orange giant star that is the brightest star in the constellation Taurus. It is 65 light years away from us. Now for the big boys…

Betelgeuse is a red supergiant and is one of the biggest stars known to be in existence. It is 640 light years away and is the second brightest (second to Rigel) star in Orion. Based on lots of complex math, Betelgeuse has a diameter estimated to be around 1000 times that of our sun. Betelgeuse is expected to become a supernova (see my past post about stars) within the next 1000 years. When this happens it will be so bright that it when people look up at the night sky from earth, it will be brighter than the moon!

Antares is also a red supergiant that is 600 light years away. It is the brightest star in the constellation Scorpius. This star is HUGE with a diameter of around 1,600 times the size of our sun. If you replaced our sun with Antares, it would eat up the inner planets and have its outer border between Mars and Jupiter.


What’s crazy is that there are almost certainly even bigger stars that we have just never seen!
If that doesn’t make you feel small and humble to the universe, you have an ego problem!

And here is the website the pictures are from, if you're interested: http://www.stumbleupon.com/su/9LspdV/www.rense.com/general72/size.htm