Mercury is a very desolate and strange world. It's extremely dense, and thought to be composed of almost 75% Iron. Like Venus it has no moon of it's own.

There is some speculation that Mercury, because of it's iron content, might be the iron core remnant of a failed Neptune or Uranus like planet. It formed to close to the Sun, and when the sun ignited, it striped the planet of all its atmosphere.

It could also be the core remnant of the planet that might have been responsible for the Asteroid belt (See Below) and fell into a close orbit with the Sun.

Image used with NASA's public release rights, Ref: NASA/JPL/Mariner

Venus is the closest neighbor and similar in size and mass to The Earth. There the similarity ends, its super dense atmosphere mostly CO2 with Sulfuric Acid clouds, make this world even hotter then Mercury even though it's further from the sun. Its temperatures in places reach over 450°C(842°F) which is hot enough to melt lead.

It's also an odd planet in that it is the only sizable planet in our solar system, without any moon. It also rotates in the opposite direction then all the other planets. On Venus, The sun rises in the West and sets in the East! There is only speculation on it's odd rotation, and nothing really proven as to why it is that way. Thankfully it orbits the sun in the same direction as the other planets.

Thumbnail of image used by courtesy rights granted by © Calvin J. Hamilton, please visit his website website http://www.solarviews.com/ for full sized images. It's also a great resource on our Solar System!

It's our home World. See our Earth page for more details. Earths moon is a bit unique, as it was formed by a collision early on in The Earths history by a object with roughly the mass of mars. So moon rocks, and earth rocks have roughly the same trace gas elements inside them.

But the moon has almost no iron in it's core, the iron from the impactor planet, (nick named Osiris by some) merged with the earths core.

Image used with NASA's public release rights, Ref: NASA/USGS/MODIS

The Red Planet as seen by the Hubble Telescope. It's another strange world in that it does have water (as the clouds prove) but is so cold and dry it's a desert planet. For a short time in it's life, it had oceans, and a substantial atmosphere. But even though it's half the diameter (size) of Earth, it only had a tenth of the mass so it atmosphere bled off into space. It's once molten iron core eventually cooled, and both the volcanoes, and the core itself shut down. When this happened its volcanic out-gassing, now done, no longer replaced the air it lost.

It 'may' have had one period of renewed warmth and water due to a large impact from a meteor.

But again, the oceans slowly froze into the ground, leaving a dead rust colored world. If it had only held maybe a half of earth mass, it would be a habitable, if a bit chilly of a world.

Although there has been some talk about 'Terraforming' Mars (making it more earth like) it really isn't practical. It just doesn't have the mass to hold onto an Atmosphere.

Image used with NASA's public release rights, Ref: NASA/StScI/Hubble

The asteroid belt is nestled between the orbits of Mars and Jupiter. It's considered either a failed planet (Jupiter's proximity prevented it from forming) or a destroyed planet. The variety of their composition seems indicate the first theory is the more likely, as does the lack of mass.

However, we've discovered the even single planets have a variety of different compositions, a destroyed world might leave behind around 5 different types of asteroids, 2 planets colliding might lead to even more, around 10 or so.

The leading theory for the destroyed scenario, has a 1.5 mass earth sized world, named Titanica, with Mars as a Habitable Moon, being impacted by a .8 Earth mass planet, asteroid, or super comet. It might have survived that, if it hadn't been for Jupiter's gravity, which finished pulling the planet apart, and dispersed it's remains into the now Asteroid belt. The lack of mass now can be explained by scattering of the remains into and out of the solar system. Mars moved into a lower orbit, after suffering a huge impact from the remains, (Hellas Impact Crater). Without it's parent planet, Mars lost it's tectonics, leading to the loss of its air. Asteroid Vesta also appears to be the core like remains of something, lending some credence to this.

Both theories have equal validity, its one of the mysteries yet to be solved.

The picture is of Asteroid Ida and it's very tiny moon Dactyl, used with NASA's public release rights, Ref: NASA/JPL/Galileo

Discovered in 1801 this planet has changed status from planet to asteriod, to planet, then back, and now finally to Dwarf Planet.

Not much is known about it other then is appears to have a thin atmosphere and is warm enough for water frost to form.

Although a Dwarf Planet it is also a member of the asteriod belt objects, and the largest containing a full third of the estimated total mass in the asteroid belt.

Image used with NASA's public release rights, Ref: NASA/StScI/Hubble

The largest planet in our Solar system. Jupiter with it whooping 63 Moons!, is a prime example of a failed solar system within a solar system. If Jupiter had only 13 times more mass, it would of been a Red or Brown Dwarf star, and it's moons would of been called Planets.

Use the link below to see a highly detailed, and one of the best photo's of our gigantic neighbor. It's one of my favorites, the amount of detail is just breathtaking. It was taken by the Cassini Space Craft as it flew by Jupiter on it's way to Saturn.

Image used with NASA's public release rights, Ref: NASA/Cassini/APOD

The second largest planet in our solar system, Saturn and its is 31 moons are currently being studied by the Cassini Space Craft.

Although it's not as as picturesque as Jupiter, its rings more then make up for that. Actually the truth is once you penetrate Saturn's hazy atmosphere, it looks a lot like the stormier Jupiter

Image used with NASA's public release rights, Ref: NASA/JPL/Cassini

The third largest planet in our solar system (bet less massive then Neptune) Uranus is a complete odd ball. Most planets equator's are lined up with the sun, however Uranus is tilted 90 degrees, such that it's poles face the sun. Which pole faces the sun depends on where it's at in it's orbit. It also has quite a few moons, 21 named and 6 still unnamed.

Also a ringed planet, it's rings are tilted along with the planet. There is only speculation as how Uranus got tilted or formed this way, as it doesn't fit with planetary models well. One speculation is that a long time ago our solar system passed through another, and Uranus got to close to that systems sun or one of it's Jupiter like worlds, which as they passed through, pulled Uranus' axis off center to it's current position.

Image used with NASA's public release rights, Ref: NASA/StScI/Hubble

The forth largest planet in our solar system (but more massive then Uranus) it probably has rocky/iron core about the size and mass of Earth and also has some very faint rings. Because of Pluto's eccentric orbit, sometimes Neptune is actually further away then Pluto.

It sports 13 moons, only one of which is sizable called Triton, a full third the size and mass of Mars.

Image used with NASA's public release rights, Ref: NASA/StScI/Hubble

The smallest planet in our system (excluding planetiods) Pluto and is companion Charon have a eccentric orbit that carries it in side the orbit of Neptune at its closest, and out into the Kruiper Belt at it's farthest. Compared to other systems, it's moon Charon is proportionately the largest for it's planets mass. Charon is fully 1/2 the diameter of Pluto, and 1/6th of it's mass.

Pluto and Charon have two small moons, Nix and Hydra which orbit around the bary center (The gravitational Center between Pluto and Charon) of the double planets.

The Pluto-Charon system will soon be visited (around 2015) by the New Horizons Space Craft.

Image used with NASA's public release rights, Ref: NASA/StScI/Hubble

The most recent addition to our Solar system, Planet Eris and it's moon Dysnomia!

First discovered in 2003, then determined a solar system object in mid 2005, prematurely announced in late 2005. It is currently the object of most interest right now. It's Larger then Pluto, and possibly even colder.

The name Eris is after the Roamn goddes of Stife and Discord, and was given this name for the issues it's discovery caused in the IAU about planet classifications.  It's moon Dysnomia, is after the roma Goddess of Lawlessness.  And intrestingchoice is as its code name Xena, the actress of Xena was Lucy Lawless.

Like Pluto, it's a member of the Kuiper Belt objects.

Artists rendering image used with NASA's public release rights, Ref: NASA/JPL/Caltech

This may be the first dwarf planet of it's class, as it's orbit exists outside of the Kuiper Belt objects, making it a  an Inner Oort Cloud object.

Artists rendering image used with NASA's public release rights, Ref: NASA/JPL/Caltech