SPACE

MERCURY

Mercury means:
In astronomy mythology, Mercury was the Roman version of the god Hermes. He was the messenger for the other gods, and for this reason Mercury is often depicted in pictures with winged sandals. In addition to delivering messages, he was also the protector of travelers, and merchants.

How much would you weigh on Mercury?
If you moved to Mercury you would not weigh as much as you do on Earth. Not because you would lose weight on the space ship, but because Mercury is smaller, and so has less gravity. If you weigh 70 pounds on Earth, you would weigh only about 27 pounds on Mercury.

The Planet:
Mercury is a world of extremes.  Because it is so close to the Sun a visitor could easily cook to death.  However because mercury spins so slowly it gets very cold in the night time, which means a visitor could also freeze to death. 
We are just starting to understand this world.  It looks a lot like our moon, because it has craters and  basins.   Scientists used to think it acted like the Moon,  but we are now learning that Mercury is in fact very different.  In 2004 NASA plans to send a orbiting probe to the planet to learn more about it. 

Moons:NO MOONS

DID YOU KNOW ?

Mercury is so close to the Sun, and so small, that it has only a very small atmosphere. It has been blown away by the Suns solar winds. That means that there is almost no air on Mercury.

VENUS

Venus means:
In astronomy mythology,Venus was the Roman goddess of love and beauty. In Greek her name was Aphrodite.

How much would you weigh on Venus?
Because Venus and the Earth are almost the exact same size, you would weigh almost exactly the same on either planet. If you weighed 70 pounds on Earth you would weigh 63 pounds on Venus.

The Planet:
Venus is a hostile planet.  Its thick cloud cover makes it impossible to see the surface, and traps much of the Sun's heat.   This extra heat gives Venus the hottest average temperature of all the planets. 
In many ways Venus is similar to the Earth.  It has active volcanoes, venusquakes, mountains and valleys.  The major difference is that Venus's atmosphere makes the planet far to hot for life. 

Moons:
Venus Has no moons.

DID YOU KNOW ?

Because Venus and the Earth are the same size, scientists call Venus Earths sister planet. For a long time most scientists thought that Venus had plants, animals, and possibly even people. However because Venus is so hot we now know that it is impossible for anything to live there.

EARTH

Earth means:
In astronomy mythology, Her Greek name was Geia. Earth was the mother of the mountains, valleys, streams and all other land formations. She was married to Uranus.

How big is the Earth?
The Earth is the biggest of all the terrestrial planets. A terrestrial planet is a dense planet found in the inner Solar System.

The Planet:
Our planet is  an oasis of life in an otherwise desolate universe.  The Earth's temperature, weather, atmosphere and many other factors are just right to keep us alive. 

Moons:
The Earth has one moon.  Its name is Luna. 

DID YOU KNOW ?

Scientists use the Earth to study all the other planets. Since no human has ever visited another planet, we have to use what we know about the Earth, and try to guess what the other planets must be like. This is called Comparative Planetology.

MARS

Mars means:
In astronomy mythology, Mars was the Roman god of war and agriculture. It may not seam like these two things go together, but they do. Mars protected those who fought for their communities, and stayed home to raise crops for food.

How much would you weigh on Mars?
If you weighed 70 pounds on the Earth, you would weigh about 27 pounds on Mars.

The Planet:
Mars excites scientists because it's mild temperament is more like the Earth's than any of the other planets.   Evidence suggests that Mars once had rivers, streams, lakes, and even an ocean.  As Mars' atmosphere slowly depleted into outer space the surface water began to permanently evaporate.   Today the only water on Mars is either frozen in the polar caps, or underground.

Moons:
Mars has two moons, their names are Deimos and Phobos. 

DID YOU KNOW ?

Mars has much higher mountains, and far deeper canyons than the Earth. Mars' biggest stretch from New York City to Los Angeles on the Earth. That makes the Grand Canyon look tiny. It Also has the Solar Systems biggest volcano called Olympus Mons.

JUPITER

Jupiter means:
In astronomy mythology, Jupiter known as Zeus in Greece over threw his father Saturn to become king of the gods. He then split the Universe with his brothers Neptune and Pluto.

How much would you weigh on Jupiter?
If you traveled to Jupiter on vacation you would be very heavy. If you weigh 70 pounds on the Earth, on Jupiter you would weigh 185 pounds.

The Planet:
Jupiter's great red spot visible in the picture to the right is where a giant storm has been raging for at least 300 years.  It's super hurricane winds blow across an area larger than the Earth. 
This giant planet has no solid surface.  Under it's atmosphere is a large liquid ocean of hydrogen and water.  What lies in between that ocean and the atmosphere?  Actually there is no in between.  The atmosphere slowly gets thicker and thicker until it becomes part of the ocean.  In other words Jupiter's ocean has no surface on which you could float a boat.  The sky slowly becomes the ocean.

Moons:
Jupiter has 28 moons.  Their names are Metis, Adrastea, Amalthea, Thebe, Io, Europa, Ganymede, Callisto, Sinope, Leda, Himalia, Lysithea, Elara, Ananke, Carme, Pasiphae W1302, W1700, W1704, W1704_2, W1800, W1903_s, W1805, W1902, W1904, W2002_2, and W1700_2. 

DID YOU KNOW ?

You can see four of Jupiter's moons With a pair of binoculars at night. Also Jupiter spins really fast. It only takes 10 hours to go from night to day on Jupiter. For that reason its middle has been stretched out. Rather than round it is short and fat. Kind of like when someone spins pizza dough really fast to stretch it out.

SATURN

Saturn means:
In astronomy mythology, Saturn was the god of agriculture, he was called Cronus by the Greeks. He is the son of Uranus, and father of Jupiter. Saturn over threw his father to become king of the gods, but was then over thrown himself by his son Jupiter.

How much would you weigh on Saturn?
Because Saturn is bigger than the Earth, you would weigh more on Saturn than you do here. If you weigh 70 pounds on Earth you would weigh 82 pounds on Saturn.

The Planet:
Saturn is a favorite object for many observers.  It's beautiful rings are 169,800 miles wide, but less thick than a football field.  In many ways Saturn is similar to Jupiter, but it is much smaller.  Under the clouds of methane and helium the sky gradually turns into liquid until it becomes a giant ocean of liquid chemicals. 

Moons:
With 30 companions, Saturn has more moons than any other planet.  The names of Saturn's moons are as follows:  Pan, Atlas, Prometheus, Pandora, Epimetheus, Janus, Mimas, Enceladus, Tethys, Telesto, Calypso, Dione, Helene, Rhea, Titan, Hyperion, Iapetus, Phoebe, S/2000 S 1, S/2000 S 2, S/2000 S 3, S/2000 S 4, S/2000 S 5, S/2000 S 6, S/2000 S 7, S/2000 S 8, S/2000 S 9, S/2000 S 10, S/2000 S 11, and S/2000 S 12.

DID YOU KNOW ?

Saturn has several hundred rings. However it is not the only planet with rings. Jupiter, Uranus, and Neptune also have rings.

URANUS

Uranus means:
In astronomy mythology, Uranus was the lord of the skies and husband of Earth. He was also the king of the gods until his son Saturn overthrew him.

How much would you weigh on Uranus?
It would take you many years to fly a rocket to Uranus. When you arrived you would weigh more because Uranus is bigger than the Earth . If you weigh 70 pounds on the Earth you would weigh 82 pounds on Uranus.

The Planet:
Uranus is very odd.  Unlike all the other planets and most of the moons in our Solar System Uranus spins on its side.  It is believed that long ago a very large object smashed into this planet.  The crash was so powerful that it completely changed the direction of Uranus' spin. 
Uranus may have an ocean of water beneath its clouds.  It has a large rocky core, and because of the tremendous pressure could possibly contain trillions of large diamonds. 
Uranus is almost identical to the planet Neptune.

Moons:
Uranus has 21 moons. Five of these moons are large, and the rest are smaller.  Their names are:  Cordelia, Ophelia, Bianca, Cressida, Desdemona, Juliet, Portia, Rosalind, Belinda, Puck, Miranda, Ariel, Umbriel, Titania, Oberon, Caliban, Sycorax, Prospero, Setebos, Stephano, and 1986U10.

DID YOU KNOW ?

Scientists think Uranus has a huge water ocean underneath its clouds.

NEPTUNE

Neptune means:
In astronomy mythology, Neptune was originally only the god of water, but was latter extended to the ocean when he became associated with the Greek god Poseidon.

How much would you weigh on Neptune?
If you weigh 70 pounds on the Earth you would weigh 84 pounds on Neptune.

The Planet:
Neptune has a giant storm much like the storm on Jupiter.   This storm is often called The Great Dark Spot.  We do not know how long this storm has been active, because it is so far away that we could not get a good view of Neptune until modern times when we began to send robot explorers.
For many centuries people did not know that this planet even existed.  It was discovered by Johann Galle and Heinrich D'Arrest in 1846. 
Neptune has six rings which circle the planet. 

Moons:
Neptune has eight moons that we know of.  Because Neptune is so far away, it is difficult to see any of these worlds.  There are probably many more moons orbiting this blue planet which we have not yet discovered.  Perhaps you will be the astronomer who discovers some of these worlds.  The names of the known moons are:  Caliban, Sycorax, Prospero, Setebos, Stephano, and 1986U10. 

DID YOU KNOW ?

Scientists think there is a very large water ocean under Neptune's clouds.

PLUTO

Pluto means:
In astronomy mythology, Pluto was thought to be the god to whom all men must eventually go. Romans believed him to be the god of the underworld. His name in Greece was Hades.

How much would you weigh on Pluto?
Because Pluto is so small you would be very light if you visited. If you weigh 70 pounds on Earth, you would only weigh 4 pounds on Pluto.

The Planet:
Pluto is smaller than 7 of the moons in the Solar System.  Because it is so small many scientists don't consider it a planet at all.  In 1999 a group of scientists attempted to redesignate Pluto as a comet. 
Pluto is the only planet that has never been visited by space craft.  Because we have never sent probes to this planet we know very little about it. 

Moons:
Pluto has one moon named Charon.  Charon is only slightly smaller than it's parent planet Pluto.  For this reason Pluto and Charon are often called double planets.  The Earth and it's moon Luna are also considered double planets.

DID YOU KNOW ?

Pluto is so far away, that no satellites have ever been sent there. This means that we have no good pictures of it. All we can do is guess what it must look like. The picture above was taken by the Hubble Space Telescope. It is the most detailed picture we have.