Mars, the fourth planet, is nearly 230 million km. from the Sun.
The planet is Earth's neighbour. It is much smaller than Earth.
Mars was named after the Roman god of war.

It is often called the Red Planet, because it is reddish in color.
There is a large amount of iron oxide (rust) in the soil and rocks.
In the night sky Mars appears as a reddish-orange dot.
Mars has two tiny moons which orbit very close to the planet.

The first spacecraft to visit Mars was Mariner 4 in 1965.
When Mariner 9 orbited Mars it found what looked like
gullies and dried up river beds. Mars has no water now.
There are mountains, volcanoes, canyons, valleys and plains.
Much of the surface of Mars is very old. There are many craters.
Ice caps at the north and south poles are composed
mostly of solid carbon dioxide (dry ice).

Mars - polar ice cap - photo taken by Hubble Space Telescope
Image Credit: NASA, J. Bell (Cornell U.), and M. Wolff (SSI)

Mars orbits the Sun every 687 Earth days and rotates
on its axis once every 24 hours and 37 minutes.
A year on Mars is almost two Earth years in length.
Mars has four seasons, but the seasons are longer than on Earth.
This is because of the orbit that Mars takes around the Sun.
It is a cold planet with lows that reach -140 degrees C (-220 F).
In the summer the temperature can be as high as 20 degrees C (68 F).

The atmosphere is quite different from that of Earth.
It consists mainly of carbon dioxide with traces of water.
During daylight wispy clouds form high above the surface.
After sunset the clouds thicken and are closer to the surface.
There are very strong winds and dust storms on the planet.

Pathfinder mission - the surface of Mars - Twin Peaks
( Image Credit: NASA/JPL-Caltech)

On July 4th, 1997, the spacecraft Mars Pathfinder successfully landed
on Mars and collected data and images for almost three months.

In 2003 NASA sent two rovers to explore the surface and geology of Mars.
This mission is called the Mars Exploration Rover Mission.
As of January 2009, both rovers are still sending back images.

The European Space Agency (ESA) mission called
the Mars Express was launched in 2003.
Photo - a large canyon Valles Marineris
NASA's Mars Reconnaissance Orbiter, launched in 2005,
continues to collect data. Photo - ancient lava flow on Mars

The Phoenix Mars Lander touched down on Mars on May 28, 2008.
It has a robotic arm to dig up soil and collect samples to analyze.
There is also a weather station on the lander.

artist's concept of the Phoenix Mars Lander just before touchdown on the arctic plains of Mars.
image courtesy of - NASA/JPL-Calech/University of Arizona


NASA site
Mars - games, activities, images

web page by J.Giannetta
updated April 2009

photo of Valles Marineris, Jan 2004, courtesy of ESA
photo of ancient lava flow, Oct 2007, Image Credit: NASA/JPL-Caltech/University of Arizona
background from "http://www.geocities.com/SoHo/2000"