Mars is the fourth planet from the Sun at 228 million kilometers (142 million miles) away.
It is the next planet after Earth, which is 149 million kilometers (92 million miles) from the Sun.
Mars is distinct from the other planets because of its red appearance giving it the nickname "The Red Planet".Many years ago some scientists even had the idea that it may have alien civilizations, due to what looked like canals and dried up riverbeds on the planet.
Mars vs. Earth
Mars has a few items in common with Earth.
Both planets have polar ice caps and they both have a similar rotation time (24 hours for Earth and 24.6 hours for Mars).
In the lowest valley of Mars the air pressure is the same as that of the highest mountain on Earth.
In fact Mars has the closest living conditions to Earth of all the planets, even though it still wouldn't be easy to live there.
Mars is cold by Earth standards, with a typical temperature range of -60°C (-76°F) to 0°C (32°F).
However in Summer at the Equator Mars can reach a nice, warm 25°C (77°F).
But Mars may have once (many billions of years ago) been much warmer and wetter, very like Earth is now.
Layers of Mars
Like Earth, Mars has an iron core mixed with sulfur, with a mantle made of silicates. Where Earth's core is molten, Mars is a solid substance and does not move, and so creates no magnetic field for Mars to protect it from solar radiation.
In fact, the lack of a magnetic field is what scientists say killed off any life that could have been present on Mars.
The mantle does not move, and is soft and pasty. There are no indications of tectonic plates on the mantle that would change the surface like we have on Earth (where the mantle movement causes volcanoes to erupt).
The crust of Mars is made of basalt, a fine grained rock, and dust.
Mars has about 38% of the gravity of Earth, so a person weighing 45 kg (about 100 lbs) would only weigh about 17 kg (38 lbs) on Mars.
The movie "John Carter" based on the book "The Princess of Mars" by Edgar Rice Burroughs, shows the hero, John Carter trying to walk, run, and jump on Mars with the lack of gravity. While probably not the most scientifically perfect demonstration, it is amusing, and an interesting idea of what it might be like to try to walk on Mars.
Rotation and Revolution
While the length of a Martian day is almost the same as Earth's at 24.6 hours, a Martian year is almost twice as long as one on Earth.
It takes 687 days for Mars to revolve around the sun. Mars rotates on its axis similar to Earth giving it four seasons, except the seasons are about six months long rather than three.
Mars has a very thin atmosphere of 95% carbon dioxide (CO2), with 2.7% Nitrogen (N2), 1.6% Argon (Ar), and the rest miscellaneous elements.
Even though the planet is almost always cloudless, Mars can produce pretty strong winds, pretty strong for Mars that is.
Since the planet is not as dense as Earth the strongest winds clocked at 90 kph (60 mph) are not as impressive as the same speed of wind on Earth.
But since the planet is covered in dust, from the lowest valley to the tallest mountain, the winds tend to blow the dust around hard enough to form sand dunes, cause avalanches, landslides, and dust storms.
Nothing is safe on Mars from dust or wind, even Olympus Mons (pictured), a volcano on Mars, and the highest mountain in the entire Solar System, has dust covering it.
Mars has two moons, Phobos (pictured) and Deimos.
Scientists believe that these moons are actually asteroids that became trapped in Mars' gravitational pull.
Phobos (meaning "fear"), orbits Mars closer than any other moon to its home planet in the solar system. Phobos may crash into Mars one day, as its orbit is beginning to decay.
Do not be alarmed, it is happening at a rate of only 60 feet per century, so it would be millions of years in the future.
Deimos (meaning "panic"), is Mar's other moon, and is the smallest moon in the Solar System.
Living on Mars
Even with the cold temperatures, dust storms, low air pressure, lack of oxygen or water, and distance against them, scientists are still discussing potential human colonization in the future.
And, NASA revealed in March of 2013 that a robotic rover named Curiosity that had been on Mars for seven months found something that made scientists extremely happy. While there, it dug up a piece of clay from what was thought to be a three billion year old lake. The clay was said to contain fresh water, nitrogen, hydrogen, and other elements that form life. We may be closer than we think.
(Images courtesy NASA.)