The gorges span about 2, miles and cut up to 4. The valleys get their name from Mariner 9, which became the first spacecraft to orbit another planet when it arrived at Mars in About 4. The highlands of the southern hemisphere, however, are studded with many extinct volcanoes, and the crust there can get up to 62 miles thick.
What happened? At some point in the distant past, the red planet gained its two small and irregularly shaped moons, Phobos and Deimos. The two lumpy worlds, discovered in , are named for the sons and chariot drivers of the god Mars in Roman mythology.
How the moons formed remains unsolved. But recent models instead suggest that they could have formed from the debris flung up from Mars after a huge impact long ago. Deimos, the smaller of the two moons, orbits Mars every 30 hours and is less than 10 miles across.
Its larger sibling Phobos bears many scars, including craters and deep grooves running across its surface. Scientists have long debated what caused the grooves on Phobos. Since the s, humans have robotically explored Mars more than any other planet beyond Earth. Currently, eight missions from the U. But getting safely to the red planet is no small feat. Of the 45 Mars missions launched since , 26 have had some component fail to leave Earth, fall silent en route, miss orbit around Mars, burn up in the atmosphere, crash on the surface, or die prematurely.
More missions are on the horizon, including some designed to help search for Martian life. NASA is building its Mars rover to cache promising samples of Martian rock that a future mission would return to Earth. In , the European Space Agency and Roscosmos plan to launch a rover named for chemist Rosalind Franklin , whose work was crucial to deciphering the structure of DNA. The rover will drill into Martian soil to hunt for signs of past and present life. Other countries are joining the fray, making space exploration more global in the process.
In July , the United Arab Emirates is slated to launch its Hope orbiter , which will study the Martian atmosphere. Perhaps humans will one day join robots on the red planet. NASA has stated its goal to send humans back to the moon as a stepping-stone to Mars. Will humans eventually build a scientific base on the Martian surface, like those that dot Antarctica? How will human activity affect the red planet or our searches for life there?
Time will tell. But no matter what, Mars will continue to occupy the human imagination, a glimmering red beacon in our skies and stories. All rights reserved. Mars Nearing Earth In , the Hubble Space Telescope snapped this photo of the red planet 11 hours before its closest approach to Earth in 60, years.
Mars is about half the size of Earth, and like its fellow terrestrial planets, it has a central core, a rocky mantle, and a solid crust. Mars has a dense core at its center between and 1, miles 1, to 2, kilometers in radius. It's made of iron, nickel, and sulfur. Surrounding the core is a rocky mantle between and 1, miles 1, to 1, kilometers thick, and above that, a crust made of iron, magnesium, aluminum, calcium, and potassium.
This crust is between 6 and 30 miles 10 to 50 kilometers deep. The Red Planet is actually many colors. At the surface, we see colors such as brown, gold, and tan. This dust gets kicked up into the atmosphere and from a distance makes the planet appear mostly red. Its volcanoes, impact craters, crustal movement, and atmospheric conditions such as dust storms have altered the landscape of Mars over many years, creating some of the solar system's most interesting topographical features.
A large canyon system called Valles Marineris is long enough to stretch from California to New York — more than 3, miles 4, kilometers. This Martian canyon is miles kilometers at its widest and 4.
That's about 10 times the size of Earth's Grand Canyon. Mars is home to the largest volcano in the solar system, Olympus Mons.
It's three times taller than Earth's Mt. Everest with a base the size of the state of New Mexico. Mars appears to have had a watery past, with ancient river valley networks, deltas, and lakebeds, as well as rocks and minerals on the surface that could only have formed in liquid water.
Some features suggest that Mars experienced huge floods about 3. There is water on Mars today, but the Martian atmosphere is too thin for liquid water to exist for long on the surface. Today, water on Mars is found in the form of water-ice just under the surface in the polar regions as well as in briny salty water, which seasonally flows down some hillsides and crater walls. Mars has a thin atmosphere made up mostly of carbon dioxide, nitrogen, and argon gases.
To our eyes, the sky would be hazy and red because of suspended dust instead of the familiar blue tint we see on Earth. Mars' sparse atmosphere doesn't offer much protection from impacts by such objects as meteorites, asteroids, and comets. The temperature on Mars can be as high as 70 degrees Fahrenheit 20 degrees Celsius or as low as about degrees Fahrenheit degrees Celsius. And because the atmosphere is so thin, heat from the Sun easily escapes this planet. If you were to stand on the surface of Mars on the equator at noon, it would feel like spring at your feet 75 degrees Fahrenheit or 24 degrees Celsius and winter at your head 32 degrees Fahrenheit or 0 degrees Celsius.
Occasionally, winds on Mars are strong enough to create dust storms that cover much of the planet. After such storms, it can be months before all of the dust settles. Mars has no global magnetic field today, but areas of the Martian crust in the southern hemisphere are highly magnetized, indicating traces of a magnetic field from 4 billion years ago. Mars in also the midst of a long-term increase in eccentricity. Roughly 19, years ago, it reached a minimum of 0.
In addition, the orbit was nearly circular about 1. Much like Earth, Mars also has a significantly tilted axis. In fact, with an inclination of This means that like Earth, Mars also experiences seasonal variations in terms of temperature. O n average, the surface temperature of Mars is much colder than what we experience here on Earth, but the variation is largely the same.
This means that at certain times of the year, Mars is actually warmer than certain parts of Earth. Summer is second longest, lasting six months, while Fall and Winter last 5. In the south, the length of the seasons is only slightly different. Mars is near perihelion when it is summer in the southern hemisphere and winter in the north, and near aphelion when it is winter in the southern hemisphere and summer in the north.
As a result, the seasons in the southern hemisphere are more extreme and the seasons in the northern are milder. It also snows on Mars. This was an expected finding, but scientists were not prepared to observe snow falling from clouds. The snow, combined with soil chemistry experiments, led scientists to believe that the landing site had a wetter and warmer climate in the past.
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