Mars is the fourth planet from the Sun, orbiting at a distance of 228 million km (142 million miles) or 1.5 AU. It is known as the “Red Planet” because it has a reddish surface due to oxidization of iron oxide in the rocks, regolith and dust.
It has two small moons, Phobos and Deimos. Interestingly, the two moons were written about in the book Gulliver’s Travels by Jonathan Swift – 151 years before they were discovered.
It is a rocky planet
Mars is the fourth planet from the Sun and it is about half the size of Earth. It revolves around the sun every 687 days and rotates every 24.6 hours (nearly the same as Earth).
Like most of the planets in our Solar System, it formed from a cloud of gas and dust that went on to merge to form the Sun. Some of this nebula formed into planets while more was pulled onto the newly formed Sun by gravity.
It took about 4.5 billion years for this process to happen. Mars is a rocky planet with a thin atmosphere and surface features reminiscent of both the impact craters of the Moon, as well as the valleys, deserts and polar ice caps on Earth.
The red colour of Mars comes from the presence of a mineral called iron oxide that is present on the surface of the planet. This makes the Martian soil appear rusty and reddish in color.
Scientists believe that the surface of Mars is covered in a large number of craters and rocks. These craters and rocks are scarred by the impact of objects that hit it over millions of years.
One of the most interesting things about this surface is that it appears to be a mixture of different materials. It is made up of a combination of silicates and metallics.
These elements were present at the time of its formation and they are what help to give Mars its unique appearance today. The rusty red colour is also the result of the abundance of iron on the planet’s surface.
Another difference between the planet and ours is that it has less mass and therefore a weaker gravitational force. This means that it is more likely to draw materials from the outer reaches of the Solar System into its core.
Hence, it has a higher concentration of heavy elements such as metals and silicates. This is what gives Mars its distinctive’red’ appearance and why it’s known as the ‘Red Planet’.
Scientists say that because of this, it is possible for life to develop on the planet. However, there are no signs of any life on the planet at this time.
It has a thin atmosphere
The fourth planet from the Sun, Mars has a thin atmosphere and two moons, Phobos (FOE-bohs) and Deimos (DEE-mohs). It has a unique rusty red appearance and its soil has iron oxide particles that give it a pink hue.
The planet’s atmosphere is composed primarily of carbon dioxide, nitrogen and argon, along with trace amounts of water vapour. Its skies are a tawny color due to oxidized dust kicked up by the surface. The chemistry of the atmosphere may suggest that it once had a much thicker, heavier atmosphere that trapped light in the planet’s interior.
Despite its thin atmosphere, Mars still experiences a range of weather conditions, including dust storms and occasional CO2 fog in its canyons. The temperature of the planet can drop to minus 80 degrees Fahrenheit and the atmospheric pressure is very low.
At the lower latitudes, the air is heated by the Martian Sun and rises to form Hadley cell wind patterns, named after English astronomer George Hadley (1685-1768). These winds flow northward and southward, in parallel, to about 30 degrees above the Martian surface.
In summer, the Hadley cells expand and the warm air rises to the equator. In winter, the warmed air descends to the polar regions where it freezes as snow or frost, depending on how cold the temperatures are.
The polar caps change in size with the seasons and contain ice that has been frozen from CO2 gas in the Martian atmosphere. The pressure of the atmosphere varies with altitude, as well.
However, at higher altitudes, the pressure increases due to seasonal variations in the amount of CO2 gas. This occurs during the northern and southern polar winters, when temperatures drop below 123deg Celsius (-189deg Fahrenheit).
Because of the different temperatures, these polar winters also cause the CO2 in the atmosphere to change from liquid to solid. It then condenses into dry ice, or “snow.”
Scientists have also found evidence that the atmosphere was once much thicker and was once able to support large oceans of liquid water on the surface of Mars. But this is a complicated question, and scientists aren’t sure what caused this atmosphere to change over time. A few leading theories include that Mars was struck by a large object, which could have ripped away some of its atmosphere and thrown it into space; and the solar wind blasted a lot of the planet’s early atmosphere into space, causing the thin atmosphere we see today.
It has a surface
Mars is the fourth planet from the Sun and the second smallest planet in the Solar System. It has an average distance of 141 million miles from the Sun and orbits it once in 687 Earth days.
The rocky surface of Mars is covered with a thin atmosphere and dust that gets blown around by the planet’s intense dust storms. The planet’s crust is mainly made up of oxygen and silicon, with traces of iron and magnesium.
Among the most interesting parts of the Martian landscape are giant volcanoes, canyons, and polar caps. The icy caps are layered with CO2 ice, and they change in size and shape with the seasons.
Researchers also found that the surface of Mars has iron oxide, or rust, which gives the planet its red color. This shows that the Martian surface was once much more hospitable to life than it is today, and suggests that there may have been water on the planet at one point.
Astronomers believe that the ancient atmosphere of Mars was rich in carbon dioxide, which heat-trapped the planet’s surface, and created a solid-state greenhouse effect. This process is still active on the planet, warming up layers of ice that sit just below the surface in the polar caps every summer.
There are also a number of other features that astronomers believe show that there was once liquid water on the surface of Mars. The gullies and dry riverbeds that mark the surface of the planet are evidence of water that flowed on the planet in the past.
The Martian surface is also covered with craters and valleys, which are thought to be remnants of a huge impact that took place soon after the planet was formed. Some craters have complex grooves and cracks that can indicate that the rocks were pushed and then fractured by a massive impact.
Scientists have discovered that there is a sub-glacial lake on the planet, which is about 20 km wide and 1.5 km below the surface. This is the first time that water has ever been detected on a planet’s surface.
It has two polar caps
Mars, the 4 planet from the sun, is a cold desert-like world with mountains and valleys as well as a variety of storm systems, ranging from localized tornado-like dust devils to planet-engulfing dust storms. Like Earth, it spins on an axis tilted about 25 degrees from its orbital plane, producing seasonal cycles that are comparable to those of our own planet.
One of the most interesting aspects of Mars is its two polar caps, which are both made of water ice. These polar caps are up to 3.7 kilometers thick and, together, they make up about 25 percent of the planet’s total ice volume.
The polar caps form each fall and winter, then melt away as spring warms into summer on Mars. This process is called sublimation.
During the summer, much of the ice in the polar cap sublimates, turning into gas, leaving behind a residual ice cap that offsets about three to four degrees from the main ice cap. This misplacement has puzzled planetary scientists since the 1970s.
A new study, based on data from the European Space Agency’s Mars Express satellite, shows that there may be liquid water beneath Mars’ south polar ice cap. This is the first independent line of evidence that there is liquid water on Mars.
This finding is a result of analysis of the radar signal produced by the MARSIS instrument on the satellite, which can see through Mars’ southern ice cap. The scientists found a region at the base of the ice cap that strongly reflected the radar signal, suggesting that there is an area of liquid water beneath the ice cap.
When the researchers analyzed the surface topography of the ice cap, they saw that it resembled a surface undulation commonly seen in ice sheets above subglacial lakes on Earth. This means that, in the past, water was trapped under the ice cap and melted back into the atmosphere, forming this feature.
On the bottom of both polar caps lie layers that are made from thousands of thin layers of water ice mixed with sand and dust that fell out of the planet’s atmosphere over hundreds of thousands of years or more. These layers are called polar layered deposits and they may be a billion years old, the researchers suggest.