Mars

Mars was named after an ancient Roman god because of the reddish colour that surrounds the planet. The Egyptians also gave it the name "Her Desher" which literally translates to "the red one". Today, Mars is frequently referred to as the "Red Planet" as the martian dust contains iron which oxidises or rusts. This causes the surface to look red.

## Exploration

Mars has been studied for over 4,000 years. From the first ancient recordings by Egyptians (when they charted the planet's orbit) to spacecrafts and rovers landing on the Red Planet. Today, a fleet of precision-built spacecrafts study Mars from all possible angles daily.

1. Six spacecrafts are in orbit of Mars daily. NASA's trio Mars Reconnaissance Orbiter, Mars Odyssey and MAVEN. ESA's managed the ExoMars Trace Gas Orbiter and Mars Express. India flew is first Red Planet spacecraft into its orbit, the Mars Orbiter Mission (MOM) which has been active since 2014.

1. Two rovers are at work studying Mars' surface. NASA's Curiosity which is exploring Mount Sharp in Gale Crater and NASA's Insight which is roaming on a site called Elysium Planitia.

1. NASA and ESA are both making plans to send new and improved rovers in 2020.

## Size and Distance

Mars is about half the size of the Earth, with a radius of 2,106 miles (3,390 kilometres).

With an average distance of 142 million miles (228 million kilometres), Mars is just 1.5 astronomical units away from the Sun. One astronomical unit (abbreviated as 'AU') is the distance from the Sun to Earth.

Sunlight takes about 13 minutes to travel to Mars.

## Orbit and Rotation

Mars completes one orbit around the Sun every 24.6 hours, which is very similar to Earth with an orbit of 23.9 hours. Martian days are also referred to as sols (short for "solar day"). A year on mars lasts 669.6 sols which is equivalent to 687 Earth days.

Mars tilts on an axis of 25 degrees, which is similar to Earth that has a tilt of 23.4 degrees. Like Earth, Mars has distinct yet longer seasons. Seasons last longer because Mars takes longer to orbit around the Sun. Earth's seasons are spread out evenly across the year, Mars' seasons can be unpredictable in length (one season could be 2-3 months long but the next martian year it could last 6-7 months).

Northern spring/southern autumn lasts 194 sols whilst northern autumn/southern spring lasts 142 days. Northern winter/southern summer takes 154 sols whereas northern summer/southern winter lasts 178 sols.

## Structure

Mars' dense core at the planet's centre is between 930 1,300 miles (1,500 to 2,100 kilometres) in radius and being made of nickel, iron and sulphur. Surrounding the core is the mantle which is 770 and 1,170 miles (1,240 to 1,880 kilometres) thick. Above that is the crust that is made of iron, magnesium, aluminium, calcium and potassium. The crust is between 6 and 30 miles (10 to 50 kilometres) deep.

## Formation

About 4.5 billion years ago, when the solar system was set into place, gravity pulling swirling gas and dust formed the fourth closest planet to the Sun. Like Earth and it other fellow terrestrial planets, Mars has a central core, mantle and crust.

## Surface

Mars is actually many colours from the surface. When we reach the surface, we can see colours like brown, gold and tan. The reason why Mars looks red is because of oxidisation or rusting from the rocks (Martian "soil") and dust. This dust is thrusted into the atmosphere and makes the planet appear red.

Whilst Mars if half the diameter of Earth, its surface is nearly the same area as Earth's dry land as a whole. Over many years, Mars' surface has changed due to volcanoes, impacts, craters and more. The dust from Mars' surface has also risen up into the atmosphere creating dust storms which have altered everything on the planet. Mars also has some of the best topographical features in our solar system.

Valles Marineris, a large canyon system on Mars, is large enough to stretch from California to New York - that's more than 3,000 miles (4,000 kilometres). The Martian canyon is at its widest measuring in at 200 miles (300 kilometres) and at its deepest with 4.3 miles (7 kilometres) - That's about 10 times the size of the Earth's Grand Canyon.

Mars is home to the largest volcano in our solar system, Olypmus Mons. It measures three times taller than Mount Everest and has a base the size of New Mexico.

Mars also appears to have a watery past with ancient river valleys, networks, deltas and lakebeds. Rocks and minerals could have only formed in liquid water from the surface. Some features also suggest that 3.5 billion years ago, Mars experienced huge floods.

There is water on Mars today, but the Martian surface makes too difficult for it to last long. Today, just under the surface of Mars, there is water but is known as water-ice as well as salty water which flows down seasonally down hillsides and crater walls.

## Atmosphere

Mars has an atmosphere made up of mostly carbon dioxide, nitrogen and argon gases. To your eyes, the sky would look hazy and red because of the suspended dust not unlike the blue sky we see here on Earth. Since the atmosphere is not made up of oxygen, meteors, asteroids and comets don't burn up when they enter Mars.

Temperatures on Mars can reach as high 20 degrees Celsius and as low as -153 degrees Celsius. If you were to stand at the equator, it would feel like spring on your feet (24 degrees Celsius) and winter above your head (0 degrees Celsius) because the sun escapes the atmosphere .

Occasionally, strong winds pull dust together creating a dust storm, after these storms, it can take months for the dust to settle .

## Magnetosphere

Mars has no global magnetic field, but areas around Mars are highly magnetised. This means that there could have been a magnetic field around Mars 4 billion years ago.

## Rings

There are no rings around Mars. However, in 50 million years when Phobos crashes or breaks into the Red Planet, it could create a permanent ring.

## Moons

Mars has two small moons, Phobos and Deimos. These may have been captured asteroids pulled in from Mars'
gravitational force.

Phobos, the largest moon out of the two, is heavily cratered with deep grooves on its surface. It slowly moving towards Mars and will possibly crash into the Red Planet in 50 million years.

Deimos is the smallest moon out of the two, it orbits two and a half times farther away from Mars. This oddly-shaped moon is covered in loose dirt that has formed craters on the surface, making Deimos appear smoother than Phobos.

## Human Life

NASA is planning to send humans to Mars by 2050. if all goes correctly, by the 22nd century we could have life on the Red Planet.