Our nearest planetary neighbour has been inspiring astronomers, stargazers and those trying to understand night sky for thousands of years, but we are forever learning more about the Red Planet. Who knows, one day we might discover even more by living on it.

Here are the Mars facts, figures and info you need to get to know the fourth planet from the Sun.

Mars as seen from Mariner 7 NASA/JPL

That depends on when you travel and how you plan on getting there. As the distance between Earth and Mars is constantly changing, so too does the amount of time it takes to get there. The quickest journey to the Red Planet by a spacecraft was Mariner 7s 1969 flyby, which took 128 days to arrive.

Due to their elliptical orbits, the distance between Mars and Earth is always changing as they spin around the Sun. At their closest approach, Mars is only 54.6 million kilometres (33.9 million miles) away. At their furthest, there are some 400 million km (250 million miles) between them.

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NASA/JPL-Caltech/GSFC/Univ. of Arizona

Mars has two moons; Phobos and Deimos. Phobos is the larger of the two but it is still tiny, with a radius of around 11km. Both moons were named after the Greek gods (and twin sons of the god Mars) of fear and terror respectively. They were discovered in 1877 by American astronomer Asaph Hall.

Mars and Earth have very similar lengths of day. One day on Mars, known as a sol, lasts 24 hours, 39 minutes, and 35.244 Earth seconds.

In 1960, the Soviet Union was the first country to attempt a flyby of Mars with 1M (known in the West as Marsnik) but the mission was unsuccessful. The USA was the first nation to reach Mars successfully when Mariner 4 made a flyby of the Red Planet in July 1965.

NASAs Curiosity rover scoops up some Martian soil (left), and the scoop carrying soil NASA/JPL-Caltech/MSSS

Alas, there have been no reported sightings of little green men (yet), but what has been discovered on the planets surface is evidence of persistent liquid water, microbe-supporting chemistry, organic molecules, active methane and rocks. Lots of rocks.

As Mars is smaller than Earth, the effect of gravity is much weaker. Thats great news if you want to lose weight quickly, because if you weighed 75kg on Earth, that would drop to just over 28kg on Mars. The formula is Weight on Mars = (Weight on Earth/Earths gravity (9.81m/s2)) * Martian gravity (3.711m/s2).

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Getty

Asteroids. Many, many asteroids. The majority of the Solar Systems known asteroids lie between Mars and Jupiter, with between 1.1 and 1.9 million of them larger than a kilometre in diameter. There are millions more smaller ones, but are so spread out the distance between them is in the millions of kilometres.

Martian dust storm NASA/JPL-Caltech/MSSS

Despite its thin atmosphere, Mars is still capable of clouds and weather. In fact, when it comes to wind, Mars has the biggest dust storms in the whole of the Solar System. If you want to know the weather right now, NASAs InSight rover is acting as an on-location weather reporter.

Valerio Pellegrini

Mars is currently home to 16 robots, with more planned in the near future. Only two are currently operational, NASAs Curiosity rover and InSight lander, and four either crash-landed on the surface or broke up on entry. To date, Mars is the only known planet in the Universe to be entirely inhabited by robots.

Internally, Mars is made up of a dense iron, nickel and sulphur core, and this is surrounded by a softer silicon and oxygen mantle. The planets 50km-thick crust consists mainly of iron, magnesium, aluminium, calcium and potassium.

Observed structure of the Milky Ways spiral arms NASA/JPL-Caltech/ESO/R. Hurtderivative work: Cmglee/Public domain

Mars can be found in space, but if you want to be more specific its the fourth planet from the Sun in our Solar System, which itself is in the Orion-Cygnus Arm of the Milky Way. If youre into astronomical co-ordinates, it currently resides at RA 0h 58m 6s | Dec +2 10 32.

Strata at Base of Mount Sharp NASA/JPL-Caltech/MSSS

The red colour of Mars comes from the high level of iron oxide in its regolith (surface material). However, why there is so much oxidised iron on a planet with virtually no oxygen in the atmosphere is still a mystery.

Mars is not the sort of place you want to go on a summer holiday. After a months-long journey, you will be welcomed by a maximum temperature of around 20C on the equator in summer. Down at the poles, Mars can get as cold as -125C. The average temperature for the Red Planet is -63C.

Earth is roughly two times bigger than Mars NASA/JPL

The diameter of Mars is 6,790km (4,220 miles), making it roughly half the size of Earth and twice as big as the Moon. This makes it the second-smallest planet in the Solar System.

Although Earth is twice as big a Mars, it is around ten times heavier! So, well let you work out the mass of our home planet knowing that the red one pushes the scales at 6.42 x 1023 kilograms.

Mars is as old as the rest of the Solar System, making it a sprightly 4.6 billion years old.

Mars takes 687 Earth days to orbit the Sun, which means it travels at a brisk 24km/s over its 9.55 AU journey (1 AU is about 150 million km, roughly the distance between the Earth and the Sun).

Mars was once a warm, wet planet thanks to an atmosphere as thick as Earths, but those days are long gone. Now its a dusty old place due to atmospheric erosion, caused by a process known as sputtering. This happens when ions carried by solar wind knock atoms out of the atmosphere and into space.

The various sources of carbon dioxide on Mars and their estimated contribution to Martian atmospheric pressure NASA Goddard Space Flight Center

Terraforming means changing a planets surface and atmosphere to be more like Earths and therefore a suitable place to live. However, for it to work we need carbon dioxide, and Mars just doesnt have enough going spare. So until we sort that out, the answer is somewhere between a very, very long time to never.

Mars has what is known as an eccentric orbit, which means its not perfectly circular around the Sun. That means the distance between the two is always changing, but at their closest it is 206 million km, while its furthest is 249 million km. This averages out to around 229 million km.

Galileo Galilei Getty Images

Mars is visible in the night sky with the naked eye, so its impossible to say exactly when anybody first saw it. There are reports of it being sighted by the ancient Egyptians two millennia BCE. However, the first to spot it through a telescope was Galileo Galilei in 1610.

A Viking Orbiter/Lander spacecraft photographed this view of Olympus Mons, the largest volcano in the Solar System Getty Images

Mars is a rocky planet, covered in impact craters, mountains, volcanoes and deep canyons stretching thousands of miles. Olympus Mons is the tallest mountain in the Solar System, stretching 21,229m above the surface of the planet. That towers more than 12km above Mount Everest.

Mars, the Roman god of War Hulton Archive/Getty Images

The planet Mars was named after the Roman god of War. He was second only to the king of gods, Jupiter, and was a pretty bloodthirsty chap. That might go some way to explaining why the Red Planet was named after him. The animals most associated with him were the wolf and the woodpecker.

A Mars 2 Lander model at the Memorial Museum of Cosmonautics in Russia NASA

The USSR was the first country to place a human-made object on the planets surface. The first attempt, Mars 2, crash-landed in November 1971, but less than a week later Mars 3 landed and remained operational for 14.5 seconds.

One of the first pictures taken by the camera on the Mars Pathfinder lander shortly after its touchdown in 1997 NASA/JPL

Weirdly, the colour of the sky on Mars is the opposite to Earth, being blue towards sunset and sunrise and reddish-pink during the day. This unusual daytime colour is caused by the vast amounts of dust containing Magnetite, an iron ore, suspended in the atmosphere.

Curiosity made these tracks (but killed no cats in the process) NASA/JPL-Caltech

Because Curiosity killed the cat. Its a joke, obvs If you need a little more explanation, NASAs Mars Curiosity Rover landed on the Red Planet in 2012, presumably on top of any Martian felines. As of publication, there have been no reported sightings of cats on Mars and this band has a solid alibi.

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Mars: Oodles of facts, figures and fun questions about the Red Planet - BBC Focus Magazine