Mars: the red planet, the last of the terrestrial planets, and our greatest hope for sustaining life beyond our own planet (so far anyways). Ever since Egyptian astronomers first discovered Mars in the heavens, humanity has been fascinated by the nearby planet. At a time just over 100 years ago, we even believed intelligent life much like our own lived on the planet’s cratered surface. Though we often hear the planet is quite similar to Earth, it’s also radically different. These differences will provide some serious challenges for landing a human mission there and sustaining life, challenges which we’ve brought up among these facts on Mars. Whether you’ve always been fascinating by space and the planets or you’re just looking to learn a bit more about our second closest planet, this list is just what you need to get up to speed. From how the planet got its name to its fearsome dust storms to the question of “Is there really organic life on Mars?”, we’ve dug into the red planet’s history to bring you these 25 Unique Facts About Mars: Earth’s Mysterious Cousin. Speaking of planets, have you checked out our 25 Curious Facts Concerning Pluto: The Demoted Planet? (we know, it’s no longer a planet).
Mars: Earth's cousin
Bearing a similar tilt to Earth – Mars has a 25° tilt while our planet has a 23.5° tilt – Mars also experiences the same four seasons, though they are more extreme.
The red planet’s seasons are much longer than ours. Due to Mars’ elliptical orbit, spring and summer are longer in its northern hemisphere while fall and winter are longer in the southern. They are also more intense with hotter summers and colder winters.
Could we breathe on Mars?
Though the red planet is often cited as a potential second Earth, we would not be able to breathe in its atmosphere made up of 96% carbon dioxide and less than 0.2% oxygen. Earth’s 21% oxygen is right about where we need to be. Scientists are currently testing microbes that can be sent ahead of humans to begin converting and creating oxygen on the planet.
The first assumption of life on Mars
In the last quarter of the 19th century, astronomers generally believed intelligent life was living on Mars. Italian astronomer Giovanni Schiaparelli noticed relatively straight lines on the Martian surface which he and other astronomers of the time believed were irrigation canals constructed by intelligent beings. As telescopes developed in the early 20th century, this assumption was proved wrong – though not before giving birth to plenty of sci-fi about the red planet, including Marvin the Martian.
How Mars got its name
Mars’ surface is rich in iron, giving it a reddish color. This composition has led to cultures as far back as the Egyptians naming it after the color. The Egyptians named it Her Desher (“the red one”), the Chinese named it “fire star”, and the Romans named it Mars, after their god of war (equivalent to Ares in Greek mythology).
A valley the size of North America
An enormous system of canyons, the Valles Marineris stretches 2,600 miles (4,200 km) across the Martian surface and is up to 4.3 miles (7 km) deep. Placing it on Earth and into context, the Valles Marineris would span from New York to San Francisco and then some.
Mars' rotation around the sun
A Martian year is significantly longer than an Earth year (the time it takes to make one rotation of the sun). On Earth, we have 365 days whereas Mars has 687 days.
The Martian day is also longer, but only slightly. One Earth day is 23 hours and 56 minutes while one Martian day is 24 hours and 40 minutes. When we do land on Mars, it will be an easier transition than if we went to Jupiter (10 hour day) or Venus (2,802 hour day).
The atmosphere on Mars is 100 times less dense than our own, making landing spacecrafts on its surface tricky as the atmosphere does not help as much in slowing down their descent as it does on our blue planet. Despite this lack of density, it is still dense enough to permit weather and winds.
Mars experiences much greater temperature fluctuations than our own planet. Whereas the coldest it has gotten on Earth’s surface is -126° F (-88° C) and the hottest 136° F (58° C), Mars fluctuates between -284° F (-140° C) and 86° F (30° C). The average temperature on each is 57° F (14° C) on Earth and -81° F (-63° C) on Mars. That’s a cold planet!
Intense dust storms
Martian dust storms are among the fiercest in the solar system and are even the largest. A dust storm can envelop the entire planet and last for many months.
The Curiosity Rover
One of the primary goals of NASA’s well-known Curiosity Rover, currently on the Martian surface, has been to plan for a human visit to the planet. Other goals are understanding the climate and geology of the planet and determining if life ever existed on Mars.
Tallest mountain in the solar system
The tallest mountain in the solar system, Olympus Mons, is a shield volcano, similar to those in Hawaii and many Pacific islands. It stands at 13.2 miles (21 km) above sea level on the Martian surface. Three times taller than Mount Everest, Olympus Mons’ surface area is the same as the entire U.S. state of Arizona.
First spacecraft exploration of Mars
The first spacecraft sent to explore Mars was the Soviet Union’s “Mars 1” in 1962. En route, mission controllers lost contact with the vehicle. The first American spacecraft to reach Mars was Mariner 4 in 1964 which sent back the first pictures of the red planet.
Water on Mars
Astronomers have known for years that water exists on Mars, locked up in its polar ice caps. However, they’ve recently found dark streaks on the planet which would indicate flowing water. Mars’ temperatures (#16) would mean the water would have to be incredibly salty to keep it in liquid form.
Martian land area
Despite being considerably smaller than Earth – about half of Earth’s diameter and a tenth of its mass – Mars has a land area similar to that on Earth due to our planet’s high amount of water. This would only apply to Mars’ current state since the Martian oceans have dried and frozen up.
Phobos, the larger Martian moon
Phobos, the larger of the two Martian moons, orbits the planet so quickly it would set twice (in the East) and rise once (in the west) every day.
Deimos, the smaller Martian moon
Deimos, the smaller moon, is so small that an astronaut on Mars would see it as a full moon just about as brightly as we see Venus in our night sky. Scientists are unsure whether both these moons are captured asteroids or true moons.
Volume-wise, Mars is much smaller than Earth. Over six whole Mars’ would be able to pack into our Earth.
Lower gravity on Mars means you would be able to hop around much easier than on Earth. Its 62.5% less gravity means 100 pounds on Earth are equivalent to about 38 pounds on Mars.
Is there life on Mars?
The most well-known supporting evidence for life on Mars refers to NASA experiments in 1996 on Martian rocks which landed on Earth. Inside, the scientists found complex organic molecules and fossilized structures which resemble microbes we are familiar with. Though these findings remain controversial, scientists today generally believe life did exist at some point on Mars (and may even still exist today).
The only other ice-capped planet
Besides our own planet, Mars is the only planet in the solar system to have polar ice caps. The southern ice cap is made of dry ice and is said to resemble freshly-fallen snow.
The Martian Grand Canyon
Mars’ equivalent of the Grand Canyon, the Noctis Labyrinthus (“labyrinth of the night”) is a highly varied area filled with steep-walled valleys and sloping canyons. Trapped between two highly volatile, techtonically-active areas of the planet, the area has been shaped by the stress of heat and water over millions of years.
Mars' moon on a destruction path
Human settlements on Mars could be threatened by Mars’ moon Phobos – thankfully not for tens of millions of years though. Each orbit, Phobos is drawn closer to Mars by the planet’s gravity. (It spirals inward at 6 feet (1.8 m) every 100 years.) Many millennia in the future, the moon will likely crash into Mars or break up above the planet’s surface, creating a ring.
First humans on Mars
In a 2010 speech at Kennedy Space Center, U.S. President Barack Obama called for the Americans to land a manned mission to Mars by the mid-2030’s, making it the most ambitious Mars exploration plan by any country on record.