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96 free Mars trivia questions with answers — science & nature quiz, new questions added Aug 2026.
50 free Mars trivia questions with answers. Mars has captivated humanity for millennia — from ancient warriors who named it after their god of war to modern scientists searching for signs of life in its rusty soil. From Olympus Mons to Perseverance, from Phobos to potato farms, how much do you really know about our most tantalizing neighbor? These 96 questions will find out.
30 of 96 questions with answers and explanations. Play the quiz
Q 01What gives Mars its distinctive reddish appearance?
Iron oxide (rust) on its surface
Mars appears red because its surface is covered in iron oxide, commonly known as rust. Iron minerals in the Martian soil oxidized billions of years ago, giving the planet its iconic reddish hue visible even from Earth.
Q 02What is the name of the tallest volcano on Mars, and the tallest known volcano in the solar system?
Olympus Mons
Olympus Mons rises about 21.9 km (13.6 miles), roughly 2.5 times the height of Everest, and is approximately tied with Rheasilvia on the asteroid Vesta as the tallest mountain yet found in the solar system.
Q 03Approximately how long is a Martian day (sol)?
24 hours 37 minutes
A Martian day, called a sol, lasts approximately 24 hours and 37 minutes. This is remarkably close to Earth's 24-hour day, making Mars one of the most Earth-like planets in terms of day length.
Q 04Which canyon system along the Martian equator runs more than 4,000 km, about ten times the length of the Grand Canyon?
Valles Marineris
Valles Marineris stretches over 4,000 km along the Martian equator, about ten times longer and five times deeper than the Grand Canyon, the largest known canyon in the solar system.
Q 05Mars's mean surface air pressure is roughly what fraction of Earth's sea-level pressure?
About 0.6%
The thin Martian air averages about 0.6% of Earth's sea-level pressure, close to the triple point of water, so liquid water on the surface would boil or freeze almost at once.
Q 06Which spacecraft became the first ever to orbit another planet when it reached Mars in November 1971?
Mariner 9
Mariner 9 beat the Soviet Mars 2 and Mars 3 probes by only weeks, then had to wait out a months-long dust storm before it could send back clear pictures of the surface.
Q 07Which is the larger of Mars's two moons?
Phobos
Phobos, about 22 km across, is nearly twice the diameter of Deimos and orbits so close to Mars that it rises in the west and sets in the east roughly every 11 hours.
Q 08What is the approximate surface gravity on Mars compared to Earth?
About 38%
Mars has about 38% of Earth's surface gravity (3.72 m/s² vs 9.81 m/s²). A person weighing 100 kg on Earth would weigh only about 38 kg on Mars, though their mass remains the same.
Q 09What is the primary component of Mars's atmosphere?
Carbon dioxide
Mars's atmosphere is about 96% carbon dioxide, with roughly 1.9% each of argon and nitrogen and only traces of oxygen and water vapour. It is also extremely thin, less than 1% of Earth's surface pressure.
Q 10What is the Hellas Planitia on Mars?
A massive impact basin
Hellas Planitia is one of the largest impact craters in the solar system, with a diameter of about 2,300 km and a depth of over 7 km. It was formed by an asteroid impact roughly 4 billion years ago and is located in Mars's southern hemisphere.
Q 11Which NASA rover famously operated for over 14 years on Mars, far exceeding its planned 90-day mission?
Opportunity
Opportunity landed on Mars in January 2004 for a planned 90-day mission but continued operating until June 2018 — over 14 years. A massive dust storm finally ended communications. It traveled over 45 km across the Martian surface.
Q 12What is the name of the helicopter drone that flew on Mars as part of the Perseverance mission?
Ingenuity
Ingenuity was a small helicopter that made the first powered, controlled flight on another planet on April 19, 2021. Originally designed for 5 flights, it completed 72 flights before its mission ended in January 2024.
Q 13In which Martian crater did the Curiosity rover land in 2012?
Gale Crater
Q 21What evidence suggests Mars once had liquid water on its surface?
Dried river channels and mineral deposits
Orbital images show outflow channels carved by catastrophic floods, branching valley networks, deltas and lakebeds, while rovers have found clays and sulfates that only form in liquid water.
Q 22What is the contrast between Mars's low northern plains and cratered southern highlands called?
The Martian dichotomy
The Martian dichotomy is the split between low, smooth northern plains and the heavily cratered southern highlands; one leading idea is that a giant early impact formed the northern Borealis basin, covering about 40% of Mars.
Q 23What is the average surface temperature on Mars?
Curiosity landed in Gale Crater on August 6, 2012. The crater contains Mount Sharp (Aeolis Mons), a 5.5 km high mound of layered sediment that scientists study to understand Mars's geological history.
Q 14Which lander, the first to complete a successful mission on Mars, touched down on July 20, 1976?
Viking 1
Viking 1 touched down in Chryse Planitia on 20 July 1976 and operated for more than six years, returning the first clear photographs from the Martian surface.
Q 15What was the name of the small rover carried by the Mars Pathfinder mission in 1997?
Sojourner
Sojourner was the first rover to operate on Mars, arriving as part of the Mars Pathfinder mission on July 4, 1997. It was about the size of a microwave oven and operated for 83 sols, analyzing rocks near its landing site.
Q 16In which crater did NASA's Perseverance rover land in 2021?
Jezero Crater
Perseverance landed in Jezero Crater on February 18, 2021. Scientists chose this location because it contains an ancient river delta, making it an ideal place to search for signs of past microbial life.
Q 17Which Perseverance experiment made oxygen from the air of Mars?
MOXIE
MOXIE (Mars Oxygen In-Situ Resource Utilization Experiment) showed that breathable oxygen can be pulled straight out of the thin Martian air, a step toward making air and rocket propellant for future crews.
Q 18Which Mars mission discovered that the planet once had a thicker atmosphere stripped away by solar wind?
MAVEN
NASA's MAVEN (Mars Atmosphere and Volatile Evolution) mission, which arrived at Mars in 2014, determined that solar wind and radiation stripped away Mars's atmosphere over billions of years, transforming it from a warm, wet world to the cold desert we see today.
Q 19Which twin rovers made up NASA's Mars Exploration Rover mission?
Spirit and Opportunity
Spirit and Opportunity landed three weeks apart on opposite sides of the planet in January 2004; built for 90 days, Spirit worked until 2010 and Opportunity until 2018.
Q 20What did NASA's Phoenix lander discover just below the Martian surface in 2008?
Water ice
The Phoenix lander, which touched down near Mars's north pole in May 2008, confirmed the presence of water ice just centimeters below the surface. The ice was observed to sublimate (turn directly from solid to gas) over several days after being exposed.
About -63°C (-81°F)
A commonly quoted average is about -63°C (-81°F). Temperatures swing from around -140°C at the winter poles to about 20°C at the equator in summer, because the thin air retains little heat.
Q 24What kind of ice forms the permanent surface of Mars's southern polar cap?
Dry ice (frozen CO2)
The southern cap keeps a permanent dry-ice cover about 8 metres thick, while the northern cap's surface is mostly frozen water. Beneath the southern dry ice lies a far larger store of frozen water.
Q 25Roughly how many of our years pass during a single Martian year?
About 1.88
A Martian year lasts about 687 Earth days, or approximately 1.88 Earth years. This is because Mars orbits farther from the Sun than Earth and therefore takes longer to complete one orbit.
Q 26What seasonal phenomenon occurs at Mars's poles that has no equivalent on Earth?
CO2 snow and dry ice geysers
Each winter carbon dioxide freezes onto the poles as CO2 snow and dry ice; in spring it sublimates from below and geysers of gas and dark sand burst through, leaving fan-shaped deposits and spider-like channels.
Q 27In Babylonian astronomy, the planet Mars was named for which deity?
Nergal
Nergal was a deity of war, plague and destruction, so the blood-red planet was linked to warfare long before the Romans named it for their own war god.
Q 28The names of Mars's two moons come from Greek words meaning what?
Fear and Dread
Phobos and Deimos are Greek for Fear and Dread; in myth they were twin sons of the war god and rode with him into battle.
Q 29Who discovered Mars's two moons in 1877?
Asaph Hall
Hall found both moons in August 1877 with the 26-inch refractor at the U.S. Naval Observatory in Washington, D.C., and nearly gave up the search before his wife encouraged him to continue.
Q 30Which astronomer built an Arizona observatory to map 'canals' on Mars that did not exist?
Percival Lowell
Lowell built an Arizona observatory and mapped elaborate canals in the 1890s-1900s, reading Schiaparelli's 'canali' (channels) as the work of an intelligent civilization.