Updated: Oct 10
Mars is the fourth planet in order from the Sun, and the closest planet to Earth. It is a terrestrial planet, meaning it has a solid surface mostly made up of rock. The planet is about half the size of Earth and is often called "the Red Planet" because of its reddish color. Mars is a subject of fascination for astronomers and space agencies, as it is the most likely candidate for potential future human exploration and colonization.
Learn all about our Solar System's Red Planet below. Discover what Mars is made of, how far it is from Earth, interesting facts and stats, astrophotography and observation tips, as well as information about Martian missions in the search for extraterrestrial life.
Mars: The Red Planet
Mars is the fourth planet from the sun and is located between Earth and the Solar System's Asteroid Belt. It is a terrestrial planet, so its makeup is unlike the outer planets Jupiter, Saturn, Uranus, and Neptune. Mars has a solid, rocky surface and a thin atmosphere mostly composed of carbon dioxide. It is smaller than Earth and is the second smallest planet in the Solar System after Mercury.
Who was Mars Named after?
Mars was known and observed by ancient civilizations, so it does not have a discovery date. However, the first telescope observation was accomplished in 1610 by Galileo Galilei, and since then the planet's movements and visual changes have been documented.
Like other planets in the Solar System, many of the names given to celestial objects in ancient times were influenced by mythology. For example, the Babylonians named the planet after their god of war, Nergal.
Interestingly, the ancient Greeks also named this planet after their god of war: Ares. Historians believe that this is due to the planet's color, red like blood and violence.
The Romans took the same approach and named the planet after their god of war as well. What was that name? Mars, of course!
Did you know? The names of the planets we use today come from Roman mythology gods and goddesses. As for constellations, the most popular namesakes come from the Greek versions.
The best way to remember the names of the planets or northern constellations is to study Roman and Greek mythology!
Size and Mass
Mars has a radius of 2,106 miles (3,390 kilometers), which is about half the size of Earth's radius. It is smaller than Earth and is a planet full of rocky features.
Its mass is 11% of Earth's. It would take approximately 7 copies of planet Mars to fill up the volume of the Earth.
Its gravitational pull compared to Earth is about 38%, meaning objects weigh significantly less on Mars. Another interesting characteristic of the Red Planet is that it has no magnetic field and a thin atmosphere. Because of this, the planet's surface is vulnerable to solar winds and cosmic radiation. Does that mean life cannot exist on Mars? Continue reading to find out!
Distance from the Sun
Mars is located approximately 142 million miles (228 million kilometers - 1.5 Astronomical Units) away from the sun. For comparison, Earth - the third planet from the sun, is 1 AU away from the sun (about 93 million miles or 150 million kilometers).
Since Mars is farther from the sun than Earth, it takes sunlight longer to reach the planet's surface. It takes about 12.5 minutes for light to travel from the sun to its surface. The distance also means that it receives less sunlight and heat than Earth, making the temperature there much colder. The average temperature on the Red Planet is minus 80 degrees Fahrenheit (minus 62 degrees Celsius). However, temperatures can fluctuate depending on the location and time of day.
Read our article Planets in Order from the Sun to learn about the Solar System's planets.
Time, Rotation, and Orbit
Let's hop on an imaginary rocket to Mars. What's a day like in the life of a Martian?
A Martian day is very similar to an Earth day. It takes a little longer to complete a full rotation than Earth but it's relatively the same. One day on Mars is equal to nearly 25 Earth hours. If you didn't know, some of the other planets rotate much faster (10 hours for Jupiter) or slower (5,832 hours for Venus). The Red Planet has the closest rotational period to Earth.
Mars experiences slight fluctuations in its rotation, and this is due to the gravitational influence of its two small moons, Phobos and Deimos. As they orbit around the planet, they exert tidal forces that cause slight changes in Mars' rotation. Learn more about the Martian moons further below.
The planet's surface speed at the equator is about 866 mph, which is slower compared to Earth's surface speed of 1,000 mph. If you can imagine yourself standing on the planet at the equator, you likely wouldn't feel yourself moving just as you don't feel yourself moving on our home planet.
Mars has an orbital period of 687 Earth days or 1.88 Earth years. This means that it takes nearly two Earth years to complete a full orbit around the sun and return to its starting position.
If you were born on Mars and celebrated your first birthday on the planet, you would be almost two Earth years old!
Interestingly, the distance between Mars and the sun varies depending on its position in the orbit. At its closest approach to the sun, known as perihelion, it is 128 million miles (206 million kilometers) away. At its farthest point, the aphelion, it is 154 million miles (249 million kilometers) from the sun.
So to sum it all up, the time and rotation on the Red Planet differ from what we're used to on Earth. The days are similar to Earth at nearly 25 hours, so one rotation would feel the same for us. However, the length of a year on Mars is twice as long as a year on Earth at 687 Earth days.
Although the length of a year on Mars might be difficult for us to comprehend, it's very interesting to consider the rate at which planets rotate and travel around the sun. The whole system operates in perfect harmony.
Can You See Mars with a Telescope?
Yes, Mars is easy to spot in the night sky and is a cool planet to observe! Despite not being as large as the gas giants, Mars is still beautiful to view through an eyepiece - especially when it is at its closest to Earth. Observers using high-quality telescopes with a long enough focal length will be able to view features like the polar ice caps and massive dust storms. If you are lucky enough to look through a large enough instrument, you might also spot its two small moons.
How to Observe Mars with a Telescope
If you are searching for a telescope to look at Mars but aren't sure which one to get, we have a few to recommend that'll last! While it might seem like a good idea to choose cheaper options, if they lack the features you need to view objects in the night sky, it'll be a waste of your budget and time. Avoid low-cost telescopes found in big box stores. Take our word for it - those deals are always too good to be true because they are manufactured with low-quality materials.
When it comes to the best telescope to view Mars and other planets, we recommend an 8", 10", or 12" Dobsonian. These telescopes are built for visual astronomy and excel at viewing planets (and the moon!).
For a complete beginner, the 8" Dobsonian (like the XT8 pictured here) is a good choice for larger planets like Jupiter but might not be enough for you if you really want to resolve the features on Mars. If you don't mind the extra bulkiness and weight of the 10" and 12" versions, pick one of these instead!
Dobsonian telescopes are best used for visual observations, but with a DSLR camera attached and some basic skills, you can take photos of the moon and planets as well.
Can you take a picture of the Red Planet from Earth?
Mars is usually one of the top 3 planets captured by beginner astrophotographers. It's a fairly easy target to photograph if you're up for it!
There are two ways you can take pictures of planets through a telescope:
By taking one individual image using a DSLR or mirrorless camera attached to the telescope. The easiest option and what is suggested for beginners.
By recording a video at a high frame rate and stacking the best frames into one image. This provides the best possible result but is an advanced technique. Typically, this is achieved with a planetary camera, but processing this data takes time and is not beginner friendly.
Would you like to learn astrophotography efficiently and at your own pace?
Invest in lessons with the Galactic Course. This course is a lifetime membership that grants you access to current and upcoming astrophotography content. Find out all you need to know about astrophotography and connections with other members. Get help from instructors that want to see you progress under the night sky.
Now that you're more familiar with Mars overall, let's dig into its history. Find out how Mars formed, its composition, if life can be sustained on the Red Planet and more.
Formation and Age
The Solar System came into existence about 4.5 billion years ago, with the birth of the sun. It expelled matter into the system, which created perfect conditions for the 8 planets to form.
The timeline of Mars' formation and evolution is still being studied by planetary scientists. However, like the other planets, it formed gravity which brought in gasses released by the sun.
Mars began its journey with a solid core that attracted nearby matter through its gravitational pull. All of that effort collected the material to build up its atmosphere over time.
Can Mars Support Life?
Mars cannot support life as we know it. That also means there are no little green men running around on the planet.
The environment on the Red Planet is too harsh to sustain life or create it. Mars has a thin atmosphere with low atmospheric pressure making it difficult for life to take hold. Water cannot exist in liquid form on its surface (but is present in the ice caps) and the atmosphere is too thin to hold oxygen which is needed for organisms to breathe. Scientists discovered the past presence of water on Mars, but it now only exists deep beneath its red dirt or on its poles. If that's not enough to dissuade you from the potential of life on Mars - the temperature on the Red Planet averages -80°F (-62°C).
What scientists are most interested in discovering is if there was a potential for life in the past. So far, there is no answer to that question. Speculation suggests that it could have existed in the past but most likely in microbial form. After all, signs of liquid water have been found on Mars, and recent discoveries hint that it might still exist underground. More research must be done to prove that Again, this is conjecture - science tells us that life on Mars does not exist.
Composition and Structure
What is Mars Made of?
Mars is mostly comprised of the following elements: silicon, iron, and oxygen. It is possible that Mars could have been a much more habitable planet in the past, but lost its atmosphere due to a weak magnetic field.
A few other elements can also be found in the planet's thin atmosphere, such as carbon dioxide and nitrogen, but they only make up 1% of the matter on Mars.
The interior of Mars was studied in April of 2023. Scientists made a major discovery by studying seismic waves, and used data from the NASA InSight mission to study "marsquakes". They found out that Mars has a solid metal inner core, surrounded by a liquid outer core, and a rocky mantle and crust.
What Does the Red Planet Look Like?
Mars's surface features, including its craters, canyons, and volcanoes, have been well-documented by several of Earth's projects to learn about it via rovers and orbiters. If you stood on the planet, you would see a deserted land of mountains and valleys. Its signature red color comes from the soil found on its surface which is made of iron oxides - more commonly known as rust. Most of the soil makeup on Mars is sand with some dust particles lingering on the surface. Stretching as far as the eye can see is red rust.
One of the most fascinating features of the Red Planet is its volcano, Olympus Mons, which is the largest in the solar system. Mars also holds the deepest canyon Valles Marineris, also known as Mariner Valley.
One surface feature found in 1976 perhaps is the most interesting of all... the Face on Mars. This formation surprised the Viking mission team as the orbiter snapped a photo of the planet and saw something "staring" back.
NASA was quick to say it was simply a rock formation that gave the illusion of a face at certain angles. The space agency shared this discovery with the public hoping to excite and it worked! The face has made its way to pop culture through movies, music, magazines, and radio.
What is the Weather Like on Mars?
Mars has a weak magnetic field, about 1% of Earth for comparison. Its magnetic field does not protect the planet from the solar wind, which contributes to its thin atmosphere.
Its distance from the sun means the temperature on the surface is cold. It ranges from -195 degrees Fahrenheit (-125 Celsius) at its coldest to 70 degrees Fahrenheit (20 Celsius) at its hottest. If you are at the equator, you might experience a perfect 70 degrees day.
Because of the planet's atmosphere and low gravity, Mars also experiences unpredictable, extreme weather conditions, such as dust storms that can cover the entire planet and last for months. The atmosphere might not be able to hold life, but it is perfect for the strong winds to thrive with gusts reaching up to 60 miles per hour.
Mars has an axis that is tilted at about 25 degrees, which is similar to Earth's (23 degrees). This tilt gives it distinct seasons, but they are more volatile than the season we experience due to the planet's atmosphere and the length of the year.
During Martian summers, the planet's southern hemisphere is tilted towards the sun and so it experiences long, warm days while the northern hemisphere has shorter, colder days. In the winter, the pattern is reversed. On a daily basis during the seasons, the tilt and place in orbit also impact the extreme temperature change between day and night.
While Mars has seasons like Earth, the weather patterns are not as diverse or predictable due to the planet's thin atmosphere and lack of large bodies of water to regulate temperature.
The Ice Caps on Mars
Mars is one of the most recognizable planets in the Solar System due to its signature red color. But you might be surprised to know that it is not always red all around. If you are lucky, you might be able to see the ice caps at its pole, giving a nice white-on-red contrast.
The ice caps on Mars form both at the north and south poles.
The north pole usually has the largest ice regions and is most varied in composition as it often includes layers of various dust matter. In Summer, the ice caps at the north pole evaporate quickly, releasing water vapor into the atmosphere.
The Ice caps on Mars are made of a mixture of water ice and carbon dioxide ice (dry ice). Scientists believe that the Martian polar ice caps play a big role in the geology and climate of the planet, as the movement of ice and dust affects wind patterns and atmospheric circulation.
Hubble Space Telescope Image of the Red Planet
The Hubble Space Telescope mostly shoots deep sky objects like galaxies, nebulae, and clusters, but it also had a hand in photographing planets too! Below you can see Mars taken by the Hubble Space Telescope, here it clearly shows one ice cap, ranges of canyons and craters, and a very clear sky!
The picture was taken when Mars was 54 million miles from Earth (87 million kilometers), between April 27 and May 6, 1999.
Blue Sunset on Mars
Why is the sunset blue on the Red Planet?
The sunsets and sunrises on Earth are orange and create the beautiful "golden hour" effect.
As you can see in the picture below taken by the Mars Pathfinder, both the sunset and the sunrise on the Red Planet appear blue, which is the complete opposite of orange. Why is that?
This is because the Martian atmosphere is thin and is mainly composed of carbon dioxide. This combination scatters light coming from the sun in a different way than nitrogen and oxygen do in Earth's atmosphere. For us, the color appears orange because of the size of the particles that sunlight passes through. When the Sun is low on the horizon of Mars, the sunlight must pass through large particles in the Martian atmosphere which scatter the light differently and in a blue color instead.
It's funny to think that the sunsets on the Blue Planet (Earth) are red, but the ones on the Red Planet (Mars) are blue.
Missions to Mars
Probes have been sent to study Mars since the 1960s. There have been many missions over the years that it would be impossible to cover them all! Below, you will find the missions to Mars that had the biggest impact on our understanding of the planet, with a short description and the year they launched.
Mariner 4 (1964)
The Mariner 4 mission is iconic because it was the very first successful flyby of Mars. It was launched on November 18, 1964, and the flyby was achieved on July 15, 1965!
Mariner 4 was the 4th Mariner mission, but only the second Mariner probe to be aimed at Mars. Mariner 1 was a failure, Mariner 2 did a successful flyby of Venus, Mariner 3 was a failure, and Mariner 4 did a successful flyby of Mars.
Viking 1 and 2 (1975)
The first spacecraft to successfully land on Mars and conduct experiments on the planet's surface.
Viking 1 was launched on August 20, 1975, and Viking 2 was launched shortly after on September 9 of the same year. Both landed on the planet about a year after their launch from Earth.
Mars Pathfinder (1996)
This mission marked the first successful deployment of a Mars rover (Sojourner), which traveled a short distance on the Martian surface and transmitted scientific data back to Earth.
The rover operated for 84 days before communications were lost.
Mars Global Surveyor (1996)
The Mars Global Surveyor mission provided the first detailed maps of the Red Planet!
It mapped the surface of Mars and studied the geology and climate of the planet. Communications with the spacecraft failed in 2006.
Mars Odyssey (2001)
The Mars Odyssey spacecraft was able to detect large amounts of water ice just below the surface of Mars. This helps scientists understand the past and present of the Red Planet. Launched in 2001, the Mars Odyssey is expected to still be active until the year 2025.
Spirit & Opportunity (2004)
The Spirit rover and the Opportunity rover are considered twin rovers. They were both designed the same way but sent to different areas of the planet to do their research. Both missions were very successful when looking at all the data gathered. On top of that, the Opportunity Rover set a record for the longest distance traveled by any vehicle on a different planet!
Mission patches for the Spirit & Opportunity Mission
The Curiosity Rover launch was live-streamed online, and we remember watching it and being super excited! The landing of the rover was incredible, and it was a relief knowing it was not broken on impact. Curiosity is equipped with advanced scientific instruments to study the geology and chemistry of Mars, and its discoveries have greatly advanced our knowledge of the planet.
Perseverance & Ingenuity (2020)
The Perseverance mission was launched in 2020, and the landing was, like Curiosity, absolutely incredible. The Perseverance rover is the most advanced ever built, and the mission included the first successful flight of a helicopter (Ingenuity, seen on the left) on another planet.
The main goal of this mission is to search for signs of ancient microbial life and prepare for future human missions to the planet.
Find out more details about each of these missions by visiting NASA's webpage of Mars missions.
The Red Planet has two moons that orbit it. They are named Phobos and Deimos after the horses that pulled the chariot for the god of war. Phobos and Deimos mean fear and panic, respectively. The Martian moons were discovered in 1877 by American astronomer Asaph Hall.
Circumference: 14,078 km (8,758 mi)
Size Comparison: About 170 times smaller than Earth
Name Origin: Greek; means "fear"
Fun Fact: Phobos is gradually getting closer to Mars and is predicted to eventually be pulled apart by tidal forces, potentially forming a ring around the planet.
Phobos is the larger of the two Martian moons, with a diameter of about 22.2 kilometers (13.8 miles). It is heavily cratered and is believed to be made up of a mixture of rock and ice. Scientists think that Phobos was once an asteroid that was captured by Mars' gravity.
Circumference: 9,474 km (5,890 mi)
Size Comparison: About 300 times smaller than Earth
Name Origin: Greek; means "dread"
Fun Fact: Deimos has an unusually smooth surface with few impact craters, suggesting that it has been resurfaced relatively recently by some kind of geological activity.
Deimos is much smaller than Phobos, with a diameter of just 12.4 kilometers (7.7 miles). It is also heavily cratered and made up of rock and ice.
Deimos could have either been an asteroid or a piece of rock from a larger body that collided with the Red Planet.
Final Thoughts and Summary of the Planet Mars
The fourth planet in order from the Sun, Mars, is not only known for being the most habitable planet in our solar system outside of Earth, but it is also a great target to observe or photograph! The planet's reddish appearance and polar ice caps make Mars a beautiful sight for both visual observers and amateur astrophotographers. Mars is often referred to as the "Red Planet" and has two small moons named Phobos and Deimos.
Type: Terrestrial planet
Name Origin: Roman god of war
Discovered in: Ancient times
Radius: 3,389.5 km
Temperatures: -63°C to 20°C
Distance from Sun: 228 million km (on average)
Day: 24.6 Earth hours
Orbit: 687 Earth days
Natural Satellites (moons): 2 (Phobos and Deimos)
Light speed from Sun: 12.0 min
If you observe this planet, you should try your hand at photographing it too! We'll have an article coming soon to teach you how to photograph Mars in-depth.