Planet Mars is the second smallest planet in our solar system, with a radius that is approximately half of Earth’s.
Mars, often called the Red Planet, has captivated the human imagination for centuries. As the fourth planet from the Sun in our solar system, Mars offers some of the most intriguing possibilities in planetary science—from the search for alien life to becoming a future home for humanity. This article explores everything you need to know about the Red Planet, including the latest NASA science, facts about Mars, and the history of Mars exploration. If you’re curious about Planet Mars or dreaming about humanity’s journey into space, this post is a must-read.
What Makes Mars So Unique in the Solar System?
Mars is the second smallest planet in the solar system, just half the size of Earth. Despite its size, it has drawn major attention due to its Earth-like features. Known as the fourth planet from the Sun, Mars is one of the most studied celestial bodies thanks to its relatively moderate distance from the Sun and the potential it holds for scientific discovery.
The planet has two moons, named Phobos and Deimos, which are small and irregularly shaped. Unlike other rocky planets, Mars has a thin atmosphere made mostly of carbon dioxide. This makes it difficult to retain heat, resulting in extreme temperatures. The planet’s polar regions feature a polar ice cap, further evidence of the planet’s dynamic environment.
How Mars got its name
Mars was named after the roman god of war, due to its red colour and apparent erratic movement in the sky. Observing from earth mars appears to travel in one direction, then loop back on itself before traveling on its original path. In fact mars has a perfectly normal orbit, as shown in the animation below, but the combination of both orbits and our position in relation to mars is the cause of this illusion.
Martian Orbit
The animation on the left shows the orbits of Mars and Earth to explain the seemingly erratic orbit that was, in part, the reason why Mars was named after the Roman god of war. Initially the planet Mars appears from Earth to be travelling east to west in the night sky of the northern hemisphere. Once the Earth ‘overtakes’ Mars it appears as if Mars jumps back in the opposite direction before continuing in its original path.
This event (known as the Martian retrograde) takes place every 2 years and is only noticeable if the position of mars is plotted over a period of several months.
How Far Is Mars From the Sun and Earth?
The distance from the Sun to Mars is roughly 142 million miles (228 million kilometres), which places it as the fourth planet from the Sun. Its orbit around Mars is elliptical, meaning this distance varies throughout the Martian year.
The average distance between Earth and Mars is about 225 million kilometres (140 million miles), though this changes due to the elliptical orbits of both planets. Earth and Mars align favourably for missions about every 26 months, which is why NASA missions are often timed with these windows to reach the Red Planet.
What Are the Most Fascinating Facts About Mars?
Let’s dive into some compelling facts about Mars. First, a day on Mars (called a “sol”) is just over 24 hours, very similar to Earth’s. However, a year on Mars is nearly 687 Earth days due to its longer orbit.
Another Mars fact: the surface of the Red Planet is home to the tallest volcano in the solar system, Olympus Mons, and the deepest canyon, Valles Marineris. These massive geological features are key highlights in any atlas of Mars and are still being studied for signs of past activity.
What’s the Surface of Mars Really Like?
The surface of Mars is a rugged and diverse terrain made of dust, sand, and rock. From massive volcanoes to dried-up riverbeds, the Martian surface tells a story of geological activity that likely occurred billions of years ago.
Craters on Mars indicate frequent meteor impacts, and the mantle of Mars contributes to its tectonic structure. Robotic rovers like the Curiosity Mars Rover have touched down on the surface, capturing invaluable data. These missions suggest that Mars was created through processes similar to Earth’s, but lacked the tectonic activity needed to sustain life.
Mars is the second smallest planet in our solar system, with a radius that is approximately half of Earth’s. Its surface area (144,798,500 km², 89,973,616 mi²) is a little less than the total surface area of land on Earth (148,940,000 km² or 57,506,055 mi²)
Also known as the ‘Red Planet’ due to its colouration from the iron oxide (hematite or rust) that covers the surface.
Martian Weather
Planet Mars, like Earth, has a tilt on its axis known as its obliquity, Earths tilt is currently at 23.44 degrees while the planet Mars has an inclination of 25.19 degrees. Its Earths obliquity which gives us our seasons however the seasons on Mars last much longer than ours. This tilt has caused ice deposits to form on its poles which, like on Earth, grow and recede with the seasons.
In 2008 NASA’s Mars Phoenix Lander not only found water at the North Polar Region but observed precipitation, similar to snow, falling from clouds. Analysis of soil in that region suggested that this was a relatively new climate which would have been warmer and wetter a few million years before.
Life on Mars
On the 6th of December 1906 the article above appeared in the New York Times. Percival Lowell, probably most famous for his work in discovering Pluto, was one of many astronomers that had seen lines across the face of planet mars. Like Italian astronomer Giovanni Schiaparelli, who saw this phenomenon in 1877, Lowell was convinced that they were canals built by an advanced civilisation.
On Earth the Suez Canal, one of the greatest engineering feats of the time, was completed on the 17th of November 1869. It linked the Mediterranean Sea with the Indian Ocean allowing merchant ships to trade between Europe and Asia without having to travel around the African continent. And by 1903 work had begun on the Panama Canal which would allow ships to travel between the north and South American Continents. The use and growth of canal networks had also been vastly increased throughout the civilised world for use in industry and these canal networks created many criss-crossing straight lines in the landscape similar to those witnessed by astronomers on the face of mars.
Schiaparelli’s map of the Martian canals from 1892 (public domain image).
Since the 1960’s NASA has been spacecraft to the planet and we now know that these canals, and indeed civilisations do not exist on mars. The canals seen by many observers were no more than an illusion created by the brain. Even the very best telescopes of the day were not able to show mars in great detail and the brain attempted to form the best image it could.
Many probes and landers have visited the planet but no signs of life have been found or that life could exist on mars. That is not to say that there was never life on mars.
What NASA Missions Have Explored Mars?
NASA’s Mars missions have played a key role in our understanding of the Red Planet. Early efforts like the Mars Global Surveyor and Mars Odyssey Orbiter provided detailed mapping and atmospheric data. Mars Express, operated by the European Space Agency but working closely with NASA science initiatives, has been orbiting since 2003.
Current missions include NASA’s Mars Reconnaissance Orbiter, which delivers high-resolution images of the Martian surface, and the Mars Science Laboratory, which deployed the Curiosity Rover. Future plans include the Mars Sample Return mission, aimed at bringing samples of Mars back to Earth.
Is There Evidence That Mars Once Had Water?
Yes, there is compelling evidence that Mars once had flowing water. Dry river valleys and sedimentary rock layers observed by the Mars Reconnaissance Orbiter and other spacecraft support this theory.
In fact, regions studied show signs of ancient lakes and even oceans, suggesting the planet was warm and had a thicker atmosphere billions of years ago. The presence of a polar ice cap today and findings related to changes on Mars indicate that water on Mars was once abundant, possibly supporting microbial life.
Could There Be Life on Mars?
The question of life on Mars has intrigued scientists and the public alike. While there is no direct evidence of current life, the possibility that life existed on Mars in the past remains open.
The search continues through missions like NASA’s Mars Science Laboratory and upcoming Mars Sample Return projects. Understanding the atmosphere of Mars and discovering biosignatures could one day confirm that Mars is the second planet we know of inhabited by life—if only microbial.
Will Humans Ever Live on Mars?
A human mission to Mars is no longer science fiction. NASA, along with private companies like SpaceX, is actively planning to send humans to Mars. These missions could take place within the next two decades.
Challenges include developing sustainable habitats, solving the problem of radiation, and ensuring food and water supply on the entire planet. Still, progress is being made, and the dream of going to Mars is slowly moving towards Mars becoming a reality. The eventual goal is to explore the Red Planet not just with machines, but with human footsteps.
What Is the Future of NASA Science on Mars?
The future of NASA science on Mars includes advanced missions that will push the boundaries of technology and planetary exploration. The Mars Exploration Program is coordinating robotic exploration and preparing for eventual human landings.
The next frontier includes the Mars Atmosphere and Volatile Evolution (MAVEN) mission, the continuation of Mars Express, and the much-anticipated Mars Sample Return mission. Tools like the Mars Orbiter and new landers will help create an atlas of Mars like never before, tracking changes on Mars and assessing its suitability for life.
Curiosity Rover
In August 2012 one of NASA’s Mars rovers named Curiosity landed on the Martian surface in the Gale Crater. Its chief mission was to determine the habitability for life on Mars; a feat NASA scientist hoped Curiosity would accomplish mid-2013. However on the 9th of February 2013 the mars rover was drilling and analysing rocks in an area known as Yellowknife Bay, an area believed to be an ancient streambed.
Analysing the rocks on Curiosity’s on-board laboratory the samples showed to contain 20% and 30% smectite which is a clay mineral that forms when water is present. Curiosity also detected minerals that indicate the water could have carried energy suitable for microbes as well as a neutral ph.
It is believed that this life supporting water would have been a liquid on the surface of Mars, billions of years ago, during a time when on Earth life would have just started. This water has since been lost due to the reduction of the Martian atmosphere and magnetosphere.
In March 2013, at a meeting in Texas, analysis was presented from three different Mars rovers showing hydrated minerals scattered throughout the Yellowknife Bay region.
John Grotzinger, a project scientist at NASA beliefs the water to be “so benign and supportive of life that probably if this water had been around and you had been on the planet, you would have been able to drink it”.
If this is the case it may prove valuable to the possibility of one day colonising the Red Planet. It is now believed, due to discoveries by Odyssey, that there is much frozen water below the surface of Mars, which if drinkable, could be drilled and used to support life today. The hope is that if the indications are correct and the water on Mars was once safe for us to drink then so may be the water locked under the Martian surface.
Where in the Solar System?
Quick Stats
|
2 |
|
|
Rings |
0 |
|
Orbit Period |
686.98 Earth Days |
|
Rotation Period |
24.62 Hours |
|
Equatorial Radius |
3,397 km (2,111 miles) |
|
Overall Density |
3.934 g/cm3 |
|
Mass (Earth = 1) |
0.10744 |
|
Gravity (Earth = 1) |
0.38 |
|
Minimum Temperature |
-87°C (-124°F or 186 °K) |
|
Maximum Temperature |
-5°C (23°F or 268 °K) |
