Mars: Quick Facts
Planetary Properties of Mars
Orbital Semimajor Axis: 1.52 Astronomical Units (227.9 Million Kilometers)
Orbital Eccentricity: 0.093
Perihelion: 1.38 Astronomical Units (206.6 Million Kilometers)
Aphelion: 1.67 Astronomical Units (249.2 Million Kilometers)
Mean/Average Orbital Speed: 24.1 Kilometers Per Second
Sidereal Orbital Period: 686.9 Days (Solar) (1.881 Tropical Years)
Synodic Orbital Period: 779.9 Days (Solar)
Orbital Inclination to the Ecliptic: 1.85 Degrees
Greatest Angular Diameter (As Viewed from Earth): 24.5”
Overall Mass: 6.42 x 1023 Kilograms (0.11 of Earth’s Overall Mass)
Equatorial Radius: 3,394 Kilometers (0.53 of Earth’s Equatorial Radius)
Mean/Average Density: 3,930 Kilograms Per Meters Cubed (0.71 of Earth’s Mean Density)
Surface Gravity: 3.72 Meters Per Second Squared (0.38 of Earth’s Surface Gravity)
Escape Speed/Velocity: 5 Kilometers Per Second
Sidereal Rotation Period: 1.026 Days (Solar) [24 Hours and 37 Minutes]
Axial Tilt: 23.98 Degrees
Surface Magnetic Field: Approximately 1/800 of Earth’s Surface Magnetic Field
Magnetic Axis Tilt (Relative to Rotation Axis): N/A
Overall Mean/Average Surface Temperature: 210 Kelvins (-81.67 Degrees Fahrenheit); Ranges from 150 – 310 Kelvins)
Number of Moons: 2 (Phobos and Deimos)
Fact #1: Mars is the fourth planet in our solar system from the Sun, and is the last of the terrestrial planets (which include Mercury, Venus, and Earth). Mars maintains a reddish-brown hue due to its surface features. Aside from the planet Mercury, Mars is the second smallest planet in our solar system, and orbits the Sun at a distance of approximately 227 million kilometers.
Fact #2: One unique feature of the Martian landscape is the existence of dust storms. Many of these dust storms are the largest in the entire solar system. Scientists believe that these storms are the result of Mars’ elliptical orbit around the Sun. Some of these storms are quite brutal, and can last for several months at a time before dissipating.
Fact #3: Unlike the Earth, it takes Mars around 687 days to complete one orbit around the Sun. The planet also tilts on its axis, causing the Martian surface to experience seasonal variations (just like Earth). However, these seasons are often twice as long as their counterparts on Earth.
Fact #4: Scientists have discovered numerous clues that indicate the presence (or former presence) of liquid water on the planet Mars. Although the existence of ice is a crucial piece of evidence for water, scientists have also discovered darkened stripes on satellite images alongside canyon cliffs and walls (indicating the possibility of water channels in years prior). The presence of liquid water is important to consider for the Martian surface, as water holds the key to potential life.
Fun Facts about Mars
Fun Fact #1: Mars is home to the largest and tallest mountain in the entire solar system, known as “Olympus Mons.” The mountain is believed to be a dormant shield volcano, with a diameter of nearly 600 kilometers, and a height of 21 kilometers. More recently, scientists have been divided over whether or not this volcano is actually dormant due to the pattern of lava flows that appear to have formed recently.
Fun Fact #2: Traces of the Martian surface have been discovered on Earth’s surface over the last few decades. Although these pieces are extremely tiny, they have offered scientists vital clues to the composition of Mars’ surface (even before the launch of space missions to Mars). Astronomers and scientists, alike, believe that pieces of the Martian surface were ejected into space by violent collisions with asteroids in years prior. These pieces then reached the Earth’s surface in the form of meteorites.
Fun Fact #3: Scholars agree that Mars was first discovered by the ancient Egyptians during the second millennium BC. Mars derives its name from the Roman god of War. Interestingly, the Sumerians also associated the planet with their god of war and plague, known as Nergal.
Fun Fact #4: It is believed by scientists that the Martian atmosphere was more dense in years past. However, due to exposure to the Sun, astronomers believe that hydrogen molecules were stripped away.
Fun Fact #5: Unlike the Earth, Mars has too moons known as Phobos and Deimos. Scientists believe that these moons were caught by Mars’ gravity, and eventually settled into an orbital pattern around the planet. After careful study of these two moons, scientists have recently discovered that Phobos is on a collision course with the Martian surface. In approximately thirty to fifty million years from now, scientists believe that Phobos will crash into the planet (or spontaneously split apart) due to the intense effects of gravity.
Fun Fact #6: Despite the prospect of manned-missions to Mars in the near future, the planet’s atmosphere and environment is extremely volatile for humans. Temperatures are extremely cold (even in mid-latitude areas), and the atmosphere is composed primarily of carbon dioxide (95 percent), nitrogen (3 percent), and argon (1.6 percent).
Fun Fact #7: Mars maintains a rotational period that is similar to Earth. One day is approximately twenty-four hours and thirty-seven minutes.
Fun Fact #8: Mars appears red due to the high-concentration of iron oxide that permeates its soil.
Fun Fact #9: Scientists have been unable to determine the composition of Mars’ inner core. However, more recent evidence tends to suggest that the Martian core is metallic in structure; composed primarily of iron, nickel, and sulfur. Surrounding this core is a silicate mantle. Scientists believe that the Martian crust is approximately fifty kilometers (31 miles). So far, scientists believe that the crust is composed primarily of magnesium, iron, aluminum, potassium, and calcium.
“Water is the key to life, but in frozen form, it is a latent force. And when it vanishes, Earth becomes Mars.”— Frans Lanting
Quotes about Mars
Quote #1: “All indications are that three and a half billion years ago, Mars looked like Earth. It had lakes. It had rivers. It had river deltas. It had snow-capped peaks and puffy clouds and blue sky. Three and a half billion years ago, it was a happening place. The same time on Earth, that’s when life started. So did life start on Mars?” -- John M. Grunsfeld
Quote #2: “I would like to die on Mars. Just not on impact.” -- Elon Musk
Quote #3: “Water is the key to life, but in frozen form, it is a latent force. And when it vanishes, Earth becomes Mars.” -- Frans Lanting
Quote #4: “Studying whether there’s life on Mars or studying how the universe began, there’s something magical about pushing back the frontiers of knowledge. That’s something that is almost part of being human, and I’m certain that will continue.” -- Sally Ride
Quote #5: “Mars is there, waiting to be reached.” -- Buzz Aldrin
Quote #6: “We imagine going to the Moon and planting a flag, going to an asteroid and mining, going to Mars and setting up a colony. And I think that expansionist mentality is very self-destructive, especially given the kind of precarious relationship we now have to the ecosystem here on Earth, because it allows us to imagine that Earth is disposable.” -- Trevor Paglen
Quote #7: “By going to Mars one day, we will make things better for us here on Earth.” -- Scott Kelly
Future Missions to Mars
As of 2018, numerous space missions are planned for the Martian planet by a variety of countries around the world. In 2020, NASA plans to launch its astrobiology rover, whereas the European Space Agency hopes to launch the ExoMars rover and surface platform in July of that same year. By 2021, the United Arab Emirates’ plan to launch their Mars Hope orbiter, which will examine the Martian atmosphere in depth.
Although no active plans have been designed for a manned-mission to Mars, many countries are hopeful to begin manned flights to Mars in the 2020s and 2030s. At the current stage of technology, these expeditions would likely be one-way trips.
Were you surprised by any of these facts about Mars?
Mars remains a fascinating point of interest for astronomers and scientists, alike. In popular culture, the planet continues to garner a similar sense of fascination from Hollywood, artists, and writers interested in the potential for alien life on the Martian surface. As more and more space probes and spacecraft observe the Martian surface (and atmosphere) in the decades ahead, it will be interesting to see what new forms of information can be learned about Earth’s distant neighbor.
Will the Martian surface unlock clues about our solar system? Will Mars offer clues about the existence of life outside of Earth? Finally, and perhaps most importantly, what does the future hold for manned-missions to the Martian surface? Will Mars eventually serve as a colony for Earth in the decades and centuries ahead? Only time will tell.
Suggestions for Further Reading
David, Leonard and Ron Howard. Mars: Our Future on the Red Planet. Washington, DC: National Geographic Books, 2016.
Petranek, Stephen. How We'll Live on Mars. New York, New York: TED Books (Simon and Schuster), 2015.
Sparrow, Giles. Mars: A New View of the Red Planet. London, United Kingdom: Quercus, 2015.
Wikipedia contributors, "Mars," Wikipedia, The Free Encyclopedia, https://en.wikipedia.org/w/index.php?title=Mars&oldid=875589855 (accessed January 7, 2019).
Questions & Answers
© 2019 Larry Slawson