TERRESTRIAL PLANETS

Introduction:

Each time you look up to the sky and see a star you are looking at a sun in another galaxy. If you were on another planet looking back at our solar system, you would see our sun as a star.

It’s believed that every sun has planets orbiting it. Our Milky Way galaxy has more planets than it has stars.

In our solar system we have eight planets: Mercury, Venus, Earth, and Mars are the inner rocky or “terrestrial” planets. Jupiter and Saturn are the outer gas giants.

Uranus and Neptune are the outer ice giants. In recent years, astronomers have designed a new class called the “dwarf planets.” These are smaller worlds, not quite big enough to be considered a standard planet, and include Pluto.

Terrestrial Planet Statistics:

Terrestrial planets are also called “telluric planets or rocky planets.” These planets have to consist of a majority of silicate rocks or metals. They must also have a hard surface and possible atmosphere.

A critical requirement is that they have a heavy core made up of mostly iron and that a portion of that core be in a molten state. It’s the molten state that creates the currents of energy as the planet rotates.

The core size can be different in each planet. The terrestrial planets that exist within our solar system are also those that are the “inner planets” or those closest to the sun: Our four terrestrial planets include Mercury, Venus, Earth, and Mars.

To be considered as a terrestrial planet it needs to share the following characteristics: a heavy molten core, volcanoes, thick or thin atmospheres, craters, mountains, canyons, few or no moons, no rings.

Mercury:

• View on Maps: google.com/maps/space/mercury
• Moons: None
• Distance from Sun: 35.98 million mi
• Radius: 1,516 mi
• Diameter: 4,879 km
• Orbital period: 88 days
• Mass: 3.285 × 10^23 kg (0.055 M⊕)
• Surface Temperature: -173 to 427°C
• Number of Moons: None
• First Record: 14^th century BCE by Assyrian astronomers

Venus:

• View on Maps: google.com/maps/space/venus
• Distance from Sun: 67.24 million mi
• Radius: 3,760 mi
• Diameter: 7,520.8 mi
• Orbital period: 225 days
• Mass:  4.867 × 10^24 kg 0.815 M⊕
• Surface Temperature: 462 °C
• Number of Moons: None
• First Recorded: 17^th century BCE by Babylon astronomers

Earth:

• Population: 7.53 billion (2017)Trending, World Bank
• View on Maps: google.com/maps/space/earth
• Distance from Sun: 92.96 million mi
• Radius: 3,959 mi
• Polar Diameter: 12,714 km
• Orbital Period: 265.24 days
• Mass: 5.972 × 10^24 kg
• Number of Moons: 1
• Age: 4.543 billion years

Mars:

• View on Maps: google.com/maps/space/mars
• Distance from Sun: 141.6 million mi
• Radius: 2,106 mi
• Polar Diameter: 6,752 km
• Orbital Period: 6.42 x 10^23 kg (10.7% Earth)
• Mass: 6.39 × 10^23 kg  0.107 M⊕
• Surface pressure: -153 to 20 °C
• Moons: (2) Phobos,Deimos
• First Recorded: 2^nd Millennium BCE by Egyptian astronomers

History of the Name:

The name for terrestrial and telluric is derived from the Latin words for Earth: Terra and Tellus. They are named so due to the similar composition of the planets to that of Earth.

In other words, they are the most Earth-like. Conditions on the two closest planets to the Sun, Mercury and Venus, are too harsh and extreme to harbor any form of life.

However, it is thought that Mars may have once had life and there is a possibility that life may still be on Mars today.

Terrestrial planets have surfaces that are rocky and may also have atmospheric gases.

It’s thought that many civilizations recognized the planet Mercury as far back as 5,000 years.

It was named about the Roman messenger god that was known for moving fast, because the planet orbited the sun more quickly than other planets.

Throughout history, Venus was one of the planets that many civilizations recognized.

Named after the Roman goddess of love and beauty, it was also known by the Greeks as Aphrodite. All of the planets in our solar system are named after male gods or mythological creatures, with the exception of Venus.

It is the only planet named after a female and it’s thought that it was because it is the brightest planet.

It’s believed that the name “Earth” is around 1,000 years old. If you notice, except for Earth, all of the planets in our solar system are named after Roman and Greek gods and goddesses.

One idea of the source of the name is that the word “Earth” is an old Germanic word that really just means “the ground.”

Another thought is that the name “Earth” is derived from the Old English word “ertha” as well as the Anglo-Saxon word “erda”, which means soil or ground.

Earth is the only known planet to support life and was formed around 4.54 billion years ago.

Mars is the fourth planet from the Sun and is one of the terrestrial planets. It has a distinctive red color and was therefore associated with battles and war and named after the Roman god of war.

The surface of Mars is a reddish-brown color due to the rusting process of the surface minerals. Another name for Mars is “The Red Planet.” Mercury is the smallest planet in our solar system and Mars is the second smallest planet.

Other civilizations throughout history have also named the planet due to its color. The Ancient Egyptians called Mars “Her Desher,” which translates to “the red one.”

Today we often call Mars the “Red Planet” due to the iron minerals on the surface. It’s the iron in the Martian dirt that has oxidized or rusted that causes it to look red.

Formation:

Planets are created when gravity pulls dust and swirling gas together. It’s believed that the planets were formed around 4.5 billion years ago. The terrestrial plants have a central core, a rocky mantle, and a solid crust.

Structure and Surface:

Mercury:

After Earth, Mercury is the second densest planet in our solar system. Mercury’s core is metallic with a radius of around 1,289 mi/2,074 km, which is about 85% of the planet’s entire radius.

Scientists believe that they have found evidence that shows that part of the metallic core is molten or liquid. The outer shell or mantle and crust is around 250 mi/400 km thick.

When you stare at the surface of Mercury, you can’t help but realize that it resembles that of our moon. The surface is covered with a lot of craters that that were caused by collisions with comets and meteoroids.

We have named a lot of these craters for famous people, including authors, musicians, and artists. Two of the craters are named for Dr. Seuss, famous author of children’s books and Alvin Ailey, a pioneer in dance.

Venus:

There are a lot of similarities between Venice and Earth, and one of the most notable is its structure. Venus has a 2,000 mi/3,200 km radius iron core.

Above the core is a mantle that consists of hot rock similar to lava that churns slowly due to the interior heat of the planet. The surface is a bulging thin rock crust that moves as the mantle shifts. This movement creates the volcanoes.

Venus is covered in valleys, mountains and tens of thousands of volcanoes. The tallest mountain on Venus is Maxwell Montes, standing over 20,000 ft/8.8 km high.

It is similar to Earth’s highest mountain, Mount Everest. The landscape is rather dusty and the temperatures on the surface can reach as high as 880 degrees F/471 degrees C.

Earth:

The Earth is made up of four main layers, beginning with the planet’s inner core which is enveloped by the outer core, then the mantle, and finally the crust.

The inner core is around 759 mi/1,221 km in radius and is a solid sphere of nickel and iron metals. The temperature of the inner core is as high as 9,800 degrees F/5,400 degrees C.

Surrounding the inner core is the outer core, which is 1,400 mi/2,300 km thick. The outer core is made up of iron and nickel fluids.

Wedged in between the outer core and the crust is the mantle which is the thickest of all of the layers. This is a hot, thick mixture of molten rock that has the consistency of caramel and is around 1,800 mi/2,900 km thick.

The Earth’s crust is the outermost layer and is an average of about 19 mi/30 km deep on land. The ocean’s bottom has a thinner crust and it extends about 3 mi/5 km from the floor of the sea to the top of the mantle.

Mars:

The core at Mars’ center is very dense and is between 930 and 1,300 mi/1,500 to 2,100 km in radius. The core is made up of iron, nickel and sulfur.

Surrounding the core is the planet’s rocky mantle which is between 770-1,170 mi/1,240-1,880 km thick. Above the rocky mantle is the crust made up of iron, magnesium, aluminum, calcium, and potassium.

The crust is between 6-30 mi/10-50 km deep.The Mars surface is divided by the hemisphere of the planet and is in two distinct types of features.

Thanks to the Mars Rovers we have been able to see the smooth look of the northern hemisphere and can see that it doesn’t have very many craters.

However, the southern hemisphere is the exact opposite, with a lot more craters as well as highlands. The craters on Mars range in sizes but it also has the biggest known crater in the solar system, called Valles Marineris.

You could stretch the crater from the U.S. West Coast all the way to the East Coast. Mars is also home to the largest known volcano in the solar system called Olympus Mons.

One of the most distinctive features on Mars is its “channels.” These channels look like they could have been made by running water.

Mars actually has many more colors than just the “red” that most people use to describe it. At the surface we see colors such as gold, tan, and brown.

The red color is due to oxidization or rusting of the iron rocks and as it rusts it creates the Martian “soil” which is called regolith.

This soil is dusty and when it is kicked into the atmosphere during storms the planet turns a reddish color.

Atmosphere. Magnetosphere, and Moon Status:

Mercury:

While some planets do have an atmosphere, Mercury doesn’t have one. Instead it has a thin “exosphere” which consists of atoms that are created with meteoroids hit the surface and the solar wind catches them and blasts them upwards.

The exosphere of Mercury is made up of mostly oxygen, sodium, hydrogen, helium, and potassium.Mercury’s magnetic field is relative to the equator of the planet.

While it has just 1% of the strength of our Earth’s magnetosphere, it does interact with the solar wind magnetic field so that it can create really intense magnetic tornadoes.

These storms funnel the hot solar wind plasma down to the planet’s surface. Once the ions hit the surface, they imbalance the atoms that are neutrally charged and quickly send them back into the sky.

Mercury doesn’t have a moon or rings.

Venus:

There are two broad layers of atmosphere on Venus including one layer that is a cloud bank covering the entire plant, and another that includes everything that is below the cloud bank.

The consistency of the clouds is very dense and they are made up of sulfuric acid and Sulphur dioxide. Between the mixtures and density, the clouds reflect around 60% of the sunlight that hits Venus back out into space.

Even though it’s the second planet closest to the sun, it is the single hottest planet within our solar system.

The atmosphere of Venus is mostly made up of carbon dioxide and has clouds of sulfuric acid droplets.

This thick atmosphere is responsible for trapping the heat of the sun and creates the intensely hot surface temperature of up to 880 degrees F/470 degrees C.

The atmosphere itself consists of many layers and the temperatures vary within each layer. Around 30 mi from the surface, the clouds have about the same temperature as we find on Earth’s surface.

If you could stand on the ground on Venus, you would look around and it would appear like a very overcast and hazy day on Earth, however, due to the heavy atmosphere, you would feel like you were 1 mi/1.6 km under water.

The slow rotation of Venus makes the magnetic field a lot weaker than on Earth. Even though Earth and Venus share similar size and seem to have similarly-sized iron cores, Earth’s faster rotation allows us a stronger magnetosphere.

Venus doesn’t have any moons or rings.

Earth:

Earth’s atmosphere consists of 78% nitrogen, 21% oxygen and trace amounts of other gases including carbon dioxide, argon, and neon. We give credit to the plant life on Earth for generating the large amount of oxygen.

During the photosynthesis process, plants consume carbon dioxide and give off oxygen. Earth’s Ozone layer consists of a special kind of oxygen that helps to absorb the harmful UV rays from the sun.

The Ozone layer protects Earth and life from the extremes of solar radiation. Our atmosphere is also responsible for both short-term and long-term weather effects on the Earth.

The atmosphere acts as a protective barrier, shielding the Earth from the impacts of meteoroids as many burn up before they have a chance to hit Earth’s surface.

The magnetic field of Earth is incredibly powerful and also plays a big part in protecting our planet from the effects of solar wind.

It’s though that the Earth’s magnetic field is due to the planet’s core, which is made up of nickel-iron, combined with the fast rotation of the Earth.

It’s important to realize that the rotation of the Earth is slowing down at nearing 17 milliseconds for every 100 years.

The slowing down process will have an effect on the length of our days, however, it will take around 140 million years before we see a day change from 24 hours to 25 hours.

The solar wind distorts the magnetic field so that if you looked at it in space it would be a teardrop shape. The solar wind is a constant stream of charged particles that the sun ejects.

When these particles are trapped in the magnetic field of the Earth they collide with the molecules in the air above the Earth’s magnetic poles.

This collusion causes the molecules in the air to glow and this is known as the Aurora Borealis or northern and southern lights.

It’s the Earth’s magnetic field that causes the compass needles to point to the North Pole, no matter which way that you turn.

However, the magnetic polarity of the Earth doesn’t always stay the same, and the magnetic field can flip. Scientists studying geological records have seen that there is a magnetic reversal every 400,000 years or so.

As far as anyone knows, this flip hasn’t caused harm to Earth’s life, and another one isn’t likely to happen for at least another thousand years.

It’s guessed that when a flip does occur, compass needles will point in many different directions for a few centuries until everything settles down; and then the compasses will point south instead of north.

Earth has one moon and no rings.

Mars:

The atmosphere of Mars is quite similar to that of Venus. It has a main component (95%) of carbon dioxide and Venus is 97%.

The difference between the two planets is that runaway greenhouse effect on Venus allows temperatures over 480 degrees C, whereas Mars never goes higher than 20 degrees C.

The variation is also credited to the density of the two atmospheres. Mars has a thin atmosphere and Venus has a thick atmosphere.

Extensive research has gone into the idea that the atmosphere on Mars might also have an impact on the presence of liquid water.

The polar caps of Mars has been found to have frozen water, and other evidence is showing that liquid water may exist below the surface of the planet.

It is also thought that at one time, Mars may have had an atmosphere strong enough to support water on the planet’s surface.

The Mars temperature can reach as high as 70 degrees F/20 degrees C and as low as -225 degrees F/-153 degrees C. The atmosphere is so thin that any heat from the sun quickly escapes the planet.

If you were standing on Mars it would appear as a hazy red color. The Mars winds can create incredibly strong dust storms that cover a lot of the planet. They can be so strong that it can take months before all of the dust settles.

Today, Mars doesn’t have a magnetic field. However, there are areas of the Martian crust in the southern hemisphere that are very highly magnetized.

This indicates that there are traces of what once was a magnetic field around 4 billion years ago.

Mars does have two small moons: Phobos and Deimos. It’s believed that these may have actually been asteroids that were captured.

The moons are shaped like potatoes and have such a small mass that their own gravity can’t make them spherical like our Earth’s moon.

The moons were named for the horses that pulled that chariots for Ares, the Greek god of war. In Ancient Greek, the word “Phobos” translates to “flight,” and “Deimos” translates to “fear.”

Phobos is the largest moon and the one closest to Mars. It’s heavily cratered with many deep surface grooves.

It is moving slowly toward Mars and it’s believed that in about 50 million years it will either break apart or crash into Mars.

Deimos is around half the size of Phobos and its orbit is 2 ½ times farther away. Deimos is strangely shaped and is covered in loose dirt that sometimes fills in the craters on its surface.

It’s due to this odd situation that it often looks smoother than Phobos.

Mars doesn’t have any rings, however, it’s thought that in 50 million years, when Phobos either breaks apart or crashes into Mars, it might create a dusty ring around Mars.

Could Life Exist?

Extreme temperatures and pressures on Mercury and Venus are too intense to be conducive to life as we know it to adapt or thrive.

Scientists don’t think that they will ever find living things on Mars as the conditions aren’t good enough for life to thrive.

However, they are seeking signs that life might have existed on the planet a long time ago when Mars was warmer and had liquid water covering its surface.

If you look around our Earth you can see that we have an incredible amount of life that exists on both the land and within the waterways and seas.

Scientists have always based our definition of “life” as the carbon-based type that we have around us, including ourselves.

They established three rules that are required for life: liquid water, some source of energy such as our sun, and a source of food.

However, in the past number of years experts have discovered Earth lifeforms that live outside of these ideas.

These lifeforms live in conditions that were previously thought to be uninhabitable, and they are called “extremophiles.”

Scientists believe that life not only developed but adapted and thrived on Earth because of our uniquely perfect distance from the sun and the gravitational effects that the moon had on the planet.

Earth isn’t too hot and isn’t too cold, and this is often called the “Goldilocks distance.” Our moon has created the tides on Earth, which in turn has helped life to develop.

The rotation of the moon around the Earth has caused an effect that is called being “tidally locked” so that the orbit and rotation periods are the same.

This lock is what causes the moon to always be facing the same way to Earth.

The size of the Earth and the distance from the sun is critical to life on Earth. The Earth is the largest of the terrestrial planets at 3,959 mi/6,371 km radius, and the fifth largest overall planet in our solar system.

Earth is an average distance of 93 million mi/150 million km from the sun or one AU (astronomical unit).

An AU is the distance from the Sun to the Earth. It takes around eight minutes for light that leaves the sun to reach the Earth.

Interesting Information:

• Our solar system’s terrestrial planets have an orbit that is relatively close to our sun and are also called the “Inner Planets.”
• The makeup of the terrestrial planets consists of a mostly iron central core and a next layer called the mantle usually consisting of silicate rocks that are rich in oxygen and silicon.
• Terrestrial planets are often referred to as “rocky” planets.
• Terrestrial plant surfaces include the existence of mountains, canyons, volcanoes, and craters.
• None of the terrestrial planets in our solar system have any rings.
• We do have one dwarf planet in our solar system that is thought to be a terrestrial-type world. Ceres has both a rocky core and an outer mantle and its surface includes mountains and craters.
• The Kepler mission sent back data that indicates that there are terrestrial planets around other stars outside of our solar system. These are Earth-sized as well as called “super-Earth” and exist throughout the galaxy. Scientists think that there could be up to as many as 40 billion such worlds in our Milky Way galaxy.

Space Visits:

Mercury:

1974-1975 Mariner 10: The spacecraft orbited Mercury three times and mapped around half of the surface of Mercury. During the Mariner 10 mission it discovered evidence that Mercury has a magnetic field.

Comparisons have shown that the magnetic field is only around 1% of Earth’s, but it’s highly active, being responsible for the solar wind tornados on the surface of Mercury.

The images that Mariner took covered around 45% of the surface of Mercury and prompted interest to launch later missions.

2004 Messenger Probe: The probe orbited Mercury for four years, sending an incredible amount of data back to Earth before it crashed into the surface.

2018 BepiColombo: The ESA (European Space Agency) launched BepiColombo as part of their first mission for the exploration of Mercury.

Even with the intense heat and temperature fluctuations, there are still locations on Mercury that are permanently shaded from the Sun’s heat.

In 2012, NASA’s spacecraft MESSENGER found water ice in the craters around the north pole of Mercury.

There may be other areas that have water ice, however, the orbit of MESSENGER didn’t include probing the southern pole.

It’s believed that meteorites or comets may be responsible for delivering ice to these locations or water vapor may have been outgassed from the interior of the planet and then out to the poles.

Venus:

Akatsuki 2010: The Venus Climate Orbiter mission (PLANET-C), or “AKATSUKI”, is studying Venus’ atmospheric circulation.

Venus Express 2005: The (ESA) European Space Agency’s Venus Express is studying the Venus atmosphere including the surface to the ionosphere.

Galileo 1989: The orbiter included ten science instruments as well as an atmospheric probe to study Jupiter, its moons, and the magnetosphere as it orbited.

Magellan 1989: Accomplished its mission as the first to ever arrive and map Venus’ entire surface.

Vega 2 1984: The sister spacecraft to Vega 1, with an almost identical mission as Vega 1.

Vega 1 1984: The most ambitious deep space mission by the Soviets with twin spacecraft designed with redundant mission goals.

Venera 16 1983: Soviet twins Venera 15 and 16 orbiters, the mission was to use radar to create a detailed map of the surface of Venus with a resolution of 1-2 km or around 1 mile.

Venera 15 1983: Soviet twins Venera 15 and 16 orbiters, the mission was to use radar to create a detailed map of the surface of Venus with a resolution of 1-2 km or around 1 mile.

Venera 14 1981: Identical to its twin, Venera 13, the Soviet mission of the spacecraft was carried out as it had three corrections midcourse on its way to Venus.

Venera 13 1981: Designed similarly to the previous Soviet twin missions, Venera 13 and 14 were spacecraft to accomplish Venus flybys.

Venera 12 1978: Soviet mission with a twin Venera 11, to accomplish a flyby and then a lander to explore the ionosphere, atmosphere, and surface of Venus.

Earth:

We have thousands of satellites orbiting the Earth to study specific areas as well as the entire Earth as a whole.

These satellites observe the atmosphere, glaciers, oceans, and the solid earth. Many of these satellites are also communication satellites, bringing us our cable television and our cell phone service.

Mars:

Of all of the planets and bodies in our solar system, Mars is the most explored and the only planet that we have sent rovers to travel the landscape and collect samples and data.

NASA, India, and ESA (European Space Agency) have spacecraft orbiting above Mars.

The robotic explorers have found a lot of evidence that at one time, billions of years ago, Mars was warmer and wetter, with a thicker atmosphere.

Recorded observations reach back as far as 4,000 years when the Ancient Egyptians charted Mars’ movements across the sky.

We have had an international fleet of spacecraft that have orbited and some that have landed on Mars, including the robotic rovers.

Strangely, there have been many attempts at sending robotic spacecraft that have failed, but we are pleased to say that many also succeeded including: Mars Odyssey, Mars Express, Opportunity rover, Mars Reconnaissance Orbiter, Curiosity rover, Mars Orbiter Mission, MAVEN and ExoMars Trace Gas Orbiter.

NASA’s InSight arrived on November 26, 2018, with communications support from the twin MarCO cubesats, the first CubeSats sent into Deep Space.

Facts about Terrestrial Planets for Kids :

• Of all of the terrestrial planets, Earth is the densest and Mars is the second densest.
• Mars has the largest mountain in the solar system called Olympus Mons.
• Earth has constantly moving and shifting tectonic plates that have given our planet one of the most diverse surfaces than any other planet.
• The type of atmospheres of terrestrial planets depend on the planet’s distance from the sun, the radius, the mass, the amount of geological activity, and surface organisms.
• The planet Venus has “domes” that are thought to have been created when lava pushed rock to the surface.
• The discovery of large volcanoes on Mars shows that the planet had active tectonic plates at one time in its history.
• Venus has acid rain that is created in the clouds within its atmosphere.

Pop Culture:

Mercury:

While many of our planets have played a part in legend and stories, Mercury seems to have been a focus of our collective imaginations.

There are a lot of science fiction writers that have used the smallest planet in our solar system for inspiration for their novels.

The list of authors include: Isaac Asimov, C.S. Lewis, Ray Bradbury, H.P. Lovecraft, and Arthur C. Clarke.

TV and movie writers also seemed to be enthralled with the little planet as part of their scripts.

The animated television show “Invader Zim,” has Mercury being changed into a giant ship prototype spaceship by an extinct group of Martians. In film called “Sunshine”, released in 2007, a spacecraft called the “Icarus II” orbits around Mercury to meet up with the Icarus I.

Even the comic strip “Calvin and Hobbes” has mention of Mercury. In one of the series Calvin and his friend Susie give a class presentation about Mercury, and Calvin fills the presentation with very questionable information such as:

“The planet Mercury was named after a Roman god with winged feet,” says Calvin. “Mercury was the god of flowers and bouquets, which is why today he is a registered trademark of FTD florists. Why they named a planet after this guy, I can’t imagine.”

Venus:

Venus was named after the goddess of love and beauty, and the name has become synonymous in our society with “women.”

An example of this was the book was written in 1992 by author John Gray, entitled “Men are from Mars, Women are from Venus,” where Gray referenced the two planets as a relationship guide for men and women.

Early 20th century science fiction writers also loved using Venus as a popular destination in their books. This was, of course, before science had discovered how horrible the surface and atmosphere was.

In today’s video games, Venus has been used as a backdrop for such games as Transhuman Space, Battlezone, and Destiny.

Even Disney fans will remember the animated film “The Princess and the Frog,” where the firefly, Ray falls in love with Venus, “the evening star”, whom he mistakes as another firefly.

Earth:

Discovering the nature of our home planet has been the topic of many books, movies, and television shows.

The well-known movie (and its sequels) “Planet of the Apes” occurs in a future where our astronauts find that intelligent apes have taken over the world and the primitive animals are the human beings.

The long-running television series and its remake “Battlestar Galactica” include a band of a war against the highly evolved cylon robots, while they search to find the long lost colony of Earth.

In many tales, writers have left the Earth as destroyed or abandoned. The television series “Firefly” and the book and film adaptation “The Hitchhiker’s Guide to the Galaxy” are two such stories.

“Titan A.E.,” the animated feature shows Earth’s destruction by a species of aliens, however, a well-placed planet builder then recreates the planet and all of the species that live on it.

Earth has remained as a base for other space exploration stories, including the iconic “Star Trek” series.

Originally created by Gene Roddenberry, Star Trek uses Earth as a leading member of The Federation of Planets, and the many spaceships that head out to explore galaxies and beyond.

Mars:

It can be easily said that Mars has captured the collective imagination of humans more than any other planet.

In the 1800s, when people first thought that there were canal-like features on the surface of Mars, they thought that these were the proof that intelligent alien species lived on the planet.

These ideas led to more stories, books, movies, and television shows than any other planet. The most notable of the situations was the 1938 radio drama of the H.G. Wells book, “The War of the Worlds.”

The broadcast was so realistic that many listeners though that there really was an invasion of Earth by Martians, and went into a panic. Television has also picked up on the idea of intelligent creatures on Mars with the 1966 series “My Favorite Martian.”

Another Mars tale on television and in books was “The Expanse.” Other stories that have taken place on Mars were transitioned to movies such as the 1990 “Total Recall” and the remake in 2012.

In this version, the ultimate tale involved terraforming Mars and a colony struggling due to lack of air.

The 2014 novel that became the movie adaptation in 2015 of “The Martian” involved a botanist that was left stranded on Mars and his struggle to survive while he awaits rescue.

https://solarsystem.nasa.gov/planets/overview/
https://www.space.com/17028-terrestrial-planets.html
https://space-facts.com/terrestrial-planets/
http://www.softschools.com/facts/space/inner_planets_facts/2411/