Top Ten Facts About Mars
10. Mars is made red by its rusty dust.
The planet Mars was named after the Roman god of war due to its blood red appearance. But what makes it red? Iron oxide! Earth and Mars both formed with fair amounts of iron, but Earth's higher mass and gravity pulled more of it down toward the center of the planet (into the core, where it now resides). The lower gravity on Mars allowed higher concentrations of iron to remain at the surface, where it was then oxidized - it rusted. How and why exactly it rusted remain mysteries, though one possibility is weathering by rainstorms from the planet's distant past.
9. Artificial "canals" on Mars? Those were an illusion.
About 150 years ago, an Italian astronomer named Giovanni Schiaparelli announced that he had seen a series of linear features streaking the Martian surface, pictured above. He called them canali, which is Italian for naturally occurring "channels," however many believed he was referring instead to "canals"--artificial waterways, which implied the presence of intelligent life on Mars. Some other astronomers claimed to see these structures as well. The possibility of intelligent life on Mars fueled many science fiction stories describing what Martians might be like. (Never mind the fact that the canals never existed, and were instead likely the result of telescope defects, optical illusions, or overactive imaginations.)
8. Life on Mars - not just the domain of conspiracy theorists!
There is an actual field of study called astrobiology, where scientists consider the possibilities of (and search for!) extraterrestrial life. In the wake of the Copernican Revolution, people were forced to expand their ideas of the cosmos. Prior to then, nearly everyone believed that the Earth was the center of the universe, which was of course a very special place to be. With discoveries by Copernicus, Galileo, and a whole slew of others, we learned that not only are we not located in the center of the universe--we're not even in the center of our own solar system!
In modern times, we've further discovered that planets are pretty common. The simple removal of Earth from the "special" and "unique" status people attributed to it led many, many scientists to believe that life should be common. Venus is the closest planet to us, but since its hellish heat and crushing pressure make life there unlikely (and very difficult to study), Mars seems to be the best candidate. Several previous and current Mars missions have been designed with the search for life in mind.
7. Mars was once a habitable planet.
So what have those missions unearthed--er, unmarsed? When NASA's Mariner 4 spacecraft performed a Mars flyby in 1965, many were either relieved or devastated to learn that life there seemed highly unlikely. Not only were artificial canals nowhere to be found, but measurements revealed a cold and dry planet with a very thin, toxic atmosphere. Later missions have painted a more complete picture of the planet, and while we still have yet to discover life we do know that the now-barren planet was once a much more hospitable world.
The famed "Martian blueberries" in the photo above are little hematite spherules which provide good environmental constraints for what Mars was like long ago (when they were formed). They are water lain deposits, which means Mars must have been a watery world in its past. NASA has even found a way to determine roughly how much water there once was on Mars, and it turns out it probably had a mile-deep ocean covering 20% of its surface!
This means that the three requirements for life - liquid water, organic molecules, and an energy source - were all present on Mars early in its history. While we can say Mars was habitable, we can't necessarily say whether or not that means it was actually inhabited. Again, missions have been conducted to try to determine if life is or has ever been present on Mars, however no conclusive evidence has been found so far.
6. Martian meteorites: proof of Martian life?
Considering that we haven’t detected any complex lifeforms (which, with all our studies of the planet, should have been apparent by now if they existed), we’re mainly looking for microbes—really simple, tiny little guys. The problem is that it’s difficult and expensive to conduct thorough microbiological studies on a planet that’s over 30 million miles away! Fortunately, there’s a pretty sweet way around the problem.
Meteorites are delivered to Earth mainly by asteroids, but in some rare cases cosmic events line up just right to deliver us samples of the red planet itself! These rare Martian meteorites represent an awesome, relatively cheap way to explore Mars (though of course we can’t pick and choose where exactly on Mars the samples come from!). ALH 84001 is one Martian meteorite that was originally selected for further study because it’s so old—about 4 billion years!
When it was examined more closely, scientists found something unexpected: little structures that resemble fossils of extra tiny microorganisms! This is an area of intense controversy, however, and most scientists do not believe ALH 84001 contains proof of past or present life on Mars.
5. Mars is home to the biggest volcano in the solar system: Olympus Mons!
Earth's largest volcano, Mauna Loa, pales in comparison to its Martian counterpart. Olympus Mons is the biggest volcano in the entire solar system, standing a whopping 16 miles high and with a volume more than 100x greater than Mauna Loa! Olympus Mons is a shield volcano, like many we see on Earth—but it grew much bigger for a couple of key reasons. For one thing, gravity on Mars is a lot lower than it is on Earth. Mars also doesn’t feature plate tectonics like Earth does. On Earth, this leads to volcano chains—magma comes up to the surface and builds up a volcano, but then the plates shift and so the next time magma is released it comes up at a different spot. On Mars, there aren’t any shifting plates, so instead of a chain of volcanoes, the volcano could just build up higher and higher.
What’s especially bizarre about Olympus Mons is that it’s so big that it doesn’t look big—or at least it wouldn’t if you were standing on top of it! The volcano’s slope is so small that it would be difficult to see a major difference in elevation, but it also spans such a wide area on Mars that some of the volcano’s curvature would be affected by that of the planet itself!
4. Mars’s Valles Marineris puts the Grand Canyon to shame.
Mars is home to a much grander canyon than Earth's! Valles Marineris is nearly 4 times longer, 20 times wider, and over 4 times deeper than the Grand Canyon. It can be seen from space as a giant scar cut across the Martian face, yet in some ways it remains a bit of a mystery. It has been difficult to determine why it's there in the first place, though a leading explanation is that the planet cracked long ago as it cooled down and then grew wider over time due to erosion.
3. Mars has two moons and may one day have a ring!
Mars's two misshapen moons, Phobos and Deimos, are very small and orbit close to the planet. Phobos, the closer and larger of the two, has a mean radius of just under 7 miles, while Deimos has a mean radius of less than 4 miles - these potato-shaped moons are practically potato-sized compared with our own!
So how did Mars get its moons? We’re actually not sure. Some scientists believe they are asteroids that wandered too close to the red planet and became trapped in orbit. The physics that this requires, however, makes it unlikely.
Regardless of how they got to Mars orbit, they won’t be there forever! Phobos is spiraling ever so slightly closer to the planet with each passing year. In around 50 million years, NASA scientists expect that it will either plunge into the planet in a fiery crash or be torn apart by Mars's gravity and create a ring.
2. Mars's missing mass was probably eaten up by Jupiter.
Earth and Mars formed in the same general region of the solar system, from similar material, in nearly the same conditions - so why is Mars barely half the size of Earth? The answer lies in how and where the planets formed. Mars is closer to Jupiter, the most massive planet in our solar system. As the planets were building up larger and larger (in a process called accretion), Jupiter's gravity disrupted a lot of the surrounding material (which also explains why the bodies in the asteroid belt didn't accrete to form one body).
1. Mars is our best bet for terraforming and colonizing another planet.
While the ethics of terraforming and colonizing another planet are up for debate, it may one day be feasible to do so - and it will eventually be necessary if humanity is to survive. As a main sequence star, the Sun will cool and balloon out into a red giant star as it runs out of fuel. When this occurs (around 4.5 billion years from now), it will swell until it encompasses Earth’s orbit. Even if we manage to solve other issues threatening the long-term survival of Earth life, it will certainly no longer be able to survive the Sun's red giant stage; at least not if it remains on Earth.
Mars definitely seems to be our best option for terraforming and colonizing another planet for a few key reasons. For one thing, it's farther away from the Sun and will survive the red giant stage much better than Earth will. It's relatively close by and similar to Earth in many regards. Although it is colder, has lower surface gravity and pressure, and we can't breathe the atmosphere, we may one day be able to make Mars our new home. According to NASA, terraforming Mars isn't possible with current technology - but advances in our technology are occurring at a fast rate, plus Mars will warm up when the Sun expands. Hopefully by the time we need to leave Earth and find a new home, we will be able to make Mars habitable.
Questions & Answers
© 2018 Ashley Balzer