Interesting facts about planet Mars

Interesting facts about planet Mars
The Planet Mars. Credit: NASA

Mars is a constant point of discussion for space explorers around the world. We've sent dozens of spacecraft there to study it. Some want to land astronauts on it. The planet is just far away to make that dream difficult, but just close enough to spark our imagination. So what are some of the most important things to learn about the Red Planet?

1. Mars had water in the ancient past.

We've been debating for centuries about whether Mars had life or not. In fact, the astronomer Percival Lowell misinterpreted observations of "canali"—the Italian word for channels—on the planet as evidence of alien-made canals. It turned out Lowell's observations were hampered by poor telescope optics of his day, and the canals he saw were . That said, several spacecraft have spotted other signs of ancient —channels grooved in the terrain and rocks that only could have formed in the presence of water, for example.

2. Mars has frozen water today.

We're very interested in the question of water because it implies habitability; simply put, life as we know it is more likely to exist with water there. In fact, the Curiosity rover's mandate on Mars right now is to search for habitable environments (in the past or present). Mars has a thin atmosphere that does not allow water to flow or remain in large quantities on the surface, but we know for sure that there is ice at the poles—and possibly frosty locations elsewhere on the planet. The question is if the ice is capable of melting enough water in the summer long enough to support any microbes.

3. Mars used to have a thicker atmosphere.

For water to flow in the past, the Red Planet needs more atmosphere. So something must have changed in the past few billion years. What? It is thought that the Sun's energy striking the atmosphere must have "stripped" the lighter forms of hydrogen from the top, scattering the molecules into space. Over long periods of time, this would lessen the amount of atmosphere near Mars. This question is being investigated in more detail with NASA's Mars Atmosphere and Volatile EvolutioN (MAVEN) spacecraft.

4. Mars has some extreme highs and lows in terrain.

Interesting facts about planet Mars
Mars Express Data from Mars South Pole. Credits: ESA/ Image Courtesy of F. Altieri (IFSI-INAF) and the OMEGA team

The surface gravity of Mars is only 37% of what you would find on Earth, which makes it possible for volcanoes to be taller without collapsing. This is why we have Olympus Mons, the tallest volcano known on a planet in the Solar System. It's 16 miles (25 kilometers) high and its diameter is approximately the same as the state of Arizona, according to NASA. But Mars also has a deep and wide canyon known as Valles Marineris, after the spacecraft (Mariner 9) that discovered it. In some parts, the canyon is 4 miles (7 kilometers) deep. According to NASA, the valley is as wide as the United States and is about 20% of the Red Planet's diameter.

5. Mars has two moons—and one of them is doomed.

The planet has two asteroid-like moons called Phobos and Deimos. Because they have compositions that are similar to asteroids found elsewhere in the Solar System, according to NASA, most scientists believe the Red Planet's gravity snatched the moons long ago and forced them into orbit. But in the life of the Solar System, Phobos has a pretty short lifetime. In about 30 million to 50 million years, Phobos is going to crash into Mars' surface or rip apart because the tidal force of the planet will prove too much to resist.

6. We have pieces of Mars on Earth

Interesting facts about planet Mars
Valles Marineris as seen in this mosaic of Viking orbiter images. Noctis Labyrinthus at the left, Melas Chasma in the middle, Hebes Chasma just left of top center, Eos Chasma at lower right and Ganges Chasma just above center right. Credit: NASA/JPL

Remember the low gravity on Mars that we talked about? In the past, the planet has been hit by large asteroids—just like Earth. Most of the debris fell back on the planet, but some of it was ejected into space. That sparked an incredible journey where the debris moved around the Solar System and in some cases, landed on Earth. The technical name for these meteorites is called SNC (Shergottites, Nakhlites, Chassignites—types of geologic composition). Gases trapped in some of these meteorites has been practically identical to what NASA's Viking landers sampled on the Red Planet in the 1970s and 1980s.

7. Mars would kill an unprotected astronaut quickly.

There are a lot of unpleasant scenarios for somebody who took of their helmet. First, Mars is usually pretty cold; its average temperature is -50 degrees Fahrenheit (-45 degrees Celsius) at the mid-latitudes. Second, it has practically no atmosphere. The air pressure on Mars is only 1% of what we have (on average) on the Earth's surface. And third, even if it did have atmosphere, the composition is not compatible with the nitrogen-oxygen mix humans require. Specifically, Mars has about 95% carbon dioxide, 3% nitrogen, 1.6% argon and a few other elements in its atmosphere.

Interesting facts about planet Mars
Phobos, the larger of Mars’ two moons, with the Stickney crater seen on the right side. Credit: HiRISE, MRO, LPL (U. Arizona), NASA

8. In the early Space Age, we thought Mars was like the moon.

The early NASA probes that flew by the Red Planet all, coincidentally, happened to image spots on the planets that had craters. This led some scientists to (mistakenly) believe that Mars has an environment similar to the moon: cratered and practically unchanging. This all changed when Mariner 9 arrived at the planet for an orbital mission in November 1971 and discovered the planet engulfed in a global dust storm. What's more, odd features were poking out above the dust—features that turned out to be dormant volcanoes. And as mentioned earlier, Mariner 9 found the vast Valles Marineris. It changed our view of the planet forever.

9. Mars has methane in its atmosphere, but we don't know how much.

Interesting facts about planet Mars
Top: Map of methane concentrations in Autumn (first martian year observed). Peak emissions fall over Tharsis (home to the Solar System\’s largest volcano, Olympus Mons), the Arabia Terrae plains and the Elysium region, also the site of volcanos. Bottom: True colour map of Mars. Credit: NASA/Università del Salento

Methane can be interpreted as a sign of biological activity—microbes emit it—or even of geologic activity. And active , it is thought, are more likely to have life on them. So the question of methane on Mars is one that scientists are trying to figure out. The consensus? There is no consensus. Telescopic observations have had wildly different measurements over the years, and few spacecraft have been designed to probe for the element in detail. The Curiosity rover has detected tenfold spikes in methane in its area, but we don't know where it came from and why the fluctuations are happening.

10. Mars is a popular spacecraft destination.

There have been so many spacecraft that attempted a Martian mission that it's hard to pick notable ones in a short article. NASA's Vikings were the first landers in 1976; in fact, NASA is the only agency that has managed to land on the planet so far. Some of its other missions include Pathfinder-Sojourner (the first lander-rover combination) in 1997, the Mars Exploration Rovers Spirit and Opportunity in 2004, and the Curiosity rover of 2012. And this doesn't even mention the fleet of orbiters that have mapped Mars over the years from the Soviet Union, NASA, the European Space Agency and India. And there are many more spacecraft to come in the next decade.


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Feb 16, 2015
This all changed when . . . when Mariner 9 discovered the planet engulfed in a global dust storm.


Astronomers knew for 50 years, or more, prior to Mariner 9 that Mars had both dust storms and clouds, as each had been observed by ground base observers.

Feb 16, 2015
The Curiosity rover has detected tenfold spikes in methane in its area, but we don't know where it came from and why the fluctuations are happening.


Um...do the fluctuations correlate to a wind direction, perhaps, so you could track it? A seasonal change?

Methane can be interpreted as a sign of biological activity—microbes emit it—or even of geologic activity.


Don't read something into data which isn't necessarily there. The Methane has it's highest concentration near the extinct/dormant volcanoes. This suggest it is of geologic/geo-chemical origin.

It doesn't rule out life, as we know there are Lithotrophe extremophiles on Earth as much as 2 miles beneath the ocean crush apparently living on trace elements in the rocks. Who knows how long it took for the bacterial colonies to migrate through fractures to populate 2 miles of rock?

If it can live in such conditions on Earth, it could probably live on mars in some subterranean hot-spot.

Feb 16, 2015
There's a big difference between the bacteria and algae most of us know as compared to those organisms though, as some of them have life cycles able to lie dormant for 100 or even 1000 years even though they are single-celled.

Are we sure Water is the culprit for the geology of Mars? What if it was colder with respect to the Sun, not warmer in the past, meanwhile geologically warmer? Remember the "Faint Young Sun" paradox?

Present-day minimum is -143C. Methane condenses to liquid at -161.49C, 18C difference which isn't too big of a stretch given weaker geology and high surface-to-volume ratio for geothermal heat.

What if the canyons and alluvial fans are cut by Liquid Methane? CO2 and Methane Glaciers?

Methane would break down into CO2 after being stripped of the hydrogen, same end as water, different start though. As the system warmed, CO2 would go through cycles of sublimation and deposition until you formed ice caps.

Feb 16, 2015
Volcanic mudslides could conceivably cover a large biologic area and trap it until it decayed (microbes) over eons, but the thing is there should be some other evidence of life or past-life in the area. With a thin atmosphere and removing water and oxygen from the atmosphere, features should survive for eons relatively undisturbed. None of our landers has seen anything to suggest the possibility of something large and biologic, such as lichens or mosses, grasses, trees, etc. They have even found any evidence of microbes, and only some direct evidence of past liquid water based on stream bed rounded rocks, and some rock chemistry from minerals known to form in hydrated environments. Aside from "water related weathering and chemistry" there has yet to be any evidence of past life on Mars.

I don't think Methane is an indicator of life or past life. It is certainly "better than nothing", but you can say that about almost anything.

Feb 16, 2015
Oh yeah, geochemical methane being present and active on Mars even after all this time is evidence that much of the methane deep inside Earth may be geochemical in origin, rather than biological, and rock chemistry processes near hot spots may need to be re-evaluated even here on Earth.

You'd think with the decades of the USGS and Icelanders studying active volcanoes they'd figure out some more specific spectrographic tests to determine the origin of methane...like, "If 'Rock type A' exists near a volcano and there is also Methane, then the Methane came from a chemical reaction at that rock type's origin."

Of course, there's the matter of how the Methane must form after the volcano actually cools, or in a completely an-oxygenic environment, else it would burn in the presence of oxygen and make CO2 and Water, and we wouldn't be detecting it.

So I take methane to be evidence that the rocks in the volcano are oxygen-depleted...

Feb 16, 2015
Needs 3/4 of an atmosphere of Nitrogen for starters, to regulate the temperature and warm up the poles. Then the CO2 will gasify naturally and the whole planet would warm up significantly. It would warm several degrees just from pressure laws alone.

Feb 17, 2015
Why wait for phobos to crash into Mars. We should help it along by building engines powered by the directed energy of several simultaneous high yield megaton nuclear explosions to force it to fall from orbit and crash into a location along its orbit where large amounts of frozen water is known to be.

In doing so we could dramatically increase the atmosphere of mars for a long enough time to get established colonies going. :)

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