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 optical illusions. That said, several spacecraft have spotted other
signs of ancient water — channels grooved in the terrain and rocks
that only could have formed in the presence of water
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:
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:
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.right side.
Credit: HiRISE, MRO, LPL (U. Arizona), NASA
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.
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:
Methane can be interpreted as a sign of biological activity —
microbes emit it — or even of geologic activity. And active planets, 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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