“”Mars is essentially in the same orbit... somewhat the same distance from the Sun, which is very important. We have seen pictures where there are canals, we believe, and water. If there is water, that means there is oxygen. If oxygen, that means we can breathe.
|—Dan Quayle, eliciting a massive facepalm from anyone who knows the slightest thing about Mars.|
Mars is the fourth planet in our solar system. It is named after the Roman god of war (known as Ares to the Greeks), due to its reddish hue. Since the beginning of the Space Age, it has been the most likely candidate for eventual planetary colonization, although we probably won't make it there for a long time.
Conditions on Mars
Mars has a diameter of 6790 kilometers which is roughly half the size, and 15% of the volume, of Earth. Its small size and low density, relative to the Earth, give it a surface gravity only 38% as strong as Earth's.
Historically, while the white areas seen on Mars' poles with a telescope were correctly identified as polar caps of water and carbon dioxide ice, the dark patches that can be seen there the same way (see picture to the upper right) were interpreted first as seas, giving birth to a nomenclature that while today obsolete is still used by amateur astronomers who observe the planet (see list here), and later on as it was clear Mars had no large amounts of surface water as vegetation changing its intensity and extension as seasons changed through the Martian year until spacecrafts finally found they were simply darker surfaces exposed after windstorms had swept away the dust, with those variations explained by the effects of said winds as the late Carl Sagan had suggested years before.
The atmosphere on Mars consists mostly of carbon dioxide with only one percent of the gas pressure of Earth's atmosphere. Dust in the Martian atmosphere gives it a light pink color during the day, and at sunset it turns a very lovely teal.
The planet currently has no magnetic field, but geological (or, rather, areological) evidence suggests that it used to have a magnetic field some billions of years in the past. A magnetic field would have kept the solar wind at bay, which would have prevented the early Martian atmosphere from being stripped away into space. It is thought that the shutting down of this magnetic field eventually left us with only the thin ghost of an atmosphere that Mars currently has.
In March 2019, the Journal of Astrobiology and Space Science carried a report that suggested life may at present exist on Mars. The journal report says that there is evidence (though it carefully qualifies its claims -- the evidence involved does not rise to the level of proof) that there exist at present "prokaryotes, lichens, and fungi" growing out of Martian soil.
Mars used to have copious amounts of liquid water flowing on its surface, up to and including potential oceans, but with the loss of the Martian primordial atmosphere, the oceans of Mars slowly evaporated into space, leaving behind a cold and dead world in their wake with most of the water in the polar caps and in the underground (see the other Wiki)
Subjugating the planet
Because conditions on Mars are more similar to Earth than any other planet, it has long been a prime candidate for eventual colonization among those who believe such a thing should happen. Only problem is that Mars is no place to raise your kids, in fact it's cold as hell. The average temperature on Mars is -46° C. Paypal billionaire-turned-wannabe-Howard Hughes Elon Musk has a plan to change all that.
This does not mean that Mars can be made hospitable; very low air pressure (less than 1% of Earth's sea level pressure),
no liquid water MYTH: BUSTED!, and an atmosphere of only 0.1% oxygen are just a few of the things that might keep you from packing up your bags and moving to the Red Planet.
Some of the more fool-hardy plans include those of Mars One, which aimed to ship astronauts one-way to Mars by 2025 before it went belly-up in 2019. The trip would be funded by a reality TV program about the
suicide mission (no joke). Most experts agree that Mars One won't be able to deliver astronauts to Mars. MIT researchers have estimated that even if colonists reach Mars they would survive for only about two months before succumbing to the elements.
Of course the final step on the conquest of Mars is to terraform it, transforming the planet in a more or less Earth-like world. Ideas abound, even if it's unclear if they would work at all and all share to be very expensive and outside of our current technologies -not to mention the issues related to hypothetical Martian life even if it amounted to just some bacteria, that would surely dislike the process-, so leave them to science-fiction.
Mars has two small moons, Phobos and Deimos ("Fear" and "Dread," the sons of the war-god Ares in Greek mythology). Both are probably captured asteroids, and both are very tiny — Phobos is only 10 miles across at its widest part, and Deimos is half that size.
Phobos has a surprisingly low density, leading some people to speculate that it may be hollow and artificial (and some fringe people to believe that it is artificial), but the current understanding is that Phobos is a rubble-pile asteroid (an agglomeration of boulders bound by gravity). Another point of interest is the so-called "Phobos monolith," a bright rock jutting out of the surface that casts a long shadow (which suggests an unusual height-to-width ratio). Phobos' orbit is slowly decaying. Astronomers predict that it will eventually crash into the planet. Deimos on the other hand has an expanding orbit. It is expected to break free from its orbit around Mars, hopefully while it's on the side not facing us. It is speculated that Mars has lost hundreds of moons in these ways over the years.
Jonathan Swift referred to two Martian moons in Gulliver's Travels (published in 1726, more than a century before their discovery in 1877). This has been used as evidence for claims of ancient astronauts and time travel, neglecting the fact that Kepler had speculated about a pair of Martian moons a century before.
Life on Mars?
As a rocky planet similar to Earth, and massive enough to retain a thin atmosphere if gases were present, Mars has been a historical favorite of science fiction writers and others who speculate about extraterrestrial life. It is fairly obvious from geographical data and close up views of sedimentation on the surface that Mars once was home to vast quantities of water in large lakes and oceans. As water is one of the known prerequisites for biological life "as we know it", it could be possible that life once existed on Mars a possibility that has received a boost after the finding of organic compounds there by NASA's
WALL-E's big brother Curiosity rover. With the relatively recent discovery of very dark patches on the surface that are thought to be extremely deep and dark sink holes and cave systems, the question about life existing now on Mars has been reopened to serious scrutiny. However, most serious exobiologists think life is more likely on the Jovian satellite Europa or Saturn's moon, Enceladus.
During the 1877 opposition of Mars, the Italian astronomer Giovanni Schiaparelli noticed a network of features on the Martian surface that he called canali— Italian for "channels" but translated into English as "canals." His observations were corroborated by other astronomers and the hypothesis that these were artificial canals built by a Martian civilization started to gain followers. A prominent figure among them was the American astronomer Percival Lowell.
There was a slight problem, though — not all astronomers saw these canals. A vigorous scientific debate followed. Experiments demonstrated that canals can occur as an optical illusion. More powerful telescopes were pointed at Mars and found no canals and early spectroscopy found no significant amounts of water. Alfred Russel Wallace felt so strongly about the canal nonsense that he wrote a book, Is Mars Habitable? A critical examination of Professor Percival Lowell's book "Mars and its canals," with an alternative explanation. The idea started to fade out after the first decade of the 20th century, and was dealt a deathblow by pictures returned from spacecraft. The first ones returned were taken by Mariner 4 in its 1965 flyby, and they showed impact craters but no canals. However, it did not photograph much of the planet. Mariners 6 and 7 flew by in 1967, and both spacecraft radioed back pretty much what Mariner 4 radioed back. Craters but no canals. Then in 1972, Mariner 9 went into orbit, and it took pictures of nearly all of the planet for the next (Earth) year. Aside from one or two features, there was not a trace of those canals.
A large proportion of (robotic) missions to Mars have failed, earning it the reputation of "the place where probes go to die". Some have blamed malevolent extraterrestrial intelligence, but a much more probable cause is shoddy terrestrial engineering. The probe-eating monster may have been squashed by a falling spacecraft, because all recent missions have been successful. (The cruelly-named Phoenix lander was not supposed to recover from the ice.)
After the success of the toy-sized Sojourner rover, brought to Mars by the Pathfinder lander in 1997, NASA decided that they need more and bigger
cars rovers. The result was the Mars Exploration Rover program and its two adorable solar-powered offspring — Spirit and Opportunity. Arriving in 2004, they greatly exceeded their design expectations. Spirit got stuck in soft soil in 2009. After attempts at extracting it failed, it switched to hibernation mode for the Martian winter in March 2010. Attempts to establish communication with it failed and NASA declared its mission ended two months later. NASA took the next step with the car-sized, laser-shooting, drill-swinging, nuclear-powered Curiosity (formerly the Mars Science Laboratory), launched in November 2011. Until June 2018, when a massive dust storm left it with no energy and NASA declared its mission ended in February 2019 as no communications were received from it, Opportunity was still operational albeit many of its systems weren't. Opportunity has been quite likely the most successful rover in the history of space exploration to date, having survived its designed lifespan by fifty-five times. It has also shattered all long distance records for space rovers having covered a distance above marathon length at 45.09 km (as of January 2018).
The latest victim of
Russian under-funding the "Mars Curse" is the Russian Fobos-Grunt probe which was supposed to land on Phobos and return a small sample of its "soil" to Earth. After being launched successfully into Earth orbit, it failed to move into Mars transfer orbit and later re-entered Earth's atmosphere, with its remains falling in the Pacific Ocean. In a rare case of a government-endorsed conspiracy theory, some Russian officials apparently think that the US might have had something to do with it. (No, they didn't mention HAARP, but apparently it was the first thing on other people's minds.)
The most likely reason that so many Martian probes have failed is that more probes have been sent to Mars than to any other planet in the Solar System. Every mission has a chance of failure — the more missions you launch, the greater the odds are that at least one of them will fail. Worse, in terms of mission delta-V requirements, Mars is easier to get to than any of the other planets. (Venus's orbit is closer to Earth's than Mars's is, but a Venus rendezvous requires cancelling a lot of the kinetic energy you have in Earth's orbit around the sun; a Mars rendezvous requires adding substantially less kinetic energy than this.) Because of this, Mars is usually the "first choice" for new and experimental space probe technology. The very first Mars mission to fail, Mariner 3, was also the first probe ever sent outside the Earth-Moon system, for example. In a way, it's kind of amazing that so many Mars missions have succeeded.
Mars pareidolia club
A picture made by NASA's Viking 1 orbiter in 1976 showing a hill that looks like a face started a new hobby — looking closely at images returned by Mars probes and trying to find as much "evidence for extraterrestrial life" as possible. Contrary to expectations, magnifying images to the pixel level and repeatedly applying the "sharpen" tool are not considered cheating. Notable participants in this quaint activity are Richard Hoagland and the Mars Anomaly Research team. Not only a 'face' but whole pyramids and causeways are claimed to be seen — with the 'face' being 'identical' to that on the Sphinx of Giza. Sci-fi pedants have been amused to note that long-running BBC sci-fi show Doctor Who broadcast a serial in 1975 called The Pyramids of Mars, featuring a baddie called Sutekh the Destroyer who was imprisoned in a pyramid. On Mars. "coincidence??" etc. etc.
Mars and the Great Flood
Mars in Silly Love Songs
Venus, similarly, was named for the goddess of love, and has a yellowish cast. When the two planets are visible from the Earth in the same area of the sky, it is said that "Venus and Mars are alright tonight". In this case they can be reasonably represented by the 1 and 3 billiards balls, respectively.
Apparently, it has been discovered by
scientists, Creation Scientists, some loony nut jobs, no one in particular that men do not actually come from Earth, but are in fact from Mars. Women, the smarter, wiser, and apparently less inclined to do anything but bake brownies, are themselves from Venus. How they survive that planet's crushing atmosphere and hellish surface temperature high enough to melt lead they're not telling.
Seekrit Mars colony
A number of fringe-type people have claimed that there is already a secret earth base on Mars. A British newspaper reported claims that an ex-US Marine known only as "Captain Kaye" had served 17 years on the Red Planet keeping colonists safe from indigenous Martians; Donald Rumsfeld was also involved. A woman, claiming to be a former Nasa employee, contacted Coast To Coast AM in 2014 to claim that astronauts had been landed on Mars by a Viking probe in 1979. Several commenters on Stack Exchange pointed out that any secret Mars mission would have to be massive in scale and insanely expensive, and people would probably have noticed. It's basically the same level of improbability as the moon landing hoax but in reverse.
Since 2002 a hoax has been circulating claiming that at the time of its closest approach to Earth, Mars will be as big as the moon in the sky. This is untrue, despite doctored photographs (of course it's very easy to alter the size of a photograph of Mars), but seems to recur every 22 months as Mars reaches its nearest point to Earth.
- Face on Mars
- Gerry Soffen
- John Brandenburg
- Ken Johnston, a former applicant for the Mars One one-way trip
- Hale crater
- Mars Fact Sheet courtesy of NASA
- Windblown Dust on Mars
- "The Solar Wind at Mars" - Science@Nasa
- Evidence of Life on Mars? Journal of Astrobiology, 2019.
- Shatner "sings" Rocket Man
- Either way it'll probably just pass us, if it even gets near us.
- Kepler's logic: the Earth has one moon, Jupiter has four (only the Galilean moons were known at that time), therefore Mars should have two, as 1,2,4 is a progression.
- NASA's Curiosity rover finds organic matter on Mars.
- Is Mars Habitable? (1907), full public domain text at Project Gutenberg
- The Planet Mars: A History of Observation and Discovery by William Sheehan, the University of Arizona Press, 1996
- [0811.2700 Mars Before the Space Age] by Barrie W Jones, 2009
- The canals of Mars: An assessment after Mariner 9 by Carl Sagan and Paul Fox, 1975
- Springtime on Mars, a
- A nice infographic by Bryan Christie
- The "Mars Curse": Why Have So Many Missions Failed?, Universe Today
- Spirit, xkcd
- What it's supposed to look like in action
- Charles Creager, Jr, July 23, 2008. "Mars, a Testament to Catastrophe." Answers Research Journal 1 (2008): 89-94.
- Retired US Marine claims he spent 17 years on MARS protecting five human colonies from Martians, The Mirror, 23 Jun 2014
- 'I saw men walking on Mars in 1979': 'Former Nasa employee' claims there was a secret manned mission to the red planet, Daily Mail, 28 Nov 2014
- Could the USA have a secret colony on Mars?, Stack Exchange, 2015
- See the Wikipedia article on Mars hoax.
- Mars Hoax Returns to Mislead Stargazers, Space.com, Aug 18, 2015