Mars — humankind’s next home?
No other planet has inspired more imaginative speculation as to its past and future suitability for life than Mars.
The fourth planet from the sun, Mars is one of the five “bright,” naked-eye planets visible in the night sky. Named after the Roman god of war, and often referred to as the Red Planet (primarily due to its distinctive blood-red colour from the iron oxide in its soil), Mars was known to ancient peoples though by various names. To the ancient Sumerians, it was “Nergal” — god of war and plague. Likewise, the ancient Greeks named it “Ares”, their god of war. Ancient Egyptians referred to it as “Her Desher” meaning “the red one.” Eastern Asian cultures called it “the fire star” after one of the five elements.
Orbiting at an average distance of 227,936,640 kilometres from the sun, Mars has a highly eccentric elliptical orbit, which at aphelia (furthest point from Sun) is seven times its distance at perihelia (closest approach). Mars is closest to Earth every 26 months. Its closest approach (55,758,000 kilometres) to Earth (in nearly 60,000 years) came in August 2013; it then shone at mag. -2.9. Prior to that, its closest approach was in September 57, 617 BC. The next closest approach will be in 2287; I think I’ll miss that one!
Mars has two moons — Phobos (meaning panic and fear) and Deimos (meaning terror and dread), mythical Greek twins who followed their father, Ares, into battle. It has the largest volcano (600 kilometres diameter) and highest-known mountain, Mons Olympus (27 kilometres high) as well as the largest canyon — Valles Marineris (up to 10 kilometres deep, 600 kilometres wide and 4,000 kilometres long) — in our solar system. A Martian year is equivalent to 687 Earth days.
The movement of Mars across the night sky has been studied since ancient times. Ptolemy, a Roman astronomer, mathematician and geographer, studied the movement of Mars, and included his calculations on this planet in his famous book Almagest, which was used as the basis for western astronomy for the next 14 centuries. Other famous astronomers, such as Tycho Brahe and James Kepler, also studied Mars in the early 17th century. Galileo was the first astronomer to view Mars through a telescope in 1610.
In 1877, Italian astronomer Giovanny Schiapelli used his 8.7-inch telescope to produce the first detailed map of Mars. He claimed to have observed numerous “canali” (channels or grooves) on the planet’s surface. These canali proved to be nothing more than an optical illusion by later observations with more powerful telescopes. Nonetheless, the purported discovery of canali (“canals” in English) gave rise to the public’s fascination respecting possible life on the planet’s surface. If these canals existed, then, surely, they must have been made by an intelligent civilization of Martians to carry water across the planet’s surface, presumably to their towns and cities.
The astronomer Percival Lowell observed Mars in his large telescope in 1894, and confirmed the existence of what he believed to be straight canals crossing the surface, as well as vast seas and large areas of vegetation. His books on Mars greatly inflamed the public’s imagination regarding a possible Martian civilization, if not existing then not too long ago in the past.
Over the following decades, numerous prominent writers added to this Mars civilization mania, among them H.G. Wells (The War of the Worlds, 1898); Edgar Rice Burroughs (Barsoom series, 1912); C.S. Lewis (Out of the Silent Planet, 1938); and Ray Bradbury (The Martian Chronicles, 1950), to name but a few.
The public’s fascination with Mars continued into the birth of the Space Age in the mid-1960s. Dozens of robotic missions to Mars have taken place by a number of countries, beginning with America’s Mariner missions in the ’60s and ’70s. These were followed by a slew of missions — the Viking landers (mid-’70s); NASA’s Mars Global Surveyor (1996); NASA’s Spirit and Opportunity rovers (2003); Europe’s Mars Express (2004); NASA’s Mars Reconnaissance Orbiter (2005); India’s Mars Orbiter Mission; NASA’s Curiosity rover (2011); Europe’s EXO Mars Trace gas Orbiter (2013) and NASA’s Insight lander (2018), to list but the more prominent missions. All these missions were sent to study the planet and to assess its suitability for potential human habitation at some point in the future.
So, will humans ever live on the Red Planet? Mars has a very thin atmosphere, composed primarily of carbon dioxide (95.3 per cent), nitrogen (2.7 per cent), argon (1.6 per cent), oxygen (0.13 per cent), carbon monoxide (0.08 per cent) and other traces gases. Humans would need to terraform the planet’s surface to make it viable for plant life (trees and crops), the primary producers of larger quantities of atmospheric oxygen, thereby enabling humans to breathe, other than from oxygen tanks.
As well, humans require water. Despite recent evidence that Mars at one time likely had large areas (perhaps oceans) of water on its surface and underground, what water it now has is currently locked away in the form of water ice in the north and south polar caps. Humans would need to adjust to Mars’ low atmospheric pressure (less than one per cent of Earth) and moderate gravity. Plus, it would take approximately one year for any manned mission to reach
Mars, a voyage complicated by the extreme radiation of outer space, and the impact of the space craft’s micro-gravity on the travellers’ physiology.
Despite such obstacles, manned missions to Mars are expected to begin later in this century or early in the next. With all that needs to be done to prepare the planet for human colonization, it is not likely that humans will live on and roam the surface of Mars until well into the 22nd century. Who knows? Perhaps your great-great-grandchildren may, one day, travel to Mars for a holiday.
Mars, along with Venus and Mercury, will be visible in the night sky later this month. Jupiter and Saturn are still visible at dusk in the southwestern sky.
Until next time, clear skies. Next week, Jupiter — mightiest of the planets.