FRIGID, RUSTY AND HAUNTED
We can’t stop looking at it, writes
THERE it was: Glowering red on the dashboard of the sky like an astrological warning light next to the full Blood Moon on Friday, July 28 — Mars.
It was calling brightly out across 35.8 million miles of space, a gulf humans have yearned to cross for as long as they have known that the lights in the sky are places. At the time of the lunar eclipse, it was the closest it has been to earth in 15 years.
That yearning has now been refreshed — if in fact it ever went away — by the discovery of a 19.3km wide lake under the southern ice cap on Mars by the European Space Agency’s Mars Express orbiter. An oasis for interplanetary dreamers. Microbes are known to inhabit similar lakes on earth, and so who knows? Could little Martian bugs be swimming around down there under almost 2km of ice that keeps the cosmic rays out and keeps the Martian water liquid?
Mars has always been the backyard of our imaginations, the place we might one day live or from where invaders would come in flying saucers to enslave us and steal our water. Our robots have crossed that space again and again.
It is not crazy in astrobiology circles these days to hold the opinion that the life that now envelops earth started on Mars and then some pilgrim microbe was brought here on an errant asteroid. We know now that the sky is an endless conveyor belt with cosmic riffraff shuffling debris from planet to planet, even star to star, as personified by Oumuamua, the wandering comet from outside our solar system that cruised blithely through the planets last winter. In the fullness of time, everything gets everywhere.
We could all be Martians, then, which could help explain the seemingly endless lure of the Red Planet. The dream of the exile to return to what might once have been Eden. Elon Musk has said he wants to die there, but he’s not ready to go there quite yet.
I grew up terrified as well as curious about the place, after I saw the previews of Invaders From Mars. The film showed a boy my age seeing a flying saucer go under a hillside, after which the townspeople, including his parents, were kidnapped and turned into robots. My parents never let me see the whole movie.
It paid homage to a part of a mythology that dated to the beginning of that century, of Mars being the dying home of a dying civilisation of super smart beings — little green men — hunkered by canals bringing water from the poles. Those visions sprang from a misunderstanding of the work of Italian astronomer Giovanni Schiaparelli, who in 1877 thought he saw long, thin lines he called canali (channels in Italian) lacing the surface of Mars. Percival Lowell, a socialite and astronomer took the notion seriously and proceeded to map what he thought were cities and canals on the planet.
All that good science fiction melodrama vanished when spacecraft images showed the real planet, cratered and dust-blown.
So, here are a few hard facts. Mars is about half the size of earth, so gravity is weaker there — only a third what is on earth, and so you could jump higher, that is if you could take a breath. The Martian atmosphere is mostly carbon dioxide, and there is very little of it anyway, the pressure is less than one per cent of air pressure here. Temperatures on the ground range from 30°C to -123°C below. A day there is 24 hours, 39 minutes and 35 seconds long and a year is 687 Earth days.
Mars is red because it is rusty. Martian dust is full of iron oxide. It is, as a travel brochure would say, a land of dramatic contrasts, with the solar system’s biggest volcano, Olympus Mons, 24.1km high, and the longest canyon, Valles Marineris, 4,023km long and 6.4km deep.
As far as we know, it is inhabited mostly by our own robots, like the rovers and the Vikings we have sent there, and the wreckage of lost landers. Some 45 space missions — not all of which made it — have been launched towards Mars by humans. There are five on the docket, including efforts by China and the United Arab Emirates, planned for the summer of 2020.
Out of all this exploration, a new story has emerged, equally haunting. Mars was a planet once splashed by oceans and carved by swiftly flowing rivers, a world warmed long ago by an atmosphere. But something happened and Mars lost its sparkling waters and its air.
Now there are only the naked shorelines, empty filaments of tributaries, silent rocks and occasional wet spots on cliff sides. If there was life here, the story goes, it died or went underground.
The newly discovered underground lake, if it is confirmed by further observations, is just the latest in the parade of hopeful signs that we might have neighbours out there somewhere.
Lately, much excitement about extraterrestrial life has been in the outer solar system, where many of the moons of Jupiter, Saturn and other gas giants have been found to be ocean worlds hiding under ice. Some of them, like Jupiter’s Europa and Saturn’s Enceladus, seem to be squirting salty plumes of water and perhaps, microbes out into space.
Nasa is planning a probe to Europa, and many astrobiologists have been pushing for a ride through the sprays of Enceladus or for a mission to send drones to explore the methane lakes of Titan, Saturn’s biggest moon. Nobody knows what alien life would look like or what it would require.
Mars is red because it is rusty. Martian dust is full of iron oxide. It is, as a travel brochure would say, a land of dramatic contrasts, with the solar system’s biggest volcano, Olympus Mons, 24.1km high, and the longest canyon, Valles Marineris,
4,023km long and 6.4km deep.