Quirks & Quarks·Analysis

Seeing the 'old Mars' in a close encounter with the Red Planet

Bob McDonald's blog: the view of Mars from Earth hasn't been this good since 2018

Bob McDonald's blog: the view of Mars from Earth hasn't been this good since 2018

Mars shines brightly in the sky over Port Canaveral in Florida in July 2018 — the last time Mars made a close approach to Earth in their orbits around the Sun. (NASA)

On Oct. 9, I pointed my telescope out my front door and Mars glowed in my viewfinder. The Red Planet was on its close approach to Earth — only 62 million kilometres away — an event that occurs about every two years.

The shimmering image shining in my eye was how Mars likely appeared to early astronomers who believed the planet could be alive. We're still trying to resolve that question. Three spacecraft are currently on their way to the Red Planet as the search for life there continues.

Mars has intrigued skywatchers for millennia because of its red colour, which you can see for yourself on any clear night in the south east over the next few weeks. Mars and Earth are doing their orbital dance where our planet overtakes Mars in its orbit, like a runner on the inside track in a race around the sun.

Mars orbits farther away from the sun than we do, so its year is twice as long as ours. So roughly every two years, the two planets meet in a "close approach." This is great for viewing as it makes Mars appear larger in telescopes. It is also a good time to send spacecraft to Mars because they don't have to travel as far.

This diagram shows the configuration of Earth, Mars, and the sun during opposition. (NASA)

'Canals' on Mars

During my observation, Mars appeared as a reddish disk with dark markings across the centre as though someone had smudged it up with a felt pen. These are the kind of markings that Italian astronomer Giovanni Schiaparelli saw in 1877 during a similar close approach. 

At that time, photography was not used in astronomy, so observers had to sketch what they saw with their eyes. Schiaparelli drew maps showing the dark areas as seas with thin lines running between them he called "canali," which in Italian means channels. 

Giovanni Schiaparelli mapped and named areas on Mars by hand. He saw channels on Mars and called them "canali." (NASA)

The image in my telescope shimmered in and out of focus because of distortion caused by our atmosphere. There were only brief moments of clarity and I strained to see if I could make out the famous lines. 

Of course, if you are looking for something, you will see it. Our brains have a tendency to fill in missing information to connect the dots, so the thin lines I thought I saw might have been from a combination of self suggestion and an optical illusion created by the telescope. But seeing it with my own eyes was a journey back in time as I imagined what was going through Schiaparelli's mind when he saw the same effect more than a hundred years ago.

The nearly full moon and Mars (the faint light at the top in the middle) appear in conjunction — close to one another — in the night sky Friday, Oct. 2, 2020, as seen from Olympia, Wash. Through most of the month of October, Mars will appear as the brightest object in its area of the sky, except when the moon is nearby. (Ted S. Warren/AP Photo)

Schiaparelli's maps caught the attention of American astronomer Percival Lowell who built an observatory that still stands today in Flagstaff, Ariz., to specifically study Mars. He also produced elaborate maps of thin lines crisscrossing Mars, but he called them canals, which imply artificial structures constructed by an intelligent civilization, not natural channels carved by rivers.  

The idea of canals on Mars became great fodder for science fiction writers such as Edgar Rice Burroughs and his stories of John Carter on Mars, or H.G Wells and the War of the Worlds. Movies and television programs dreamt up Martians of all sorts, from hideous monsters intent on conquering Earth to the mischievous My Favourite Martian. But it wasn't until we went there with robotic spacecraft that the true face of Mars was revealed. And what a disappointing face it was. 

The true face of Mars

The first closeup images taken by by Mariner 4 in 1965 showed a cratered landscape that looked more like the moon than a civilized world. The first global maps made from orbit in 1979 did indeed show channels that were carved by ancient rivers, but they had dried up long ago. Sadly, there were no canals.

This view of channels on Mars came from NASA's Mariner 9 orbiter. (NASA/JPL-Caltech)

The first big mission to actually look for life on Mars was the twin Viking landers in 1976, that carried laboratory equipment to analyze scoops of Martian soil. When the red dirt was fed nutrients and heated, the soil gave off oxygen, just as if it contained microscopic life. But another experiment failed to find any organics, the carbon based ingredients of life, so the results became ambiguous.

That didn't stop conspiracy theorists from seeing other signs of life in the photos from Mars such as the famous face, which turned out to be shadows cast on a hill, other hills near the face that looked like pyramids, a rock that resembled  a squirrel, all kinds of optical illusions of light and shadow, but none of them signs of Martian life.

This image, taken by the Viking spacecraft July 31, 1976, shows a human-like face on the surface of Mars. NASA scientists say the image is as an optical illusion caused by the angle of the sun. (NASA/Associated Press)

Our other robotic explorers have shown that Mars used to be a warmer wet world with lakes, rivers and possibly an ocean in the distant past, billions of years ago. But then the planet entered an ice age and never recovered. Water froze into polar caps, much of the atmosphere burned off into space, leaving the cold, dry desert world we see today.

Did life evolve in those ancient lakes? Is it still there today frozen underground or hiding in underground caverns? Mysterious Mars is still hiding its secrets.

This image shows multiple channels one to 10 metres wide on a slope in the Hellas impact basin on Mars. On Earth, we would call them ravines. (NASA/JPL/The University of Arizona True ravines on Mars)

But this February, we may come a step closer to an answer when the American lander Perseverance scoops up some Martian soil and stores it to be picked up by a later mission and returned to Earth for more detailed study. Perhaps then we will discover if our neighbouring planet is, or was ever alive.

Until then, take a glance up at the red starlike object in the night sky over the next couple of weeks. If you have access to a telescope, try to see those tantalizing dark markings with your own eyes. Perhaps you will see what look like lines. The canals are not really there, but imagine a world that was once like the Earth, and maybe, just maybe, harboured some kind of alien life.

About the Author

Bob McDonald is the host of CBC Radio's award-winning weekly science program, Quirks & Quarks. He is also a science commentator for CBC News Network and CBC-TV's The National. He has received 12 honorary degrees and is an Officer of the Order of Canada.