Yet another claim that someone's seen life on Mars
Since the 1800s people have thought they've seen evidence of life on the Red Planet
A retired entomologist from Ohio University presented what he believes is evidence of insect life on Mars based on photographs taken by rovers on the surface of the Red Planet. His claim, as you might expect, is being treated with loud scepticism, and the press release issued by his university has been withdrawn.
But this is the latest in a long history of claims for life on our planetary neighbour.
Mars has tantalized us with the possibility of alien life nearly as long as telescopes have been pointed at it. As early as 1813 astronomers noticed that Mars was in some sense a "living" planet, with white polar caps that melted back in the Martian spring. But it was probably Giovanni Schiaparelli's observations around 1877 that led to the most widespread speculation. He saw peculiar streaks on the Martian surface he called canali, which is Italian for channels. Some interpreted this, though, as "canals," which set off intense speculation that these features had an artificial origin.
No one took this idea more seriously than American businessman and astronomer Percival Lowell who built his own observatory in Flagstaff, Arizona, partly to study Mars. Based on his observations, he drew somewhat fanciful maps of the canals, convinced they were built by an intelligent civilization of Martians.
Of course this sparked the idea that if the Martians were sophisticated enough to build a planet-wide system of irrigation canals, they could be smart enough to build spaceships and invade the Earth, which became a staple of pulp science fiction.
Satellite imagery makes canals disappear
All of this speculation was based on fuzzy images in Earth-based telescopes. It was not until the late 1960s, when robots were finally sent to Mars, that we got the first close-up images of the surface, and saw that the canals were nowhere to be found. There was evidence of channels. However these are not the massive rivers Schiaparelli thought he saw, but were carved by water that flowed on Mars in the distant past. Since then, evidence has accumulated suggesting that about three billion years ago Mars was warmer and wet, with rivers, lakes and even an ocean.
But despite those possibilities, none of the robots that have landed on Mars have found any evidence of life there today, or fossils of life from the past, though there's still intense interest in studying this question.
Still, that hasn't stopped imaginative speculators from seeing what they believe to be signs of life all over Mars. The first came in 1976 with the Viking mission that was sent to look for life in the Martian soil. While the results of those experiments were inconclusive, there was one low-resolution image taken from orbit that looked like a face. This prompted all kinds of speculation that it was some kind of monument. Later high-resolution images, taken when the Sun was at a different angle, found it to be just a hill that happened to have interesting shadows across it.
Later, triangular hills were said to be pyramids, while other faces, apparent ancient artifacts and animals have been spotted in spacecraft photos.
Hardy for hostile environment
Now the latest claim to life on Mars is a series of photos that appear to look like insects.
Remember this is being proposed by an entomologist, who is trained to see insects everywhere. The scientists who work on the Mars missions and examine these photos in extreme detail every day looking for signs of life no doubt find all this amusing.
It's easy to be fooled by fuzzy images of rocks with interesting shapes and tricks of sunlight and shadow. There's a well-known phenomenon called pareidolia in which the human brain interprets lifelike shapes from random patterns. No doubt there will be future claims of animals or artifacts to come out of the thousands of pictures sent back by the Mars rovers.
Unfortunately, Mars in an incredibly hostile environment where even the toughest life forms would have trouble surviving. The temperature and pressure are too low for liquid water to exist and without an ozone layer, ultraviolet light from the sun penetrates right through the thin atmosphere. So anything crawling around on the surface would have to be incredibly hardy.
That is not to say there couldn't be life on Mars, it could be underground in deep caves, under the ice caps or embedded in permafrost. We just haven't found it … yet.