NASA’s Phoenix lander has at long last provided direct evidence of water on Mars. And it’s been a long time coming. Back in the nineteenth century, an italian observer, Giovanni Schiaparelli, wrote that he saw “channels” or “grooves” (canali) on the red planet. Percival Lowell, betrayed by what we call un faux ami in French, preferred to read canali as canals; ie, structures built by sentient life to transport liquid from one place to another. Running with this radical interpretation of the text (as Jones puts it,* “description becomes interpretation”), Lowell built a huge observatory near Flagstaff and set up an observing program to find more evidence of life on Mars. (Yes, I know, it’s confusing: NASA’s lander is named Phoenix, like the city in Arizona, and I’m talking about Flagstaff, a different city in Arizona. Chill!)
Over the next thiry years of his life, Lowell observed the red planet through a fine 23-inch refractor, and he continued to insist that he had observational evidence of construction on Mars (here is a drawing Lowell made of Mars in 1905). Such construction, he thought, could only have been the result of sentient beings cooperating on a planetwide scale.**
Turns out that Lowell, and the other observers who insisted they saw canals on Mars, were misled by an actual optical phenomenon, rather than purely wishful thinking. When observing at the limit of the eye’s resolution, the brain constructs straight-line patterns linking unrelated features, even though the linking structures themselves do not exist in the image. There is a convincing explanation of this phenomenon in William Hoyt’s book, Lowell and Mars.
On the other hand, the evidence for water on Mars (just not in canals), is everywhere we look. Giant canyons, larger than any canyon on Earth; seasonal appearance and disappearance of ice at the north and south poles; sculpted dunes. While all of these features can be explained by inferring the existence of surface water on Mars in the past, none of these features is actual physical direct evidence that such water existed. Dunes can be aeolian instead of wave-formed; the ice at the poles actually is carbon dioxide, not water; the canyon could have been the result of geothermal or tectonic processes (although Mars doesn’t have plate tectonics). The point is, all of this speculation about the presence or absence of water on Mars can be rendered moot by going there and finding it. And that’s just what NASA did yesterday:
Laboratory tests aboard NASA’s Phoenix Mars Lander have identified water in a soil sample. The lander’s robotic arm delivered the sample Wednesday to an instrument that identifies vapors produced by the heating of samples.[…]
The soil sample came from a trench approximately 2 inches deep. When the robotic arm first reached that depth, it hit a hard layer of frozen soil. Two attempts to deliver samples of icy soil on days when fresh material was exposed were foiled when the samples became stuck inside the scoop. Most of the material in Wednesday’s sample had been exposed to the air for two days, letting some of the water in the sample vaporize away and making the soil easier to handle.
“Mars is giving us some surprises,” said Phoenix principal investigator Peter Smith of the University of Arizona. “We’re excited because surprises are where discoveries come from. One surprise is how the soil is behaving. The ice-rich layers stick to the scoop when poised in the sun above the deck, different from what we expected from all the Mars simulation testing we’ve done. That has presented challenges for delivering samples, but we’re finding ways to work with it and we’re gathering lots of information to help us understand this soil.”
According to the article on discovery.com,
The ice confirmation earlier this week was accidental. After two failed attempts to deliver ice-rich soil to one of Phoenix’s eight lab ovens, researchers decided to collect pure soil instead. Surprisingly, the sample was mixed with a little bit of ice, said Boynton, who heads the oven instrument.
Researchers were able to prove the soil had ice in it because it melted in the oven at 32 degrees — the melting point of ice — and released water molecules. Plans called for baking the soil at even higher temperatures next week to sniff for carbon-based compounds.
And although this water does not appear to have come from canals built by martians, it is indeed martian water. At least, that’s what our best direct evidence to date tells us. The next step? A return of samples from Mars to Earth. And that’s what NASA and ESA are planning with Aurora, which is already being designed, and might see launch as early as 2020.
*For more on the history of Mars before the Space Age, see the article of the same name by Barrie W. Jones in the Cambridge Journal of Astrobiology.
For more on Percival Lowell, check out Lowell and Mars by William Graves Hoyt.
For a Librarything list of my books on Mars, click here.
**If I were ever to sit down with Percy Lowell for a beer, I’d be sorely tempted to ask him: “if we so-called sentient beings can’t cooperate on a local, let alone a planetwide scale here on Earth, what makes you think ancient martians could? Don’t tell me it’s a response to a global threat like climate change. We have only to look at the world today to know that sentience is highly overrated as a way to respond to global disasters.” But this conversation could never happen because, as everyone knows, you only get one person in history to have a beer with. That being the case, I’d probably have to choose Ernest Hemingway, even though I’m not all that fond of his writing. Hemingway, or maybe the Buddha.
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