Unlike certain corners of the UK tabloid press, I’m not about to proclaim that NASA has found life on Mars, because that’s just silly (and completely false). However, NASA has spotted signs of life on Earth. I realize that might sound just as wacky, but bear with me.
Using their Advanced Land Imager (ALI) on the EO-1 satellite, NASA has managed to identify a region of the Arctic where bacteria is staining the ice. Borup Fiord Pass on Ellesmere Island in the Canadian Arctic is unique in that it is the only known location on the planet where sulfur is being pumped to the surface via a natural spring over ice. The result is a dirty yellow stain with contrasting white surroundings.
When flying over the location in a helicopter, the yellow hue is obvious (pictured top), but from space, it’s hard to spot. In fact, identifying such a small area would normally be impossible for a satellite, but NASA scientists are a smart bunch and they’ve overcome this problem.
Using a special sensor inside ALI called Hyperion, scientists have been able to see wavelengths of light that are invisible to our eyes. Hyperion is able to see beyond the visible spectrum and gather hyperspectral data so sensitive that they now have the capability to ‘see’ the sulfur staining from space, mapping the Borup Fiord Pass runoff. As this sulfur has a specific chemical “fingerprint,” the strength of this fingerprint in the spectrum of light being given off by the stained ice means that they can estimate the quantity of the element that is there.
This sounds awesome, but why is sulfur so important?
The key thing here is that this sulfur is a byproduct of a complex biological mechanism that is occurring. Hydrogen sulfide — the foul rotten egg-smelling gas — is dissolved in the water beneath the Canadian ice and through complex interactions with microbes, the hydrogen atoms are stripped from the sulfur atoms. (Hydrogen sulfide — H2S — is a molecule consisting of two hydrogen atoms and one sulfur atom.) The EO-1 satellite is seeing the stain of elemental sulfur being carried to the surface, acting like a highlighter pen, pointing to the microbes’ location.
So, NASA is seeing, for the first time, evidence of microbial life from space. Do you see where I’m going with this? Yes, now NASA has means to look for signs of life elsewhere in the solar system.
Take Europa, one of Jupiter’s moons, for example. It’s a rocky world (a little smaller than our moon), covered with ice. It is thought there might be liquid water in the form of sub-surface oceans, potentially harboring life. But how do we find Europa life if it’s there? We could send a lander to drop a drilling probe through the kilometers-thick ice or attempt to find a huge fissure to access the sub-surface ocean.
Or we could just send a satellite to orbit Europa, with an instrument on board similar to Hyperion, to begin surveying the European ice for yellow stains.
NASA is keen to point out that the system is far from perfect, but it is very encouraging that the EO-1 satellite can accurately map the distribution of sulfur deposits from space, closely matching the photographs taken by a helicopter far below.
Of course, looking for hydrogen sulfide-eating microbes that ooze elemental sulfur means that we’ll be looking for similar biological processes we observe on Earth. So we have to assume Europa Brand™ life is similar to Earth Brand™ life. But as the only life we know of exists here on Earth, it’s not a bad assumption to make.
Source: NASA Earth Observatory