Nasa’s far-flung space robots keep finding signs of water everywhere
ROBOTIC explorers have found signs of long-lost water on Mars and extensive ice still present on the dwarf planet Ceres - evidence that water truly is almost everywhere we look.
The results were announced last week at the fall meeting of the American Geophysical Union – the world’s largest gathering of Earth and space scientists. There, Nasa scientists discussed the results from several of the dozen space probes currently exploring the universe beyond our planet.
The rover Curiosity has been trundling across the Martian landscape for more than four years. But recently, the plucky robot rolled onto a patch of ground with veins of calcium sulfate, in the form of the mineral gypsum, running through it. Hiding within those veins was the element boron, which usually appears only in once-flooded sites where the water has evaporated away.
According to scientists at the Los Alamos National Laboratory, the discovery in Mars’ Gale Crater suggests that there was once liquid water on the Red Planet - and that the water was habitable. The calcium sulfate and boron could only precipitate out of water that was between 32 and 140 degrees Fahrenheit and was not too acidic.
The boron was identified by a ChemCam built at Los Alamos. The camera works by shooting a laser at a rock, exciting the electrons of the atoms within it. Those electrons then emit distinctive wavelengths of light, depending on the element; by reading the spectrum that shines back at it, the instrument can figure out what elements the rock contains.
This was the first discovery of boron on Mars, and the latest finding suggesting that Mars used to be much wetter, warmer and far less hostile than it is now.
Gale crater – a 100-mile-wide canyon with Denali-sized Mount Sharp at its centre – is thought to be the site of a former lake. As Curiosity climbs the slopes of Mount Sharp, it has found varying levels of clay, boron and other types of rock. These variations could hint at the lake environment that may have existed there billions of years ago.
“There is so much variability in the composition at different elevations, we’ve hit a jackpot,” California Institute of Technology geologist John Grotzinger, Curiosity’s chief scientist, said in a statement.
Scientists have been seeking evidence of past or present life on Mars for four decades, without success. But the boron finding adds to the evidence that the planet may have had the kinds of dynamic environments that are known to support organisms on Earth.
“A sedimentary basin such as this is a chemical reactor,” Grotzinger said. “Elements get rearranged.”— Washington Post