Mars Is a Lot Like Hawaii, Curiosity Finds

Of all the places on Earth that come to mind as being “Mars-like,” most people would probably point to the hard, dry Mojave desert. But, surprise, surprise, new data from NASA’s Curiosity rover has revealed that Mars’ Gale Crater is actually more akin to Earth’s Hawaiian Islands. Mineralogical analysis has revealed that, despite being on different planets, both areas are rich in the same type of volcanic soils.

The find comes from Curiosity’s first-ever in-depth analysis of Martian soil. During the week of October 29, Curiosity scooped some samples from an area researchers have named Rocknest into its chemistry and mineralogy instrument (CheMin).

CheMin can do some pretty neat science, like using X-ray diffraction to study soil and powdered rock samples. By interpreting how it X-rays bounce off their surfaces, the scientists behind CheMin can determine the structure of minerals in Martian soil. It’s a common tool chemists use on Earth, but this is the first time X-ray diffraction has been used on Mars – Curiosity is, after all, the first ever Martian chemistry set (Spirit and Opportunity were both designed as mobile geology kits).

Getting the X-ray diffraction instrument to the red planet was a feat in itself. Scientists had to shrink the typically refrigerator-sized instrument down to about the volume of a shoebox.

What CheMin scientists found from the first X-ray view of Martian soil (above) was crystalline feldspar, pyroxenes, and olivine mixed with some amorphous material. In English, that means the soil sampled is similar to the volcanic soils commonly found on Mauna Kea in Hawaii. The sample from Gale Crater had at least two distinct components that speak to the environment on Mars: particles distributed globally by Martian dust storms and sand that appears to have originated locally.

But while the similarity between the Gale Crater area and Hawaii might seem exciting, mission scientists weren’t surprised. It’s further confirmation of the theory that the dust and surface material on Mars is mineralogically similar to basaltic material with roughly half the soil being non-crystalline material like volcanic glass or weathered glass. And unlike other areas Curiosity has sampled, neither of these soil components show any evidence of past interactions with water.

On the whole, the discovery is consistent with the idea that Gale Crater has transitioned through time from a wet to dry environment. The ancient rocks like conglomerates suggest flowing water was once present, but the minerals in the younger soil show a much more limited interaction with water.

Curiosity has been at Rocknest for about a month and will likely roll off on its way to Glenelg in a week or so. But first, scientists are going to uplink the part of the experiment that feeds the CheMin sample to the SAM – sample analysis at Mars – instrument. SAM has already found traces of methane, a gas commonly produced by living organisms on Earth, but it’s far too soon to say what’s making the gas on Mars – NASA learned in 1976 that there aren’t herds of cattle roaming the red planet creating enough methane to affect the environment like they do on Earth.

Regardless of what science comes next, it’s clear there’s a lot of neat discoveries still to come. So, as Curiosity lead scientist John Grotzinger from Caltech eloquently put it, “stay tuned."