Looking for life on Mars isn’t as simple as looking for life on Mars.
There are environments to consider, and it turns out rustier might be better.
Hey guys, Amy with you on DNews today.
Our planet isn’t the same all around.
There are different environments on Earth that affect the life forms that grow in an
area.
The same goes for Mars; there are different environments around the planet.
This is a good thing because it means there are multiple places to be looking for life.
But at the same time, it also means astrobiologists studying the planet need to narrow down what
makes for a life-harboring environment.
Gale Crater is a good place to start..That’s NASA’s Curiosity rover’s current stomping
or properly roving ground.
Not only is there a three-mile high stratified mountain in the middle of the crater offering
a look at Mars’ geologic history, the area shows evidence of past water and atmospheric
methane, two things that speak to past life.
But this evidence of water and methane isn’t enough.
The cells that make up any organism need energy to function, and that energy can’t come
from nowhere.
So the question is where on Mars might those energy sources be?
Are there places on Mars where possible organics could get their energy?
Green rust might be an answer.
We’re all familiar with rust, that lovely, orange-reddish, corrosive thing that happens
to iron metals when left exposed to moisture and oxygen in the air.
But when there isn’t enough oxygen to fully oxidize the iron minerals, say, in Mars’
carbon-dioxide rich atmosphere, the effect is slower and develops into less complete
form of rust called green rust.
Green rust is uncommon on Earth but not unheard of.
It’s been found in water-logged soils, groundwater, and in 2012 was discovered in the oxygen-free
water of Lake Matano in Indonesia.
This rare and highly reactive iron mineral played an important role in ancient oceans.
Its presence in oceans suggest it was instrumental in removing nickel from ancient water sources,
a critical process for some life forms that use it and the dissolved nutrients it carries
as a nutrient for producing methane.
And its possible that, on Earth, green rust exposed to the early atmosphere would have
done the same thing, helping our planet generate the oxygen-rich environment that has harbored
life like us.
So what this means is that these two types of iron minerals have different redox states
and different numbers of elections, which could allow the mineral to take in or give
up electrons to act as a catalyst.
Green rust can absorb and concentrate nutrients, as well as accept and donate electrons for
life.
Because Mars’ surface is high oxidized, it’s possible that green rust exists just
under the surface, which means we’ll have to dig to find it.
Some scientists want to try to detect green rust using Curiosity’s laser, measuring
the spectroscopy of the scattered light.
Upcoming missions, namely NASA’s InSIGHT lander and the European Space Agency’s Exomars
mission will have the provision to drill into the surface.
But we also need to learn a little more about this rare green rust and how it can possibly
support habitability.
So are you guys going to look at the rusted bits on your cars a little differently now?