A number of factors affect a planet's color. Earth's mostly blue tinge, for example, is because of water. Our planet, however, could be as red as Mars, yet it's not. Why? A new study points to iron.
The lack of iron is what keeps Earth from looking as red as Mars, explains a new research. Conversely, it's the abundance of iron that gives the Red Planet its signature auburn glow, which is actually rust.
Why Earth Isn't Red
While Earth definitely has iron in its crust, and while it's possible for rocks on our planet to turn red overtime, Earth just doesn't have as much iron as Mars. For a long time, scientists have known that something within Earth's crust is stealing all the iron away. They thought it was the mineral magnetite.
But this new study, published in Science Advances, says it's not magnetite and brings up another possible mineral: garnet.
"We conclude that garnet fractionation, owing to its preference for ferrous over ferric iron, results in simultaneous oxidation and Fe depletion of the magma," the researchers conclude.
Is Garnet Depleting Earth's Iron?
To be sure, the researchers make clear that it's hard to pinpoint any single mineral as the sole culprit for diminished iron levels in Earth's crust, and they also expect to meet skepticism for their theory. It's also hard to determine the exact mineral absorbing massive amounts of iron, since these processes happen beneath the surfaces of active volcanoes and are therefore hard to examine.
Even still, garnet appears frequently in the spots where iron depletion occurs, unlike magnetite. What's more, almandine, a mineral under the garnet group, is laden with iron and is formed under hot, high-pressure environments — the conditions where iron depletion takes place.
It should be noted, however, that much of the study is based on garnet-rich rocks called xenoliths, which have found their way to the surface. Granted, this process isn't as direct as watching the actual iron depletion occur, but for now it's the most effective means of observing geological processes that happen underground.
So, until a new research challenges this new garnet theory, it appears magnetite isn't the mineral depleting Earth's iron levels. Chalk it up to garnet why Earth isn't red, according to the researchers. Hopefully others build upon this new work and investigate further.
Would you like for Earth to look as red as Mars? As always, feel free to sound off in the comments section below!
