New research upends theory about why Mars is red

Studying Mars

Of all the planets in our solar system, Mars is one of the most studied. Its close proximity to Earth has made it an obvious choice for exploration over the past few decades.

The Red Planet

Even among non-experts, Mars is known for being covered in dust and for having a sort of rusty hue. Indeed, it is often referred to as the "Red Planet."

Presence of rusted iron

For years now, scientists have understood that the planet’s red color comes from rusted iron minerals in the dust that is found all over it.

The question at hand

For the avoidance of doubt, the fact that Mars is red is not being contested. Rather, the new study offers a different explanation for why the planet is that color.

Rust on Earth

For those not familiar with the chemical processes that produce rust, this is largely the same process that forms rust here on Earth.

Transported by winds

It was moved about by strong Martian winds, the likes of which still kick up dust storms on the planet today.

No water detected

These analyses did not detect any evidence of water, which led researchers to believe the type of iron oxide present on Mars was hematite.

Timing

Furthermore, it must have formed later in Mars’ history, after the planet is believed to have had lakes and rivers on its surface.

Ferrihydrite

Ferrihydrite differs from hematite in the sense that it forms in the presence of cool water.

Age-old question

Scientists have long since wondered about the exact composition of the iron oxide found on Mars.

Data from various devices

The new study used data collected by various devices, including the European Space Agency’s Mars Express Orbiter and the ExoMars Trace Gas Orbiter.

Interpreting the results

According to the study’s authors, this discovery offers some interesting clues about the planet’s geologic and climate history.

Scope of the study

It is important to note that this recent study did not focus on exactly when Mars’ ferrihydrite reserves were formed.

Going back further

This is as opposed to millions of years before, when the planet would have been warmer and wetter.

Period of volcanic activity

Indeed, this was a period of intense volcanic activity that likely triggered ice-melting events and interactions between water and rock.

In the Martian rock

Researchers believe that in addition to being in the dust, ferrihydrite may also be present in the layers of Martian rock.