Envision the early days of our Solar System, going back billions of years. The Sun was cooler and less luminous, however there have been two planets, Earth and Mars, with liquid water covering large parts of their surfaces. Neither world was completely suspended over thanks into the substantial presence of greenhouse gases, such as carbon dioxide. Both can have even had primitive forms of life in their young oceans, paving the way for a bright, biologically friendly future. Over the past couple of billion years, both planets have undergone remarkable changes.

However, for some reason, while the Earth became oxygen remained temperate, and watched life explodes on its surface, mars just died. Its oceans disappeared, it lost its own air, and no life signs have been found there. There has to be a reason why Mars died while Earth survived. It took decades, but science has eventually figured out it. Among the magnificent characteristics of Earth is the history of life on the world is written to the fossil record. Over hundreds of millions of years, sediments have been deposited both on land and in the oceans, with numerous creatures leaving their telltale imprints in them.

Of all of the sedimentary rocks on Earth, about ten percent of them are limestone, that are frequently composed of the remnants of marine organisms such as coral, amoebas, algae, plankton, and molluscs. Limestone is largely made from calcium carbonate, while some forms also have magnesium and silicon present. The carbonate part, however, is universal to limestone on Earth, along with other ocean deposited minerals such as the magnesium rich dolomite. It is the CO2 in the air which leads to the formation of carbonate rocks, as. The gaseous CO2 in the air gets soaked up by the ocean until there is an equilibrium point attained.

And then oceanic CO2 combines with minerals found in the water. Either forming chemical precipitates or grains. Which then get deposited on the ocean floor, leading to sedimentary rock formation. There are geochemical and biological origins such as the limestone we find on Earth, which makes it one of the richest rocks on Earth’s surface. It is usually thought that the majority of the ancient CO2 air of Earth finally wound up in our surface limestone. There’s an overwhelming amount of proof that Mars had a past. Seasonal ices can be seen not only at the poles, but also in different pools and craters dotting the Martian surface. Features like dried-up riverbeds, frequently featuring oxbow bends like those found on Earth, flow through the landscape. Evidence of early flows leading into excellent oceanic basins, possibly even involving tide rhythmites, abounds all across the red planet. These attributes might have been telltale signs of a historical past where the liquid water was abundant, but that is no longer the case today.