Despite the fact that to date, scientists have been able to detect more than 4,000 exoplanets, the Earth is still the only known place where life exists in the universe. Life on Earth is present in various forms: from ubiquitous microorganisms to higher animals and humans, capable of even influencing the planet's climate. Be that as it may, the solar system offers many potential options for where biological life could form. According to phys.org portal, one of these places was our neighbor Mars, which in the distant past owned vast and rich in minerals oceans and seas.
What were the oceans on Mars?
The red planet Mars is the closest planet to Earth after Venus. Due to the fact that under the dense atmosphere of the "morning star" the prototype of the biblical hell is hidden, Mars was and remains the most suitable place for the creation of the first extraterrestrial colony of mankind. So, the planet is located relatively close to the Earth, the details of its surface can be easily observed even in a small telescope due to the absence of a dense atmosphere on Mars, and the temperature and pressure of the red planet's surface make it possible to judge the presence of liquid water on it, which is so important for human existence. Studies of dried-up river deltas and ancient lakes show that water did indeed flow on Mars, and life could exist in the oceans of the planet. In order to find an answer to the question of whether life outside the Earth is possible, scientists decided to analyze the types of chemistry of ancient Martian water, which could be rich in salts and minerals, similar to those found on the blue planet.
Ancient oceans of Mars
As you know, one of the clay minerals, smectite, can trap ions in water using ion exchange. So, even after the loss of water, smectite retains its ionic composition inside its inner layers. It is known that salinity, acidity and the presence of certain gases in water are fundamental properties of natural waters. Recent remote sensing measurements on Mars indicate that its ancient environment may provide clues to the early habitability of the red planet. In particular, analysis of the properties of water in the sediments of Gale Crater suggests that they may have formed in the presence of a large amount of liquid water with characteristics similar to those of the earth.
Due to the fact that at one key moment in the history of the planet, all the liquid on Mars began to evaporate, the rising level of minerals in the oceans of the planet provided the local liquid with a persistent smell of hydrogen sulfide and a bitter taste of water. Such characteristics somewhat limit the variety of life forms that potentially inhabited the ancient Martian lakes, but do not completely destroy them. As you know, there is a huge variety of billions of life forms on Earth, so the theory that alien life could arise on Mars seems quite convincing. However, this raises a mystery: why have we still not found any tangible evidence of the ancient habitability of the red planet?