Mars may have remained habitable for a longer period of time than thought

A warm and humid climate suitable for life existed on Mars for the first hundred million years of its history. However, scientists have now concluded that it may have lasted longer than previously thought.

Mars. Source: starwalk.space

Warm climate on Mars

A recent paper published in Nature Communications claims that a warm and humid climate may have lasted much longer on Mars than previously thought. This significantly affects estimates of how realistic it is to find a life on it now.

Scientists have long agreed that Mars had liquid water and a much denser atmosphere in its early days than now. But regarding when exactly it all ended, there are very different estimates. However, the most common estimate is 4.1 billion years.

And that figure has been called into question in a new study. According to its authors, a warm climate on Mars persisted at least until 3.9 billion years ago. The main reason to think so is new estimates of when the red planet’s global magnetic field disappeared.

The planet’s magnetic field stops heavy charged particles flying from the Sun. If Earth didn’t have it, they would crash into the atmosphere, break down molecules, and individual atoms would be lost in space. This is the fate that happens to most of the atmosphere and water on Mars.

Martian dynamo

The source of a planet’s magnetic field is its solid core, which rotates at a slightly different speed than the rest of the mass. This is called the dynamo effect. This was once present on Mars as well. However, the Martian “electric motor” stopped at the very beginning of the planet’s existence.

At least, such a conclusion scientists previously made on the basis of the study of the oldest craters of the red planet. When a large celestial body crashed into it, the rocks melted. If any magnetic field existed at that moment, it should have “preserved” in the rocks, making them magnetic as well.

However, the magnetic fields of old Martian craters are extremely weak. And this has led scientists to believe that the Martian dynamo had already weakened when they formed. However, a new study proves that this is not the case.

Scientists used a powerful microscope and once again examined the structure of the famous Martian meteorite Allan Hills 84001. They came to the conclusion that it actually did experience a strong enough magnetization, just at that moment, the field of Mars changed its polarity, and this was taken for its absence.

Provided by phys.org