Extraterrestrial life has been a craze for humans for a long time. People are still fascinated by the fact that life might exist in other places besides Earth. One of the most popular sources is our space neighbor, Mars.
Mars is actually only about half the size of Earth, but they have around the same amount of land. Mars’ also has the highest mountains, deepest trenches and others. Mountains such as Mt. Olympus can’t exist on Earth because the gravitational pull is too strong. Unlike Earth, Mars’ magnetic field only forms in some places, unlike Earth which has it all around. Mars’ polar caps also move and change compared to our planets locked ice caps.
Mars is also similar to Earth in ways, too. Like mentioned, The area of land is about the same between Mars and Earth. Days are about the same length on Mars. They both have polar caps and are tilted on their axes, creating similar seasonal changes. Both planets also an atmosphere, but they differ, Mars’ is much thinner.
But what make it so life can exist on Earth, but not present day Mars? Though temperatures can reach up to 70 degrees fahrenheit, the average temperature is negative 80 degrees, much too low for us to survive on Mars alone. Even though Mars atmosphere is mostly carbon dioxide, it is far too thin to trap much heat.. Earth also has a magnetic field that’s powerful and can be found all across the globe. There are only traces of faint magnetic fields on Mars as of today. The magnetic field does more than tell you the directions, it protects Earth from harmful radiation. It may also help the Earth keep its atmosphere and water. On Mars, you wouldn’t have the protection of Earth’s magnetic field.
As mentioned, we do know human life can’t exist on Mars without equipment, but what about bacteria. Bacteria was here on Earth billions of years before us, and has a long time to adapt to radiation, coldness, and everything else. Bacteria lived in space before, so does that mean it has the adaptability to live on Mars?
In one experiment, bacteria was put in a test chamber with freezing temperatures and high level of carbon dioxide, similar to the land on Mars. Most species of bacteria survived. Though this does not prove anything, ( Mars is also exposed to solar radiation) it show that bacteria fits the conditions of Mars and may have lived on it in the past. In the past... so what about the past?
Mars has changed a lot and was completely different in the past. For one thing, liquid water flowed freely. For this to happen, the temperature need to be just right, suggesting that Mars’ atmosphere was once at least as thick as Earth’s. Mars also most likely had a more complete magnetic field based on how there are traces left of it. These factors hint that life existed on Mars.
So what happened? Why did life vanish on Mars? One reason may be because of Mars’ magnetic field being destroyed (ex. meteorites). This caused the Red Planet to be exposed to harmful radiation of the sun. Life either died or took shelter underground. Another reason is because Mars’ atmosphere diminished to what it is now. The causes include it escaped due to low gravity, asteroid collisions, or the most interesting theory, the “runaway refrigerator” effect. Water vapor condenses because of Mars’ coldness due to being far from the sun. The carbon dioxide then combines with the condensed water and mixes into the rock. As the atmosphere leaks away, it gets colder and the process continues until Mars basically well, freezes itself. These two features shape Mars into what it is now today.
There is a high chance that life existed on Mars in the past, because how it fitted the conditions for life (as we know of) to thrive. But now, Mars is likely just a lifeless, barren desert of sand and ice, a fragment of it’s past. Maybe in the future, life will be discovered or return to this seemingly extinct planet.