Scientist believe that mars might have once sustained life. There are many factors and signs that earth isn't the only planet in the solar system to have created life. This is an incredibly important fine as it shows that life is much more likely in other solar systems as well.

The biggest piece of evidence surprisingly is on earth. A meteorite that landed on earth around 16 million years ago (long after the dinosaurs) was found. Within this meteorite we found fossils. Really small fossils but fossils none the less of bacteria. However this is questionable evidence as the bacteria from earth could have contaminated the rock as well as the entry to earths atmosphere could have made small indentures. However we have found yet another rock that was analyzed with better tools.

This second rock landed on earth around thirteen thousand years ago. In this second rock we have found embedded underneath the surface and also we can be almost completely positive that entry into earths atmosphere did not cause it and also that what ever blue it off of mars did not cause it.

As we investigated the surface and certain magnetite crystals in the meteorite we found signs of bacteria. Many sceptics believed that this could be elements within the meteorite that broke down due to impact however a fourth of the crystals contain trace signs of life. Sadly we can't tell at what time the meteorite was blasted off of mars.

Many people wonder why the only bacteria fossils we have found from mars are on earth however it should be noted that the rovers we have on mars don't have the same incredibly advanced technology that we have on earth in labs.

The biggest reason why mars can't sustain life is its magnetic field. Unlike earth mars has a weak magnetic field that cannot protect its surface from the radiation of its sun. However we have found in the surface of Mars certain bands that are strong evidence that Mars used to have a much stronger magnetic field strong enough even to protect life. Why the magnetic field got weaker is unknown however certain scientist believe that the fact that mars doesn't have tectonic plate activity is the reason why the magnetic field is so weak.

We have also found minerals that flourish while under liquid water. We have found certain areas that have enough of this mineral to show that water was there for long periods of time.