(CNN) Life could have found a way to establish on Mars 4.48 billion years ago, according to a new study. That's when gigantic meteorites stopped crashing into the Red Planet and inhibiting life.

Life could have thrived between 3.5 billion and 4.2 billion years ago, which predates the earliest evidence of life on Earth by 500 million years.

Once the planets in our solar system formed, the frequency and the size of meteorites in the solar system diminished. That gradual decline opened a window in which the conditions were right for life to form and remain.

Tiny igneous zircon grains within this rock fragment were fractured by the launch from Mars but otherwise unaltered for more than 4.4 billion years.

But there are different ideas about when the heavy meteorites ceased. Some scientists believe that the planets endured a later stage of bombardment 3.8 billion years ago.

For the new study, researchers studied the oldest-known mineral grains from meteorites that they believe originally came from the southern highlands of Mars. By looking at them on an atomic level, the researchers determined that the minerals were unchanged since they formed and crystallized near the Martian surface.

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