Ancient microbes may help us find extraterrestrial life forms.

Using light-capturing proteins in living microbes, scientists have reconstructed what life was like for some of Earth's earliest organisms.

This process could help us to find signs of life on other planets.

The earliest living things (formed 4.2 billion years ago) existed without an ozone layer that protects them from exposure to radiation.

These microbes evolved rhodopsins proteins with the ability to turn sunlight into energy, using them to power cellular processes.

Using machine learning, the researchers team analyzed rhodopsin protein sequences from all over the world and tracked how they evolved over time.

Then, they created a type of family tree that allowed them to reconstruct rhodopsins from 2.5 to 4 billion years ago, and the conditions that they likely faced.

The researcher also hopes to take what they learned about the behavior of early Earth organisms and use it to search the skies for signs of life on other planets.