How did life begin? It’s the oldest question of science, and one of the most difficult to comprehend, but a new study published in the journal Nature Microbiology may have unveiled some extremely important details on how it all happened — and the answer may surprise you.

The study claims that all life today descended from a microbe that existed four billion years ago and may have survived in hydrothermal environments.

These primitive life forms probably dwelled in hot springs rich with iron, and probably didn’t do much other than consume hydrogen, carbon dioxide and nitrogen gases. But they may be where we came from.

To come to their conclusions, researchers sorted through 6.1 million genes found in single-celled organisms today, and they found 355 protein groups that were likely retained from an ancestor microbe.

Scientists are calling it the Last Universal Common Ancestor, or LUCA, and they believe it lived with the Earth was just 560 million years old.

It’s actually a controversial finding. Some believe that life formed in extreme environments like deep sea vents or the sides of volcanoes, while others thought that Darwin’s original theory that it sprung up from warm ponds was more likely.

“The concept of a last universal common ancestor of all cells (LUCA, or the progenote) is central to the study of early evolution and life’s origin, yet information about how and where LUCA lived is lacking,” the abstract states. “We investigated all clusters and phylogenetic trees for 6.1 million protein coding genes from sequenced prokaryotic genomes in order to reconstruct the microbial ecology of LUCA. Among 286,514 protein clusters, we identified 355 protein families (∼0.1%) that trace to LUCA by phylogenetic criteria. Because these proteins are not universally distributed, they can shed light on LUCA’s physiology.”