A new discovery on Comet 67P/Churyumov-Gerasimneko by the Rosetta spacecraft has gotten scientists majorly excited.

The European Space Agency’s Rosetta spacecraft, which deployed the Philae lander to the comet back in late 2014, has detected the presence of the amino acid “glycine,” which living organisms use to make proteins, according to an ESA statement.

It’s a potentially massive discovery: the building blocks of life are sitting on a barren comet speeding through empty space, giving credence to the idea that comets and asteroids may have brought life to Earth billions of years ago. The finding could further refine our search for life, and may suggest that it’s not outlandish to believe the life exists nearby.

Scientists also found phosphorus, the first time it has been found on a comet. Phosphorus is another key element for living organisms.

It’s not the first time scientists have found glycine on the remnants of a comet — they did so with comet fragments found in Utah in 2006, but concerns about contamination meant that scientists couldn’t confirm this.

“This is the first unambiguous detection of glycine at a comet,” says Kathrin Altwegg, principal investigator of the ROSINA instrument that made the measurements, and lead author of the paper published in Science Advances today. “At the same time, we also detected certain other organic molecules that can be precursors to glycine, hinting at the possible ways in which it may have formed.”

“We see a strong link between glycine and dust, suggesting that it is probably released perhaps with other volatiles from the icy mantles of the dust grains once they have warmed up in the coma,” she adds. “Glycine is the only amino acid that is known to be able to form without liquid water, and the fact we see it with the precursor molecules and dust suggests it is formed within interstellar icy dust grains or by the ultraviolet irradiation of ice, before becoming bound up and conserved in the comet for billions of years.”