Scientists already knew ancient Mars used to look a fair bit like Earth, but now it turns out the Red Planet might’ve looked a whole lot more like our planet than we thought.

The data comes from some new intel provided by NASA’s Curiosity Rover, which shows significant amounts of oxygen once permeated the atmosphere of Mars. Yeah, that’s right — Mars apparently had a whole lot of oxygen back in the day, which means the odds of there once being life on the planet are still pretty decent.

According to Gizmodo, NASA used the ChemCam instrument on Curiosity to discover high levels of manganese oxides in the planet’s rocks. The rover found the levels while exploring the Kimberly region of Gale crater, and the mineral-filled cracks in the sandstone there. The manganese oxides mean free-floating oxygen could have once existed in fairly high levels, along with lakes of liquid water.

So, what happened to this potentially habitable atmosphere on our celestial neighbor? The research team believes oxygen leaked out of the water into the atmosphere when the planet’s magnetic field collapsed. With no magnetic field, and the low gravity on the planet anyway, it lost its hydrogen. Then the oxygen eventually bled into the rocks and turned them all that trademark red color. Which, as red as that planet is now, means there was probably a whole lot of oxygen there at one point.

So, terraformers, get to work.

(Via Gizmodo)