The dwarf planet was discovered last year and since then, scientists have been baffled by Ceres’ bright, white spots located on one of its large craters.

The first conclusion was that they were large deposits of salt and after further analysis, published in a recent study, scientists have come up with a new theory. The Occator Crater is where the white spots are at their brightest and its here that huge concentrations of sodium carbonate – a substance usually found in household cleaning products here on Earth – which is formed in underwater hydrothermal vents and sodium carbonate being responsible for the bright, white spots.

The carbonate-rich planet would be one of the highest concentrated of carbon ever discovered which doesn’t coincide with the theory that material was deposited on the planet through asteroid collisions millions of years ago. A second study theorizes that the planet is much drier than first thought which poses the question of how the carbonate formed if there wasn’t sufficient water.

It could be that the interior of Ceres is much warmer than previously thought and could mean water was present underneath the surface with the salts being remnants of minerals once dissolved.

“The minerals we have found at the Occator central bright area require alteration by water. Carbonates support the idea that Ceres had interior hydrothermal activity, which pushed these materials to the surface within Occator,” stated Maria Cristina De Sanctis, investigator on the Dawn spacecraft.

The mystery could be the key to the origin of water in our solar system and its role and ability to retain itself.

“Understanding water on Ceres—how much it has, how it attained and retained it, whether it formed in the asteroid belt or further out—has really important implications for the formation of the solar system overall,” Michael Bland of the US Geological Survey said. “I think Ceres is a great target for Dawn and future missions, as a way to bridge the inner and outer solar system.”

The two studies were published in Nature and Nature Geoscience.