NASA on Wednesday said it might know why dwarf planet Ceres has glowing spots. New studies published in Nature propose two different theories: One, that the bright spots are comprised of salt; and two, the bright spots might be filled with ammonia-rich clays. Either way, NASA says the findings pose questions about how the space rock was formed in the first place.

Using false colors, scientists were able to locate over 130 bright spots covering the dwarf planet, many of which are associated with impact craters. When the impact craters were formed, scientists believe a subsurface layer of briny water-ice was uncovered. That, in turn, is producing a bright material when viewed under false color.

The typical surface of Ceres is generally thought of as dark—like fresh asphalt—making the bright spots stick out even more.

“The inner portion of a crater called Occator contains the brightest material on Ceres,” NASA explained. Occator itself is 60 miles (90 kilometers in diameter, and its central pit, covered by this bright material, measures about 6 miles (10 kilometers) wide and 0.3 miles (0.5 kilometers) deep. Dark streaks, possibly fractures, traverse the pit. Remnants of a central peak, which was up to 0.3 miles (0.5 kilometers) high, can also be seen.”

Now that the mystery of Ceres’s bright spots has been solved, it’s time to figure out how that enormous pyramid formed on the dwarf planet. NASA says Dawn is currently orbiting Ceres at a distance of about 240 miles, and will continue to take observations on through the new year.