The bright spots of Ceres
The account
Lights glowing at the bottom of a crater on Ceres were thought to be signs of an alien base or cities.
What investigators found
They are salt deposits, mainly sodium carbonate, left by salty water that rose from the interior.
The story
In 2015, as the Dawn probe approached Ceres, the largest object in the asteroid belt, its images revealed very bright patches in the middle of a dark surface. The most intense ones were in Occator Crater and looked like glowing beacons. Online, there was no shortage of talk about artificial lights.
As the probe got closer and analyzed the reflected light, the mystery was solved. The patches are salt deposits, chiefly sodium carbonate, which shine because they reflect far more light than the surrounding terrain. They formed when salty water from the interior reached the surface and evaporated. The discovery turned Ceres into a more interesting world than anyone had imagined, with signs of a brine reservoir hidden beneath the crust.