NASA's Dawn spacecraft has been drawing closer to the dwarf planet Ceres and the observations have caused an uproar over the source of mysterious bright spots on the object's surface.

The most recent images of the mysterious planet provided new information on the spots, and also revealed a "pyramid-shaped peak" present on an otherwise flat landscape.

"The surface of Ceres has revealed many interesting and unique features. For example, icy moons in the outer solar system have craters with central pits, but on Ceres central pits in large craters are much more common. These and other features will allow us to understand the inner structure of Ceres that we cannot sense directly," said Carol Raymond, deputy principal investigator for the Dawn mission, based at NASA's Jet Propulsion Laboratory.

The new images, taken at a distance of 2,700 miles above Ceres, reveal even more small bright spots within a crater than were previously visible. There are now at least eight visible spots next to the largest bright area, which researchers believe is about six miles wide.

While the source of the spots remains unknown, researchers believe they are being caused be a highly reflective material such as ice or salt. Dawn's visible and infrared mapping spectrometer allows scientists to identify specific minerals on Ceres' surface because every mineral reflects its own range of visible and infrared waves. As the spacecraft continues to send back more information, the researchers hope to gain new insights into the source of the spots.  The new images also reveal what is believed to be a mountain with steep slopes that rises about three miles into the air.