The latest batch of images from NASA’s Dawn spacecraft are back on Earth. And, Ceres’ bright spots remain a mystery.
At least eight bright spots can be seen just to the right of the biggest bright spot. What are they? The only thing NASA is certain of is that whatever it is, it’s reflective. Ice and salt are the leading theories, but scientists are looking into other possibilities.
Right now, Dawn is surveying Ceres at an orbit of about 2,700 miles above the dwarf planet. Ceres’ mysterious bright spots lie in a crater that measures about 55 miles across. Scientists estimate the bright spot in the middle of the crater is 6 miles wide. As Dawn takes closer and closer images, more tiny bright spots have become visible.
Solving Ceres’ bright spot puzzle
Ceres’ mysterious bright spots shouldn’t stay mysterious much longer. Dawn is equipped with a visible and infrared mapping spectrometer. This instrument helps scientists identify specific minerals on Ceres by looking at how light is reflected. Each mineral has a unique signature based on the range of visible and infrared light wavelengths it reflects.
Identifying what the bright spots are is just the first step. Then, scientists will want to know why only this part of Ceres has bright spots. Is there some type of local geological activity in this area? That’s just one of many questions scientists are asking themselves right now.
Dawn gets closer
Dawn will stay in its current mapping orbit until June 30. The spacecraft will spend all of July getting closer to Ceres. By early August, Dawn will be just 900 miles above the dwarf planet’s surface.
Hopefully, we’ll have a definitive answer on the bright spots then.
Dawn gets even closer in December when it will be 235 miles above Ceres.
The rest of Ceres
There is a lot more to Ceres than a handful of bright white spots.
“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.
Dawn also imaged a huge mountain on Ceres’ surface. (top right of the image)
Scientists believe it rises about 3 miles above the surface.
You can also see peaks inside of several craters, especially on the bottom right and left of the image below.
The surface of Ceres reveals evidence of activity in the past including flows, landslides and collapsed structures. Depending on what those bright spots are, Ceres may still be active.
Image credits: NASA