NASA is 'puzzled' by its best photo yet of these mysterious white spots in space

We just got our best look yet at a strange cluster of bright spots on Ceres, a dwarf planet in the Asteroid Belt, that scientists have spent months puzzling over.

NASA's Dawn spacecraft returned the close-up shot (below) of a giant 4-mile-deep crater on Ceres. The spacecraft snapped the photo from less than 1,000 miles above the surface, and the image is three times more detailed than the last batch of images beamed to Earth from about 250 million miles away.

In the new image, you can clearly see a patch of the bright spots at the base of the crater:

Dawn also recorded new video footage of the crater.

The video's images are color-coded to show differences in elevation. The distance between the lowest point, at the center of the crater (dark blue), to the highest point, on the rim of the crater (brown), spans about 4 miles:

The new images are inspiring more questions about the mysterious world than answers.

For example, the strange bright spots on Ceres reflect much more sunlight than the material around them. Many scientists initially thought they might be patches of ice or even ice volcanoes, but new measurements of how reflective the bright spots are came in lower than what you'd expect from ice.

"We are now comparing the spots with the reflective properties of salt, but we are still puzzled by their source," Dawn's principal investigator Chris Russell said in a press release.

That's not the only mystery on Ceres though. Back in August - on a completely different side of the planet - scientists found a mountain that sticks up four miles high from an otherwise flat area. It's cone-shaped and about the same height as Alaska's Mount McKinley, which is the tallest peak in North America.

Scientists aren't sure what geological process formed it, or why one side appears dark and the other side is covered with light streaks:

"It's unusual that it's not associated with a crater," Paul Schenk, a geologist working on the Dawn mission, said in the release. "Why is it sitting in the middle of nowhere? We don't know yet, but we may find out with closer observations."

We'll continue getting more data as Dawn orbits closer and closer to Ceres, and hopefully we'll finally figure out what those mystery bright spots are.

"Dawn has transformed what was so recently a few bright dots into a complex and beautiful, gleaming landscape," Marc Rayman, Dawn's chief engineer and mission director, said in a separate statement from NASA. "Soon, the scientific analysis will reveal the geological and chemical nature of this mysterious and mesmerizing extraterrestrial scenery."