Is there life out there? You can add dwarf planet Ceres to the list of planets and moons in our own solar system backyard that might be harboring some.
Scientists have detected ice on the planet's surface, which could mean Ceres is hiding an ocean below its frozen crust.
Where There's Water, There Might Be Life
When NASA's Dawn spacecraft was first approaching Ceres, a rocky planet that sits in the asteroid belt between Jupiter and Mars, it saw plumes of water vapor rising from the surface.
"If we have water in liquid form, could we have life?" planetary scientist Timothy Titus told Scientific American. "It's one of the more exciting things with these plumes, that they could be a potential exobiology target."
But after the probe finally arrived at Ceres in spring 2015, we didn't see any more plumes. It looked like the planet may not hold water after all.
See more photos of Ceres:
Dwarf planet Ceres may have a huge ocean that could support life
This image, made using images taken by NASA's Dawn spacecraft, shows Occator crater on Ceres, home to a collection of intriguing bright spots. (Photo via NASA/JPL-Caltech/UCLA/MPS/DLR/IDA)
NASA's Dawn spacecraft spotted this tall, conical mountain on Ceres from a distance of 915 miles (1,470 kilometers). The mountain, located in the southern hemisphere, stands 4 miles (6 kilometers) high. Its perimeter is sharply defined, with almost no accumulated debris at the base of the brightly streaked slope.
The intriguing brightest spots on Ceres lie in a crater named Occator, which is about 60 miles (90 kilometers) across and 2 miles (4 kilometers) deep.
NASA's Dawn spacecraft took this image that shows a mountain ridge, near lower left, that lies in the center of Urvara crater on Ceres.
NASA's Dawn Spacecraft took this image of Gaue crater, the large crater on the bottom, on Ceres. Gaue is a Germanic goddess to whom offerings are made in harvesting rye.
(Photo via NASA)
This Feb. 19, 2015 image shows the swarf planet Ceres provided by NASA, taken by the agency's Dawn spacecraft from a distance of nearly 29,000 miles (46,000 kilometers). It shows that the brightest spot on Ceres has a dimmer companion, which apparently lies in the same basin, seen at center of the image. Dawn is preparing to rendezvous with the largest object in the asteroid belt located between Mars and Jupiter, scheduled to go into orbit Friday, March 7 after a three-year journey. Dawn is about 590 miles (950 kilometers) in diameter. (AP Photo/NASA/JPL-Caltech/UCLA/MPS/DLR/IDA)
This March 1, 2015 photo provided by NASA shows Ceres is seen from NASA's Dawn spacecraft just a few days before the mission achieved orbit around the previously unexplored dwarf planet to begin a 16-month exploration. The image was taken at a distance of about 30,000 miles. (AP Photo/NASA)
Robert Mase, right, project manager for the Dawn mission at Nasa's Jet Propulsion Laboratory, speaks at news conference, with Carol Raymond, deputy project scientist at JPL, left, at JPL in Pasadena on Monday, March 2, 2015. NASA's Dawn spacecraft is scheduled to slip into orbit around the dwarf planet Ceres on Friday, the last stop in a nearly eight-year journey. (AP Photo/Nick Ut)
Robert Mase, project manager for the Dawn mission at Nasa's Jet Propulsion Laboratory, speaks at news conference at JPL in Pasadena on Monday, March 2, 2015. NASA's Dawn spacecraft is scheduled to slip into orbit around the dwarf planet Ceres on Friday, the last stop in a nearly eight-year journey. (AP Photo/Nick Ut)
This morning, our @NASA_Dawn mission arrives at the dwarf planet #Ceres: http://t.co/49tIUjqOj2 http://t.co/bFHlRte7Nj
Dawn robotic spacecraft next to Ceres and Vesta, members of the asteroid belt, to study them in space. - Elements of this image furnished by NASA
The ice deposit is younger than the 8 million-year-old crater, so whatever smashed into Ceres and formed the crater didn't bring the ice with it. One explanation is that a landslide exposed pieces of an ice sheet.
The discovery is exciting because the presence of an ice sheet could mean Ceres has a giant, sub-surface ocean of liquid water like Europa or Enceladus. And where there's water, there might be life.
Scientists will collect more data to determine if Ceres is frozen solid, or if an ocean is churning beneath an icy shell.