April 16, 2015
The discovery of extraterrestrial life in our solar system may be as close as our asteroid belt.
Denise Stephens of the Department of Physics and Astronomy and Jani Radebaugh of the Department of Geological Sciences joined Julie Rose on BYU Radio’s Top of Mind show on March 5 to discuss Ceres, an icy dwarf planet in the asteroid belt that promises to have all of the ingredients needed to support life.
NASA’s Dawn Mission entered Ceres’ orbit on March 6 and will spend the next several years studying the mysterious dwarf planet and collecting clues to how our solar system formed, and where the materials needed for life are found in the solar system.
“For a long time we might have thought Ceres was just a cold, dead rock like a lot of the asteroids in the asteroid belt, but it turns out Ceres isn’t like that,” said Radebaugh.
The dwarf planet was long considered a small, rocky asteroid because 19th-century astronomers couldn’t see Ceres closely enough to tell how big it was or whether it was round. After further study by the Hubble Space Telescope, Ceres was bumped up to its current status as a dwarf planet when the category was created in 2006.
Made up of rock, metal, and a substantial amount of ice, Ceres is a “good place to look for evidence of life,” Radebaugh explained.
Scientists predict that Ceres may have a liquid ocean under an icy crust, which would lead to a rounder shape than some of Ceres’ crater-covered neighbors. Several other asteroids and meteorites in the asteroid belt have thin layers of frost, but Ceres is the only object in the asteroid belt with a rocky core surrounded by a thick layer of water ice, making it of particular interest to scientists, Stephens said.
“Ceres is a bit of an unsolved mystery,” said Radebaugh. “We’ve been able to see it for a while as the probe has gotten closer and we’ve noticed several bright spots that have to be a reflection from either salt or ice that came from the interior of the planet.”
Also of interest to scientists is how Ceres formed. The planets in our solar system formed by a “process of accretion,” meaning dust collected like a snowball to eventually form a planet, Stephens explained. Jupiter’s gravity interacts with the protoplanets in the asteroid belt and usually prevents smaller clumps and asteroids from forming larger planets, making the fairly large Ceres especially unusual. However, scientists are not sure if Ceres formed in the asteroid belt or perhaps was moved there after forming somewhere else.
“If they did find evidence that it formed elsewhere in the solar system and survived a trip in and ended up in the asteroid belt…that would really surprise me,” said Stephens. “I am more likely to believe that it formed where it is. But that would be very exciting.”