The bright spots on Ceres, the dwarf planet between Mars and Jupiter, have been the subject of a lot of interest and speculation for months now. The bright spots were one of the biggest surprise of NASA’s Dawn mission. For over a year, the NASA’s Dawn spacecraft has been mapping the surface of the rocky dwarf planet in exceptional detail, and the bright spots (which reflect much more light than their darker surroundings), gained worldwide attention when they were discovered, looking so much like illuminated human cities when photographed from orbit.
The most obvious of the Ceres bright spots is inside the Occator crater, and the speculation surrounding the spots indicates that perhaps Ceres is much more “active” than its asteroid neighbors.
The speculation surrounding the bright lights on Ceres led sky watchers to look for explanations everywhere, from the humdrum to the inexplicable. In December 2015, scientists announced that run-of-the-mill salt is behind the bright spot phenomenon on the dwarf planet Ceres.
Today, though, Astronomy reports that new research into the Ceres bright spots indicates that the bright spots are changing in inexplicable, unexpected ways.
According to the report, new observations obtained using the HARPS spectrograph at the European Southern Observatory’s (ESO) in Chile demonstrated completely unexpected changes in the Ceres bright spots.
Not only do the bright spots change when Ceres rotates, they also show other variations that are less easily explained. According to these observations, the material of the Ceres bright spots (whatever it may be) is volatile and perhaps even subject to evaporation in the warmth of the sun.
The new, more precise, observations of Ceres, made possible with the HARPS equipment, were made possibly by Paolo Molaro, the lead author of the study and associate at the INAF–Trieste Astronomical Observatory. He had some words on Ceres, as well.
“As soon as the Dawn spacecraft revealed the mysterious bright spots on the surface of Ceres, I immediately thought of the possible measurable effects from Earth. As Ceres rotates, the spots approach Earth and then recede again, which affects the spectrum of the reflected sunlight arriving at Earth”
A day on Ceres lasts nine hours, and according to scientists the velocities of the spots away from and toward the Earth would be small; roughly 12 MPH. However small, though, this motion is enough to be detectable by HARPS.
Over a bit more than two nights in July and August 2015, the team led by Molaro observed Ceres and its bright spots. In addition to the expected observations, the team found something more.
“We did find the expected changes to the spectrum from the rotation of Ceres, but with considerable other variations from night to night.”
The conclusion? The changes observed by the team are possibly due to the existence of “volatile substances that evaporate under the action of solar radiation.” The team believes that when the spots inside the Occator crater on Ceres are exposed to sunlight, they form “plumes” that very effectively reflect that sunlight. Ultimately, the plumes are very temporary. According to the researchers, they evaporate “quickly,” become non-reflective, and produce the other visible changes observed by scientists.
Additionally, due to the differences in the effect from day to night, night to night, additional random patterns become visible on both long and short timelines.
If the new theory regarding the ever-changing spots on Ceres holds up to scientific scrutiny, it would unequivocally define Ceres as different from Vesta and other large asteroids with which Ceres shares the asteroid belt. This is because Ceres, despite its relative isolation, seems to be active on the inside. It’s also known to contain ample water, but it’s uncertain whether or not the water in question has any relation to the mysterious Ceres bright spots.
Thus far, no one knows what process may be driving the “leakage of material” from the surface of the dwarf planet. However, whatever the process or material may be, scientists believe that it is this that is the source of the mysterious and heretofore unexplained Ceres bright spots.
[Image Courtesy Of NASA Handout/Getty Images]