A reader writes concerning Ceres and some white spots:
I refuse to believe the bright spots on Ceres are just reflections. A reflection would vary in intensity with rotation. I need a better explanation.
Since one of the white spots had been previously observed by HST, it’s doubtful that this is a camera artifact / defect. Here is a report on the white spots.
NASA’s Dawn spacecraft has beamed home the best-ever photo
of the mysterious bright spots that speckle the surface of the dwarf planet Ceres.
The new image resolves Ceres’ strange spots, which are found inside a crater about 55 miles (90 kilometers) wide, into a cluster comprised of several patches, some of which were not visible in previous photos
“At least eight spots can be seen next to the largest bright area, which scientists think is approximately 6 miles (9 km) wide,” NASA officials wrote in a statement today (June 22). “A highly reflective material is responsible for these spots — ice and salt are leading possibilities
I speculated that perhaps Ceres was perhaps not rotating quickly enough, but space.com reports otherwise:
A day on Ceres lasts a little over 9 Earth-hours, while it takes 4.6 Earth-years to travel around the sun.
At least, I’d think it would be fast enough to cause a variability in reflection. IO9.com presents speculation from the principal investigator (the link IO9 has for the principal investigator is broken, otherwise I’d use it), Chris Russell:
“Ceres’ bright spot can now be seen to have a companion of lesser brightness, but apparently in the same basin. This may be pointing to a volcano-like origin of the spots, but we will have to wait for better resolution before we can make such geologic interpretations.”
The comment section also has some semi-viable speculation.
Volcanos require a magma layer, but several moons have known volcanic activity – usually caused by the gravitational proximity of the primary – Ceres has no primary.
I briefly speculated that it might be chemical, but given the HST observations are more than a decade old, you’d think the material involved in the reaction would be exhausted, unless lower temperatures slowed down the reaction – but then would it be visible? But my chemical knowledge is miniscule.
Finally, the IO9 story also tells us what makes a scientist a scientist:
I admit it: I’m totally jazzed that we’ve got such a blatant mystery staring right at us, daring us to figure it out with ever more obvious clues!
