Ceres and its Shiny Spots

A pair of mysterious shiny patches that reflect sunlight have been found on Ceres. The bright spots were imaged by the Dawn spacecraft, which is whizzing through space on its way to Ceres, and should arrive in orbit on March 6. It'll be the first spacecraft to study a protoplanet at such close range.

What is Ceres?

Ceres is the largest object in the asteroid belt that lies between the orbits of Mars and Jupiter, and was discovered in 1801. It's about 950 kilometres wide, and prior observation tells us that it consists of a mix of rock and frozen water.

Possible origins of Ceres Shiny Spots

The possibile origins of the Ceres shiny spots could be:

1. It is suspected that the frozen water might be the cause of the shiny patches. Most of Ceres' ice is hidden below the surface, but when it bumps into other objects in the asteroid belt it could expose patches of this type. That's the working hypothesis, anyway. Though it's countered by the fact that the shiny patches are only reflecting about 40 percent of the light falling on them. Ice should reflect nearly 100 percent. That's being explained away as a result of Dawn's distance from the target.
2. The bright spots are due to cryovolcanic eruptions driven by radioactivity deep inside the protoplanet, which spew ice, rather than lava, out onto the surface. Water vapour measurements back this hypothesis, but they could also have come from ice.
3. It's not ice at all, but actually a class of minerals called magnesium silicates that have been detected on other asteroids. There are not yet any evidence of this on Ceres, making it the least likely possibility.

The Dawn spacecraft will take photos as it approaches, and then many more once it arrives in orbit and properly orients itself to face the surface.

In short, this is one astronomical mystery that likely won't go unsolved for long.

What do you think about?