The next few months is going to be one of the more interesting times in planetary science that I can remember. We have multiple probes returning some very interesting data that so far has no explanation. So, I thought it was time we speculated on what it all is.
First up, Ceres. The Dawn Mission is in orbit right now, and its findings so far are very unusual. Among other unexpected findings, the most interesting are the ‘bright spots’ seen in various images, and in particular two very prominent bright spots in one crater.
Best image so far of those spots is here: Ceres Bright Spots.
Adding to the mystery is the fact that infra-red imagery shows some bright spots on the planet as being colder than the surrounding material, suggesting that they might be exposed ice. However, the two brightest spots do not show up in infra-red at all, suggesting they are at ambient temperature. Puzzling!
The other weird thing on Ceres is the discovery of a single mountain, 5km high. Ceres Mountain Image. It seems to be the only thing like it on the entire body.
As background info, The Hubble has already detected plumes of water vapor around Ceres.
Next up: Pluto. We are going to get the best (and only) high-res imagery from it when the New Horizons spacecraft flies by on July 15. But right now, all we have are the first color images, and they look strange. One side of Pluto has what looks to be a thick dark band at the equator, while on the other side there are four large dark spots along the equator, each one about 300 miles across.
In addition, it was thought that Pluto’s moon Charon was like our moon - formed from bits of Pluto after a collision. But Charon is much darker than Pluto, which you can see here. Fascinating.
Please, no talk of space aliens, ‘pyramids’, or other nonsense. I’m interested in what you all think might be the cause of any of these features.
My first thought about Ceres is that we’re looking at an ice ball with a thin coating of crust over it, and the bright spots are areas where meteors have punched through the crust, exposing the ice. But if these features are old I would expect the ice to ablate away and for the hole to collapse in on itself. Also, that doesn’t explain why the two brightest spots appear to be at ambient temperature.
The other possibility is cryo-volcanism. If Ceres has an active interior, we could be seeing the results of saltwater eruptions. The bright spots could then be salt left over after the plumes fell back to the surface under gravity. Areas that are still cold could be exposed vents, while the neutral areas could be salt residue left from an older eruption. That would also explain the mountain - it’s a cryovolcano. Maybe they happen from time to time but eventually subside under gravity, which is why they don’t stick around to litter the surface. But I’m just spitballin’. And I can’t explain why Ceres would have an active interior without the kind of gravitational stress that moons like Enceladus or Europa are under.
As for Pluto, I have no idea - other than perhaps hydrocarbons causing the dark spots. Pluto has an atmosphere when it’s warm enough, so maybe it’s got an active hydrocarbon environment like Titan?
Anyway, if you’d like to play along and throw in your guesses or any other comments about this, I"d be glad to hear it!
Then there’s the Rosetta Mission and its lander which is trying to wake up.
It’s going to be a fascinating summer.