I promised good science and space articles from time to time when something strikes my interest and here today we have a good one. Do you recall a couple of years ago that Pluto was downgraded to “dwarf planet” status. Did you know that Pluto was not the only “dwarf planet”?
Well it’s not and there is some very exciting news about another little dwarf planet in our very own solar system.
Ceres (pronounced “series”) is in the asteroid belt but it’s not really an asteroid at all. Technically, Ceres is a dwarf planet, making it an improbable body that’s of immediate interest to astronomers. There are jets of what looks to be water vapor spewing up into space leading to speculation about the possibility of alien life. Sadly it is unlikely that Ceres actually holds life, but because it is a dwarf planet stuck in the asteroid and that water vapor is jetting up into space we have a major astronomical mystery and we may soon get some answers. Oh did I mention that there are two bright spots on the planet? More on that shortly.
The Dawn spacecraft (image below) arrived at Ceres last week carrying a scientific payload that was previously trained on the second largest object in the asteroid belt, called Vesta. Using its pioneering ion propulsion system, which provides low, constant thrust with remarkably little on-board fuel, Dawn was able to not just perform a flyby, but bump itself into a stable orbit. Soon, Dawn’s ion thrusters will direct it into a similar spiral around Ceres, making it the first ever multi-target mission to enter a stable orbit around two different objects in deep space.
In orbit, Dawn will spend several weeks spiraling down to its “science orbit,” from where it will be able to take detailed surface readings with its multiple scientific payloads. Primarily, it will build a map of the surface of Ceres in the visible and infrared portions of the spectrum and look at the chemical composition of the surface rocks.
Of course the real main question has to do with the Ceres mystery: why does the dwarf planet have bright spots and water vapor jetting up into space?
The bright sports are something that astronomers first noticed several months ago, in addition to the water vapor. There seems to be a well-defined bright spot on the surface of Ceres. Closer inspection has revealed that it is actually two bright spots, both apparently located at the bottom of a major crater. This led some to speculate that they might be cryovolcanoes which are planetary pimples that spew frozen substances rather than molten ones. However NASA believes the spots may be even more important than that. The official theory is the bright spots are actually static reflections of the Sun’s light, and probably arise from either ice or salt fields. If this is true – wow.
Why does this have the Wow factor?
Well it is because water is the primary substance we associate with life. Ceres has long been thought to harbor a subterranean ocean, and these bright spots might mean that some ancient meteor actually blasted down to give us a clean view of the frozen surface. On the other hand, these could be enormous fields of reflective salt crystals, which would be equally amazing in its own way. The spots could even be caused by large amounts of exposed metals, though if we do find some wonderful ore deposits, we’ll be able to do little more than drool over them.
Artist concept of the Dawn spacecraft near Mars. Image credit: NASA/JPL
Future Exploration of Ceres
An extended mission to Ceres would probably only be possible if launched from a Mars station.
Ceres is so massive that it probably maintains a very thin atmosphere of its own, but perhaps more impressive is that it is also the only body in the asteroid belt known to have been rounded by its own gravity, helping to define it as a dwarf planet. The main reason most asteroids tend to be oblong is that they are not’t heavy enough to exert enough gravitational force to make their own rocky structures flow. Ceres presents a nice surface for science (and perhaps someday visitation) because its life history means it does not have nearly so irregular a surface.
Is there a life on Ceres? Probably not and we should find out shortly. However even without life Ceres is turning out to be one very interesting place I would like to visit.