Our last stop on the Chile trip was San Pedro de Atacama, a hiker's paradise that now serves as the headquarters for the APEX microwave telescope (a friend of mine was using it while we were there) and the ALMA microwave radio telescope array, located at 16,400 feet (5,000 meters). It's so high up that you have to be examined by a doctor before they let you visit. Everyone in our group passed the test... except me. (I was on antibiotics, fighting a sinus infection I'd picked up in Denver.)
As I result, I don't have first-hand descriptions... but these are some of the photos that Katie took and shared with us:
But along with the telescopes, we also got to visit a couple of the remarkable sites near San Pedro... the El Tatio hot springs and geysers (best seen at sunrise, which meant an early start for us) and the "Valley of the Moon", a remarkable collection of mountains and valleys carved by wind and water.
And that's where Ceres comes in. As you may recall (see Bob's posts) the Dawn spacecraft is orbiting Ceres, getting closer and closer to the mysterious white spots seen on its surface. One theory has it that they are patches of ice left by geysers on the surface of Ceres. Well, here are some geysers at 14,000 feet in the dry desert of Chile:
But an equally possible theory is that the white spots are salt deposits left behind after the water evaporated into space. And that's where the "Valley of the Moon" comes in.
As you may have heard, this desert only gets rain about once in a hundred years; but one of those times was just this past spring. And the rocks here are full of salts like gypsum, or even regular rock salt (NaCl as halite). They were the site of salt mines as recently as the 1960s. And with all that rain, a lot of salt got dissolved into the water... and then left behind as the water evaporated. So, for the moment, this valley has a remarkable white patina:
So maybe they should rename it, The Valley of Ceres?