The South Pole Station is built on top of a two mile thick ice sheet, a giant glacier slowly flowing roughly towards the Atlantic Ocean. (The elevation is technically only 9300 feet, but the weight of the ice has compressed the earth underneath it making the ground itself below sea level). The ice moves about 10 meters a year towards the ocean. That means the station moves along with it. But the geographic south pole is more or less constant - so the moving ice pulls the station farther and farther away from the pole each year.
Every year on January 1st the location of the geographic pole is re-measured and a new marker designed by the winter overs of the previous winter season is placed on a metal pole in this new position. This year's marker shows the locations of all the planets with respect to the Sun on January 1st, 2013. We all know that the International Astronomical Union changed the definition of a planet some years ago, demoting Pluto to a dwarf planet. As such, Pluto doesn't show up on the top of the marker. But the winter overs felt bad for old Pluto and decided to place it on the bottom of the marker, where all the winter overs signed the marker.
The 2013 Pole Marker, with the locations of all the planets, the Sun, and the Moon on January 1st, 2013.
Pluto isn't defined as a planet any more, but the winter overs put it on the marker anyway underneath with their signatures.
Now, I've mentioned in the past that the South Pole Telescope is about a kilometer from the station, and we walk back and forth a couple times just about every day to do our work. I also wrote last year about the 100th anniversary of the first people (Amundsen and Scott on two separate expeditions) arriving at the South Pole. Well, it turns out that the telescope was built away from the station in the direction that the ice is moving. Since it's about a kilometer from the station, and the ice is moving about 10 meters a year, you might expect that the position of the South Pole when Amundsen and Scott reached it for the first time should be pretty close to the telescope. And indeed, that is the case! During the centennial celebrations last year a post was placed at the location the geographic south pole was at in 1912, when Amundsen and Scott first reached the Pole. It's within a couple hundred feet of the telescope! VERY nifty.
The position of the South Pole in 1912 is only a couple hundred feet from the telescope.
The 2013 marker looking towards SPT and the direction the ice is moving. Hundreds and hundreds of mile away in this direction is the Atlantic Ocean.
A kilometer away is SPT and the South Pole in 1912. The ice is ever moving.
Finally, the weather was ugly yesterday but we had to head out to the PolCal source 4 km from the station. The cloud cover was breaking in the direction of the Sun while we were out there and we got treated to the closest thing to a sunset in months.