Cloudcroft, New Mexico
Anthony Aguirre, Janna Levin
Horizon - How BIG is the Universe?
Traffic - Red Shift
For cosmologists, the expansion of the universe is not a problem. In fact, it's a gift. If space is stretching, then the wavelength of light from
the galaxies is stretching too. The greater the distance, the redder the light. This red shift effect is the mapmaker's vital tool for measuring
distance. And red shift was the key to the next vital stage in mapping the universe.
A survey to pinpoint the exact location of the galaxies, stretching 5.5 billion light years from Earth.
It started here, one of the more unusual towns in America. Welcome to Cloudcroft, New Mexico. A place where you don't have to be an astronomer to
map universe. Everyone in town can have a piece of the action.
Frances Cope "To us, it's wonderful – I mean, it's just part of our everyday life. On a clear night my husband will say 'Well, you're
going to be busy tomorrow!'."
Frances Cope
Frances Cope has been working here for two and a half years. At the last count, she'd mapped a quarter of a million galaxies.
Frances Cope "It can be very therapeutic but mostly it's, to me personally, it's a sense of fulfilment"
Tracey Naugle
Tracey Naugle trained as a mechanic, then retrained in galactic exploration.
Tracey Naugle "It's neat that you are a part of discovering new galaxies, it's kind of a good feeling."
Kristina Heuhnerhoff
Kristina Heuhnerhoff is a freelance writer. Mapping the universe helps her wind down.
Kristina Heuhnerhoff "It's very Zen, I think, because you are, you know, you're putting things where they're supposed to be."
They all work with this man. David Schlegel, a cosmologist from the University of California at Berkeley. When he first came to town the
map of the universe was almost empty.
David Schlegel "The only pictures we had of the full sky were on photographic plates, images taken by Palomar Sky Survey in the 1950s. And
actually we were still using that in the 1990s, that was the best picture that we had of the full sky."
David Schlegel
The Palomar survey was practically a museum piece – photographed on fragile glass negatives. Even by 1998, only 30,000 galaxies had been
placed on the map of the universe. That's when David joined the Sloan Digital Sky Survey at the nearby Apache Point Observatory.
David Schlegel "We had the sense that it was going to be this great thing that was starting, but it hadn't actually started yet. What we wanted
to do was something much more ambitious and actually get a map of the million brightest galaxies on the sky."
The task required measuring the distance, and therefore the red shift, for every single one of these galaxies.
David Schlegel "Obviously you need to look at more than one galaxy at the time, so that's the trick. If you were a futurist you'd say, 'Well,
it's the 1990s, we have computers and we have robots.' The folks designing the Sloan though, decided to take the pragmatic approach and say,
well, we actually want this thing to work."
Instead of robots, the ingenious system they came up with required a far more human touch. And they would have to go aroundn the universe not
once, but twice.
David Schlegel "It's really doing two maps of the sky."
Pretty Picture
The first time around, they didn't measure any red shifts. The telescope simply took photographs… A map of the sky, but in two dimensions
only. It doesn't give the distance to each galaxy – yet.
David Schlegel "We actually have from those images not very much idea of where these things are in three-dimensional space. So at some level,
it's just a pretty picture."
But the next age was the trick. They printed the pretty pictures in metal.
Galaxy Location Plate
David Schlegel "Each of these holes corresponds to our two-dimensional location of a galaxy on the sky, where if I look at this hole, that
the longitude on this coordinate, the latitude in this coordinate, and so the whole design of this system is to, as efficiently as possible,
get the light from that one galaxy into that specific hole."
The plugging team from town connected every galaxy with a fibre-optic cable then fitted the plate back over the telescope.
Second time around, the telescope measures the red shifts for these specific galaxies alone. 1000 galaxies on a plate, nine plates a night and
one million galaxies in total on a map crafted by human hands.
Kristina Heuhnerhoff "It's hard to wrap my head around the idea that we're looking at… You know, with 1,000 fibres, looking at 1,000 galaxies,
and its… I have a hard time wrapping my head around that the universe is that big."
