Golden Age on the High Planes

Golden Age on the High Planes

by Adam Frank for McGraw-Hill

What will people 1,000 years from now think of this moment in history? What will we be remembered for? It is doubtful that there will be much recollection of "Britney Spears," "Chris Rock" or "Limp Bizkit." No one will know who "Harry Potter" was. One thousand years is, after all, a very long time. If we are remembered at all it will, most likely, be for our achievements in science. Of those achievements, Astronomy will probably head the list. From the discovery of extra-solar planets to understanding how the Universe itself was formed, the days we share are astonishing due to the rate at which truly fundamental questions are being answered one after another. When you consider that people have been pondering these questions for at least a few thousand years it is easy to conclude that we live in a "Golden Age" of astronomy.

What makes this Golden Age possible? Is it because theoretical astrophysicists like myself have come up with new ideas so profound they've revolutionized our understanding of the sky? While I would like to claim this to be the case the real heroes of this revolution are not theorists and their math but observers and their instruments. This new age of discovery is driven by ambitious new telescope projects and the high-technologies that make them possible. With these new instruments we are opening up new windows on the heavens, seeing farther and with more clarity than ever before. From the orbiting Hubble Space Telescope to the giant 8-meter Keck telescope in Hawaii, each project has had its own unique impact on changing our view of the sky. Now, in the high desert of South America a new kind of "big eye" on the sky in taking shape. Its name is ALMA and "she" carries the promises of pushing our astronomical revolution to even further extremes.

ALMA stands for Atacama Large Millimeter Array. It is a very large, very ambitious and very expensive project of the U.S. National Science Foundation and the European Space Organization. ALMA will be a collection of 64 large "radio" telescope dishes set out on the Atacama high desert in Chajnator, Chile. Each telescope will be 12 meters across. By acting in concert, all 64 telescopes will combine to act like a single instrument the size of a football field. That is BIG and just the construction of the site will pose major challenges. The Atacama Desert lies 16,000 feet above sea level. When completed, it will be the highest and most remote observatory in the world. ALMA will be set so far high that altitude sickness will be a major concern for construction workers and scientists alike.

Why bother putting an astronomical observatory in such an inhospitable place? ALMA is designed to "see" light with wavelengths in the millimeter range (in between radio and infrared light). This is a wavelength "window" that astronomers are dying to pry open as many key processes in astrophysics produce most of their light right in the millimeter range. Unfortunately, the atmosphere has kept that window mostly shut for too long. The atmosphere absorbs a good deal of the incoming millimeter light. Water vapor, in particular, acts as a sponge for millimeter radiation. Only by putting ALMA above a good part of the atmosphere in a super-arid location can astronomers have any hope of really seeing the millimeter sky.

Getting high and dry and being very big will give ALMA a chance to see cosmic events in an entirely new way. ALMA will be able to pick up extremely faint signals allowing it to see events that stretch far back in time. One of its primary tasks will be pick light from the earliest epochs of the Universe when galaxies where just being assembled. These young galaxies will be enshrouded in dense clouds of gas and dust. Millimeter light can pass right through these dense regions giving astronomers clearer views of the "construction process."

The resolution of all those telescopes will also be extraordinary. ALMA will be able to distinguish objects that are 1/1,000 the width of the Saturn on the sky. That combined with the penetrating power of millimeter light will allow ALMA to see deep into regions where stars and planets in our own galaxy are forming.

Galaxy, star and planet formation do not even begin to exhaust the list of astronomical topics that ALMA will impact. Astronomy may be a big topic but ALMA is going to be a BIG telescope. Most all aspects of astrophysics will feel ALMA's reach. It is going to be a new gold standard for advancing this rapidly accelerating Golden Age.

Questions to Ponder

What would be other difficulties involved in building such a large high-tech project in so remote a location?
Come up with one argument for, and one argument against, funding so large a project? Are we taking money out of hungry people's wallets? Think about the Golden Age concept. Does that justify the cost?

Check Out These Websites

Get the Latest News on ALMA
http://www.eso.org/projects/alma/