At sundown on any given night, mountaintop turrets around the world rumble to life as astronomers train their telescopes on the sky. The quest: to write the history of the cosmos from clues they find in feeble starlight from the edge of the visible universe.
Now groups in Europe and North America aim to build observatories that would leave Galileo breathless. They envision behemoths up to four times bigger than today's largest optical telescopes, which currently rely on 10-meter (33-foot) light-gathering mirrors.
These ambitions are pushing this corner of astronomy into the era of "big science," where the cost of building and operating world-class observatories or laboratories outpaces a single country's willingness to foot the bill. Major projects are planned, built, and run by a host of international partners. The era has long since dawned on fields such as high-energy physics, fusion-energy research, and other areas of space science. Now, the highly visible and highly competitive field of ground-based astronomy stands on the threshold.
Last week, the European Southern Observatory, a consortium of 11 European countries, gave its astronomers the OK to spend 57 million euros ($75 million) to develop designs for a 40-meter telescope. Astronomers hope to start using it in 2017.
In North America, two groups – a consortium of US and Canadian universities and a separate alliance of US and Australian research institutes and universities – are working on 30-meter and 22-meter designs. Their designs cleared key reviews earlier this year, and one group has cast its first mirror. They are now refining the designs and trying to raise the money and organize the management structures to build and run them. Price tags for each of the North American projects range from $500 million to $750 million – roughly the amount NASA paid to build and launch its latest Mars probe.
"Every country likes to do its own thing and get the rewards that come from doing that," acknowledges Malcolm Longair, an astrophysicist at Cambridge University in England, who served on a high-level panel reviewing the wish list of projects US astronomers have developed for this decade. That list included these large telescopes. But a hefty price tag and operating costs may mean only one of the North American projects will be built. And even that one may require broader cooperation than it currently enjoys.
For many astron-omers, the scientific case for these mammoth telescopes is air-tight. To answer many of the big questions in their field, astronomers need to observe light from the earliest stars, which brought the 14 billion-year-old universe out of its dark infancy. It takes a lot of glass on the ground to capture such faint photons. And researchers need to be able to separate closely-spaced objects across vast distances. It demands the latest technology aimed at removing the distorting effects of Earth's atmosphere from incoming light.
While the US plans to put the James Webb Telescope in orbit by 2013, researchers will need larger ground-based counterparts to help them interpret what the space telescope sees, notes Richard Ellis, an astronomer at the California Institute of Technology.
Astronomers say they have enough high-level research to keep three ground-based telescopes in this new size class busy for decades. But telescopes have annual operating costs that typically hit 10 percent of the construction price.
Because of these high costs, the US scientific review committees have suggested that only one of the two North American projects can expect long-term federal support. The other may have to be built and operated exclusively on foundation grants or money from other private sources.
But now that the Europeans have allocated the money for a detailed design, "this is a big signal that we are serious about this," says Guy Monnet, the project scientist for Europe's 40-meter telescope project. "We have a real project" that should give any discussions about deeper trans-Atlantic cooperation a firmer foundation.