SANTA CRUZ, California — Four hundred years after Galileo’s telescope revolutionized humanity’s view of the universe, a gigantic telescope is in the works that could take us to a new, deeper level of understanding.
The enormous Thirty Meter Telescope, with a primary mirror the size of a blue whale, is part of a new generation of super powerful ground-based telescopes. Scheduled for completion in 2018, it will have nine times the collecting power of the Keck telescopes and 12 times the resolution of the Hubble Space Telescope. From its recently selected location atop the volcanic dome of Mauna Kea in Hawaii, the pioneering telescope will provide an extremely detailed look at the universe.
“As we learn more, the cosmos become more mysterious and require more human ingenuity to get to the next step,” Jerry Nelson, UC Santa Cruz physicist and TMT project scientist, said at a public talk Thursday.
Once finished, the new telescope will allow astronomers to see faint objects clearer than ever before. It will be able to focus on and indentify extremely distant structures that currently appear as blurry smudges in the Hubble Deep Field. As yet, no one knows what these objects are.
This new resolution will provide insights into the both dark matter and dark energy. And it will widen the search for planets orbiting stars outside our solar system. For the first time, we will be able to routinely image direct light from these exoplanets, garnering information on their atmospheric chemistry and dynamics.
The new TMT will also be able to see further back in time than any previous telescope, all the way back to the formation of the first stars and galaxies that followed the universe’s “Dark Ages.”
An adaptive optics system will aid the telescope’s ability to see into deep space. Atmospheric turbulence usually distorts light coming from distant stars. So the adaptive optics system uses a sodium laser to probe current conditions, and information about the turbulence is fed into a small deformable mirror, which makes real-time corrections to the atmosphere’s quivering. The effect is sort of like putting glasses on to correct for blurred vision — the end result is a much crisper image.
Without adaptive optics, ground-based astronomy couldn’t compete with space-based projects such as Hubble. The system is considered so vital that Nelson refers to it as the “heart and soul of the mirror and telescope.”
Nelson has been called the father of the modern telescope, because it was his innovative design in the 1970s that allowed for the creation of big telescopes like the 10-meter Keck. His segmented mirrors have completely transformed the field of astronomy, leading UC Santa Cruz astronomer Sandy Faber to call him a modern day Galileo.
Previously, telescope mirrors larger than 5 meters were considered unfeasible because of many problems: They were hard to cast, their supports were delicate and breakable, and they would warp under their own weight.
Nelson realized that segmenting the main mirror into separate hexagonal pieces could solve all these problems. His design positioned the individual mirrors in a honeycomb-like arrangement and used an intricate computer guidance system to make them act as one, larger unit.
The first telescope to take advantage of this new plan was Keck, which has main mirrors composed of 36 individual pieces. The reflector on the Thirty Meter Telescope will be an order of magnitude leap above this with 492 small mirrors.
Telescopes have doubled in size every 30 years over the last century, and in the not-too-distant future, Nelson predicts we will see 50- and even 100-meter telescopes.
This is not to say that such undertakings will be easy. At an estimated cost of $970 million, the TMT will require an international consortium that includes the University of California system, Caltech, Canada, and Japan. Further funding will come from the Gordon and Betty Moore Foundation, which committed $200 million to the project.
“The discoveries we’re going to make from TMT will simply increase our thirst for even bigger telescopes with even greater capabilities,” says Nelson. “So as long as we retain our curiosity and have the wealth to build these kinds of things, I think we’re going to see bigger things.”
Source : http://www.wired.com/wiredscience/2009/11/thirty-meter-telescope/