UA unveils mirror for world's largest telescope

TUCSON, AZ (Tucson News Now) - When comes to cutting edge astronomy, bigger is better, and local scientists are playing a key role in building one of the biggest sky watchers ever.

The Giant Magellan Telescope, or GMT, being built in Chile will bring us closer than ever to seeing the beginning of the universe.

Its seven massive mirrors are being made at the University of Arizona.

Mirror Number Three was unveiled Friday.

It was a big moment at the UA where Tucsonans became the first people on this planet to see the giant mirror that will eventually be part of the world's largest telescope.

It happened in a spot that few people know exists.

Here's the clue: While the Wildcats are creating football stars inside the stadium, under the stadium, UA scientists are reaching beyond the stars.

"The mirrors that we make here are the largest mirrors that have ever been made," says Dr. Buddy Martin of the UA's Steward Observatory Mirror Lab.

Martin is a mirror polishing scientist.

The mirrors being made in Tucson are 8.4 meters, or 25 feet, across.

Mirror Number 3 has just come out of the oven, so to speak.

"It takes about a year to go through the cycle of building the mold and casting the mirror, letting it cool down to room temperature, which is what we've reached right now," Martin says.

This mirror soon will be going through a grinding and polishing process to create a nearly perfect surface.

It must reach an accuracy of one millionth of an inch or better.

GMT project managers are here from Pasadena, California, to celebrate the milestone for the record-breaking telescope.

"We have the most glass of any telescope in the world. We've got to polish it still, but this is a big day," says Giant Magellan Telescope Project Director Dr. Patrick McCarthy.

Mirror Number 1 is finished.

Mirror Number 2 is on its way to completion.

They all started as raw chunks of glass, each a little smaller than a football, that were melted and spun creating the honeycomb-like mirrors.

That honeycomb construction makes them the lightest mirrors while still being as stiff as a solid mirror.

Both qualities are necessary to reduce distortion.

Each is about one-fifth the weight of a solid mirror.

Together, they will form the world's largest telescope, a machine that will be able to see further and more clearly than ever before.

It holds the promise of solving some of the mysteries that confound us.

Could there be life on other planets?

"It'll be used to find planets around other stars distant from the sun, including relatively small planets, similar to the earth that might hold life. And we hope to be able to detect the presence of life one day with telescopes like this," Martin says.

"We're not going to see the little creatures walking around on the surface, but we may see the signature of life in the atmosphere--say, oxygen in the atmosphere of another planet. That signal is so faint that existing telescopes don't have a hope of detecting it, but the new generation of telescopes, including the Giant Magellan Telescope, will eventually have a good chance of being able to detect that presence of life," Martin continues.

Scientists say they are excited to look back in time to the first galaxies that formed in the universe.

Light first emitted from those ancient places has been traveling a very long time.

"You're looking for light that's traveled literally 12 billion years and not much of that gets to the earth and not much of it gets to our telescope. So you need as much collecting area as you can to get that light that's traveled so long to come to us and tell us what happened in the beginning," McCarthy says.

Asked what Galileo would think of all this, McCarthy says, "He would marvel at the technology, but the basic drive and the same questions and approach, they're the same as he had. But he got it all started."

Construction is set to begin on the GMT in Chile in 2014.

Steward Observatory Mirror Lab scientists expect to have the seventh and final mirror for the GMT finished in 2022.