Astronomical Mirrors Open Deep Window Into the Early Universe

At a mirror-making lab, discoveries depend on a hair's width of polished perfection.

The universe doesn't spill its secrets easily, say scientists who are making immense mirrors meant to be the engines of future astronomical discoveries.

In a look at the Steward Observatory Mirror Laboratory at the University of Arizona, in Tucson, we meet people on a quest for near perfection: making telescope mirrors with impossibly polished surfaces, smoothed down to a billionth of an inch (0.0254 nanometers).

Some of the mirrors will stretch 26 feet (7.9 meters) across, a technical tour de force necessary for observatories to peer farther into space, and thus further back in time, where they can glimpse the epoch of the oldest galaxies.