This is scientific American 60 second science. I'm Christopher Intagiyata.

To study the heavens, it's all about the photons.

We in astronomy are always greedy. We want every photon that we can collect.

Drew Phillips, astronomer at the University of California observatories.

More photons, he says, basically means more science about incredibly faint

distant objects.

And that's where the optics problem comes in,

because incoming light reflects off several mirrors

before it comes out the business end of a telescope.

And mirrors aren't perfectly reflective.

The traditional mirror coating, aluminum,

reflects only about 90% of light.

Bounce that light around a few times in a telescope

and you lose valuable

photons. The throughput, the actual number of photons that are detected in the end

in a modern spectrograph, you're doing good if you get 30%. So you want the

most reflective material for your mirrors, like

silver, which reflects 97 to 99% of visible and infrared light respectively. Big

improvement over aluminum, but silver's got its problems too.

It is finicky, it's subject to tarnish and oxidation and corrosion.

So Phillips and his team have borrowed a trick from the computer industry called atomic layer deposition.

The technique allows them to take a silver-coated mirror

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