Joe Palca

Everybody knows that there's just one moon orbiting the Earth. But a new study by an international team of astronomers concludes that everybody is dead wrong about that.

"At any time, there are one or two 1-meter diameter asteroids in orbit around the Earth," says Robert Jedicke, an astronomer at the Institute for Astronomy at the University of Hawaii.

There's a small spacecraft called Messenger that's been orbiting the planet Mercury for a year. Today, at the Lunar and Planetary Science Conference in Houston, astronomers revealed what they've learned about the innermost planet in our solar system, and some of the new knowledge is puzzling.

Maria Zuber, a planetary scientist at the Massachusetts Institute of Technology, studied a large crater 900 miles across called Caloris.

My sister is no science writer, and I'm no baker, but recently our worlds melded in a surprising way.

Here's what happened: Last October, I attended a workshop on artisanal bread and cheese-making at Salt Water Farms in Lincolnville, Maine. Farm manager Ladleah Dunn introduced us to the concept of making sourdough bread with levain, or starter, instead of packaged yeast.

A telescope in Arizona has taken some of the clearest pictures ever of distant celestial objects, including the first images of the innermost planet in a planetary system 127 light years from Earth. They achieved this astronomical tour de force using something called adaptive optics, a technique that eliminates the blurring caused by the Earth's atmosphere.

If you think astronauts just want dehydrated dinners and freeze-dried ice cream, think again. After a few days in space, they start reaching for the hot sauce.

In fact, they may start craving foods they didn't necessarily like on Earth.

Every 10 years, about two dozen of this country's top astronomers and astrophysicists get together under the auspices of the National Research Council and make a wish list. The list has on it the new telescopes these astronomers would most like to see built. At the last gathering, they said, in essence, "We most want the Large Synoptic Survey Telescope."

Here's why. A synoptic survey is a comprehensive map of every square inch of the night sky. The Large Synoptic Survey — LSST — will do that multiple times.

Scientists can spend years working on problems that at first may seem esoteric and rather pointless. For example, there's a scientist in Arizona who's trying to find a way to measure the age of wild mosquitoes.

As weird as that sounds, the work is important for what it will tell scientists about the natural history of mosquitoes. It also could have major implications for human health.

There are few more sybaritic pleasures than scratching an itch.

But according to a study just out in the British Journal of Dermatology, the intensity of the scratching delight varies with the location of the itch.

The world's largest mirrors for the world's largest telescopes are made under the football stadium at the University of Arizona.

Why there? Why not?

"We wanted some space, and it was just used for parking some cars, and this seemed like a good use," says Roger Angel.

Angel is the master of making big mirrors for telescopes. For 30 years he has been using a method called spin casting to make the largest solid telescope mirrors in the world.

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