Joe Palca

Joe Palca is a science correspondent for NPR. Since joining NPR in 1992, Palca has covered a range of science topics — everything from biomedical research to astronomy. He is currently focused on the eponymous series, "Joe's Big Idea." Stories in the series explore the minds and motivations of scientists and inventors.

Palca began his journalism career in television in 1982, working as a health producer for the CBS affiliate in Washington, DC. In 1986, he left television for a seven-year stint as a print journalist, first as the Washington news editor for Nature, and then as a senior correspondent forScience Magazine.

In October 2009, Palca took a six-month leave from NPR to become science writer in residence at the Huntington Library and The Huntington Library, Art Collections, and Botanical Gardens.

Palca has won numerous awards, including the National Academies Communications Award, the Science-in-Society Award of the National Association of Science Writers, the American Chemical Society James T. Grady-James H. Stack Award for Interpreting Chemistry for the Public, the American Association for the Advancement of Science Journalism Prize, and the Victor Cohn Prize for Excellence in Medical Writing.

With Flora Lichtman, Palca is the co-author of Annoying: The Science of What Bugs Us (Wiley, 2011).

He comes to journalism from a science background, having received a Ph.D. in psychology from the University of California at Santa Cruz where he worked on human sleep physiology.

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.

Companies making genetically modified animals face a regulatory morass in this country. It's not always clear which federal agency has responsibility for regulating a particular animal, and even when one agency does take the lead, the approval process can drag on for years.

The companies say this uncertainty means their technologies may die without ever being given a chance.

Take the case of the British company Oxitec. It has developed a genetically modified mosquito that the company says can be used to combat a disease called dengue.

When scientists want to test new therapies for cancer or heart disease, they frequently turn to mice for help. For most mice, this isn't the best thing that could happen to them. Being a research subject has definite disadvantages, at least for mice.

But most people prefer a new therapy be tested in a rodent rather than making a human patient the guinea pig — if you'll forgive the twisted metaphor.

Hurricanes topple plenty of trees, but when you think about it, the more amazing thing is that many trees can stand up to these 100-mile-per-hour winds.

Now a French scientist has come up with an explanation for the resilience of trees. And astonishingly, the answer was first described by Leonardo da Vinci 500 years ago.

Leonardo noticed that when trees branch, smaller branches have a precise, mathematical relationship to the branch from which they sprang. Many people have verified Leonardo's rule, as it's known, but no one had a good explanation for it.

This just in: After 15 years of deliberation, the U.S. Food and Drug Administration has yet to decide whether it will approve a genetically modified salmon for human consumption.

Now there's a catchy lead. But the truth is, the long-running regulatory saga of AquaBounty's application to sell salmon with a growth hormone gene from one fish plus a promoter of an antifreeze gene from another — which help it grow twice as fast as typical farmed salmon — does not seem headed toward a conclusion.

It's time to go back to Mars. Once every two years, the orbits of Earth and Mars are aligned just right, so it's possible to send a spacecraft from here to there. That special time is now.

Scientists in California think they've figure out why flies like beer. That may sound a bit trivial, but in fact it could lead to new ways of combating plant and animal pests.

That flies like beer is well known. "The attraction of flies to beer was first reported in the early 1920s," says Anupama Dahanukar. She's part of an inter-disciplinary program involving neuroscience and entomology at the University of California, Riverside. She's been studying how flies recognize chemicals, so answering the question of why flies like beer is actually quite relevant to her research.

People get very riled up about foie gras, the fatty liver of ducks and geese.

Some are bothered by the force feedings the ducks and geese undergo to produce those fatty livers, which are 6 to 10 times the normal size. Others fear the fat itself – although foie gras enthusiasts insist that the delicacy is "surprising low in bad fats, and high in good fats."

A controversy erupted earlier this year over who deserved credit for what many say is the most important astronomical discovery of the 20th century: the realization that the universe was expanding.

In 1929, American astronomer Edwin Hubble proposed that the more distant a galaxy is, the faster it appears to be receding from us, a concept that is known as Hubble's law.

Astronomer Mario Livio has worked with the Hubble Space Telescope for more than 20 years. "So clearly, anything Hubble is of interest to me," he says.

It doesn't happen often, but there are times when a single book turns the world on its head. Isaac Newton's Principia unraveled the mystery of gravity. Charles Darwin's On the Origin of Species explained how evolution worked.

But before either of these, there was On the Revolutions of the Heavenly Spheres by Nicolaus Copernicus. It was published in 1543. In it, Copernicus made the astounding claim that Earth revolves around the sun, not the other way around.

It's a huckster's dream: "Try the new Burmese Python Diet. No calorie counting or special foods. Eat whatever comes along, up to a quarter of your body weight. Not only is it good for your waistline; it's good for your heart."

Trouble is, what works in pythons probably won't work for humans.

Pythons employ what scientists call a "sit and wait foraging tactic." In other words, they lie around in a Burmese jungle and wait for the food to come to them. And of course, this can mean months between meals.

Richard Larrick has been bothered by something for two decades.

"Twenty years ago, I'd done a paper with some graduate students just showing that in hotter temperatures, pitchers are more likely to hit batters with pitches," says Larrick, a professor at the Fuqua School of Business at Duke University.

Was it because they would sweat more, and the ball might get slippery and hard to control? Or was it something intentional?

Researchers in New York are reporting an advance in creating cloned human embryos. The embryos would not be used for reproduction, but rather the creation of embryonic stem cells. Many scientists believe that human embryonic stem cells made this way could revolutionize medicine.

The advantage of stem cells made this way is that they could be personalized to an individual.

Astronomers are lining up to use a powerful new NASA telescope called SOFIA. The telescope has unique capabilities for studying things like how stars form and what's in the atmospheres of planets.

But unlike most of the space agency's telescopes, SOFIA isn't in space — it flies around mounted in a Boeing 747 jet with a large door cut on the side so the telescope can see out. Putting a telescope in space makes sense: There's no pesky atmosphere to make stars twinkle. But why put one on a plane?

Weird things jump out at me in press releases.

Take the press kit NASA prepared for the GRAIL mission. GRAIL consists of two nearly identical spacecraft that are on their way to the moon. Once there, they will make a precise map of the moon's gravitational field. Such a map will help scientists refine their theories about how the moon formed and what the interior is made of.