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.

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.

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.

Migratory songbirds like Swainson's thrushes spend their winters in South and Central America. But as spring approaches, they fly thousands of miles north to Canada.

Along the way, these little birds show endurance that would shame even the toughest athletes. They can fly for up to eight hours straight without stopping for food or water.

Scientists know how birds cope without food during the flights: They burn fat. But until now, they haven't figured out the water question. How do migrating birds avoid dehydration after all that flying?

In 1969, astronaut Alan Bean went to the moon as the lunar module pilot on Apollo 12. Although the trip going to the moon covered the same distance as the trip back, "returning from the moon seemed much shorter," Bean says.

People will often feel a return trip took less time than the same outbound journey, even though it didn't. In the case of Apollo 12, the trip back from the moon really did take somewhat less time. But the point remains that this so-called "return trip effect" is a very real psychological phenomenon, and now a new scientific study provides an explanation.

Scientists may have found a critical weakness in Plasmodium falciparum, the parasite that causes malaria. Researchers say the discovery provides a promising target for new malaria therapies.

Scientists in Australia are using a bacterium to try to stop a deadly virus in its tracks.

There's a revolution underway in biology. Scientists are coming to understand genetics isn't just about genes. Just as important are smaller sequences of DNA that control genes.

These so-called regulatory elements tell genes when to turn on and off, and when to stop functioning altogether. A new study suggests that changes in these non-gene sequences of DNA may hold the key to explaining how all species evolved.

A lot of simple things in science turn out to be quite complicated. Take, for example, coffee: you may have noticed that a spilled drop of coffee doesn't dry as a brown blob, but rather as a clear blob with a dark ring around the edge.

It's taken physicists more than a decade to figure out why this effect, known technically as "the coffee ring effect," happens. But now they think they have an answer.

Any time you report on promising but preliminary results about a new therapy for a lethal disease, you worry that you might be raising false hopes. So be warned: Although this is a "good news" story, it's preliminary. Don't expect to find it at a hospital near you any time soon.

Can the most modern of technologies help solve the health woes in the poorest countries in the world? Some biomedical engineers say yes. They are designing diagnostic laboratories that fit on something as small as a credit card, and give results in minutes instead of hours or days.

These devices are sometimes referred to as a "lab on a chip." To use them, all you need to do is obtain a drop of someone's blood.

NASA's space shuttle may be down for the count, but robotic planetary missions are up, up and away. Before the end of this year, three new solar system probes are due to launch.

Juno To Jupiter

Why Jupiter? Well it's big. "It's the largest of all the planets. In fact, it's got more material in it than all the rest of the solar system combined," says Scott Bolton, a planetary scientist at the Southwest Research Institute and principal investigator for the Juno mission.

Let's say you're a vampire bat, and you are trying to decide where to bite your victim. You want a spot rich in blood, right? But how do you find such a spot?

Turns out, vampire bats have a kind of remote sensing ability that can tell them where there is a warm patch of skin on a nearby animal. And a warm patch of skin means there are blood vessels just below the skin surface. And now scientists have identified the molecular basis for this remote sensing ability.

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