Joe Palca

For the past decade, scientists have been toying with the notion of encapsulating medicine in microscopic balls.

These so-called nanospheres could travel inside the body to hard-to-reach places, like the brain or the inside of a tumor. One problem researchers face is how to build these nanospheres, because you'd have to make them out of even smaller nanoparticles.

Tell people you're doing a story about the life spans of Korean eunuchs, the typical reaction is a giggle or a cringe.

But if you can overcome your visceral response to the topic, a study scientists in Korea did is quite interesting, both for what they found, and the way they found it.

Several scientists have shown that there is a link between longevity and reproduction: the greater the fertility, the shorter the life span. This has been fairly well established in nonhuman animal species, but proving it's the case for humans has been tricky.

At this point it's just an interesting hypothesis, but it's possible that understanding cat coloration could help scientists understand resistance to infectious diseases.

It's human nature to hope for positive results after spending months or even years conducting a research study. In well-designed studies, however, scientists identify in advance the criteria for success, so their optimism won't color their conclusions when the study is completed.

A man is not a mollusk, and many men probably think that's a good thing. And it's not just because a mollusk is a squishy invertebrate with a shell. It's also because for at least one species of mollusk, the males do all the heavy lifting when it comes to childcare.

The species of mollusk we're talking about is Solenosteira macrospira, a marine snail about 2 inches long. These snails live off the coast of Baja California, and during the mating season, the beach is awash with male and female snails in connubial bliss.

Scientists in Germany have been able to get enough DNA from a fossilized pinky to produce a high-quality DNA sequence of the pinky's owner.

"It's a really amazing-quality genome," says David Reich of Harvard Medical School in Boston. "It's as good as modern human genome sequences, from a lot of ways of measuring it."

The pinky belonged to a girl who lived tens of thousands of years ago. Scientists aren't sure about the exact age. She is a member of an extinct group of humans called Denisovans. The name comes from Denisova cave in Siberia, where the pinky was found.

You may not be familiar with the name Roger Angel, but if there were ever a scientist with a creative streak a mile wide, it would be he.

Angel is an astronomer. He's famous for developing an entirely new way of making really large, incredibly precise telescope mirrors. But his creativity doesn't stop there. He's now turned his attention to solar power, hoping to use the tricks he learned from capturing distant light from stars to do a more cost-efficient job of capturing light from the Sun.

NPR science correspondent Joe Palca is on a mission this summer to answer the deep, burning questions of summertime. So far he's taught us how to build a campfire, explained the best way to roast a perfect marshmallow and explored the icy mystery of brain freeze.

The Mars rover Curiosity is beginning its fifth day on the red planet, and it's been performing flawlessly from the moment it landed.

That's been especially gratifying for NASA landing engineer Adam Steltzner. Last Friday, while Steltzner was still on pins and needles waiting for the landing to take place, I told the story of Steltzner's decision as a young man to give up his life as a rocker and go for a career in space engineering.

The newsroom at NASA's Jet Propulsion Laboratory is beginning to thin out as the Mars Science Laboratory transitions from an exciting news story, to a long duration — possibly very long duration — exploration of the geologic and environmental history of Mars.

For the reporters still in the newsroom, fatigue is beginning to set in. BBC science correspondent Jonathan Amos has been at it nonstop for 30 hours. I feel a bit guilty for stepping out and getting a few hours sleep.

Joe Palca describes the mood of NASA Mars scientists in the wake of the landing overnight, what the latest pictures and data are from the surface of the red planet and what mission scientists are going to do next with Curiosity.

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STEVE INSKEEP, HOST:

It's MORNING EDITION from NPR News. I'm Steve Inskeep.

They were pretty cheerful at NASA this morning after an unmanned vehicle set down on the surface of Mars.

JOHN HOLDREN: If anybody has been harboring doubts about the status of U.S. leadership in space, well, there's a one ton automobile-size piece of American ingenuity...

(SOUNDBITE OF CHEERING AND APPALUSE)

HOLDREN: ...and it's sitting on the surface of Mars right now, and it should certainly put any such doubts to rest.

NASA has sent rovers to explore Mars before. But three words explain what makes this latest mission to Mars so different: location, location, location.

The rover Curiosity is slated to land late Sunday in Gale Crater, near the base of a 3-mile-high mountain with layers like the Grand Canyon. Scientists think those rocks could harbor secrets about the history of water — and life — on the Red Planet.

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SUSAN STAMBERG, HOST:

These are tense times for scientists and engineers at NASA's Jet Propulsion Lab in Pasadena. Late Sunday night Pacific Time, they'll learn if nearly a decade of hard work will result in a priceless scientific laboratory landing safely on Mars or if the rover known as Curiosity will turn into a useless pile of junk. Everything depends on what happens during the seven minutes of terror, the time it takes the probe to go from the top of the Martian atmosphere to the planet's surface.

The cool weather in London is good news for the Olympic athletes because their bodies won't need to put as much energy into cooling off.

But most of us aren't lucky enough to be headed to London, and we could use some help keeping cool.

When you get hot you sweat — but it's not enough to just sweat. To cool off, you need that sweat to evaporate. It's evaporation that drains the heat from your body.

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STEVE INSKEEP, HOST:

We're remembering this morning the first American woman to go into space: Sally Ride. She died yesterday in San Diego. Ride made her historic trip into space in 1983 aboard the space shuttle Challenger, a trip that made her an instant folk hero. NPR's Joe Palca has our report.

JOE PALCA, BYLINE: Sally Ride was born on May 26th, 1951. She grew up in the San Fernando Valley, just outside Los Angeles, where she went to Westlake High School.

SUSAN OKIE: She prided herself on being an underachiever.

Hot tea on a hot day? Not for me, thank you. Not my idea of how to cool down.