Joe Palca

When Neil Armstrong set foot on the moon 50 years ago, it was an inspiring moment for people around the world.

But another kind of explorer is responsible for much of the modern enthusiasm for space exploration.

"Since the days of Apollo, the greatest adventures in space have been these robots that have gone all over the solar system," says Emily Lakdawalla, a self-described planetary evangelist at the Planetary Society.

MARY LOUISE KELLY, HOST:

The path of a total solar eclipse passed over a major observatory in Chile this afternoon. NPR science correspondent Joe Palca was there. He saw the eclipse from the Cerro Tololo Inter-American Observatory from where he joins us now live.

Hey, Joe.

JOE PALCA, BYLINE: Hey, Mary Louise. How are you doing?

KELLY: I'm well. Thank you. And I'm thinking, I have actually - I have seen a couple of total solar eclipses. I have never seen one from an observatory, which I'm guessing is a pretty darn good place to see one.

RACHEL MARTIN, HOST:

Later today, an eclipse will sweep across the Pacific Ocean and then pass over parts of Chile and Argentina. One thing that makes this eclipse special is that it's going to pass directly over a major observatory in Chile. And you know who is there right now at that observatory? Our own Joe Palca.

Hi, Joe.

JOE PALCA, BYLINE: Hi there, Rachel. How are you?

MARTIN: I'm well. I'm going to try to pronounce this - the observatory is called Cerro Tololo, correct?

PALCA: That's right. It's the Cerro Tololo Inter-American Observatory.

Updated July 2 at 9 a.m. ET

Billions of fish in the Pacific Ocean will be treated to an awe-inspiring celestial event today. That's because a total solar eclipse will be visible over a huge swath of the southern Pacific.

Land animals including humans in Chile and Argentina will also get to observe the total spectacle, as will anybody connected to the Internet. And most parts of South America will be able to see a partial eclipse.

RACHEL MARTIN, HOST:

There's a mole stuck in the ground on Mars - not the small, furry animal but a probe on NASA's Mars InSight lander called the mole. It's a probe that was supposed to go 15 feet beneath the Martian surface, but it got stuck after only going one.

NPR's Joe Palca has more.

It's easy to take corned beef sandwiches for granted. There's no mystery about them. They simply exist.

But corned beef sandwiches, along with everything else in the universe, raise a critical question in the minds of physicists: Why do they exist?

In the earliest moments of the universe, energy turned into matter. But matter comes in two forms, matter and antimatter. And when a particle of matter encounters a particle of antimatter, they annihilate each other — and all you're left with is light.

MARY LOUISE KELLY, HOST:

NASA has a frequent flyer program that's out of this world - literally. People who sign up to send their names to Mars on the next rover mission will earn 313,586,649 award miles from the space agency. NPR science correspondent Joe Palca has details.

Small drones can do big jobs: Firefighters can use them to find hot spots in blazes, environmental monitors can find the source of hazardous chemical leaks. One just delivered a human kidney for transplant surgery.

But it takes lots of power to spin four helicopter blades fast enough to keep a quadcopter-type drone in the air. Most can only stay aloft for about 30 minutes.

ARI SHAPIRO, HOST:

A NASA probe on Mars is hearing things. And in this case, that's good news. The lander called InSight is supposed to listen for marsquakes, the Martian equivalent of earthquakes. Now it's heard one maybe. NPR's Joe Palca has more.

ARI SHAPIRO, HOST:

People who vacation in Hawaii often go for the beautiful beaches and lush rainforests. NPR science correspondent Joe Palca recently stumbled across an unexpected attraction in the town of Princeville. It's on the north side of the island of Kauai. Joe sent us this postcard.

JOE PALCA, BYLINE: This is just hilarious. You drive past the golf course, down a subdivision to a dead end and you look in people's backyards. And you see albatross.

CATHY GRANHOLM: Yeah. I have a little melodrama going on in my yard.

A team of astronomers led by an undergraduate student in Texas has discovered two planets orbiting stars more than 1,200 light-years from Earth.

Astronomers already knew of about 4,000 exoplanets, so finding two more might not seem like huge news. But it's who found them and how that's getting attention.

Is there an efficient way to tinker with the genes of plants? Being able to do that would make breeding new varieties of crop plants faster and easier, but figuring out exactly how to do it has stumped plant scientists for decades.

Now researchers may have cracked it.

Modifying the genetics of a plant requires getting DNA into its cells. That's fairly easy to do with animal cells, but with plants it's a different matter.

Opportunity lost.

NASA has officially declared an end to the mission of the six-wheeled rover on Mars. Opportunity lost power in a dust storm last June, and all efforts to make contact have failed.

"Our beloved Opportunity remained silent," Thomas Zurbuchen, associate administrator for NASA's Science Mission Directorate, said Wednesday at NASA's Jet Propulsion Laboratory in Pasadena, Calif. "With a sense of deep appreciation and gratitude," he added, "I declare the Opportunity mission as complete."

Many vaccines and some medicines, such as insulin, have to be delivered by injection. That's a pain, both for patients and for health care providers. But two groups of researchers are trying to put some of these medications in pill form to avoid the needle.

Scientists have evidence that a mountain 3 miles tall, in the middle of a crater on Mars, may be made largely from dust and sand.

To get the data for that surprising conclusion, the researchers MacGyvered a navigation instrument on the NASA rover Curiosity, and turned it into a scientific instrument.

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