Nell Greenfieldboyce

Nell Greenfieldboyce is a NPR science correspondent.

With reporting focused on general science, NASA, and the intersection between technology and society, Greenfieldboyce has been on the science desk's technology beat since she joined NPR in 2005.

In that time Greenfieldboyce has reported on topics including the narwhals in Greenland, the ending of the space shuttle program, and the reasons why independent truckers don't want electronic tracking in their cabs.

Much of Greenfieldboyce's reporting reflects an interest in discovering how applied science and technology connects with people and culture. She has worked on stories spanning issues such as pet cloning, gene therapy, ballistics, and federal regulation of new technology.

Prior to NPR, Greenfieldboyce spent a decade working in print, mostly magazines including U.S. News & World Report and New Scientist.

A graduate of Johns Hopkins, earning her Bachelor's of Arts degree in social sciences and a Master's of Arts degree in science writing, Greenfieldboyce taught science writing for four years at the university. She was honored for her talents with the Evert Clark/Seth Payne Award for Young Science Journalists.

Everyone knows that caffeine can keep you awake, but a new study shows that the world's most popular drug can actually interfere with your body's internal sense of time.

"The circadian clock is way beyond 'sleep and wake,' " says Kenneth Wright, a sleep and circadian physiologist at the University of Colorado, Boulder. "The circadian clock is present in cells throughout our entire body. It's in your fat cells; it's in your muscle cells. It's in your liver, for example, as well as in your brain."

Scientists today laid out a truly worst-case scenario for global warming — what would happen if we burned the Earth's entire supply of fossil fuels.

Virtually all of Antarctica's ice would melt, leading to a 160- to 200-foot sea level rise.

"If we burn it all, we're going to melt it all," says Ken Caldeira, a climate scientist at the Carnegie Institution for Science.

Scientists have discovered the fossilized remains of an unusual human-like creature that lived long ago. Exactly how long ago is still a mystery — and that's not the only mystery surrounding this newfound species.

The bones have a strange mix of primitive and modern features, and were found in an even stranger place — an almost inaccessible chamber deep inside a South African cave called Rising Star.

Cellphone records could help epidemiologists predict which cities and towns might be hit next by dengue, the most rapidly spreading mosquito-borne disease in the world.

That's because cellphone records let scientists track how people actually move around, says Amy Wesolowski, a researcher who models epidemics at the Harvard T.H. Chan School of Public Health in Boston.

Here is a pop quiz: How many trees are on the planet?

Most people have no idea.

A new study says the answer is more than 3 trillion trees — that's trillion with a T, and that number is about eight times more than a previous estimate.

It seems to be part of human nature to want to belong to a group. People constantly form groups, in all kinds of situations, and high-stakes negotiations on climate change are no exception.

Ever heard of the Umbrella Group? Or the Like-Minded Developing Countries? How about the Group of 77? (Here's a hint — it doesn't actually have 77 countries.)

Picking a mate can be one of life's most important decisions. But sometimes people make a choice that seems to make no sense at all. And humans aren't the only ones — scientists have now seen apparently irrational romantic decisions in frogs.

Little tungara frogs live in Central America, and they're found everywhere from forests to ditches to parking lot puddles. These frogs are only about 2 centimeters long, but they are loud. The males make calls to woo the females.

For wildlife biologists, unmanned aerial vehicles are like a dream come true.

Instead of struggling through rugged, difficult terrain to get to the animal they want to study, they can just send in a drone with a camera.

And as drones get cheaper and more available, everyone in biology seems to have new ideas for how to use them, says Mark Ditmer, a wildlife ecologist at the University of Minnesota, St. Paul.

But how do the animals feel about these little UFOs hovering overhead?

Scientists have just sequenced the first genome of an octopus, and it was no trivial task.

"The octopus has a very large genome. It's nearly the size of the human genome," says Carrie Albertin, a biologist at the University of Chicago.

As technology to sequence DNA has gotten faster and cheaper, scientists have unraveled the genes of all kinds of creatures. But until now, no one had done an octopus — despite its obvious appeal as one of the weirdest animals on Earth.

Take a close look at a house cat's eyes and you'll see pupils that look like vertical slits. But a tiger has round pupils — like humans do. And the eyes of other animals, like goats and horses, have slits that are horizontal.

Scientists have now done the first comprehensive study of these three kinds of pupils. The shape of the animal's pupil, it turns out, is closely related to the animal's size and whether it's a predator or prey.