David Kestenbaum

David Kestenbaum is a correspondent for NPR, covering science, energy issues and, most recently, the global economy for NPR's multimedia project Planet Money. David has been a science correspondent for NPR since 1999. He came to journalism the usual way — by getting a Ph.D. in physics first.

In his years at NPR, David has covered science's discoveries and its darker side, including the Northeast blackout, the anthrax attacks and the collapse of the New Orleans levees. He has also reported on energy issues, particularly nuclear and climate change.

David has won awards from the American Association for the Advancement of Science, the American Physical Society and the Institute of Electrical and Electronics Engineers.

David worked briefly on the show This American Life, and set up a radio journalism program in Cambodia on a Fulbright fellowship. He also teaches a journalism class at Johns Hopkins University.

David holds a bachelor's of science degree in physics from Yale University and a doctorate in physics from Harvard University.

What would happen if Congress doesn't raise the debt ceiling and the U.S. defaults on its debt later this month? The broad economic implications are unpredictable, but a default could cause huge trouble for the global economy.

But whatever happens to the global economy, one thing is clear: People all over the world who have loaned the U.S. government money won't get paid on time.

Tuesday is a big day for Obamacare. The online marketplaces where people can shop for health insurance are supposed to open for business.

No one really knows who is going to sign up — not the Obama administration, not the insurance industry, not the president's critics. Yet the success of the law hangs on this question: Will the right mix of people sign up? In particular, will healthy people buy health insurance?

The government of Ecuador has abandoned a plan that would have kept part of the Amazonian rainforest off limits to oil drilling. The initiative was an unusual one: Ecuador was promising to keep the oil in the ground, but it wanted to be paid for doing so.

For more of our reporting on this story, please see our recent column in the New York Times Magazine, and the latest episode of This American Life.

Why does anyone buy Bayer aspirin — or Tylenol, or Advil — when, almost always, there's a bottle of cheaper generic pills, with the same active ingredient, sitting right next to the brand-name pills?

Matthew Gentzkow, an economist at the University of Chicago's Booth school, recently tried to answer this question. Along with a few colleagues, Gentzkow set out to test a hypothesis: Maybe people buy the brand-name pills because they just don't know that the generic version is basically the same thing.

Climate change seems like this complicated problem with a million pieces. But Henry Jacoby, an economist at MIT's business school, says there's really just one thing you need to do to solve the problem: Tax carbon emissions.

"If you let the economists write the legislation," Jacoby says, "it could be quite simple." He says he could fit the whole bill on one page.

Basically, Jacoby would tax fossil fuels in proportion to the amount of carbon they release. That would make coal, oil and natural gas more expensive. That's it; that's the whole plan.

In many parts of the developing world, drinking a glass of water can be deadly — especially for young children, who can die of diarrheal diseases contracted from dirty water.

So getting clean water to people in the developing world has been a top priority for aid groups for a long time. But it's been a surprisingly hard problem to solve.

Over the past decade, some 39,000 people have come forward voluntarily to tell the IRS about offshore money they haven't been paying taxes on. This group provides a small window into the world of people who are hiding money in offshore havens. (It's a world we've been trying to learn more about, partly by setting up an offshore company in Belize.)

I spoke yesterday with Dan Sichel, a Wellesley economist and a Lady Gaga fan. Both of these facts are relevant for this story.

The U.S. government is about to tweak the way it measures the economy, and some of the biggest changes will affect the entertainment industry.

Under the current system, Sichel told me, Lady Gaga's sales of concert tickets, online songs and CDs all count toward gross domestic product. But the value of the time she spends in the studio working on new songs isn't counted. That's about to change.