NPR/TED Staff

Earth may not be the only place in our solar system with life, says James Green. New data shows life might have existed on Mars, and could exist now. But what does that mean for us on Earth?

Stephen Petranek says, in the next decade, we will send humans to colonize Mars. He lays out the technology--from water-extraction to bricks made of Martian soil--that'll make life possible there.

Lucianne Walkowicz is all for space exploration, but says we shouldn't expect Mars to save us from a damaged Earth. She warns us not to lose sight of preserving the home we already have.

Fast fashion is wreaking havoc on the environment. That's why Jessi Arrington makes a point of (almost) never buying anything new. She explains how she builds a sustainable wardrobe that looks great.

Oysters filter water, their shells form protective reefs and habitats, and regenerate into more oyster shells. Kate Orff uses oysters to revive depleted ecosystems — like those around New York City.

Millions of tons of plastic flow into the ocean each year. David Katz's Plastic Bank helps turn off the tap — and gives the poor an income source — creating a circular economy around plastic waste.

We're often told that economic growth is good, but Kate Raworth says our addiction to growth is destroying the planet. To thrive in the 21st century, she says we need a new circular economic system.

Meklit Hadero hears joyful music everywhere: in laughter, nature, language, and even the sounds of cooking. She believes her job as a musician is to uncover joy and create music from it.

Simone Giertz is an inventor of useless robots. She finds joy and freedom in learning to build machines that are meant to fail. She shares that joy with millions through her YouTube channel.

Yuval Noah Harari says data is the new source of political power, and he worries that big data and AI technology threaten to destroy liberal democracy.

Extremist groups have co-opted the Internet's connective power to recruit members. Yasmin Green explores how the Internet has allowed extremism to spread, and how technology can combat it.

Children's YouTube is full of addicting content for kids, which can lead users to disturbing and inappropriate videos. James Bridle explains how the Internet's profit structure drives this phenomenon.

Edward Tenner says we shouldn't fear technology's unintended consequences. He argues for taking the long view of history, and that human ingenuity often finds solutions to negative consequences.

When Kashmir Hill filled her home with smart devices, she knew they would collect massive amounts of her personal information. She wanted to understand: what's the ultimate cost of that data mining?

Often, people who don't understand the law or can't pay for lawyers end up being mistreated. Lawyer Vivek Maru calls for a global community of paralegals to place the law on the side of the people.

Brett Hennig says democracy — and the process of voting — is broken. To fix it, he has a radical suggestion: replacing politicians with a demographically representative selection of random citizens.

The bail system disproportionately impacts low-income people of color and pressures defendants into pleading guilty. But Robin Steinberg is implementing a plan to fix this--without waiting for reform.

Animals like chimpanzees are autonomous beings with rich emotional lives, says animal rights lawyer Steven Wise. He's working to get courts to recognize them as "legal persons" and grant them rights.

When we look around, it feels like we're seeing an objective reality. But neuroscientist Anil Seth says everything we perceive, from objects to emotions, is an act of informed guesswork by the brain.

In 2009, Drew Philp bought an abandoned house in Detroit and worked with neighbors to fix it up. He discovered the power of 'radical neighborliness' to rebuild his struggling neighborhood.