When we hear the word radiation, it's tempting to picture huge explosions and frightening mutations. But that's not the full story — radiation also applies to rainbows and a doctor examining an X-ray. So what is it, really, and how much should we worry about its effects? Matt Anticole describes the different types of radiation. [Directed by Tinm...

At the center of a galaxy more than 55 million light-years away, there's a supermassive black hole with the mass of several billion suns. And now, for the first time ever, we can see it. Astrophysicist Sheperd Doeleman, head of the Event Horizon Telescope collaboration, speaks with TED's Chris Anderson about the iconic, first-ever image of a bla...

As the year 1905 began, Albert Einstein faced life as a "failed" academic. Yet within the next twelve months, he would publish four extraordinary papers, each on a different topic, that were destined to radically transform our understanding of the universe. Larry Lagerstrom details these four groundbreaking papers. [Directed by Oxbow Creative, n...

When radium was first discovered, its luminous green color inspired people to add it into beauty products and jewelry. It wasn't until much later that we realized that radium's harmful effects outweighed its visual benefits. Unfortunately, radium isn't the only pigment that historically seemed harmless or useful but turned out to be deadly. J. V...

The universe began in a Big Bang nearly fourteen billion years ago, and has been expanding ever since. But how does the universe expand and what is it expanding into? Sajan Saini explains the existing theories around the Big Bang and what, if anything, lies beyond our universe. [TED-Ed Animation by Wooden Plane Productions]

Julian Treasure says our increasingly noisy world is gnawing away at our mental health -- even costing lives. He lays out an 8-step plan to soften this sonic assault (starting with those cheap earbuds) and restore our relationship with sound.

Speaking as both an astronomer and "a concerned member of the human race," Sir Martin Rees examines our planet and its future from a cosmic perspective. He urges action to prevent dark consequences from our scientific and technological development.

How does a robin know to fly south? The answer might be weirder than you think: Quantum physics may be involved. Jim Al-Khalili rounds up the extremely new, extremely strange world of quantum biology, where something Einstein once called "spooky action at a distance" helps birds navigate, and quantum effects might explain the origin of life itself.

There's an irony behind the latest efforts to extend human life: It's no picnic to be an old person in a youth-oriented society. Older people can become isolated, lacking meaningful work and low on funds. In this intriguing talk, Jared Diamond looks at how many different societies treat their elders -- some better, some worse -- and suggests we ...

What does it take to build a national movement? In a captivating conversation with TEDWomen curator Pat Mitchell, Marian Wright Edelman reflects on her path to founding the Children's Defense Fund in 1973 -- from the early influence of growing up in the segregated American South to her activism with Dr. Martin Luther King Jr. -- and shares how g...

In 2007, Paul Rothemund gave TED a short summary of his specialty, DNA folding. Now he lays out in clear, abundant detail the immense promise of this field -- to create tiny machines that assemble themselves.

Paola Antonelli, design curator at New York's Museum of Modern Art, wants to spread her appreciation of design -- in all shapes and forms -- around the world.

More than 100 years after Albert Einstein predicted gravitational waves -- ripples in space-time caused by violent cosmic collisions -- LIGO scientists confirmed their existence using large, extremely precise detectors in Louisiana and Washington. Astrophysicist Gabriela González of the LIGO Scientific Collaboration tells us how this incredible,...

Lighting up the TED stage, Nobel laureate Al Gore takes stock of the current state of climate progress and calls attention to institutions that have failed to honor their promises by continuing to pour money into polluting sectors. He explains how the financial interests of fossil fuel companies have blocked the policymaking process in key count...

How exactly does gender work? It's not just about our chromosomes, says biologist Karissa Sanbonmatsu. In a visionary talk, she shares new discoveries from epigenetics, the emerging study of how DNA activity can permanently change based on social factors like trauma or diet. Learn how life experiences shape the way genes are expressed -- and wha...

In a mind-bending talk that blurs the line between science and art, Tomás Saraceno exhibits a series of air-inspired sculptures and installations designed to usher in a new era of sustainability, the "Aerocene." From giant, cloud-like playgrounds suspended 22 meters in the air to a balloon sculpture that travels the world without burning a singl...

What if tiny microparticles could help us solve the world's biggest problems in a matter of minutes? That's the promise -- and magic -- of quantum computers, says Matt Langione. Speaking next to an actual IBM quantum computer, he explains how these machines solve complex challenges like developing vaccines and calculating financial risk in an en...

Brute computing force alone can't solve the world's problems. Data mining innovator Shyam Sankar explains why solving big problems (like catching terrorists or identifying huge hidden trends) is not a question of finding the right algorithm, but rather the right symbiotic relationship between computation and human creativity.

Top climate scientist James Hansen tells the story of his involvement in the science of and debate over global climate change. In doing so he outlines the overwhelming evidence that change is happening and why that makes him deeply worried about the future.

Big Data is everywhere — even the skies. In an informative talk, astronomer Andrew Connolly shows how large amounts of data are being collected about our universe, recording it in its ever-changing moods. Just how do scientists capture so many images at scale? It starts with a giant telescope ...

At TEDIndia, Pranav Mistry demos several tools that help the physical world interact with the world of data -- including a deep look at his SixthSense device and a new, paradigm-shifting paper "laptop." In an onstage Q&A, Mistry says he'll open-source the software behind SixthSense, to open its possibilities to all.

In this absorbing look at emerging media and tech history, Peter Hirshberg shares some crucial lessons from Silicon Valley and explains why the web is so much more than "better TV."

¿Sabes que la velocidad de la luz es tan rápida, que si el sol estallará ahorita, nadie se daría cuenta hasta dentro de 8 minutos? Miguel Alcubierre, un físico teórico, comparte y explica en esta iluminante charla algunas de las teorías de la física que nos ayudan a conceptualizar nuestro entendimiento del tiempo y del espacio.

A net-zero future is possible, but first we need to flip a mental switch to truly understand that we can stop the climate crisis if we try, says Nobel laureate Al Gore. In this inspiring and essential talk, Gore shares examples of extreme climate events (think: fires, floods and atmospheric tsunamis), identifies the man-made systems holding us b...

Robert Wright uses evolutionary biology and game theory to explain why we appreciate the Golden Rule ("Do unto others..."), why we sometimes ignore it and why there’s hope that, in the near future, we might all have the compassion to follow it.

In tough economic times, our exploratory science programs -- from space probes to the LHC -- are first to suffer budget cuts. Brian Cox explains how curiosity-driven science pays for itself, powering innovation and a profound appreciation of our existence.

We've known about global warming for 50 years and done little about it, says Google.org director Larry Brilliant. In spite of this and other depressing trends, he's optimistic and tells us why. From Skoll World Forum, Oxford, UK, www.skollfoundation.org

At the heart of the Milky Way, there's a supermassive black hole that feeds off a spinning disk of hot gas, sucking up anything that ventures too close -- even light. We can't see it, but its event horizon casts a shadow, and an image of that shadow could help answer some important questions about the universe. Scientists used to think that maki...

Jane Poynter tells her story of living two years and 20 minutes in Biosphere 2 -- an experience that provoked her to explore how we might sustain life in the harshest of environments.

At the 2007 EG conference, Kevin Kelly shares a fun stat: The World Wide Web, as we know it, is only 5,000 days old. Now, Kelly asks, how can we predict what's coming in the next 5,000 days?