5 487 168

Stephen Hawking asks big questions about the universe

In keeping with the theme of TED2008, professor Stephen Hawking asks some Big Questions about our universe -- How did the universe begin? How did life begin? Are we alone? -- and discusses how we might go about answering them.
2 114 673

Big history

Backed by stunning illustrations, David Christian narrates a complete history of the universe, from the Big Bang to the Internet, in a riveting 18 minutes. This is "Big History": an enlightening, wide-angle look at complexity, life and humanity, set against our slim share of the cosmic timeline.
1 310 840

Making sense of string theory

Physicist Brian Greene explains superstring theory, the idea that minscule strands of energy vibrating in 11 dimensions create every particle and force in the universe.
871 890

Is our universe the only universe?

Is there more than one universe? In this visually rich, action-packed talk, Brian Greene shows how the unanswered questions of physics (starting with a big one: What caused the Big Bang?) have led to the theory that our own universe is just one of many in the "multiverse."
374 846

Why our universe might exist on a knife-edge

The biggest surprise of discovering the Higgs boson? That there were no surprises. Gian Giudice talks us through a problem in theoretical physics: what if the Higgs field exists in an ultra-dense state that could mean the collapse of all atomic matter? With wit and charm, Giudice outlines a grim fate -- and why we shouldn't start worrying just yet. (Filmed at
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308 524

Is this our final century?

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.
168 501

What we can learn from galaxies far, far away

In a fun, exciting talk, teenager Henry Lin looks at something unexpected in the sky: distant galaxy clusters. By studying the properties of the universe's largest pieces, says the Intel Science Fair award winner, we can learn quite a lot about scientific mysteries in our own world and galaxy.
154 005

The discovery that could rewrite physics

On March 17, 2014, a group of physicists announced a thrilling discovery: the “smoking gun” data for the idea of an inflationary universe, a clue to the Big Bang. For non-physicists, what does it mean? TED asked Allan Adams to briefly explain the results, in this improvised talk illustrated by Randall Munroe of xkcd.
142 079

Distant time and the hint of a multiverse

At TEDxCaltech, cosmologist Sean Carroll attacks -- in an entertaining and thought-provoking tour through the nature of time and the universe -- a deceptively simple question: Why does time exist at all? The potential answers point to a surprising view of the nature of the universe, and our place in it.
127 725

Jill Tarter's call to join the SETI search

The SETI Institute's Jill Tarter makes her TED Prize wish: to accelerate our search for cosmic company. Using a growing array of radio telescopes, she and her team listen for patterns that may be a sign of intelligence elsewhere in the universe.
116 380

Let's not use Mars as a backup planet

Stellar astronomer and TED Senior Fellow Lucianne Walkowicz works on NASA's Kepler mission, searching for places in the universe that could support life. So it's worth a listen when she asks us to think carefully about Mars. In this short talk, she suggests that we stop dreaming of Mars as a place that we'll eventually move to when we've messed up Earth, and to start
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102 473

Symmetry, reality's riddle

The world turns on symmetry -- from the spin of subatomic particles to the dizzying beauty of an arabesque. But there's more to it than meets the eye. Here, Oxford mathematician Marcus du Sautoy offers a glimpse of the invisible numbers that marry all symmetrical objects.
102 268

Chemical scum that dream of distant quasars

Legendary scientist David Deutsch puts theoretical physics on the back burner to discuss a more urgent matter: the survival of our species. The first step toward solving global warming, he says, is to admit that we have a problem.
100 837

How we found hundreds of potential Earth-like planets

Astronomer Dimitar Sasselov and his colleagues search for Earth-like planets that may, someday, help us answer centuries-old questions about the origin and existence of biological life elsewhere (and on Earth). Preliminary results show that they have found 706 "candidates" -- some of which further research may prove to be planets with Earth-like geochemical
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89 012

Roy Gould and Curtis Wong preview the WorldWide Telescope

Educator Roy Gould and researcher Curtis Wong show a sneak preview of Microsoft’s WorldWide Telescope, which compiles images from telescopes and satellites to build a comprehensive, interactive view of our universe.
88 732

The sound the universe makes

We think of space as a silent place. But physicist Janna Levin says the universe has a soundtrack -- a sonic composition that records some of the most dramatic events in outer space. (Black holes, for instance, bang on spacetime like a drum.) An accessible and mind-expanding soundwalk through the universe.
84 025

What time is it on Mars?

Nagin Cox is a first-generation Martian. As a spacecraft engineer at NASA's Jet Propulsion Laboratory, Cox works on the team that manages the United States' rovers on Mars. But working a 9-to-5 on another planet whose day is 40 minutes longer than Earth's has particular, often comical challenges.
79 211

Peter Diamandis on Stephen Hawking in zero g

X Prize founder Peter Diamandis talks about how he helped Stephen Hawking fulfill his dream of going to space -- by flying together into the upper atmosphere and experiencing weightlessness at zero g.
72 442

This new telescope might show us the beginning of the universe

When and how did the universe begin? A global group of astronomers wants to answer that question by peering as far back in time as a large new telescope will let us see. Wendy Freedman headed the creation of the Giant Magellan Telescope, under construction in South America; at TEDGlobal in Rio, she shares a bold vision of the discoveries about our universe that the
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71 907

A sci-fi vision of love from a 318-year-old hologram

Science fiction writer Monica Byrne imagines rich worlds populated with characters who defy our racial, social and gender stereotypes. In this performance, Byrne appears as a hologram named Pilar, transmitting a story of love and loss back to us from a near future when humans have colonized the universe. "It's always funny what you think the future is going to be like
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70 571

Let's look for life in the outer solar system

Physicist Freeman Dyson suggests that we start looking for life on the moons of Jupiter and out past Neptune, in the Kuiper belt and the Oort cloud. He talks about what such life would be like -- and how we might find it.
64 687

The caves and the moon

Bill Stone, a maverick cave explorer who has plumbed Earth’s deepest abysses, discusses his efforts to mine lunar ice for space fuel and to build an autonomous robot for studying Jupiter’s moon Europa.
64 585

Shedding light on dark matter

Physicist Patricia Burchat sheds light on two basic ingredients of our universe: dark matter and dark energy. Comprising 96% of the universe between them, they can't be directly measured, but their influence is immense.
56 456

How radio telescopes show us unseen galaxies

Our universe is strange, wonderful and vast, says astronomer Natasha Hurley-Walker. A spaceship can't carry you into its depths (yet) but a radio telescope can. In this mesmerizing talk, Hurley-Walker shows how she probes the mysteries of the universe using special technology that reveals light spectrums we can't see.
41 968

How spectroscopy could reveal alien life

Garik Israelian is a spectroscopist, studying the spectrum emitted by a star to figure out what it's made of and how it might behave. It's a rare and accessible look at this discipline, which may be coming close to finding a planet friendly to life.
40 187

Finding planets around other stars

How do we find planets -- even habitable planets -- around other stars? By looking for tiny dimming as a planet passes in front of its sun, TED Fellow Lucianne Walkowicz and the Kepler mission have found some 1,200 potential new planetary systems. With new techniques, they may even find ones with the right conditions for life.
29 094

What it takes to do extreme astrophysics

All over the planet, giant telescopes and detectors are looking (and listening) for clues to the workings of the universe. At the INK Conference, science writer Anil Ananthaswamy tours us around these amazing installations, taking us to some of the most remote and silent places on Earth.
22 655

This is Saturn

Planetary scientist Carolyn Porco shows images from the Cassini voyage to Saturn, focusing on its largest moon, Titan, and on frozen Enceladus, which seems to shoot jets of ice.
8 290

Math is the hidden secret to understanding the world

Unlock the mysteries and inner workings of the world through one of the most imaginative art forms ever mathematics with Roger Antonsen, as he explains how a slight change in perspective can reveal patterns, numbers and formulas as the gateways to empathy and understanding.
1 048

3 moons and a planet that could have alien life

Is there life beyond Earth? Join NASA's director of planetary science James Green for a survey of the places in our solar system that are most likely to harbor alien life.

What the discovery of gravitational waves means

More than a billion years ago, two black holes in a distant galaxy locked into a spiral, falling inexorably toward each other, and collided. "All that energy was pumped into the fabric of time and space itself," says theoretical physicist Allan Adams, "making the universe explode in roiling waves of gravity." About 25 years ago, a group of scientists built a giant
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What a planet needs to sustain life

"Venus is too hot, Mars is too cold, and Earth is just right," says planetary scientist Dave Brain. But why? In this pleasantly humorous talk, Brain explores the fascinating science behind what it takes for a planet to host life and why humanity may just be in the right place at the right time when it comes to the timeline of life-sustaining planets.

How we'll find life on other planets

Astronomer Aomawa Shields searches for clues that life might exist elsewhere in the universe by examining the atmospheres of distant exoplanets. When she isn't exploring the heavens, the classically trained actor (and TED Fellow) looks for ways to engage young women in the sciences using theater, writing and visual art. "Maybe one day they'll join the ranks of
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The untapped genius that could change science for the better

Jedidah Isler dreamt of becoming an astrophysicist since she was a young girl, but the odds were against her: At that time, only 18 black women in the United States had ever earned a PhD in a physics-related discipline. In this personal talk, she shares the story of how she became the first black woman to earn a PhD in astrophysics from Yale and her deep belief in
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Why Earth may someday look like Mars

Every minute, 400 pounds of hydrogen and almost 7 pounds of helium escape from Earth's atmosphere into outer space. Astrophysicist Anjali Tripathi studies the phenomenon of atmospheric escape, and in this fascinating and accessible talk, she considers how this process might one day (a few billion years from now) turn our blue planet red.