The answer is satellites, stars, planets, asteroids and maybe even aliens.

Aliens have invaded ancient history: they've cropped up in humanity's past through popular television and movies, displacing facts with absurd yet commonplace beliefs like "aliens built the pyramids." Archaeologist Sarah Kurnick illustrates why these misconceptions perpetuate racist and xenophobic notions of history and culture -- and demonstrat...

Imagine a life living among the stars, traversing the universe, interacting with aliens ...

Humorist John Hodgman rambles through a new story about aliens, physics, time, space and the way all of these somehow contribute to a sweet, perfect memory of falling in love.

Astrophysicist and TED Fellow Sarah Rugheimer searches for aliens -- but not the cartoony green kind. She's looking for extraterrestrial microbes by studying how these single-celled organisms emit gases, which could reveal evidence of them throughout the cosmos. Wondering if we're really alone in the universe, Rugheimer identifies two big hurdle...

The universe is incredibly old, astoundingly vast and populated by trillions of planets -- so where are all the aliens? Astronomer Stephen Webb has an explanation: we're alone in the universe. In a mind-expanding talk, he spells out the remarkable barriers a planet would need to clear in order to host an extraterrestrial civilization -- and make...

Why have we not yet found proof of alien life? According to astrophysicist Avi Loeb, we simply haven't dedicated the proper resources. Diving into unidentified phenomena such as the Oumuamua asteroid, he explores his scientific search for extraterrestrial technology, envisioning a future where a higher interstellar intelligence helps us improve ...

What's out there waiting to make contact?

Stand by for an animated exploration of the famous Fermi Paradox. Given the vast number of planets in the universe, many much older than Earth, why haven't we yet seen obvious signs of alien life? The potential answers to this question are numerous and intriguing, alarming and hopeful. [Directed by Andrew Park, narrated by Chris Anderson].

Could there be intelligent life on other planets? This question has piqued imagination and curiosity for decades. Explore the answer with the Drake Equation -- a mathematical formula that calculates the possibility of undiscovered life. [Directed by Jeremiah Dickey, narrated by Jill Tarter].

Today is the anniversary of the best-worst day of your life. The best part was discovering a subterranean city on Mars. The worst part was when you lost contact with Earth. You and the other 99 scientists have spent the year engineering your survival, but you're almost out of water and solutions. Can you figure out how the last civilization live...

Is there alien life out there? After decades of hoaxes, sci-fi speculation, and government hearings, the evidence has come up short. But according to astronomer Dr. Beatriz Villarroel, it may be that we’re looking for the wrong signs. Here, she shares her team’s latest discoveries and argues that the search for alien artifacts may not be futile.

James Cameron's big-budget (and even bigger-grossing) films create unreal worlds all their own. In this personal talk, he reveals his childhood fascination with the fantastic -- from reading science fiction to deep-sea diving -- and how it ultimately drove the success of his blockbuster hits "Aliens," "The Terminator," "Titanic" and "Avatar."

The "aliens" of Earth live in the deepest parts of the ocean, and marine biologist Alan Jamieson has the photographs to prove it. Explore the depths with Jamieson as he challenges what you may believe (or have been told) really lies waiting in the world's darkest, most remote waters. A fascinating, bizarre and surprisingly peaceful dive into the...

Imagine aliens land on Earth a million years from now. What will these curious searchers find of us? They will find what geologists, scientists, and other experts are increasingly calling the Anthropocene, or new age of mankind. David Biello explains how the impacts that humans have made have become so pervasive, profound, and permanent that som...

The fact that no one knows the answer to this question is what makes it exciting. The story of physics has been one of an ever-expanding understanding of the sheer scale of reality, to the point where physicists are now postulating that there may be far more universes than just our own. Chris Anderson explores the thrilling implications of this ...

We all love parsing the twists and folds of a good old-fashioned mystery -- of all kinds.

You and nine other individuals have been captured by super-intelligent alien overlords. The aliens think humans look quite tasty, but their civilization forbids eating highly logical and cooperative beings. Unfortunately, they're not sure whether you qualify, so they decide to give you all a test. Can you solve this hat riddle? Alex Gendler show...

Much science fiction features white male heroes who blast aliens or become saviors of brown people. Octavia E. Butler knew she could tell a better story. She built stunning worlds rife with diverse characters, and brought nuance and depth to the representation of their experiences. Ayana Jamieson and Moya Bailey dive into the works of the vision...

Is Earth really the only life-sustaining planet? These speakers think there might just be something or someone else out there -- and urge us to keep looking for it.

(NOTE: This talk was given in 2010, and this field of science has developed quickly since then. Read "Corrections & Updates" below for more details.) 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 elsewher...

Is there life on Venus? Quantum astrochemist Clara Sousa-Silva makes the case for a new way to seek and possibly discover habitable planets -- and shares her research into a poisonous, smelly molecule that might signal life beyond Earth.

Love: it’s what makes the world go round. And also: all you need. As well as that thing, in addition to war, in which all is fair. Here, TED Talks about this most basic of human emotions.

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.

It can be easy to believe that humans are insignificant. We're specks of dust on a random planet in a vast universe. Less powerful than elephants. Fewer than ants. But David Deutsch believes that's all beside the point, because humans possess one unique skill: attaining knowledge. David Deutsch -- Oxford professor, father of quantum computing, r...

It's an incredible discovery: an abandoned alien space station filled with precursor technology. Now every species in the galaxy is in a mad dash to get there first, but you've got a problem. Your ship can't hold enough fuel to get you there unless you vent caches of it into space at precise points and then come back for the fuel later. Can you ...

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.

In October 2017, astrobiologist Karen J. Meech got the call every astronomer waits for: NASA had spotted the very first visitor from another star system. The interstellar comet -- a half-mile-long object eventually named `Oumuamua, from the Hawaiian for "scout" or "messenger" -- raised intriguing questions: Was it a chunk of rocky debris from a ...

The most notable talks of 2018, chosen by TED Curator Chris Anderson.

Something massive, with roughly 1,000 times the area of Earth, is blocking the light coming from a distant star known as KIC 8462852, and nobody is quite sure what it is. As astronomer Tabetha Boyajian investigated this perplexing celestial object, a colleague suggested something unusual: Could it be an alien-built megastructure? Such an extraor...