Videos

Math

In a lively show, mathemagician Arthur Benjamin races a team of calculators to figure out 3-digit squares, solves another massive mental equation and guesses a few birthdays. How does he do it? He’ll tell you.

Web cartoonist Randall Munroe answers simple what-if questions ("what if you hit a baseball moving at the speed of light?") using math, physics, logic and deadpan humor. In this charming talk, a reader's question about Google's data warehouse leads Munroe down a circuitous path to a hilariously over-detailed answer — in which, shhh, you might actually learn something.

Think you're good at guessing stats? Guess again. Whether we consider ourselves math people or not, our ability to understand and work with numbers is terribly limited, says data visualization expert Alan Smith. In this delightful talk, Smith explores the mismatch between what we know and what we think we know.

Space

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.

It sounds like science fiction, but journalist Stephen Petranek considers it fact: within 20 years, humans will live on Mars. In this provocative talk, Petranek makes the case that humans will become a spacefaring species and describes in fascinating detail how we'll make Mars our next home. "Humans will survive no matter what happens on Earth," Petranek says. "We will never be the last of our kind."

Technology

Explore a speculative digital world without screens in this fanciful demo, a mix of near reality and far-future possibility. Wearing the HoloLens headset, Alex Kipman demos his vision for bringing 3D holograms into the real world, enhancing our perceptions so that we can touch and feel digital content. Featuring Q&A with TED's Helen Walters.

3D printing has grown in sophistication since the late 1970s; TED Fellow Skylar Tibbits is shaping the next development, which he calls 4D printing, where the fourth dimension is time. This emerging technology will allow us to print objects that then reshape themselves or self-assemble over time. Think: a printed cube that folds before your eyes, or a printed pipe able to sense the need to expand or contract. Read more and see different programable materials here.