Deep beneath your feet is a molten ball of energy the same temperature as the surface of the sun -- an immense clean energy source that could power the world thousands of times over, says technologist and climate activist Jamie C. Beard. How do we tap it? She lays out a surprising solution, and an unlikely alliance, to harvest geothermal energy from the Earth's core and get it to anywhere in the world.

Former NFL quarterback Alex Smith almost died after a particularly rough tackle snapped his leg in 2018 -- yet he was back on the field just two years later. In this inspiring talk, he shares his hard-won insights on overcoming fear, self-doubt and anxiety that could help anyone endure life's challenges. (This talk contains graphic images.)

As actress Nicole Maines points out, we all unwittingly play supporting roles in each others' life stories -- for better or worse. With charm and aplomb, she shares her experience growing up as a trans youth, emphasizing the big and small ways community acceptance can affect the course of a deeply personal journey.

Global obesity rates are on the rise, but body shaming campaigns are doing more harm than good, says medical anthropologist Nancy N. Chen. Reflecting on how the cultural histories of body ideals have changed over time, she offers a new way to view ourselves and our health by enhancing body diversity to close the gap between what's ideal and what's real.

Could an everyday clothing item help protect your health? In this quick talk, TED Fellow Alicia Chong Rodriguez introduces us to a smart bra designed to gather real-time data on biomarkers like heartbeat, breath and temperature. Learn how this life-saving gadget could help close the gender gap in cardiovascular research -- and, finally, usher women's health care into the 21st century.

In this fascinating conversation, cosmologist and TED Fellow Katie Mack delves into everything from the Big Bang theory to what we see at the edge of the observable universe to a few ways the cosmos might end. Stay tuned to hear Mack recite an original poem on the wonder and marvel of existence. (This conversation, hosted by deputy director of the TED Fellows program, Lily James Olds, was part of a TED Membership event. Visit ted.com/membership to become a TED Member.)

Government deficits have gotten a bad rap, says economist Stephanie Kelton. In this groundbreaking talk, she makes the case to stop looking at government spending as a path towards frightening piles of debt, but rather as a financial contribution to the things that matter -- like health care, education, infrastructure and beyond. "We have the resources we need to begin repairing our broken systems," Kelton says. "But we have to believe it's possible."

Sci-fi writer Chen Qiufan doesn't fear a dystopian future. Instead, he believes developments in artificial intelligence will make all of our lives better, healthier and safer. He takes us on a tour of the next 20 years of AI and shares some astonishing predictions for the advancements in science and technology that could await us. "For every future we wish to create, we must first learn to imagine it," he says.