Watch Earth's magnetic shield protect the planet from a pelting by the solar wind. See how the sun's energy drives a remarkable planetary engine, the climate.
Dark matter: The matter we can't see - James Gillies
The Greeks had a simple and elegant formula for the universe: just earth, fire, wind, and water. Turns out there's more to it than that -- a lot more. Visible matter (and that goes beyond the four Greek elements) comprises only 4% of the universe. CERN scientist James Gillies tells us what accounts for the remaining 96% (dark matter and dark energy) and how we might go about detecting it. View the complete lesson at TED-Ed.