Bending Starlight
▶ DRILLLight has no weight — but it still bends when it passes a heavy object, because it follows the curved space around it. So when a star's light skims past the Sun, the star appears shifted from where it really is. During a total eclipse the Moon blocks the Sun and the stars beside it become visible — and in 1919 Eddington measured exactly this shift, matching Einstein and not Newton. It's the photo that made Einstein world-famous. Use the Explain it for a kid / a grown-up switch to set the depth.
The big idea — light has no weight, but it still bends when it passes a heavy object, because it's following the curved space around it (last drill). So a star whose light skims the Sun looks shifted from where it really is. In 1919 a total eclipse let astronomers see stars right next to the Sun, and Eddington measured this exact shift — the first time anyone caught gravity bending light. It matched Einstein perfectly and made him famous overnight. (The real shift is tiny — about 1.75 arcseconds — and is cranked way up here.)