Exercise 1: What the 1919 Eclipse Test Actually Measured — Possible Solution =============================================================================== Einstein's general theory of relativity predicted that light from distant stars would bend by a specific, calculable amount as it passed close to the Sun's own gravitational field. Under normal daylight conditions, this effect can't be observed at all, since the Sun's own brightness completely overwhelms the faint light of nearby stars - a total solar eclipse, briefly blocking the Sun's own light, is the real, practical condition needed to actually see stars positioned close to the Sun in the sky. Eddington's team photographed the positions of stars visible near the Sun during the real 29 May 1919 eclipse, then compared those positions against photographs of the same stars taken months earlier, when the Sun was nowhere near them in the sky. If general relativity were correct, the stars near the Sun should have appeared to be displaced slightly outward from their normal position, by the exact real amount Einstein's equations predicted. The result that would have falsified the theory: if the stars had shown no displacement at all, or a displacement of a genuinely different real amount than Einstein's specific prediction, the theory would have been directly contradicted by real, observed data. Instead, the measured displacement matched Einstein's real prediction closely enough to be treated as confirmation. ANSWER: Eddington's team measured whether starlight passing near the Sun during the 1919 eclipse was displaced by the exact amount Einstein's theory predicted. If the stars had shown no displacement, or a displacement of a different real amount than predicted, the theory would have been falsified - the theory only survived because that specific, real, checkable prediction turned out to be correct. WHY THIS WORKS AS AN ANSWER ------------------------------ This explains the specific real mechanism (comparing star positions near vs. away from the Sun) and names the specific real result that would have falsified the theory, rather than only stating that a test occurred.