Einstein Right Again: Even the Heaviest Objects Fall the Same Way

The pulsar and the inner white dwarf are in a 1.6-day orbit. This pair is in a 327-day orbit with the outer white dwarf, much further away. (Credit: SKA organization) Albert Einstein’s been having quite a few weeks! First his “imaginary elevator” thought experiment was confirmed with unprecedented precision, then his theory of relativity was shown to create gravitational lenses as expected even in other galaxies. And today, we learn that a central tenet of relativity still holds even at gravitational extremes. It’s no annus mirabilis, but it ain’t bad. Today’s news, which appears in the journal Nature, concerns the equivalence principal, which roughly says that falling objects should all fall the same way. It sounds obvious put that way, of course, but the idea that heavier objects should fall at the same rate as lighter objects (discounting air resistance) still surprises people. The idea is that gravity accelerates heavier ...