Way back in 1913, everyone hailed Niels Bohr’s new model of the atom. It pictured electrons orbiting a central nucleus like planets orbit the sun, and it’s still the most common picture of the atom today. You can find it on countless science t-shirts and in TV shows like The Big Bang Theory, but here’s a reality check: scientists replaced it way back in the 1920’s. But before we start pushing for more accuracy in our media (and I think we should), this old model still has something to teach us about how scientists today tackle big problems. Physics was changing fast at the start of the 20th century, when a young Niels Bohr was out to prove his worth. In college, he worked obsessively in a competition

Einstein desperately wanted a unified theory of physics. Thanks to gravitational waves-the poster child of general relativity-his wish might just come true. Gravitational waves are ripples in the fabric of spacetime that reverberate from the source of a gravitational disturbance. Einstein had predicted gravitational waves as part of his general theory of relativity, but scientists confirmed their existence just this past February. Gravitational waves behave like electromagnetic waves except that the latter travel in spacetime; the former, however, is an actual disruption in spacetime itself. String theory, meanwhile, says that if you zoom in on an elementary particle, you’ll see a vibrating string