Artist's concept of the Hera mission gliding past Didymos to Dimorphos. Image credit: ESA For a hot second back in 2004, it looked like there was a couple percent chance the asteroid 99942 Apophis just might crash into the planet Earth on April 13, 2029. And even if it didn’t hit in 2029, there was a small chance that if it passed through just the right place in Earth’s atmosphere on that Spring Day, it just might come back and hit Earth exactly 7 years later on April 13, 2036. These were the heady years after the movies Armageddon and Deep Impact when everyone thought they knew just how bad...