Every day there are asteroids whizzing through space and some come close to Earth. Space Rocks can tell you if there are any that are considered potentially dangerous nearby, or if you want it can tell which is the nearest asteroid to us right now. Space Rocks is meant to be fun, so all the calculations on impact energy are based on simplifications, such as the asteroids being made of rock (some are, but others are ice or iron) and that they hit head-on and not at a glancing blow. The reality is that we're not likely to be hit by anything substantial any time soon, so don't worry!
“Alexa, ask space rocks what is the nearest asteroid”