“So far we have found two large near-Earth asteroids that are about 1 kilometer across, a size that we call planet killers.”Two of the recently observed asteroids have orbits that safely skirt Earth, but one of the rocks—a 0.93-mile-wide (1.5-kilometer) asteroid dubbed 2022 AP7—has an orbit that may eventually put it on a collision course with Earth.If the worst were to happen, space agencies on Earth would have their first real-world (or real off-world) situation to employ an asteroid defense maneuver like the recent DART mission, which intentionally smashed into an asteroid named Dimorphos in September, slightly altering the asteroid’s orbital trajectory.The success of DART means NASA can now develop a more robust planetary defense strategy, should we ever need to redirect a threatening rock.Space-based observatories like Hubble and Webb always face away from the Sun, because the star’s intense light and heat could fry the observatories’ instruments.That makes the work of the Dark Energy Camera all the more important—in the recent case, it found a potential threat to Earth that might otherwise have remained invisible to us."