NASA’s Europa Clipper spacecraft has captured images of interstellar comet 3I/ATLAS as the object — perhaps the oldest ever seen by astronomers — whizzes through the inner solar system.

Today is the day that astronomers, amateur stargazers and alien conspiracy theorists alike have been waiting for: interstellar comet 3I/ATLAS is as close to Earth as it will ever get.

Since then, space agencies and observatories around the world have trained their instruments on 3I/ATLAS to study it during its flyby—it’s a rare opportunity to examine material from outside our solar...