Political observers are watching the situation with interest.
There may be microscopes involved, bringing us ever closer to the heart of the matter; but even microbiology is objective, adding to knowledge by putting space between an object and its observer.
Many innocent bystanders were injured by the explosion.
There were two bystanders who witnessed the accident, but neither of them went to help.
A bystander videotaped the police beating using their cell phone.
The explosion killed an innocent bystander.
i'm like this useless bystander
These instruments detect linear acceleration, tilt and other directional cues to keep them from dive‐bombing the ground or, worse, unsuspecting bystanders.