Re: What if you shot a laser beam at a series of mirrors that would bounce it

If you really manage to overcome the problem of getting a beam into
a closed loop (closed means closed to getting out as well as closed
to getting in!), it would go around a few times, weakening at every
reflection (real mirrors are imperfect and impose losses) and through
interaction with athmospheric particles, until you cannot see it any
more. This takes a few milliseconds, at most.
With (theoretical) perfect mirrors and in perfect vacuum, the beam
would circle forever.

Greetings from Indonesia,
    Frank Berauer