Yes, you would. Light travels at a speed of about 186,000 miles per
second. For every 186,000 miles away you send your mirror, you can see
something two seconds earlier. Send it far enough away, and you can see
stuff that happened longer in the past.
Two limitations, however:
1) If the mirror is far enough away and not big enough, your
telescope will not be able to distinguish close objects. A big mirror
helps (but you have to keep your mirror all at the same distance,
otherwise you get a mixture of times).
2) You cannot see anything earlier than when you sent your mirror
up. In fact, you usually will get such a small glimpse into the past it
may not be worth the effort (videotape is a cheaper way to preserve
3) And then there are clouds, buildings, the sun, and other stuff to get in the way.
(republished on 07/29/06)