a mirror on the Moon
... that scientists shooting lasers at a mirror on the Moon discovered that their telescope was not where it should be?
... that scientists shooting lasers at <b id="mwAbU"><a href="./Laser_Ranging_Retroreflector" id="mwAbY" rel="mw:WikiLink" title="Laser Ranging Retroreflector">a mirror on the Moon</a></b> <i id="mwAbc">(pictured)</i> discovered that <a href="./Lick_Observatory" id="mwAbg" rel="mw:WikiLink" title="Lick Observatory">their telescope</a> was not where it should be?