Suppose it's a very clear night. You take a laser-pointer, and briefly allow it to "shine" into the sky. Will the photons emitted from your laser actually make it millions of miles into space? Or will they somehow "dissipate" and not make it that far? It would be very cool to think that just you or I could actually cause something to travel off into space and even long after we're gone, that that beam of light will still be traveling off into the stars.