Once on the discovery channel, I saw a special on Time Travel & Time Machine. They showed various types of designs, some ridiculous & some interesting..One that caught my attention was a "spiral" glowing machine..It was spiral shaped containing lasers (as far as I can remember)..Cant remember the name of the scientist, but he was a black american.. He claimed that once active, the machine would make it possible for future generations to send back messages back in time, but only the time since it was made active (the machine) . Now my question is : Can it be possible that our grandsons & great grandsons may be sending us messages through some time machine or actually coming back in time? I know the ques sounds a bit impractical, but everything is possible in science..Remember, prior to the Apollo episode, people used to laugh on scientists talking of moon missions!