Time Travel Explained

This news was on discovery channel a few days: They made a loop of lazer light and they sent a subatomic particle through it. the results aren’t clear yet,but they said that this would be a huge success, since if they were able to send a subatomic particle, then they would soon be able to send bigger things.I would also like to add that it is not necessary to get proof from the future if  time travel was possible. what if they decided it is best if they let us figure it out alone, or if they wanted to send the proof at year 2050 instead of now so we could be more advanced and opened minded and not use it badly to earase our ancestors?What if they had already tried to give us proof but when they arrived to this time they where 300 feet off the ground where the time machine would be in the future?What if they had already gone back in time and changed history?We will never know.What if time travel was too dangerous and they could not send humans or they would desentigrate?And they cant send a robot through time since we would dissect the robot and learn from its structure and so learning technology that is too advanced for us?What if we humans got extinct because of the time machine and couldnt go back in time to warn us?