Time Travel.

Is it real? Will it ever be? Will it possibly happen within our lifetime?
Well I have the answer to that last question.

All you really need to do is write a letter to yourself in the future, with explicit instructions on what to do if time travel was already invented.
Record the date and the time that you want to know the truth in the letter, asking your future self to come back to this particular time, so as to hasten the discovery of time travel and perhaps further advance the technology whilst you are still alive and of course the possibility of claiming credit for such an invention should your future self decide that your present self would just need to wait till when time travel was actually invented IF it would actually be invented. You would need to be hungry for fame and fortune to the extent that you'd be willing to risk the disruption of the space-time continuum for this to work. But really, who isn't these days?

And of course, the latter reason would give many individuals a reason to come back in attempt to gain said fame and fortune for themselves, that's if these time traveling machines or portals or whatever means is widely distributed (which is probably the case should your future self actually appear at the stipulated date and time in your letter, unless you are a genius scientist/inventor that can invent time machines - which would go against the required conditions of this entire experiment, not to care about the possibility of disrupting the continuum. Doesn't apply of you are an evil mad scientist - in either case it would be wiser to keep the machine hidden from the public, which on second thought, would prove this experiment a failure should someone else be the inventor of said time machine. This outcome is highly probable in my case since I currently have no knowledge of manipulating time my joining materials together to form a system capable of interacting with a manmade idea.

There is also the possibility of time travel being pulicized but controlled with rules and regulations such as never leaving a trace or letting the people in the past know of your existence in their times. You could try asking yourself to leaving a nonexplicit sign, perhaps creating 7 markings on your bedroom door frame etc.

But these signs no matter how discreet, may also have been thought of by the time governing body of the future and there mgjt be measures already implemented to ensure they never happen. Maybe someone will destroy the letter? Who knows.

So results?

If your future self appears, time travel will exist.

If a sign you stated in the letter appears, time travel exists OR someone read your letter while you went to the toilet and tried to fool you.

Nothing happens. Now, this is tricky. It doesn't necessarily mean time travel won't exist. It may mean it exists but you didn't manage to acquire a machine (all this past tense grammar for a future action is whack), time travel exists but only in the distant future after you've died (you can also rule out resurrection here), you didn't meet the conditions of th experiment, the time trail rules were too stringent that even your greedy self-loving future self didn't manage to bypass it, OR your letter got destroyed/lost before the machine was invented.