First of all, I have pondered this for a while.
Now as for some of the things I have read here:
Time is not physical and is only a definition.
This in my opinion is wrong. Time has to be a physical object. Saying that it is only a definition can’t be true, as a definition is only our perception of what something is, and perceptions can be wrong.
But perhaps time is only a definition. Well, definitions have parts. You can manipulate these parts. Which would place times definition as an object, which can be manipulated. So, if we manipulate times definition, then perhaps we can manipulate time itself.
Wormholes are needed for time travel
Quite a few people seem to believe this. I don’t. If wormholes are required for time travel, then why can’t we find them. Do they exist naturally in nature, or do they have to be found?
My theory
Well, over the past few days, and reading some articles on dimensions, and expanding on some of my previous theories, I have come up with a new one. As it begins, there are multiple (as in Googals and up) of separate timelines. It is physically impossible to travel to the same timeline, and if it was ever accomplished the whole timeline would be destroyed (basically a paradox creates destruction). It is possible to travel to separate timelines, and it would be possible to influence events in them without changing events in your base timeline. You could also avoid the paradox of existing at the same time in two different places, since it isn’t really you who exists in that timeline, if you exist at all. All these timelines are bundled together like a cord. These are encased in time itself. Time is a gigantic circular tube. All of these timelines exist in it. Time itself does not move. The timelines rotate to different points in time itself, creating the illusion of time passing, when in fact time is not passing, but time is only creating gravitational distortions on the timeline itself, which the produces the phenomenon of time passing. Time is encased in the mysterious and unknown “Dark Energy” as I believe I once read it called that. It is a mysterious and most powerful force in any place that ever existed. This dark energy never ends, it extends forever, and has the ability to rip apart time itself. So now we have arrived at how you travel in time. You manipulate the “dark energy” so that a tube for safe passage exists (possibly the function of a wormhole). This then opens a separate point in another timeline, which creates a place to enter that timeline. This means that a dimension strong enough to withstand “dark energy” is needed, which is why time itslef conforms to the shape of the small timelines. The pressure is so great it distorts time itself. So with all of that said, time travel is not impossible only improbable for quite a few years to come.
Now who is the crackpot? 
(Yes, I have that much time on my hands)
