Nah we've had them. We just lock them in mental hospitals.

Maybe it's impossible to travel back in time?

I prefer the theory of "OMLY FORWARD!"

Basically, you can only travel forwards in time because going backwards violates causality

However

Because of the possible 4th dimensional geometry of the universe and what that means for how it behaves over deep time intervals, it could theoretically be possible to go so far forward you end up back in time.

This possibility relies on the accuracy of the theory of the bang and crunch cycle, which basically states that the universe is a bubble of infiniteness and that if you figure out how to ride out a big crunch and following big bang, you can just keep fast forwarding infinitely until random happenstance takes you far enough forward in time to a universe that is identical to ours except you're arriving to a point that is identical to one that was "back in time" from where you started.

It's probably one of the more depressing takes on time travel since it's impossible to ever go "home" but then again in that sense you've never returned to the home you left from in the morning, because the one you return to exists forward in time from where you left.

Or they're the things 99% of people are calling 'aliens.'

Why an interstellar species would travel light years to come to this pale blue dot in ships that don't really interfere and look like our own just a few hundred to thousand years more advanced is kind of hand waved away.

But if those sightings are in fact accurate, it sure seems like our narcissistic species would be pretty interested in our past selves once the tech existed.

The vulkan science proved time travel impossible

Listen, the only logical conclusion to stop time tavel fuckery is a cascading series of event that cause all time travelers to be killed before tbey discover time teavel, or otherwise foil the discovery. The result is a nice clean timeline. I know this to be true because that technology would NOT be used responsibly

Or the timeline they are from is not our timeline

Incorrect. The child support liability on multiple timelines could no longer be insured.

maybe they don't visit us because we never call or text

or it's impossible lol, today physics and teories agree that time travels to the past is impossible, it's go against literally everything, or ours theories are worng, but well it's working to this day

Now I just wanna watch Primer again.

The future doesn't exist, and the past is inaccessible to our Temporality.

There was an interesting physics paper recently that suggested that time travel was possible, but you wouldn’t be able to travel to before when the machine was built. Of course, it also would require an impossibly huge amount on energy, but that’s a problem for the engineers.

If time travel existed, why would anyone come to this time period where everything is fucked up?

And if the tech is regulated to stop altering the timeline, they could be here in disguise. Possibly literally invisible to us because they're only permitted to observe and not actually take part in anything. It could even be that time travel works like Paycheck and not The Time Machine, and you're just able to look into the future/past but not actual travel to it.

Or the branching timeline scenario in Back to the Future is the reality of things, so even if you went back in time to talk to yourself as a younger person, that happens in a totally different dimension than the one you were in when you yourself were a younger person.

I believe the only viable timeline is the one where time travel is never invented because if you create the machine to go back to prevent something happening then there is no need to create the time machine.

Which yes is an actual paradox

Back to the Future had an extremely convoluted time travel theory that didn't actually make sense, but one interesting idea they sparked is that you create branching timelines when you go back to the past. Meaning your present timeline remains unaltered, but you basically skip to a new reality when you time travel. Essentially, they claimed the multiverse exists and you travel across dimensions, not necessarily time, when you used the Delorean.

Maybe this is why we never meet time travelers. Because our current universe is an unaltered world and any time traveling that happens here just sends people to other universes instead of our established timeline.

This theory is kind of nightmare fuel when you consider Doc and Marty left Marty's girlfriend on her porch in a dark future and just expected her to be there when they "fixed" the timeline. Nah, bro. You just abandoned her in the darkest timeline. The girl you picked up was an alternate reality version of her.

*EDIT: Back to the Future, not Bank to the Future.

If you were a historian with a time machine doing original research for your doctoral dissertation, you’d probably prioritize visiting the most poorly-documented eras first—the Information Age would be at the very bottom of your list.