You know what they say: the best time to build a time machine is 50 years ago.

I think that's basically the movie Primer too, they'd turn the machine on, go hide in an apartment for X amount of time, then go back to the machine and emerge 5 minutes after they turned it on and just walked away.

But gravity effects time, sticking close to a planet isn't going to be hard.

Ironically enough the first (if we ever get them) time machines are going to be a hell of a lot like modern "UFOs" are described. You couldn't risk landing on the planet, elevation changes are what's really a nightmare to account for. Show up and hour early and everything is a foot higher because of how fast we're spinning.

So you'd want a space craft, because space is big and empty. And realistically it's going to take something bigger than a telephone booth or even the 1980s embodiment of Florida on four wheels with a hood designed to do cocaine off of to house a time machine.

Damn physic laws removing the fun from physics

That's not really true. First, if you can invent time travel you can probably do the math to calculate positions of objects. Second, even if you do need a beacon, you could use something that already exists. For example, radio waves. Earth has been shooting off radio waves for a fair amount of time now. That could be used as a beacon. Also, you could do something like having your time machine do small jumps, check it's relative position, then adjust. This would solve just about every issue.

Basically half the plot of quantum break

You can easily cross calculate between various, inertial frames of reference. The problem is that earth isn't sitting still in an inertial frame. We spin around the sun, and we orbit the center of our galaxy. We also get nudged about by the pull of other stars.

Tracking a time jump (or technically a time-space jump) would be easy, if you just wanted to be within the solar system. With measurements the earth-moon gap would not be too hard. Hitting a surface exactly would be another story. Miss by a meter and your cut in half by a wall or floor.

Not enough people bust out ipso facto anymore.

Also agree, but mostly chuffed on the phraseology.

On average, yep.

If i had a vaccume and a carbon nanotube rotating such that the ends are moving at the speed of light, and another going the opposite direction (no net rotational inertia outside the device), I would have a dimensional anchor as moving it would cause spacetime to exceed the speed limit.

Voila, I just created a sci-fi plot device

My theory is time doesn't actually exist, it's a construct we made up to explain cause and effect. You can't travel back in time for the same reason you can't unbreak an egg. You'd have to figure out how to reverse entropy which per our understanding of physics is the most impossible of all impossible things.