If I travel back in time it's not really the same time anymore is it?

There are in fact impossible paradoxes that ensue when talking about going back in time. I simply believe it's a false concept; that time doesn't have a backwards and a forwards, just a rate. It's a measure of change, and you can't "unchange" something without changing something else again. To go back in time you'd have to unchange the whole universe back to a certain point, which is impossible.

You're travelling back-in-time. Set the course to 1900. You're there, and you will not see any difference until you make something that could change the future too. The Past and the Future will be the same according to Time Travel Concept. The Future is more accepted than going back in time to the Past by Scientists who always dwell in dreams.

'Travel around Earth' is Distance per Time. But when if you go far away from Earth, the Distance per Time calculation changes with respect to Time. The Time will start to run faster...

So think about Wormholes, it is a shortcut to some other place which is trillions of light years far away. Thus Time Travel is a mystery... It makes long distance into very short in time. Time Travel deals with all the nature of Physics.

The usual way out of this in sci-fi is to say that your past actually does have you appearing there via time travel.

Time per time is a meaningless scalar only if you don't have a time machine.

Time is constant throughout the universe except where gravity or acceleration are involved.

Not surprisingly there are two theories about that.

The first is that it is the same time because it's already happened and only self consistent actions could happen. This is called the Novikov Self-consistency principle.

The second is that it isn't the same time because it didn't happen like that in the time traveler's history. This is called the "Many Worlds Interpretation".

One idea about past time travel is that youcan travel back to a point in the "many worlds" that is similar (or identical) to your past. You can then affect the future of that worldline, which will turn out different from the worldline you left.

Typical time travel conundrum. Think about it this way, you could ever only travel back to the point in which the device to travel through time is created. If it wasn't ever created, it would never exist, thereore, wouldn't be possible. Your question is moot.

Since traveling back in time is not possible, this question can be tossed in the irrelevant pile.

The excepted theory is you would create another timeline

Have you considered that it might be the same time,

but there wouldn't be anything there anymore?

Does anybody REALLY know what time it is?

(does anybody really care?)