What do you mean, Time-travel.

When i travel point to point at earth-ball. between these points is measured distance. If i go very fast. I go fast. If i go very slow. I go slow. Distance is same, between point to point.

What different is earth-ball and place(space) where earth-ball is? Hmm. It is same place. It has same physical laws. I see it at night, when i look up. Earth atmosphere is 'see through', not invisible.

Time is not material thing. Universe cannot be time. Time is measuring-unit.

But if you mean, travel time, back or forward at our life. It is also same fact. We cannot. Do we have? Yes. I have dreaming many times, that if i have time-travelling equipment, i go back time, when earth was nature condition. But. It is a dream, what can do only brain-view.

So. Forget this time-travel at real life. It is science-fiction, humans brain-mind-image dream. Real life round of us is being and nice. Sometimes ugly. But we, humans made our problems. So we can also solve our problems.