infact i believe it was mathematically expressed that earth has to be in the center of the universe.
Copernicus presented his theory of Heliocentrism 500 years ago, though the church later forced him to renounce his theory.
Actually, you can have 2 points of view on this problem... a personal point of view and a universal point of view.
From a personal point of view, everything around you is perceived trough your senses, trough you. In .this case, it is not the earth who is the center of the universe but it is you who are the center of the universe as the only starting analytical point.
In the universal point of view… we are talking about a presumptive infinite amount of space, and in this case, any given point in an infinite system can be considered a center. Of course, there is still the structure point of view, that would make suns center of a solar system, a certain point in space center of a galaxy, etc. But no point in space can be considered as being the absolute center of a infinite universe, so our humble planet can be as good as any.
It is only a mater of reference systems. As dear Einstein said “The same event, observed from 2 different reference systems might occur differently for each observer depending on the reference system they are in. [common known as the baseball ball theory]”
About the topic at hand, time travel is mathematically impossible, or at least, backward time travel would be. We said the world travel… that means movement… that calls for the basic law of movement where T=dD/dS [T= time, D= distance, S= speed]. To have a negative time value we would have to have either a negative speed value or a negative distance value. Of course, there is a theory about the time line, being possible to bend until a certain point intersects another but the estimations for the amount of energy required or the implications of that would be rather impossible at the time being. Another theory would be that about bending the space factor but that is useless in our case since it would not result in a negative space coefficient nor negative speed.
