it's about the time machines stupid...

"A time machine is a device which brings about closed timelike curves—and thus enables time travel—where none would have existed otherwise. The physics literature contains various no-go theorems for time machines, i.e., theorems which purport to establish that, under physically plausible assumptions, the operation of a time machine is impossible. We conclude that for the time being there exists no conclusive no-go theorem against time machines...There are at least two distinct general notions of time machines, which we will call Wellsian and Thornian for short..."

More than just a ghost of a machine, this time machine eats CTC's.

Our defs have changed...

There is a large body of knowledge surrounding the concept of time. Both philosophy and physics have provided foundations in our current understanding. Early discussions about time appeared in the writings of the Hebrews and the Zoroastrian Iranians. Aristotle's Physics , the arguments of Newton and Leibniz, Godel's solutions to equations of Einstein's relativity, Hawkings' public lectures, all have contributed to this body of knowledge.

Of course, only Time will tell.

There is a basis...

The common objection to time travel deals with resolving 'the paradox'. What happens to the time traveler if they journey back in time and kill their mother at birth?. Well, of course in theory, the traveler would never have been born so the journey couldn't have be made; but if the journey never occurred then the mother would be born - which means the traveler would have been born and could have made the journey - and on and on! This is the paradox.

The two most-discussed solutions to this paradox include the posit that the past is completely and irreversibly defined. This first solution, the past is totally defined, dictates everything that has happened (or as some say -needs to happen) cannot be changed. The paradox is avoided since nothing can change the timeline of history, including the attempt to kill the mother. Seems that the murderer will bungle the attempt each time. Time can't be altered, nothing changes.

The other solution is the quantum idea of parallel universes. Far more complex, it depends on an understanding (or awareness!) of the theories/laws of quantum physics. Again, the paradox is avoided, for when the traveler kills their mother, a new quantum universe is created - a parallel universe - where the mother and the traveler never existed. The original universe still remains unchanged. The prominent champion of the parallel universe theory is Stephen Hawking: http://www.hawking.org.uk/lectures/warps.html