[Right_Wing_Madman]

physics has devolved into an cerebral circle jerk expounding ridiculous ideas like string theory, alternate universes, time travel, and dark matter.

There's no physical evidence supporting string theory and alternate universes, however time travel and dark matter are real. If I fly in a spaceship faster than a relative observer, time moves slower for me (Einstein's theory of relativity) - proven through experiementation. Physical evidence also shows dark matter exists: galaxies have a gravitational pull of about 10 times greater than they should be and all stars in a galaxy rotate around the center at the same speed, which is in violation of Newton's laws of gravity. "Dark matter" is that missing matter which accounts for the gravitational pull of these observable phenomenon.

[IronJack]

Time dilation (the phenomenon you describe) is not the same as time travel. Time travel consists of reversing the movement of a system from higher energy to greater entropy. It would essentially allow you to unring a bell.

Dark matter is a ridiculous theory concocted to explain the gravitational discrepancy you noted. It’s a perfect example of forcing reality to fit the equation, since it is “observable” only by its absence.