Twin paradox

The twin paradox in physics is a thought experiment in special relativity. It involves identical twins, one of whom makes a journey into space in a high-speed rocket and returns home to find that the twin who remained on Earth has aged more. 
The paradox depends upon the unspoken idea that the passage of time is the same in all circumstances. But this is not correct. Time is relative and the speed of light through a vacuum is the only constant. And the universe is relativistic, not Newtonian. Every single test which has been made has shown this.