Gravitational Time Dilation

 Time is like elastic, large bodies of gravity such as Earth compresses time around us. This is called Frame Dragging. Earth's gravity causes a Gravitational Time Dilation making our time here on Earth moving slower and our galaxies time moving faster.

An example: 

Say extraterrestrials placed Adam & Eve here on Earth 5000 years ago. The ETs leave Earth in their UFO/UAP and positioned their spaceship in a arm of the Milky Way. The extraterrestrials spacetime has now sped up because their time is bound by the gravity of our galaxy.

They would see thousands of Earth years pass in a matters of weeks. The reason for this is Gravitational Time Dilation!