Excerpts from “Paradoxes of Time and Space”

   Imagine that a man travels into outer space on a rocket at near the speed of light and then returns to earth. According to Einstein’s theory of relativity, the man will find he has not aged as much as his identical twin brother who stayed home. Time will have passed more slowly on the rapidly moving rocket than on the slow-moving earth. This disparity in the passage of time is often called time dilation. This story of the twins is called the twin paradox, since it runs contrary to our expectations. . . .
   Apart from time dilation caused by motion, Einstein also discussed time dilation caused by gravitation. Imagine a beam of light moving up from the surface of the earth. According to the laws of physics, the light must lose energy as it climbs against the pull of gravity. The frequency of a beam of light is proportional to its energy. So as the light climbs upward, its frequency drops. Now suppose the light is coming from the face of a clock situated on the earth’s surface, and that a person in outer space is using this light to see the clock. A person on earth can observe that for every second ticked off by the clock, the light will vibrate through a certain number of cycles. The person observing the clock from outer space will also see that the light vibrates through this many cycles in the time the second hand ticks off one second.
   For the observer in outer space, however, the light has a lower frequency than on earth. So he’ll see the earth clock running slower than his own clock. Relative to the observer in space, time on earth must be passing more slowly. Calculations show that for a person in outer space, time on the earth’s surface would seem to pass only slightly more slowly. But time on a planet with an extremely strong gravitational field would pass very slowly indeed.
   These examples show that modern physics allows for remarkable transformations of space and time. And apparently, similar ideas are found in Vedic literature. We find an example in the story of a king named Kakudmi, who was able to travel to the world of Brahma and experience Brahma’s scale of time. Here is the story, as related in the Srimad-Bhagavatam: