Once, in a battle, the deities were defeated by the asuras. Tormented by arrows, they sought help from king Muchukunda. King Muchukunda agreed to help them and fought against the asuras for a long time. Since the deities did not have an able commander, king Muchukunda protected them against the onslaught by asuras, until the deities got an able commander like Kartikeya, the son of Lord Shiva. Then Indra said to the king Muchukunda, "O king, we, the deities are indebted to you for the help and protection which you have given us, by sacrificing your own family life. Here in the heaven, one year equals three hundred and sixty years of the earth (relatively). Since, it has been a long time, there is no sign of your kingdom and family because it has been destroyed with the passage of time. We are happy and pleased with you, so ask for any boon except Moksha (liberation) because Moksha (liberation) is beyond our capacities".
Muchkunda asks Indra for a boon to sleep. While fighting on the side of the deities, King Muchukunda did not get an opportunity to sleep even for a moment. Now, since his responsibilities were over, overcome by tiredness, he was feeling very sleepy. So, he said, "O King of the deities, I want to sleep. Anyone who dares to disturb my sleep should get burnt to ashes immediately".
Indra said, "So be it, go to the earth and enjoy your sleep, one who awakens you would be reduced to ashes".
After this, King Muchukunda descended to earth and selected a cave on a hill [some locate this to mount Girnar ], where he could sleep without being disturbed.
Later he was used by Krishna to kill kalyavana.
Here in above incident is proof of einstein's theory of relativity. Are there any other incidence?