#2-ans

X- Albert Einstein
Y-special theory of relativity and not theory of relativity...
The funda:
Einstein's "mass expansion": states that when the mass of the body is less than infinity, the object is part of the universe; on the contrary, if the mass is equal to infinity, the universe is part of the object.
m=(rest mass)/(1-(v^2/c^2))^.5
when krsna transformed into light, his inertial velocity becomes equal to the velocity of light and hence the mass becomes equal to infinity .. so the universe became the part of him(object).