Einstein Mass Energy Equivalence (E = mc2) was first expressed in his paper Annus Mirabilis during 1905.
In physics, mass–energy equivalence is the concept that the mass of an object or system is a measure of its energy content.
A physical system has a property called energy and a corresponding property called mass; the two properties are equivalent in that they are always both present in the same (i.e. constant) proportion to one another.
The equivalence of energy E and mass m is reliant on the speed of light c and is described by the famous equation: E = mc2
bhūmir āpo ‘nalo vāyuḥ
khaḿ mano buddhir eva ca
ahańkāra itīyaḿ me
bhinnā prakṛtir aṣṭadhā || Srimad Bhagavad Gita, Chapter 7, Verse 4
Translation : Earth, water, fire, air, ether, mind, intelligence and false ego—all together these eight constitute My separated material energies.
Thus, this mass–energy relation states that the universal proportionality factor between equivalent amounts of energy and mass is equal to the speed of light squared. This also serves to convert units of mass to units of energy, no matter what system of measurement units is used.
Krishna also stated in Gita that, Soul can neither be created nor destroyed. It just transfers from one body to another, that is from one form to another or one body to another.
Many years later, science said, Energy can neither be created or nor be destroyed it can only be changed from one form to another.
This proves that soul is nothing but energy.
nainam chindanti sastrani nainam dahati pavakah na cainam kledayanty apo na sosayati marutah
Translation : The soul can never be cut into pieces by any weapon, nor can he be burned by fire, nor moistened by water, nor withered by the wind.
It just leaves old body and finds new body.