| − | Actually, according to the relativistic formula <math>E^2 = m^2*c^4+p^2*c^2</math>, momentum is not strictly dependent on rest mass, but is dependent on energy as well. Since light has energy, it can have momentum under relativity. | + | Actually, according to the relativistic formula <math>E^2 = m^2c^4+p^2c^2</math>, momentum is not strictly dependent on rest mass, but is dependent on energy as well. Since light has energy, it can have momentum under relativity. |