Question #2363c Physics Light and Reflection Properties of Light 1 Answer Eddie May 7, 2017 The photon has zero rest mass (#m_o#), it travels at the speed of light in every reference frame. But in terms of its relativistic energy #E^2 = p^2 c^2 + m_o^2c^4#, then #m_o = 0 implies E = pc#. So the photon has relativistic momentum and mass. https://en.wikipedia.org/wiki/Solar_sail Answer link Related questions Question #c0381 Question #5f9d5 Question #5f9d9 Question #f8fdc Question #5f9e5 Question #c7bc6 Question #5f9f1 Question #c038d What is the relationship between the speed of light, wavelength, and frequency of... Question #5fa05 See all questions in Properties of Light Impact of this question 1658 views around the world You can reuse this answer Creative Commons License