What do scientists mean by light? When did the cosmos become transparent? Is light the same everywhere in the cosmos? If man flew at the speed of light, would time stand still?
Light is part of the spectrum of electromagnetic radiation from the range of wavelengths visible to the naked eye. It is sometimes said that visible light, which would be pleonasm, if the term light were not used in a broader sense to denote electromagnetic radiation of any wavelength (for example, ultraviolet rays, which are not visible to the naked eye, and which cause fluorescence of various materials, are often called black light). About a thousand billion photons from the Sun fall on top of the pin every second on a sunny day. How much energy is that? Why do all plants and animals, including man, emit a constant amount of photons, proportional to the degree of their development in evolution? It is assumed that tachyons travel faster than light, does that mean they travel backwards through time?