Light moves outward from any source, such as the sun, in all directions radially, or along straight lines (so long as it does not encounter a gravitational field) with the unimaginable velocity of 186,000 miles per second. As it advances it vibrates or oscillates back and forth across its path in all directions at right angles to this path, unless it is plane polarized light, in which case its vibrations are confined to one plane only.