According to the principles of special relativity, the observed speed of light remains constant for all observers, regardless of their relative motion. The speed of light in a vacuum is approximately 299,792,458 meters per second (or about 186,282 miles per second).
Therefore, if a ray of light is emitted from a rocket ship moving at any speed v relative to Earth, the observed speed of light on Earth will still be the same as the speed of light in a vacuum, which is approximately 299,792,458 meters per second.
This concept is one of the fundamental tenets of special relativity, as described by Albert Einstein's theory. It states that the speed of light is an absolute constant and is not affected by the motion of the source or the observer.