According to Einstein's theory of special relativity, as an object approaches the speed of light, several interesting phenomena occur. From the perspective of a stationary observer, observing an object, such as a starship, moving at or near the speed of light, a few effects would become apparent:
Time Dilation: Time would appear to slow down for the moving object relative to the stationary observer. This means that clocks on the moving starship would seem to tick more slowly compared to the observer's clocks. The effect becomes more pronounced as the starship approaches the speed of light, and time essentially slows down for the starship.
Length Contraction: Lengths in the direction of motion would appear to contract from the perspective of the stationary observer. This means that the starship would appear shorter in the direction of its motion as it approaches the speed of light.
Doppler Effect: The light emitted by the starship would undergo a significant redshift. The wavelengths of light would be stretched out, shifting towards the red end of the electromagnetic spectrum. This is known as the relativistic Doppler effect and is a consequence of the relative motion between the starship and the observer.
Brightness: As the starship moves at high speeds, its apparent brightness would decrease due to relativistic effects. The energy of photons emitted by the starship would spread out over a larger volume as a result of length contraction, leading to a decrease in apparent brightness.
It's important to note that these effects are based on the principles of special relativity and are not directly observable in our everyday experiences. They emerge from the mathematical framework of the theory and have been experimentally verified in various experiments involving high-speed particles.