Aero-Terms!

Aero-Terms are designed to be a daily reminder of the terms, names, acronyms and explanations of the unique language that populates the aviation world. Aerospace, sport aviation, fixed wing, helo, you name it... it's all fair game.

Aero-Terms should serve as a quick but intriguing reminder of the terms you may use every day, or an introduction to an aspects of the Aero-World you may not yet be familiar with. ANN also encourages readers to go beyond the FMI link, and further research any intriguing terms.

Suggestions for future Aero-Terms are ALWAYS welcome, as are additions or discussion of the explanations given for each Aero-Term.

Aberration Of Light

The aberration of light is a phenomenon in which light appears to be slanted (the angle at which the light appears to be coming is different than the angle at which it's actually coming) if the observer is in motion. (An analogous situation is watching rain fall from a moving train - although a raindrop is falling straight to the ground, it will appear to fall at a slant, and the slant increases as the train's speed increases.) The aberration of light is due to the fact that light travels at a finite speed (as do the raindrops). The aberration of light was discovered and demonstrated by James Bradley (an English amateur astronomer) in 1725. The discovery of the aberration of light was one of the first proofs that the speed of light was finite; it also provided an early estimate of the speed of light (Bradley calculated that the time it took for light to travel from the Sun to the Earth was 8 minutes and 12 seconds).

FMI: www.fourmilab.ch/cship/aberration.html