This should be an easy one but I couldn’t find it in the archives. Who began the convention of using the light-year as a standard unit of distance? Is it one of those ideas that migrated from sci-fi into real science?
All I cn find so far is that Miriam Webster puts the date of coinage at 1888.
Remember when your dog ate my goldfish, and you lied and said I never had a goldfish? Then why did I have the bowl, Bart? Why did I have the bowl?
Perhaps it was mentioned in Camille Flammarion’s story “Lumen”. He was the first to explore the relativistic effects of faster than light travel (almost 20 years before Einstein). “Luman” was published in 1887 and could possibly be the first coinage that Miriam Webster dates to 1888.
From the site… http://www.astro.keele.ac.uk/AstSub/astro104/stars01.html
"Halley used his proper motion measurements to attempt to find the distances to the stars:
-assumed that Arcturus moves at same speed as the Earth’s orbital velocity (30 km/s).
-used trigonometry to calculate distance – 2 light years
-Light Year is distance light travels in one year (9.5 million million km).
-His method is not valid, but did show that stars must be a long way away. "
Now whether that site is correct or not…
I have some resources at home which might give some insight into the origin of this term. Related to this, there is a whole history to how the speed of light was determined. It might be closely related to this history - or a spur thereof.
Some dates leading up to the light year as an unit of measure:
In 1676 Roemer estimated C based on observations of the moons of jupiter. Fizeau made the first terrestrial measurement in 1849 using a toothed wheel. Michelson refined this value using rotating mirrors.
If I remember correctly, the term was coined by Dr. Marcellus P. Lightyear, of the Oxford College of Physics. Hope this helps.
An infinite number of rednecks in an infinite number of pickup trucks shooting an infinite number of shotguns at an infinite number of road signs will eventually produce all the world’s great works of literature in Braille.
When I have a question about a word or phrase I try www.onelook.com it has 500 dictionaries you can search from. Some words are only in dictionaries from 1911.
But now I have seen it written as: Light Year, Lightyear & Light-year
Swell.
light-year "lit-'yir\ noun (1888)
1 : a unit of length in astronomy equal to the distance that light travels in one year in a vacuum or about 5.88 trillion miles (9.46 trillion kilometers)