Photography looking back in time

[cliveh]

I wonder if someone like Fox Talbot ever thought that photography could be used to look back in time. I'm thinking of a recent image taken by the James Webb telescope showing an image that took the light 2500 years to reach it.

 

[bluechromis]

I wonder if someone like Fox Talbot ever thought that photography could be used to look back in time. I'm thinking of a recent image taken by the James Webb telescope showing an image that took the light 2500 years to reach it.

They say that JWST can collect images where the light took over thirteen billion years to reach us. In Talbot's time they had little conception of how big is the universe. They knew the speed of light and if they had accurate information about the distance of astronomical objects they could have deduced that it would have taken the light a long time to get here from distant objects and thus the image was of the object as it was in the past. But it wasn't till mid 1920s that there was a consensus of astronomers that there were other galaxies beyond the Milky Way. So Talbot would not have been aware of the most extreme effects of time delay. In Talbot's time they did begin measure the distance to nearby stars using the parallax method. The astronomer William Hershel played a critical role is creating photo fixers. There was an early connection between astronomers and photographers. So hypothetically Hershel or other scientists could have crossed paths with Talbot and imparted to him that the light from the stars of measured distance represented the past of those stars.

 

[cliveh]

Thanks for such an excellent reply.

 

[cliveh]

View attachment STSCI-J-p22033b-4000px.jpg

 

[Alan Johnson]

William Herschell lived 1738-1822. I think it was his son John Herschell 1792-1871 who put Fox Talbot on to Hypo fixer.

Sir John Frederick William Herschel (The J. Paul Getty Museum Collection)

Explore the collection of the J. Paul Getty Museum at the Getty Center and the Getty Villa.

www.getty.edu

 

[Alan Johnson]

A love of light : Herschel, Talbot & photography

research-repository.st-andrews.ac.uk

Larry J Schaaf on the photographic collaboration of Herschel & Fox Talbot.
Not mentioned, but they likely discussed astronomy too.

 

[reddesert]

The finite speed of light was discovered in the late 17th century by Ole Romer from the timing of eclipses of Jupiter's moons - https://en.wikipedia.org/wiki/Rømer's_determination_of_the_speed_of_light Remarkably, he was within 30% of the modern value. It took a while to be accepted, but by Talbot's time this was established scientific fact that I expect he was aware of.

However, the size of the universe, or galaxy, was much less well known. Through measurements of parallax (or lack of observable parallax) and of binary stars, the Herschels (William, Caroline, John) understood that the stars are very far away, and William published the idea of the Galaxy as a flattened disk of stars in 1785: https://en.wikipedia.org/wiki/William_Herschel#/media/File:Herschel-galaxy.jpg

In the 18-19thC, as others have said, the Galaxy was thought to be the extent of the universe, other nebulae were not yet understood to be separate galaxies. I don't know offhand what the Herschels thought the extent of the Galaxy was, but guessing they knew it was at least hundreds of light years across. (It's actually a few ten thousands and we are ~8 kiloparsecs from the center, about 25000 light years.) Measurements of the extent and size of the Milky Way were systematically incorrect until the discovery of interstellar absorption by Trumpler in the early 20thC. I am not aware of who first wrote about the philosophical implications of the finite speed of light on seeing stars as they were in the past.