[alexander_busek]

I wonder if Euclid (or any other telescope) will ever discover Einstein rings displaying multiple images of the same galaxy at distinctly different periods of times, and with sufficient resolution to make it possible to make substantive statements about the distant galaxy's evolution over time.

In the case of a nearly "perfect" Einstein ring like the one discussed in this article, the different paths the light from the original galaxy takes are more or less equal in length, and thus show the galaxy at basically the same moment in time.

But imagine an Einstein ring with images of the same galaxy at different ages - separated by, say, 100 million years (because the paths were 100 million light-years shorter or longer)!

Regards,

[Nateman]

...Einstein rings displaying multiple images of the same galaxy at distinctly different periods of times...

A ring with 4 images was used to successfully predict a Supernova explosion. The light went on slightly longer paths and the path lengths could be calculated . When a supernova appeared in one of the images a successful prediction of when it would appear in another image was achieved.

Physicists used einsteins relativity to successfully predict a supernova explosion.

[Nateman]

This is a Wiki Article about a Supernova prediction using an Einstein Ring.

[Nateman]

Wiki Article about a predicted Supernova using a Einstein ring .