In this task, we ask you to elaborate the sentence without changing its general meaning. You can do so by explaining further the input sentence, using more precise wording, adding qualifiers and auxiliary information etc.
One example: The Inheritance Cycle is a series of fantasy books written by Christopher Paolini.
Solution is here: The Inheritance Cycle is a tetralogy of young adult high fantasy novels written by American author Christopher Paolini.
Explanation: The output sentence elaborates on the input sentence without changing its general meaning e.g. "tetralogy of young adult high fantasy novels".

Now, solve this: This idea was later discarded : the nucleus and the ring have the same redshift , and the ring shows knotty structure which would not be visible with gravitational lensing .
Solution:
This idea was later discarded because the nucleus and the ring have the same redshift , and because more advanced telescopes revealed the knotty structure of the ring , something that would not be visible if the ring were the product of gravitational lensing .