In article , "Robert L.
Oldershaw" writes:

"The Impossibly Early Galaxy Problem"

http://arxiv.org/abs/1506.01377

Tension mounts, indeed!

This indicates that galaxy formation is not completely understood. If
it were, of course, no-one would work on it.

Remember, galaxy formation is not computed/simulated from first
principles, but models and algorithms are developed in association with
observations. (This does not mean, though, that they have no predictive
power.) So, we can learn something from new observations! Great!