“In naturalistic models, the farther a planet is from the middle of the nebular gas and dust cloud, the longer it would take for that planet to form. The alleged 4.5-billion-year age assigned to the solar system is not enough for the two most distant planets, Uranus and Neptune, to have formed in this way. Hence Uranus and Neptune both falsify the nebular hypothesis regarding their origin from it.
One secularist astronomer has commented: “What is clear is that simple banging together of planetesimals to construct planets takes too long in this remote outer part of the solar system. The time needed exceeds the age of the solar system. We see Uranus and Neptune, but the modest requirement that these planets exist has not been met by this model.”2
And astronomy Prof. Martin Duncan wrote: “It‘s clear that our level of sophistication of studying planet formation is relatively primitive. … So far, it’s been very difficult for anybody to come up with a scenario that actually produces Uranus and Neptune.”3”
See more about this here: https://creation.com/planets-uranus-and-neptune