Dark Matter
About 90% of the Universe is missing!
Man's wisdom is so limited - we can't even find 90% of the Universe. It is called "Dark Matter" because we can't see it.
How do we know it is missing? Because observations of the speed, rotation and gravitational forces of known objects within the Universe don't add up. According to scientific theory, they shouldn't be moving the way they do. There either needs to be a lot more mass (Dark Matter) to generate the required gravitational forces to "hold" things together or there is an additional unknown force at work.
There are various concepts to try and describe what it might be; such as black holes or "string theory".
If you look up black holes on Wikipedia you will find the following statement "Such observations have resulted in the general scientific consensus that, barring a breakdown in our understanding of nature, black holes do exist in our universe." This roughly translates as "there are some observations that fit with the theory of black holes and with some of the rules of the Universe, so black holes must exist". Slightly flimsy proof, if proof at all.
Richard Dawkins is quoted as saying that "we now know 90% of everything". This is ironic, when the reality is that we don't know about 90% of everything.
From what we currently know, spiral galaxies should break up, with stars flying off in all directions. Some people have said that it is almost like there is an invisible hand holding the galaxies in place.

Colossians 1:16, 17 "For by him all things were created: things in heaven and on earth, visible and invisible, whether thrones or powers or rulers or authorities; all things were created by him and for him. He is before all things, and in him all things hold together."