One of the more peculiar parts of our universe is the presence of a great deal of mass that we cannot see. When looking at the gravitational effects on the mass in the universe, it is apparent that a significant amount of matter must be present but is not visible to us, leading to its subsequent naming, dark matter. The discovery of the accelerating expansion of the universe led scientists to believe that gravity must be counteracted in some way. Since the expansion of the universe is not slowing down with time, there must be some source of energy or force present that acts over such great distances. This mysterious fifth type of force was given the name dark energy. Although “dark” is not used in the same way as with dark matter, it is used here to indicate the lack of knowledge regarding the source of this energy and the mystery of how it propagates throughout space.
It has been commonly accepted in the scientific community that observable matter comprises about only 4-5% of the total mass of the universe. Thus, faced with this enormous discrepancy, the idea of invisible mass and a gravity-repelling force were incorporated to make sense of this confusion. Due to the relative modernity of this assertion and our technological limitations, there is little known about the specifics of both dark matter and dark energy. It will be interesting to follow the progression of research on these concepts and how our perceptions of spacetime and the universe change if further discoveries about dark matter/energy are made.