My question is, are mainstream cosmologists using “dark matter” and “dark energy” to prop up inherent problems of the big bang model of the universe’s origin?
I understand that some people take issue with inflationary big bang models, but to say that dark matter and dark energy were invented without any scientific justification (i.e., invoking the Tooth Fairy) paints a distorted picture. Although much about dark matter and dark energy remains to be discovered, both stand on a strong evidential basis.
The concept of dark matter readily flows from observations of our galaxy (and many others) and a straightforward application of Newtonian gravity. Measurement of an object’s orbit uniquely determines the amount of mass inside that orbit.1 For decades, astronomers have measured the orbits of Milky Way stars and stars in other galaxies. They used this information to determine the amount of mass in each respective galaxy. They have also added up all the mass from stars emitting detectable light (any form of electromagnetic radiation) for those galaxies. In every instance, astronomers find that the mass needed to explain the orbits exceeds the mass of the visible stars. Astronomers refer to the difference between required mass and visible mass as dark matter (you can charge scientists with a lack of creativity in naming things). Using a similar process, scientists find abundant evidence for dark matter in the vicinity of the Sun as well as in gigantic clusters of galaxies.
Strong evidence also supports the existence dark energy, which was discovered more recently than dark matter. One interesting measurement—independent of the methods that discovered dark energy in the first place—pertains to the large-scale structure of the universe (or how galaxies are clustered together).
Obviously, scientists don’t have a complete and final understanding of the cosmos. Thus, room for alternative models exists, even models without dark matter or dark energy. However, those competing models must explain the current evidence at least as well as inflationary big-bang models do, and right now non-big-bang models fail to meet that standard.