For the past few years, a series of controversies have rocked the well-established field of cosmology. In a nutshell, the predictions of the standard model of the universe appear to be at odds with some recent observations.
There are heated debates about whether these observations are biased, or whether the cosmological model, which predicts the structure and evolution of the entire universe, may need a rethink. Some even claim that cosmology is in crisis. Right now, we do not know which side will win. But excitingly, we are on the brink of finding that out.
To be fair, controversies are just the normal course of the scientific method. And over many years, the standard cosmological model has had its share of them. This model suggests the universe is made up of 68.3 percent “dark energy” (an unknown substance that causes the universe’s expansion to accelerate), 26.8 percent dark matter (an unknown form of matter) and 4.9 percent ordinary atoms, very precisely measured from the cosmic microwave background—the afterglow of radiation from the Big Bang.
It explains very successfully multitudes of data across both large and small scales of the universe. For example, it can explain things like the distribution of galaxies around us and the amount of helium and deuterium made in the universe’s first few minutes. Perhaps most importantly, it can also perfectly explain the cosmic microwave background.