Dark Energy Controversy: Part 1
In 1998, two separate teams, using different type Ia supernova data, went out to show that the universal expansion was slowing down due to gravity, but instead found just the opposite, that the universal expansion was accelerating. This was very controversial and very unexpected; in fact, it was so different to the accepted theory that scientists simply assumed they could quickly downplay the results.
Scientists were committed to ensuring that the supernovae results did indeed point towards an accelerating universe: potential flaws in the observations were analysed and over the next few years independent measures were taken that all supported the conclusion. The fact that it was two separate sets of data that original showed the acceleration result probably helped to win scientists over so quickly; within a few years, most scientists were convinced that the universe’s expansion was accelerating, perhaps due to some kind of dark energy. Ethan Siegel from Starts With A Bang says:
It suddenly occurred to me that if you wanted to eliminate this one thing, dark energy, it would take a minimum of six separate observations to be overturned. And that was it; it was suddenly unreasonable to me that I would reject dark energy.
While there was really no dispute over the acceleration result after checks and additional confirmations, scientists had really very little idea about what the dark energy actually could be. Despite this, scientists were quick to point out that the cosmological constant fitted the acceleration result; it’s exactly what you’d expect to see if a cosmological constant made up about 70% of the critical density. So, dark energy was introduced into the standard model in this way, which is known as the Lambda-cold dark matter model. This could have been the end of the controversy…
Filed under: Controversy 'stoking', Cosmology as a science, Dark Energy, Internal controversy, Lambda-CDM, Observation | 1 Comment