The astronomer and science popularizer Carl Sagan famously said that there are more stars in the universe than grains of sand on Earth.
With that in mind, understanding the shape of our universe is a gargantuan task; and yet, the scientific community has made great strides in mapping the cosmos in recent years.
New, improved measurements of dark energy by a team of researchers from the University of Portsmouth, lends weight to the belief that the entire universe is totally flat.
Understanding dark energy
We don't know the source of dark energy; and yet, we can measure its influence and impact across the universe. By improving the way this mysterious force is measured, a team of cosmologists from the University of Portsmouth found that the universe is very likely to be spatially flat.
"This result shows the power of galaxy surveys to pin down the amount of dark energy and how it evolved over the last billion years," Lead author Dr. Seshadri Nadathur said in a press release.
"We’re making really precise measurements now and the data is going to get even better with new surveys coming online very soon."
Studying over a million galaxies and quasars
Previously, scientists measured dark energy by tracking supernovae in the night sky. The Portsmouth scientists' method swept over the data of over a million galaxies and quasars collected by the Sloan Digital Sky Survey, before presenting its findings in a research paper published in the journal Physical Review Letters.
The results of the study confirm the model of a cosmological constant dark energy and a spatially flat universe with unprecedented accuracy. The data also casts doubt on recent suggestions of positive spatial curvature that were based on measurements of the cosmic microwave background (CMB) by the Planck satellite.
The Hubble constant
Dr. Florian Beutler, a senior research fellow at the ICG, who was also involved in the study, said that the findings also allowed a new precise measurement of the Hubble constant — the value of which is the subject of ongoing debate amongst the scientific community.
“We see tentative evidence that data from relatively nearby voids and BAO favor the high Hubble rate seen from other low-redshift methods," Beutler explained. "But including data from more distant quasar absorption lines brings it in better agreement with the value inferred from Planck CMB data.”
The debate about the speed at which billions of rocks and shining balls of gas hurtle through the emptiness of space continues as our knowledge of the universe continues to expand.