Florian Beutler, a Ph.D. student at the International Centre for Radio Astronomy Research (ICRAR) in Perth, Australia has arrived at a means of determining how fast the Universe is expanding, with the most accurate measurement ever made.
Beutler has calculated the speed at which the Universe is expanding by means of the Hubble constant. He noted that a key number is the Hubble constant in astronomy as it’s used to calculate the size and age of the Universe.
The expanding Universe moves other galaxies away from our galaxy, and the Hubble constant demonstrates how fast the galaxies are moving by linking how far they are from our galaxy. Analyzing the light from another galaxy will show its rate of movement and direction, which is easy to determine. However, determining the distance of the galaxy from Earth is more challenging. This has been accomplished by noting the brightness of individual objects in the galaxy and coupling that information with what we know about the object to determine its distance.
But this means of measuring a galaxy’s distance from Earth has some intrinsic errors, which was the inspiration for Beutler’s different approach. In his work, which was published in the Notices of the Royal Astronomical Society that appears monthly, he uses data from the work of a survey observing over 125,000 galaxies. He performed his study, which has been named the 6dF Galaxy Survey, on the eastern Australian telescope, the UK Schmidt Telescope. This survey, which covers nearly half of the sky, is the largest survey to date of nearby galaxies.
Observing the clustering of the galaxies that were surveyed and measuring this clustering along with other observations of the early Universe, Beutler succeeded in measuring the Hubble constant with a certainty of over 95 percent.
One of Beutler’s co-authors, Matthew Colless, Professor and Director of the Australian Astronomical Observatory, observed that Beutler’s means of determining the Hubble constant provides an independent verification that is as precise as other methods, noting further that Beutler’s measurement is in line with other previous one, which offers a provision for a check on that previous work.
In addition, this is a measurement that can be further finessed with data from other galaxy surveys that have been taken.