THE HUBBLE SPACE TELESCOPE CAN BE USED TO TAKE MEASUREMENTS THAT WILL HELP ANSWER SOME OF THE BIGGEST QUESTIONS ABOUT THE UNIVERSE. CREDIT: NASA/STSCI.
Scientific puzzles don’t come much bigger than these. How old is the Universe? How big is it? And what is its ultimate fate?
A single number, Hubble’s constant, is the key that can unlock all of those questions, but it’s a number that has proved notoriously hard to accurately measure. Hubble’s constant is the rate at which the Universe is expanding. The first team to accurately make that measurement was co-led by Jeremy Mould, now a professor at Swinburne University of Technology and professorial fellow at the University of Melbourne. Continue reading Measuring the Universe from start to finish→
THE 3.9 METRE ANGLO-AUSTRALIAN TELESCOPE IS COLLECTING OPTICAL GALAXY DATA FOR THE GAMA SURVEY. CREDIT: BARNABY NORRIS.
A new ‘super survey’ is producing the largest database of galaxy measurements, spanning the last five billion years of cosmic history. The International Galaxy and Mass Assembly (GAMA) project is combining data from ground-and space-based observatories to measure the ‘haloes’ of dark matter that surround galaxies.
“The Cold Dark Matter (CDM) model of cosmology makes predictions about how galaxies cluster and, in many cases, collide and merge,” says Andrew Hopkins, a GAMA team member. “Our measurements of the speeds of galaxies will reveal the distribution of dark matter, and enable us to test the CDM model.”
PHOTO: DARK MATTER DOMINATES GALAXIES AND GROUPS OF GALAXIES, YET ITS IDENTITY REMAINS UNKNOWN. CREDIT: DAVID MALIN, AUSTRALIAN ASTRONOMICAL OBSERVATORY.
Australian astronomers have long been contributing to our understanding of a strange cosmological phenomenon—the Universe’s missing matter.
In the early 1970s, Ken Freeman of the Australian National University (ANU) determined that spiral galaxies must contain more matter than we can see. He postulated that dark matter—an invisible material first proposed 40 years earlier—must make up at least half the mass of these galaxies. Now, patches of dark matter are thought to be scattered across the Universe, playing a major role in holding galaxies and groups of galaxies together. Continue reading Spinning galaxies reveal missing matter→
WiggleZ will hunt for dark energy in the faint patterns of 293,000 distant galaxies. Credit: NASA / ESA / HUDF09 Team
A project to produce more than double the number of galaxy distance measurements than all other previous surveys, could lead to an explanation of one of nature’s biggest mysteries—whether dark energy, an invisible force that opposes gravity, has remained constant or changed since the beginning of time.
