NGC 4258, the first galaxy whose distance was measured using the maser technique in 2000. The latest galaxy measured by the technique is seven times more distant and is a step towards providing astronomers with a new estimate of the expansion rate of the universe.
Credit: X-ray: NASA/CXC/Univ. of Maryland/A.S. Wilson et al.; Optical: Pal.Obs. DSS; IR: NASA/JPL-Caltech; VLA: NRAO/AUI/NSF
“While the present value of the Hubble constant does a good job setting the size and age of the universe, an even better number is needed to help understand dark energy,” Braatz told Cosmos Online.
Dark energy is a mysterious force that represents about 74% of the universes’ mass, and acts like the Hubble constant, ensuring the universe expands rather than collapses from the effects of gravity. An independent measure of the Hubble constant could improve models used by cosmologists to understand the nature of dark energy.
"Ambitous and important"
“We will eventually need to measure angular diameter distances of about ten or more such galaxies to reach the precision in the Hubble constant needed to help constrain dark energy,” said Braatz, a goal he hopes to attain in the next five years.
Australian astrophysicist Lisa Harvey-Smith, from the University of Sydney’s Astrophysical Maser Group said the project was “ambitious” but very important. “Understanding the scale of the universe is important to all astronomers,” she said.
“Finding an alternative measurement for the Hubble constant is fundamental to the age and expansion of the universe – everything cosmologists are arguing about,” added Lisa Harvey-Smith.
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