Radio astronomers demonstrate vital tool for unraveling mystery of dark energyJune 9th, 2009 - 3:32 pm ICT by ANI
Washington, June 9 (ANI): Radio astronomers have directly measured the distance to a faraway galaxy, providing a valuable “yardstick” for calibrating large astronomical distances and demonstrating a vital method that could help determine the elusive nature of the mysterious Dark Energy that pervades the Universe.
“We measured a direct, geometric distance to the galaxy, independent of the complications and assumptions inherent in other techniques,” said James Braatz, of the National Radio Astronomy Observatory (NRAO).
“The measurement highlights a valuable method that can be used to determine the local expansion rate of the Universe, which is essential in our quest to find the nature of Dark Energy,” he added.
Braatz and his colleagues used the National Science Foundation’s Very Long Baseline Array (VLBA) and Robert C. Byrd Green Bank Telescope (GBT), and the Effelsberg Radio Telescope of the Max Planck Institute for Radioastronomy (MPIfR) in Germany to determine that a galaxy dubbed UGC 3789 is 160 million light-years from Earth.
To do this, they precisely measured both the linear and angular size of a disk of material orbiting the galaxy’s central black hole.
Water molecules in the disk act as masers to amplify, or strengthen, radio waves the way lasers amplify light waves.
The observation is a key element of a major effort to measure the expansion rate of the Universe, known as the Hubble Constant, with greatly improved precision.
That effort, cosmologists say, is the best way to narrow down possible explanations for the nature of Dark Energy.
“The new measurement is important because it demonstrates a one-step, geometric technique for measuring distances to galaxies far enough to infer the expansion rate of the Universe,” said Braatz.
Dark Energy was discovered in 1998 with the observation that the expansion of the Universe is accelerating. It constitutes 70 percent of the matter and energy in the Universe, but its nature remains unknown.
Determining its nature is one of the most important problems in astrophysics.
“Measuring precise distances is one of the oldest problems in astronomy, and applying a relatively new radio-astronomy technique to this old problem is vital to solving one of the greatest challenges of 21st Century astrophysics,” said team member Mark Reid of the Harvard-Smithsonian Center for Astrophysics (CfA). (ANI)
- Now, measure universe 3 times farther using super-sharp radio 'eye' - Feb 21, 2011
- NASA debunks one alternate theory to dark energy - Mar 15, 2011
- Green Bank Telescope to shed light on mysterious 'dark energy' of universe - Jul 22, 2010
- New experiment may reveal how first galaxies formed and evolved - Dec 09, 2010
- Researcher computes universe's expansion speed - Jul 28, 2011
- Largest 3D map of universe unveiled - Aug 09, 2012
- Scientists create largest-ever three-dimensional map of distant universe - May 02, 2011
- Massive galaxy cluster weighs as much as 800 trillion Suns - Oct 14, 2010
- Could city lights help locate alien civilisations? - Nov 04, 2011
- Measuring the cosmic distance using supernovae - Oct 25, 2010
- Astronomers identify extremely unusual galaxy - Mar 22, 2012
- 10 new massive galaxy clusters discovered - Nov 02, 2010
- Cosmic clocks can help unravel universe's mysteries - Jun 25, 2010
- Report enlists top priority research activities for astronomy and astrophysics - Aug 14, 2010
- Hubble telescope spots dwarf galaxies - Nov 11, 2011
Tags: astronomical distances, expansion of the universe, faraway galaxy, geometric technique, green bank telescope, hubble constant, james braatz, light waves, max planck, max planck institute, million light years, national radio astronomy, national radio astronomy observatory, national science foundation, radio astronomy observatory, radio telescope, radio waves, robert c byrd, very long baseline array, water molecules