According to the National Aeronautics and Space Administration (NASA), dark energy, a mysterious form of force attributed for the accelerated expansion of the universe, makes up 68.3 percent of the cosmos.

The National Academy of Sciences said that the nature of this unknown energy is possibly the most important question in the field of astronomy today. Unveiling its mystery can greatly advance humanity's understanding of space, matter and time, but dark energy remains elusive.

In a bid to better understand this mysterious force, an international team of astronomers created the biggest-ever 3D map of distant galaxies. The scientists hope that this map could help them come up with the most precise measurements yet of dark energy.

The map relied on new measurements by the Sloan Digital Sky Survey (SDSS) III's Baryon Oscillation Spectroscopic Survey (BOSS) program. The SDSS is an ambitious astronomical survey that aims to provide detailed optical images covering over a quarter of the sky and a three-dimensional map of about a million galaxies and quasars.

BOSS measures the universe's expansion by measuring the size of Baryonic acoustic oscillations within three-dimensional distribution of galaxies.

Baryonic acoustic oscillations are anomalies or fluctuations of the distribution of matter in the universe, which is revealed by pressure waves that traveled through the early universe but became frozen in the matter distribution of the universe 400,000 years after the Big Bang.

By measuring the distribution of galaxies through the size of baryonic acoustic oscillations since that time, astronomers can more precisely measure how dark matter and dark energy influenced the expansion rate of the universe.

BOSS principal investigator David Schlegel, an astrophysicist at Lawrence Berkeley National Laboratory, said that they were able to construct the largest map for studying 95 percent of the universe that is dark.

The map shows dark matter gravitationally pulling galaxies toward other galaxies, and on a larger scale, reveals the effects of dark energy ripping the universe apart.

To come up with a precise measurement of the ancient pressure waves, BOSS needs to make an unprecedented galaxy map much larger than those by previous surveys.

"Using this map we will now be able to make the most accurate possible measurements of dark energy, and the part it plays in the expansion of the universe," said study researcher Florian Beutler from the Institute of Cosmology and Gravitation at the University of Portsmouth.

The construction of the map is described in a series of papers submitted to the Monthly Notices of the Royal Astronomical Society.

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