Scientists said the newly-developed 3D map allows astronomers to determine the amount of matter and dark energy that make up the present-day universe, which is now 13.8 billion years old. It is, as Gizmodo’s George Dvorsky wrote on Friday, “one of the most precise measurements of the expansion of the universe to date, and confirms a leading explanation for the dark energy physicists believe is driving that expansion”. “We are making our results and map available to the world”, Tinker added. They could then see a sharp connection between that newly born universe and the clustering of galaxies 7 to 12 billion years later.
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A slice of the researchers’ map showing about 1/20th of the sky.
The dots are colored in function of the distance towards Earth, with yellow for close galaxies and purple for distant ones. Galaxies appear to be highly clustered, revealing superclusters and voids. The map contains 48,741 galaxies, which is about three percent of the total BOSS survey set. Grey patches are small regions without survey data.
This worldwide team of scientists that are led by a British team all helped put together this most intensive map of the universe, that is also based on the Baryon Oscillation Spectroscopic Survey that focused on pressure waves that are observed travelling throughout deep space. Shaped by a continuous tug-of-war between dark matter and dark energy, the map revealed by BOSS allows astronomers to measure the expansion rate of the universe and thus determine the amount of matter and dark energy that make up the present-day universe.
The construction of the map is described in a series of papers submitted to the Monthly Notices of the Royal Astronomical Society.
According to Dr. Tinker and his colleagues, BOSS measures the expansion rate of the Universe by determining the size of the baryon acoustic oscillations (BAO) in the 3D distribution of galaxies. Scientists calculated a baseline “acoustic scale” for the BAO by measuring pressure waves that traveled through the universe when it was just 400,000 years old.
The result is that galaxies are preferentially separated by a characteristic distance, that astronomers call the acoustic scale. The original BAO rate can be determined by measuring pressure waves from the formation of the early universe which provides a yardstick to measure further expansion.
To view the oscillations, researchers looked at ancient soundwaves that became frozen in matter roughly 400,000 years after the Big Bang. The scientists hope that this map could help them come up with the most precise measurements yet of dark energy. They also tried to find out what were the effects of the dark energy in the expansion of the Universe. This map includes 120,000 galaxies over 10% of the survey area. The SDSS-III collaboration is a multi-filter imaging and spectroscopic redshift survey using a dedicated 2.5m wide-angle optical telescope, located at Apache Point Observatory in New Mexico.
Astronomers have mapped he universe based on a great survey of the universe in order to observe how dark energy is changing regions of the known cosmos. Baryon Oscillation Spectroscopic Survey program is created to focus on sound wave fluctuations between 7 billion and 2 billion years ago.
In a statement from SDSS-III, he commented that the latest have tied into a clean cosmological picture, providing strength to the standard cosmological model, emerged in the past 18 years.
Interestingly, the map shows that large clusters of matter tend to form due to their gravitational attraction, as predicted by general relativity.
Initial analysis of the map, Beutler said, indicate that the dark energy readings show that the universe’s expansion is evolving very slowly, if at all. Image credit: Jeremy Tinker / SDSS-III Collaboration.
Read the entire press release from BOSS co-leader Rita Tojeiro here.
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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. Founded in 1931, Berkeley Lab’s scientific expertise has been recognized with 13 Nobel prizes.
