In an attempt to better understand the nature of the expansion of our universe, scientists have created a 3D map plotting the locations of 1.2 million galaxies. This map may help give astronomers new details about how the universe has been expanding, which will help us learn more about the mysterious force that scientists believe has been driving the expansion.
Published in a new study, the 3D map shows 650 cubic billion light years, which is just a quarter of the known universe. Each point in this map isn’t a star: it’s an entire galaxy. The map was created by scientists working on the Baryon Oscillation Spectroscopic Survey (BOSS), a program of the Sloan Digital Sky Survey III (SDSS-III).
This survey examined fluctuations in the density of regular matter, which serve as a “robust standard ruler for measurements of cosmic distances.” Those fluctuations, called baryonic acoustic oscillations, are an ideal tool for plotting the relative positions of each galaxy. In the map, the purple dots mark the galaxies that are farthest away, while the yellow ones represent galaxies that are closer to us. This is important, because it allows scientists to figure out the relative motion of each object, which in turn lets them determine just how fast they’re moving away from one another.
Scientists have always wondered exactly how big the universe is, but it wasn’t until 1929 that Edwin Hubble (the guy they named the telescope after) began measuring how galaxies move away from an observer. This is called a redshift, which occurs as the wavelength of energy lengthens, moving toward the red end of the spectrum. Hubble recognized that this meant that the universe itself was expanding. This is a fundamental theory that led to even bigger revelations, such as the Big Bang.
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SOURCE: The Verge, Andrew Liptak