A quarter of the universe in one nifty, 3D graphic
While it may seem impossible to wrap our heads around the idea of one galaxy, scientists have created a 3D map in an effort to better understand the size and scope of 1.2 million galaxies. The map, which was created by scientists from the Baryon Oscillation Spectroscopic Survey (BOSS), a program within Sloan Digital Sky Survey III (SDSS-III), was recently published in a study and represents 650 cubic billion light years – aka just one quarter of the entire universe.
Pinpointing the exact size of the universe is no easy task and one that has kept astronomers busy since the dawn of astronomical study. The first major breakthrough occurred in 1929 when Edwin Hubble discovered the phenomenon called a “redshift,” providing evidence for an expanding universe. Combining that information with the estimated mass of the universe, researchers naturally assumed the expansion of the universe was slowing down.
That all changed when, in 1998, two teams of scientists independently found the universe to be expanding at an accelerating rate. Today, scientists generally accept the theory that dark energy is the invisible force behind the universe’s expansion. In line with that theory, BOSS measured density fluctuations of regular matter called “baryonic acoustic oscillations” (for which the survey is named) providing a "robust standard ruler for measurements of cosmic distances."
Credit: Jeremy Tinker and SDSS-III
Looking at the map, you’ll notice millions of points in various colors that represent the galaxy’s distance from Earth. Yellow dots mark the galaxies that are closest while purple points mark those that are the farthest away. How far away exactly? Try 12 billion light years.
In a press release, University of St. Andrews astronomer Rita Tojeiro said the team saw "a dramatic connection between the sound wave imprints seen in the cosmic microwave background 400,000 years after the Big Bang to the clustering of galaxies seven to twelve billion years later. The ability to observe a single well-modeled physical effect from recombination until today is a great boon for cosmology.”
While scientists still lack the ability to definitively measure dark energy, observing the nebulous force’s effect on its surroundings can provide a clearer idea of how the universe works. And, lucky for us without scientific minds, we get to look at a really cool map of the galaxies in the process.