The Universe Has No Sense of Direction, New Study Finds
Scientists have discovered that the universe looks the same in all directions.
In a new study published in Physical Review Letters, the researchers have found that the universe is neither stretching in a preferred direction or spinning, but rather expanding identically in every direction. While the stars and galaxies that fill the universe form unique patterns, the universe itself does not have a preferred location or direction, and that there are no irregularities or differences that could orient a space traveler.
The researchers studied measurements of the cosmic microwave background (CMB)--the remnant radiation from the Big Bang--taken between 2009 and 2013 by the European Space Agency's (ESA) Planck satellite, the same satellite that captured data about the polarization of CMB across the sky. The researchers modeled a comprehensive variety of spinning and stretching scenarios and how these could be seen in the CMB, including polarization. But if the stretching and spinning had been present, there would have been hot and cold spots or distortions along a particular axis in the real map of the cosmos from Planck, but they did not find any.
"The finding is the best evidence yet that the universe is the same in all directions," Daniela Saadeh of the University College London Physics and Astronomy and first author of the study, said in a news release.
"Our current understanding of the universe is built on the assumption that it doesn't prefer one direction over another, but there are actually a huge number of ways that Einstein's theory of relativity would allow for space to be imbalanced. Universes that spin and stretch are entirely possible, so it's important that we've shown ours is fair to all its directions."
The findings of the study support the assumptions made in cosmologists' standard model of the universe, which assumes that the universe is isotropic and appears the same in every angle or direction.
According to the researchers, there are ways that the universe could be anisotropic or different depending on the direction it is viewed from. If the universe expands at different rates in different directions, then the universe could be anisotropic and would mean serious implications on a large number of studies about the cosmos. It would also influence how the universe would look to this day.
"This is a serious challenge, as we found an enormous number of ways the Universe can be anisotropic," Stephen Feeney of Imperial College London and collaborating author in the study, said in the same statement.
"It's extremely easy to become lost in this myriad of possible universes -- we need to tune 32 dials to find the correct one."
The new study is the most in-depth analysis on a long-held assumption in physics, using a wealth of data from the Planck satellite.