The universe may appear formless because it is so vast, but it has a shape that astronomers can observe. So, what does it look like?
Physicists believe that Universe flat. Several lines of evidence point to this flat universe: the residual light from the great explosionthe rate of expansion of the universe in different locations, and the way the universe “looks” from different angles, experts told Live Science.
David Spiergel (Opens in a new tab), a theoretical astrophysicist and professor emeritus of astrophysics at Princeton University, has researched the shape of the universe for decades. In a 2003 study published in Astrophysical Journal (Opens in a new tab)Spiergel measured anomalies in the cosmic microwave background (CMB), the residual light from the Big Bang, which was observed by NASA’s Wilkinson Microwave Anisotropy Probe (WMAP) and later by the European Space Agency’s Planck spacecraft.
The amounts of positive and negative energy in a flat universe are exactly the same, thus canceling each other out. If the universe had a curvature, one would be higher than the other. “A flat universe corresponds to a universe without energy,” Spiergel told Live Science.
In this case, WMAP measurements of the CMB fluctuations suggested that the universe was infinite and flat. Spergel also compared these measurements with those made by the European Space Agency’s Planck spacecraft, which further constrained the potential shapes the universe could take.
“We can measure the curvature with some uncertainty, so we can say the curvature is zero with some uncertainty,” Spergel said. “While we can reduce uncertainty, at best we are only constraining engineering.”
Another reason Spergel is positive that the universe is flat is its rapid expansion, which was captured by Hubble constant. Because the universe came out of existence in the form of a compressed ball issue To expand outward at remarkable speeds, all that stretching made it flat, or at least as close to flat as possible.
Evidence for the flatness of the universe also appears in what is known as the critical density. At a critical density, the hypothetical universe will be flat and eventually stop expanding, but only after an infinite time, according to Swinburne University of Technology (Opens in a new tab) in Australia. If the hypothetical universe were more dense than this, it would be curved like a ball and eventually collapse in on itself due to gravity A proposed phenomenon known as the “big crisis”.
But all measurements of our real universe indicate that it is just below a critical density, which means that the universe is flat and will expand indefinitely.
There’s another piece of evidence that the universe is flat: it’s isotropic, meaning it looks the same from every angle. Anton Chudaikin (Opens in a new tab)a physicist at Russia’s Nuclear Research Institute, and his colleagues looked at data on oscillations in ordinary or “baryonic” matter, as well as models of how atomic nuclei heavier than hydrogen formed shortly after the Big Bang, estimating the curvature of the universe.
“In different geometries, matter and light evolve differently, which allows us to extract the three-dimensional shape of the universe from the observational data,” Chudaikin told Live Science.
Research published in the magazine physical review d (Opens in a new tab), found that the universe was flat with an accuracy of 0.2%, and the researchers wrote in the study: “The data we collected indicate that the spatial curvature corresponds to zero.” “This means that our universe is within infinite statistical uncertainty.”