Most of the objects we can see in space, such as stars and planets, are spherical, but is this true of the universe as a whole? Is the universe also spherical or is it some other shape? There are three possible shapes of the universe: flat, hyperbolic, and spherical. The shape of the universe depends on its curvature. Zero curvature means flat, negative curvature means excessive, and positive curvature means shallow. Which of these three shapes describes our universe?
How the shape of the universe is determined
The three possible shapes of the universe depend on the value of the curvature. NASA
Determining the shape of the universe is no easy task. After all, the universe is unimaginably gigantic, so determining its shape is difficult. To determine the shape of the universe, scientists must calculate the distance to the most distant regions of space that we can see, and then determine the curvature along that distance. The most distant we can physically see is the Cosmic Microwave Background Radiation (CMBR), over 13.7 billion light-years away. The CMBR is the oldest known light in the universe, and as far as we know, it is the first form of light since the Big Bang. So the CMBR is the maximum possible distance we can see.
To determine the curvature of space, scientists must draw a giant triangle. The base of the triangle is the Earth’s orbit around the sun, while the two lines joining the base are the distance from the CMBR. By knowing the size of Earth’s orbit and the distance from the CMBR, scientists can determine the curvature of these lines. By calculating the curvature, scientists can then determine the shape of the universe depending on whether the curvature is negative, positive, or zero.
Although the exact shape of the universe is still widely debated among scientists, CMBR observations have revealed that our universe has a curvature of zero, meaning that the universe is flat. However, don’t think that a flat universe is as flat as a sheet of paper. In contrast, a flat universe is still three-dimensional. Furthermore, the universe could be so large that any attempt to determine its shape is pointless. After all, a large universe that has curvature would seem indistinguishable from one that doesn’t, assuming it’s big enough.
Is the Universe Infinite?
The shape of the universe determines whether or not the universe is finite or infinite in extent. To describe the topography of space, scientists use the term bounding box to describe the size of the universe. For example, a universe that has no boundaries is infinite, while a universe that has boundaries would be finite. Whether or not the universe has boundaries depends on its shape. For example, a spherical universe would be solid and have boundaries, so it would be finite. Meanwhile, a flat universe can be either infinite or finite. If the universe is truly flat, as most data suggests, space can be either infinite or finite.
Aidan Remple July 17, 2022 in Science
