What is the shape of the universe?

• The universe is flat, hyperbolic or spherical
• The shape of the universe depends on the curvature of space
• The shape of the universe will determine whether space is finite or infinite

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1. How the shape of the universe is determined
2. Is the universe infinite?

Most of the objects we can see in space, such as stars and planets, are spherical, but is this also true of the universe as a whole? Is the universe also spherical or has another 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 hyperbolic, and positive curvature means surface. Which of these three shapes describes our universe?

How the shape of the universe is determined

The three possible shapes of the universe, depending on the value of the curvature. NASA

Determining the shape of the universe is no easy task. Still, the universe is unimaginably gigantic, and therefore 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 over that distance. The farthest 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. Thus, 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 to the CMBR. Knowing the size of Earth’s orbit and the distance to the CMBR, scientists can determine the curvature of these lines. By calculating the curvature, scientists can 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, the CMBR observations revealed that our universe has a curvature of zero, meaning that the universe is flat. However, don’t think of the flat universe as being flat like a sheet of paper. Rather, the flat universe is still three-dimensional. Furthermore, the universe may be so large that any attempt to determine its shape is pointless. After all, a large universe that has curvature will appear indistinguishable from one that does not, assuming it is large enough.

Is the universe infinite?

The shape of the universe determines whether the universe is finite or infinite in its space. To describe the topography of space, scientists use the term finiteness 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 compact and have boundaries, so it would be finite. Meanwhile, a flat universe can be infinite or finite. If the universe is in fact flat, as most data suggests, space could be infinite or finite.

Aidan Remple July 17, 2022 in Science