Every object in front of our eyes has a shape. The Earth we live on, the solar system that encompasses it, and even the Milky Way galaxy that contains numerous solar systems all have specific shapes. But what about the shape of the universe?
Determining the shape of the universe is akin to trying to infer the shape of a house while staying inside it. What would the universe look like if you could somehow step outside of it and take a view?
The spherical shape is the prediction of many people. Because many people think that after the Big Bang, the universe has been expanding at the same speed in all directions. However, according to current studies, the speed at which the universe is expanding is different for different direction.
According to Einstein's general theory of relativity, the universe is likely to exist in 3 forms. They are,
- Flat shape
- Spherical shell
- Saddle shape
According to cosmologist David Spergal , "the shape of the universe tells its past and future". The fate of the universe depends on its shape.
This shape varies depending on its density, which refers to how much mass (or) matter is spread out over the volume of the universe.
Critical density:
Objects with a lot of mass, warp the spacetime fabric of the universe. When it reaches a certain density, the universe stops expanding. This density is called The critical density. Scientists have estimated that its value may be in the range of 1/10²⁶ kg/m³ to 3/10²⁶ kg/m³ .
Perhaps, if the density of the universe were greater than this density, it would be in the shape of a spherical shell . [A closed coconut shell-like structure]
Image credit: wikimedia commons |
The universe, which began with a big bang at some point on the surface of this system, will expand in all directions and meet at another point in this planetary system. After this, the universe will stop expanding. Here, the universe cannot be infinite.
After this, scientists believe that the universe is likely to contract again. This event has been named "The Big Crunch" .
Perhaps, if the density of this universe were equal to its Critical density, it would continue to expand in a flat shape, without end.
When the density of the universe is less than its original density, it continues to expand in a saddle shape.
Shape of the universe:
As the universe expands, all the objects in it move away from each other. In the early twentieth century , astronomer Edwin Hubble discovered that all the distant galaxies were moving away from our Milky Way galaxy. This led him to predict that the universe was expanding.
Then in 2001, The Wilkinson Microwave Anisotropy Probe was launched by NASA to study the cosmic microwave background .
It's another goal is to discover the shape of the universe. Based on the information obtained from this, in 2013, scientists from NASA announced that "The universe is flat."