What does the universe look like?

This is a great question, and one that many astronomers and physicists have spent their careers trying to answer.

The widely accepted theory is that the universe began with the Big Bang- a massive explosion which propelled all matter in the universe outward and is continually expanding to this day. When explosions occur in space, we might expect them to take a rounded shape like bubbles which form from air being passed through a bubble-wand....

This is a great question, and one that many astronomers and physicists have spent their careers trying to answer.

The widely accepted theory is that the universe began with the Big Bang- a massive explosion which propelled all matter in the universe outward and is continually expanding to this day. When explosions occur in space, we might expect them to take a rounded shape like bubbles which form from air being passed through a bubble-wand. Contrary to this phenomena, scientists believe the universe is generally flat! Based on the density of the observable universe, we can infer that it is infinite on all sides, or flat. Astrophysicists rely on density to determine the shape of the universe as an extension of the Big Bang theory, which suggests that all matter is continually expanding outward. Density describes the spread of matter throughout volume, and in a finite or spherical universe, we would expect the density of matter to "build up" towards the outer limits. 

It has also been suggested that the universe has a slightly curved shape, like a saddle. This is based on observations of variations in the temperature of cosmic background radiation.