You have undoubtedly heard about the Big Bang, which is the most accepted belief about the origin of the universe. The idea that the primordial universe was smaller than the size of an atom and made of such dense and energy-rich particles that at some point, this speck could no longer contain itself. It exploded with such ferocity that it cast energy out faster than the speed of light and rapidly expanded. Its rate of expansion slowed down so that the energy converted into matter that coalesced into the stars, planets, and galaxies that populate the universe today.
Does that sound bizarre? It is one of the dozens of theories about the universe that stretch the limits of science and imagination. Some of these theories may cause you to question everything that you thought you knew about the nature of reality – which is kind of the point. The universe is weird. Keep reading to discover theories about the universe that will keep you thinking.
String theory turns everything you thought you knew about physics on its head.
In middle school science, you probably learned about the different particles that compose atoms: electrons, protons, and neutrons. Then there’s the tinier particles inside, quarks. You also learned about other forces, such as electromagnetism (what causes magnets to stick and electrical current to flow). Don’t forget about gravity, the strong nuclear force (what causes protons to stick together despite their positive-positive repulsion). What about the weak nuclear force (which causes nuclear decay)? If you went on to high school physics, you might know something about how gravity is contained in a particle known as the graviton, similar to how light is contained in the photon. You also have neutrinos, tiny particles that are akin to electrons but lack any electrical charge.
All of these particles and forces make up the Standard Model of physics. We expect that matter is composed of particles that predictably interact with each other through mathematical formulas. The problem is that the math doesn’t explain the universe, and in particular, gravity. However, what does fit the math is replacing those particles with very, very tiny strings. These strings vibrate in different ways, and the vibrations determine what particle or force they appear to be. Imagine that they are the strings on a violin, and the way that the violinist strums them determines what note is played. The particles and forces that the Standard Model explains are musical notes played by vibrating strings.