The Big Bang Theory

The Big Bang – What Happened?

13.8 Billion Years Ago: The universe began as a tiny, hot, and dense point called a singularity.

This singularity suddenly expanded in an event called the Big Bang, releasing enormous energy.

• In the first fractions of a second, the universe grew exponentially in a process known as cosmic inflation.

• As the universe cooled, particles formed.

• Protons and neutrons combined to create atoms like hydrogen and helium, the building blocks of stars and galaxies.

How Do We Know?

Evidence such as the Cosmic Microwave Background, galaxies’ redshift, and Hubble’s Law all provide crucial insights into the expansion of the universe and support the Big Bang theory.

• Cosmic Microwave Background (CMB):
A faint glow of radiation detected in space, considered the leftover heat from the Big Bang.
• The Redshift of Galaxies:
Light from distant galaxies shifts to the red end of the spectrum, showing that they are moving away, meaning the universe is expanding.
• Hubble’s Law:
The farther away a galaxy is, the faster it moves away from us, proving that space is expanding.

Fun Facts

Here are some interesting facts about the universe:

• The universe is expanding faster than the speed of light in some places!
• You can hear echoes of the Big Bang as radio signals in space!
• The Big Bang didn’t happen at one point in space—it happened everywhere at once.
• The universe was once the size of a grain of sand before it expanded.

Review

Let’s quickly recap what we learned about the Big Bang theory:

• What was the tiny, hot, and dense point at the universe’s beginning called? Singularity
• What is the leftover heat from the Big Bang called? Cosmic Microwave Background (CMB)
• What particles formed first after the Big Bang? Atoms
• Which law explains that galaxies move faster as they are farther from us? Hubble’s Law