What were the original two elements in our universe?

The original two elements in our universe were Hydrogen and Helium.

1. The Big Bang: The universe began with the Big Bang around 13.8 billion years ago. This event produced a very hot, dense, uniform mixture of matter and energy.

2. Formation of Hydrogen and Helium: As the universe expanded and cooled, protons and neutrons began to combine to form the nuclei of simple elements. This process is known as nucleosynthesis. About three minutes after the Big Bang, the universe cooled enough to allow the formation of these light elements. The most abundant element produced was hydrogen, along with smaller amounts of helium and trace amounts of lithium.

3. Formation of the first atoms: As the universe continued to cool, it eventually reached a temperature where electrons could combine with these nuclei to form neutral atoms. This happened about 380,000 years after the Big Bang. At this point, the universe was filled with a "fog" of hydrogen and helium atoms.

4. Formation of the first stars and galaxies: Over hundreds of millions of years, gravity pulled these atoms together to form the first stars and galaxies. The intense heat and pressure in the cores of these stars triggered nuclear fusion, creating heavier elements like carbon and oxygen. These heavier elements were released into the universe through supernova explosions, seeding the universe with the raw materials for future generations of stars and planets.