The Big Bang of Primeval Atom!

How the Big Bang Idea Originated (Genesis of the Theory)

The roots of the Big Bang theory began in the early 20th century:

1. Albert Einstein (1915)

• Introduced the General Theory of Relativity, which showed that space and time are part of the same fabric.
• His equations suggested the universe should be either expanding or contracting.

1. Georges Lemaître (1927)

• A Belgian physicist and Catholic priest.
• Proposed that the universe began from a single, extremely dense point called the “primeval atom.”
• This is considered the first version of the Big Bang theory.

1. Edwin Hubble (1929)

• Discovered that galaxies are moving away from us.
• The farther a galaxy is, the faster it’s receding.
• This is Hubble’s Law, confirming that the universe is expanding.

Who Named It “The Big Bang”?

The term “Big Bang” was coined by Fred Hoyle in 1949 during a BBC radio broadcast. Ironically, Hoyle did not believe in the Big Bang. He used the term sarcastically to mock the idea. But the name stuck — and became the accepted term in science.

How the Theory Developed Further?

The Big Bang theory gained strong support through later discoveries:

1. Cosmic Microwave Background Radiation (CMB)

• Discovered accidentally in 1965 by Penzias and Wilson.
• This faint microwave glow is leftover energy from the early universe.
• It is one of the strongest proofs of the Big Bang.

1. Abundance of Light Elements.

• Predictions about amounts of hydrogen, helium, and lithium formed in the first few minutes match observations.

1. Large-scale structure of the universe.

• How galaxies and clusters are arranged fits with expansion from an early hot, dense state.

Connection Between Space and Time

Einstein’s theory shows:

• Space and time form a single four-dimensional continuum: ‘spacetime’.
• You cannot have space without time, or time without space.
• When the universe began expanding, time began flowing.

So the question “What happened before the Big Bang?”is like asking:

• “What is north of the North Pole?”
• At the North Pole, directions lose meaning.
• Similarly, before the Big Bang, before” loses meaning.

Did Time Exist Before the Universe? — Scientific Views

Scientists have different views, but the standard cosmological model says:

• Time began with the Big Bang.
• There was no “before” in the normal sense.

However, some theories attempt to explore this:

1. Quantum Gravity Models

These suggest the universe may have existed in a quantum state before classical time emerged.

2. Multiverse Theory

Suggests many universes exist, each with its own spacetime. Our universe’s Big Bang might be one event in a larger cosmic landscape.

3. Bounce Models (Loop Quantum Cosmology)

The universe may have gone through cycles: expansion → contraction → expansion In this view, something existed “before,” but not time as we understand it.

4. Stephen Hawking’s “No-Boundary” Proposal

Hawking compared the beginning of the universe to the South Pole on Earth:

• The South Pole is a special point, but not a “beginning” of south.
• In his model, time becomes “smooth” like a curved surface; there is no sharp point where time begins.

Quantum Fluctuations and the Vacuum

The idea that the universe arose from “nothing” is misunderstood.

Physics says:

• True emptiness does not exist.
• Even in a vacuum, quantum fluctuations constantly appear and disappear.
• Energy can spontaneously arise for tiny moments.

Some physicists propose that the universe might have emerged from these fluctuations, but this is still debated.

Final Summary:

• The Big Bang is an expansion, not an explosion.
• Space and time began together; time likely did not exist “before.”
• Lemaître proposed the theory; Hubble found evidence; Hoyle named it sarcastically.
• Modern physics shows there is no real emptiness — quantum fluctuations always exist.
• Scientists continue exploring what, if anything, existed before the universe.

courtesy : Vishakan Thambi