25 Key Facts About The Big Bang Theory You Might Not Know

Posted by , Updated on October 2, 2017


Accepted by majority of the modern astronomical community, the Big Bang Theory is the prevailing cosmological model and leading explanation of how the Universe began. While the main principle of the theory is quite well known (the Universe was formed by a sort of a massive blast of some ancient energy and has been expanding ever since), there are many facts about it that most people actually don’t know. What are these facts? From the Cosmic Egg to the Big Crunch, here are 25 Key Facts About The Big Bang Theory You Might Not Know.


Proponents of the Big Bang Theory believe that the Universe-forming Big Bang occurred around 13.7 billion years ago.

big bangSource: big-bang-theory.com

According to the theory, the Universe ballooned faster than the speed of light in the first second after it was born. That, by the way, does not violate Einstein's principles of speed as he said that the speed of light is the maximum speed anything can travel within the Universe...not the Universe itself.

speed of lightSource: space.com

Talking about Albert Einstein, the legendary physicist actually dismissed the theory when it was presented to him as a possibility. He rejected the idea that the Universe might have emerged from a much smaller and denser state.

Albert EinsteinSource: forbes.com

The concept that the expanding Universe could be traced back in time to an originating single point was first conceived by Belgian astrophysicist and cosmologist A. G. Lemaitre in 1927.

outer spaceSource: encyclopedia.com

Known as the cosmic microwave background, a cosmic fog that permeates the universe in every direction is considered the best evidence of the Big Bang Theory.

cosmic microwave backgroundSource: space.com


Despite the name of the theory, many experts suggest that what happened those 13.7 billion years ago, was actually a kind of expansion rather than explosion.

space expansionSource: big-bang-theory.com

Some scientists suggest the entire early Universe could have once been habitable. They even claim that some planets might have hosted microbial life forms for some 15 million years after the Big Bang.

bacteriaSource: space.com

The single super-concentrated point which later became the Universe before the Big Bang was called the “primeval atom” or the “cosmic egg.”

outer spaceSource: forbes.com

As incredible as it sounds, some scientists believe that right before the Big Bang, the Universe was compressed into a super hot and dense mass that was just a few millimeters across.

hand holding pebbleSource: nationalgeographic.com

The state of the Universe before the Big Bang is sometimes also referred to as a singularity. Singularities are zones that defy our understanding of physics because they are thought to have infinite density.

outer spaceSource: big-bang-theory.com

Many scientists believe that nothing (no time, space, or energy) existed before the singularity appeared that later turned into the Universe.

nothingSource: big-bang-theory.com

Proponents of the Big Bang Theory argue that the laws of physics and chemistry formed in the first few fractions of the first second of the Big Bang. These laws are manifested in the properties of the fundamental forces of gravity, the strong force, electromagnetism, and the weak force.

electromagnetismSource: encyclopedia.com

The name of the theory was actually coined by its most fervent detractor, Fred Hoyle. The English astronomer, who favored the Steady State Theory of the Universe, first used the term “Big Bang” during a BBC radio broadcast in 1949.

Fred Hoyle monumentSource: forbes.com

It was calculated that the early Universe was hot and dense enough to make virtually all the helium, lithium, and deuterium (hydrogen with a neutron attached) present in the Universe today.

atomSource: symmetrymagazine.org

Calvin and Hobbes, a daily comic strip by American cartoonist Bill Watterson, came up with an alternative name for the Big Bang, calling the event "Horrendous Space Kablooie." Surprisingly, the new name achieved some popularity among scientists.

Calvin and HobbesSource: democraticunderground.com

There was no “Eureka moment” associated with the discovery of the Big Bang Theory. Instead, it was a long process that took scientists years to develop into its current form.

space centerSource: space.com

When scientists Penzias and Wilson accidentally discovered the cosmic microwave background in 1964, they had no idea what it was. In fact, they thought it was a problem with their antenna caused by pigeons' droppings.

PigeonsSource: smithsonianmag.com

The fluctuations in the cosmic microwave background are only about 100 microKelvin in magnitude, which suggests the early Universe was almost 100% uniform. However, it was these slight fluctuations what gave rise to stars, galaxies, and other structures we see in the Universe today.

outer spaceSource: forbes.com

While light elements were formed in the first second after the Big Bang, heavier elements later "condensed" inside stars and spread widely in supernova explosions.

supernova explosionSource: damtp.cam.ac.uk

It's estimated that for the first 380,000 years, the Universe was essentially too hot for light to shine as the enormous heat from the Big Bang only created a dense plasma.

outer spaceSource: space.com

There are still some things and phenomena in the space (such as the dark matter or the dark energy) that are not explained by the Big Bang Theory itself.

dark energySource: symmetrymagazine.org

Next to the cosmic microwave background, there are 3 other proofs of the validity of the theory - expansion of the Universe according to Hubble's law, relative abundances of light elements, and distribution of large-scale cosmic structures. These are sometimes called the Four Pillars of the Big Bang Theory.

Hubble TelescopeSource: damtp.cam.ac.uk

According to the theory, the expansion of the Universe is still accelerating due to dark energy, an unknown form of energy that is believed to make up about 72% of the Universe.

outer spaceSource: space.com

In 2011, for the first time ever, astronomers found astronomical objects without heavy elements when they discovered pristine clouds of primordial gas. Since these gas clouds had no heavy elements, they likely formed in the first few minutes after the Big Bang.

gas cloudsSource: news.ucsc.edu

In one of possible scenarios for the ultimate fate of the Universe known as the Big Crunch, the Universe will eventually stop expanding and start collapsing in on itself. Then, however, another Big Bang might happen.

Big CrunchSource: space.com

Photos: Feature Image: shutterstock, 25. pixabay (public domain), 24. wikimedia commons (public domain), 23. pixabay (public domain), 22. static.pexels (public domain), 21. wikimedia commons (public domain), 20. Design Alex Mittelmann, Coldcreation, Lambda-Cold Dark Matter, Accelerated Expansion of the Universe, Big Bang-InflationCC BY-SA 3.0, 19. wikimedia commons (public domain), 18. static.pexels (public domain), 17. antony_mayfield via flickr, CC BY 2.0, 16. wikimedia commons (public domain), 15. JohnKeatBlack ScreenCC BY-SA 4.0, 14.  NASA/JPL-Caltech (public domain), 13. Mark Hurn, Plaque to Sir Fred Hoyle – geograph.org.uk – 1409956CC BY-SA 2.0, 12. pixabay (public domain), 11. Greg WilliamsCalvin wikiworldCC BY-SA 2.5, 10. Biswarup Ganguly, Understanding the Universe Exhibition – BITM – Kolkata-2015-02-28 3340CC BY 3.0, 9. Max Pixel (public domain), 8. pixabay (public domain), 7. wikimedia commons (public domain), 6. ESO/VPHAS+ team, VST images the Lagoon NebulaCC BY 4.0, 5-3. wikimedia commons (public domain), 2. ESO, Two very different glowing gas clouds in the Large Magellanic CloudCC BY 4.0, 1. anonymous, Big crunchCC BY-SA 3.0

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