We all learned in our science class at school that the universe started with The Big Bang. Today’s blog is hopefully going to tell you what actually banged, when it banged and how we know this bang actually happened!
In the very beginning space, time and absolutely everything we can see and feel was compressed into an infinitely hot and dense point. All of what would become the laws of physics, chemistry and biology were contained within this point. Imagine if you will, every piece that would make up every star, planet and galaxy compressed into one very tiny space. This is known in physics as “The Singularity”. Eventually the pressure exceeded and BANG!
This event happened 13.8 billion years ago to be fairly precise and that is how old our universe is. This was a catastrophic event in what would become space and early matter accelerated away in all directions faster than the speed of light!
The very first microscopic pieces of matter to form were atomic particles known as protons, neutrons, and electrons. They appeared around 3 minutes after the Big Bang but a electrically neutral nuclei didn’t arrive for thousands of years later. The three main building blocks of matter born in the early universe were hydrogen atoms, small amounts of lithium and my personal favourite helium.
Large clouds of these elements formed unbelievable clouds in space which would cool down considerably to start making stars. Our sun itself is a star. It is good to note that the sun isn’t on fire or burning, it is hydrogen atoms joining (fusing) together into helium atoms. The process continues throughout the life of the star and has been taking place since very close to the beginning of time itself.
Star clusters came to be and soon after galaxies were forming. As there was more matter in space, it became attracted through gravity and started to fuse together. This is another nice opportunity to tell you all that space is not devoid of gravity, there is enough of it up there to keep the stars orbiting the centre of the galaxy, which contains a supermassive black hole called Sagittarius A. In galaxy formation there is thought to be a supermassive black hole at the centre of every galaxy but don’t panic, it’s not going to suck everything into it. I’ll go into blackholes in great detail in a future post and I promise you won’t be disappointed.
Other atoms and particles were created as the universe cooled as time went on. The more matter there is, the more gravity is present. Iron, ammonia and other metallic elements were born to become cores of planets. Gravity attraction built all of our planets bit by bit until we ended up with 8 planets and their moons orbiting them. It’s also good to note that gravity is not a downward force, it is circularly inward in all directions hence why planets and moons are spherical and galaxies are predominantly round.
So how do we know this happened? With radiation detecting telescopes. In space we can see radiation scattered in all directions throughout the observable universe. It is called The Cosmic Microwave Background Radiation and is visible to this day with a radio telescope. It is the earliest known light and makes the big bang theory consistent. Edwin Hubble (physicist and man who the space telescope is named after) observed that that the universe is expanding. The expansion rate is 71km per second per megaparsec (a parsec is a unit of distance used in astronomy). This is called the Hubble Constant in Physics.
So if we know the universe expanding with the current laws of physics, we can turn the clock back using Einstein’s General Relativity theory and take the universe back to the dense point – the singularity.
Our own earth is 4.54 billion years old, and life on our early earth wasn’t too pleasant. The earth was extremely hot and was bombarded with rocks and meteors as our solar system hectically formed. Some biologists argue that these rocks hitting the earth contained hydrogen and oxygen which would eventually become – you guessed it… WATER. Water seems to be the basis for all life in most conditions and this oxygen then helped to form our atmosphere which protects the earth’s life.
So I will leave you with this. Space based telescopes can see galaxies billions of light years away from us. All galaxies have billions of stars and there could be trillions of planets orbiting those stars. If the above theory is correct about the origin of life on earth after the big bang for our planet. What are the chances this happened on billions of other planets? Billions of light years from earth.
Brought to you by Jude Morrow. Edited by Amy King.