How old and big is Our Universe?

Do you ever stop and wonder about the planet you live on? Have you ever thought about whether there is life on other planets or not? The biggest question is – How old and big is the universe? It is much bigger than us and all planets combined. Age is just a number. However, you should know the age of the universe because it is important to know where you reside. According to scientific research, the planet is 13.81 billion years old. Imagine if the universe had to blow candles on its birthday! Is there such a big cake to accommodate that many candles?

What is Universe?

The Universe is everything that exists. It includes the physical matter as well as energy. It includes all the planets, galaxies, stars and all the contents of the space. The word comes from a French word called Univers which came from a Latin word called Universum. The definition says that it is made up of two elements – time and space. Is the size of Earth infinite? How did the scientists find out the age? Everything seems like a mystery to you but we have explained it all in this article.

The question is – How did the scientists get to know the age of the universe? Well, there are two methods for that.

  1. By measuring how it is expanding so fast.
  2. By the study of old objects.

We shall cover two aspects in the article –

Firstly, we would try to find out how the Scientists determined the age of the universe.

Secondly, we would be discussing about the size of the universe. A romantic poet would use phrases like, “I love you more than the whole universe.” Nothing can be bigger than the universe but feelings of fondness cannot be measured and so, it is always compared to the universe.

night sky

How old is our universe?

Science is objective and there can only be one answer to the question. The Universe is estimated to be 13.81 billion years old. Our Universe was hotter and smaller earlier but now it has expanded and cooled down. You would need to understand the theory of Big Bang Theory to know the age of the universe.

The Big Bang Theory is basically the explanation of how this universe began. The scientific theory explains how the universe started and then the galaxies and stars were made. The Universe was made up of four cosmic forces. It was small, hot and dense. There were no stars, structure, form or atoms which are termed as a singularity.

big bang theory
Evolution of the universe. cosmic timeline and evolution of stars, galaxy and universe after big bang

The discoveries in Physics and Astronomy show us that our Universe did have a beginning. Most people think that God created the Universe but the Scientists have discovered that there is no divine power behind it. The universe kept expanding and that is how the Scientists and Astronomers were able to measure the age.

The Universe is older than we thought it would be and it comprises of ingredients that you would not have imagined. It has been expanding since the day it was born. However, it is expanding slowly but that is good news for us because it is cooling down. In the beginning, it was hot and compressed. Do you know that it is expanding at a rate of 67.3 kilometres per second? In order to measure the expansion rate, you would need to understand the Hubble Constant.

It is a unit of measurement which is used to describe the expansion of the universe. According to NASA, if the universe’s expansion rate slows down, it is because there is a dark matter which is interrupting the growth. If the expansion is taking place fast then there is dark energy which is pushing it to expand faster. Hubble constant, also known as Cosmology, is used for measuring the expansion rate.

There are many factors which determine the value of this constant. What matter controls the universe? Density also plays a key role here. In order to determine the composition and density, the Scientists rely on WMAP. It is a mission by NASA which is called Wilkinson Microwave Anisotropy Probe and ESA Planck (space probe). These missions are able to determine the composition, expansion rate and density of the universe. There is a concept of observable universe. Whatever light that we see, it has been travelling for 13.8 billion years. Planck calculated the Universe to be 13.81 billion years old. It studied the cosmic microwave background.

hubble's law and constant
Hubble’s law and constant


What are the ingredients of the universe? What is it made up of? You would be enthralled to know that it is made up of 4.9% of normal matter, 26.8% of dark matter and 68.3% of dark energy.

The normal matter consists of protons, electrons and neutrons. The stars and books around you are all made up of normal matter. Dark matter is invisible to the human eyes. We only see the effects of it. How? It is through gravity. It controls the behaviour of galaxies.

In the year 1998, the Dark Energy was discovered. This is the most vital factor in the expansion of the universe. It is believed that the scientists looked for the oldest stars to determine the age. Astronomers use globular clusters to renovate the history of the galaxy. The globular clusters are the dense collection of stars.

The oldest ones are between 11 billion years to 18 billion years. The number is uncertain but it is certain that the Universe cannot be younger than the stars.

The cosmic microwave background (CMB) is electromagnetic radiation left over from an early stage of the universe in Big Bang cosmology

Can we measure the size of the universe?

How big is the universe? If the universe has been expanding over the period of time then the size must be changing as well. The size also depends on the shape. The scientists predicted that it may be like a sphere, infinite and just like a saddle. Some also said that it could be flat and infinite.

An infinite universe has no possibility of being measured. It has a finite age but the size is unknown. Many Scientists came up with theories that the observable Universe is 46 billion light years. The universe is a big place. How big is it? The observable universe has been measured as 28 billion parsecs which is 93 billion light years. If you went on an expedition to cover the entire distance, it would move on forever. According to Science, we do know that universe does end somewhere. However, it is some far off place which is unknown.

If you started calculating the distance between New York City to the moon or the distance from India to the planet Venus, you will not be able to measure the size still. The Astronomers use light years to determine the size of the universe. Do note that one light year equals to 9,458,000,000,000 kilometres. So, if the Universe is 46 billion light years then you can do the calculation.

Also, you need to understand that the observable universe is only the part which we can see. The universe is much larger than that.

Mulit Universe

Do we live in a Multiverse?

Could be we be living in a multiverse? What does that mean? We feel that we live in one universe but there is a possibility that there could be multiple universes. It is also called meta-universe. The multiple universes within thin the multiverse is referred to as parallel universes or alternative universes. In the year 1952, Erwin Schrodinger gave an inspiring lecture and he warned the audience that theory may seem lunatic. He mentioned that there could be other universes. According to Stephen Feeney and his colleagues of University College London, the universe is bruised and there are chances that it collided with other universes many times.

Scientists discovered a cold spot several light years away. The spot is cooler than its neighbouring areas. The Scientists believed that the universe collided with another bubble universe and it may have caused the bruise known as the cold spot. If our Scientists find more evidence then we would be able to get the first evidence of another universe.

In a nutshell, the size of the observable universe is 46 billion light years but it is just the observable part. It is far bigger than we think it is. Astronomers and scientists are still trying to measure the size. As for the age of the universe, you do know the factors that play an important role to determine the age. It is the expansion rate and also, the age of the stars. Isn’t it amazing that we live in the universe and we are just a small part of it? What if there is no end to it? Would it ever be possible to travel the universe? We are not sure about that but it is given that the topic is interesting.