Everything that we can touch, sense, feel, detect, and measure is part of the Universe. It includes stars, planets, light, dust clouds, galaxies, and time. Before the Universe was born, matter, space, and time were non-existent. The Universe is made up of millions of galaxies. Each of these galaxies has millions of stars in them. As the exact size of the Universe remains unknown to us, we cannot see its edge. The Universe neither has an edge nor a centre.Â
Birth of the Universe
The Big Bang Theory explains the birth of the Universe. When the age of the Universe was only 10-34 of a second or more, a huge explosion happened in the Universe, and it led to the expansion of the Universe. The speed of its expansion was faster than the speed of the light. During this time, the size of the Universe doubled at least ninety times. During the first three minutes after the Universe came into existence, the Big Bang nucleosynthesis happened, and the light elements were born. Around 9 billion years after the Big Bang, the birth of our solar system took place. The Universe that we know today was created in 7 days.
Composition of the Universe
The Universe is made up of all matter and energy. The mass of the Universe is composed of baryonic matters, which are galaxies, planets, clusters, and gas clouds. This mass can be observed. The mass of the Universe that remains invisible is called dark matter. The Universe also has dark energy. The elements found in the Universe after half a billion years after it was formed, were helium and hydrogen, and these particles were not heavy. 0.3% of the Universe is made up of neutrinos. Dark energy constitutes about 73% mass of the Universe.Â
How old is the Universe?
One of the most debated questions in Astronomy is how old our Universe is. Many astronomers believe that the age of the Universe is 13.8 billion years. According to some, our Universe is much older, while others believe it is much younger. The age of the Universe is calculated using various ways. One of the ways of calculating the age of the Universe is to find the most ancient planet, star, or galaxy in the Universe. Methuselah is the oldest planet discovered so far. It is around 14.5 billion years old. GN-z11 is the oldest galaxy discovered so far. It is around 13.4 billion years old and about 32 billion light-years away from the Earth.Â
How old is the Earth?
The Earth is about 4.54 billion years old, so the Universe is around 3 times older than our planet Earth. The Milky Way Galaxy is around 13.5 billion years old. The oldest black hole discovered to date is around 13.8 billion years old.Â
What do you mean by a galaxy?
We live on a planet named Earth. Earth is part of our solar system. Our solar system is a tiny part of a galaxy called the Milky Way. Like other galaxies, there is a huge black hole in the middle of our galaxy. Besides the Milky Way Galaxy, there are many other galaxies in the Universe. According to the studies performed by many scientists, it is estimated that it has a hundred billion galaxies in it.Â
Types of galaxies
Galaxies have different kinds of shapes. Some of the galaxies are spiral in shape, like the Milky Way Galaxy. Their appearance is like a pinwheel with curved arms. Some other galaxies are elliptical. Some galaxies do not have regular shapes and look like a splash.
The future of the Universe
- The Big Freeze Theory:Â The observations made so far suggest that our Universe will keep expanding, and as it expands, it will become cooler. A time will come when the Universe will be too cold, and then there will be no life. This theory is named the Big Freeze Theory.Â
- The Big Crunch Theory: Another theory suggests that our Universe will expand in the reverse order. When this happens, the Universe will collapse again and may lead to another Big Bang. This theory is called the Big Crunch Theory.Â
- The Big Rip Theory:Â According to this hypothesis, everything in the Universe will get torn into shreds. During this process, the dark energy will be stronger than gravity. It is the Big Rip Theory.Â
Conclusion
There are endless mysteries associated with the Universe. Scientists could put forward certain theories regarding the content, formation, shape, and age of the Universe. There are many questions about the Universe that are yet to be answered. There are many theories regarding the age of the Universe. Similarly, people worldwide are eager to know what will happen to the Universe in the future. Cosmologists have put forward many theories to predict the future of the Universe.Â