Astronomy
Our Universe is 13.8 billion years old, it emerger through the famous “Big Bang”. After this, gamma rays burst 13.1 billion years ago leading to the formation of the first galaxies some 12.85 billion years ago. Our galaxy- “The milky Way” is said to be formed about 11 billion years ago and its disk formed 8.8 billion years ago. Then the formation of the solar system took place 4.57 billion years ago. Our solar system included many planets and one of them came to be known as Earth where life exists at the moment. The oldest rocks known on Earth are approximately 4.4 billion years old. Life has evolved on this planet for years and years. Starting with algae as evidence of life emerging on Earth 4.1 billion years ago, now we have a huge population of mankind, animals, aquatic life, plants and trees on this planet. But all of these have also evolved gradually, primates became apes, apes became hominids, evolution continued and finally became homo sapiens.
The universe follows a chronology that can be used to predict its past as well as future.
- The very early universe: In this stage, four fundamental forces of interactions emerged: firstly gravitation, then electromagnetic, then weak and strong interactions. The space started expanding and cosmic inflation caused supercooling of the hot universe.
- The early universe: This period of the universe lasted for about 370,000 years. Here, subatomic particles started forming containing both matter and anti-matter.
- The Dark Age: In this period large-scale structures starts emerging in the universe. This age continued from 370000 to 1 billion years. After the process of recombination and decoupling, the universe was transparent. This was the period where rocky planets emerged and the universal temperature was also suitable for liquid water.
- The universe as we know now: This period is currently in progress and started about 1 billion years ago to 12.8 billion years ago. Solar systems emerged in this period along with the first traces of life. Dark energy keeps accelerating the expansion of the universe whereas thinning of matter helps in slowing down the process.
- The far future of the universe: At some time, the universe will end and stars will no longer be born again. Expansion of the universe will be limited to local galaxies. And after this universe will meet its fate and expand into infinity obliterating into nothing quantifiable.
The Universe has been in constant change. All its elements are not steady but in motion all the time. It is believed that the Earth in coming millions or billions of years would again observe gamma-ray burst, sea levels will rise, a major asteroid will hit its surface and a supervolcano will erupt, even ice age may take place again, Sun’s temperature will increase, its core will burst, all kind of life on Earth will be destroyed, all planets will become rocks and sun will become a white dwarf. The stars will also eventually run out of fuel and there will come an eternal night in the universe with only darkness around. And soon the universe will end slowly and gradually leaving only the white dwarf sun to light the universe with its fading luminosity among dead stars, and black holes. During this time if we are to find that multiverse is a possibility then maybe we will also find ways to travel to other habitable universes. They also say that the universe will start over again. But all this is based on current theories. Future is still being written.