The universe was born with the Big Bang, as a hot, dense point. Each second in the universe is approximately a hundredth of a billionth of a trillionth in age, so when the universe was just 10 to 34 seconds old, it experienced an incredible burst of expansion, known as inflation. The space expanded faster than the speed of light and during this period, the universe doubled in size, at least 90 times more than after the Big Bang.
After inflation, the growth of the universe continued but at a comparatively slower rate than before. However, as the space expanded, the universe began to cool and therefore, matter began to form. Roughly, 380,000 years after the Big Bang matter cooled enough for atoms to form and during the era of recombination a transparent, electrically neutral gas was formed. This created the initial flash of light, which is detectable today as “Cosmic Microwave Background Radiation”.
After this point, since there were no stars or bright objects formed yet, the universe plunged into darkness. However, 400 million years after the Big Bang, the universe emerged from the dark ages and during the “Epoch of Reionization” clumps of gas collapsed enough to from the first stars and galaxies.
The picture above shows the “Global Cluster” that has an estimated age of approximately 13.5 billion years. The Global Cluster is among the first objects of the galaxy, which was formed after the Big Bang.
The picture above shows the “Solar System”. Nine billion years, after the Big Bang our “Solar System” was born. The universe is estimated to be 13.7 billion years old and the solar system is estimated to be 4.6 billion years old.
The picture above shows that the space between the galaxies is expanding. This means as space expands, it carries galaxies, stars and planets away from each other, but these embedded objects stay exactly the same size.
The expansion of the universe gradually did slow down as matter in the universe began to form and pulled on gravity. However, five to six billion years after the Big Bang, a mysterious force known as “Dark Energy” began speeding up the expansion of the universe again. This phenomenon continues till today.
There are a few exceptions though. The “Andromeda Galaxy” instead of moving further away from the “Milky Way” is actually moving towards it. This is because the pull of gravity between the Andromeda and Milky Way is so strong that it overcomes the expansion of the universe. Scientists state that this pull of gravity will cause both these galaxies to collide in about four billion years.
However, billions of years from now, the force of expansion may overcome the force of gravity that holds galaxies together. Therefore, this expansion would become so strong that stars, planets and matter itself may get torn apart. This is one of the theories on how the universe will come to an end and if this is true, then the space between plants, stars and even atoms will expand in the far future.