The creation of the universe is one of the deepest mysteries that mankind has tried to explain.  We do not know how the universe was created, who created it, or why they created it in the first place.  So far, two main theories have been put forward to explain how our universe came into being, and which one you believe largely depends on your personal beliefs about the source of life and the whole of humanity.  The Big Bang theory suggests that everything in the known universe was caused by an explosion from an infinite tiny point of space and time.

Big Bang

Before the Big Bang

 The (moment) before everything starts is called cosmic inflation.  The cosmic inflation era, in theory, lasted from 10-36 seconds to 10-33 seconds later.  In that incredibly short time, all the matter in the universe has doubled itself to a trillion times more.  And it is the expansion that gave birth to what we know today as our universe.

 What Happened in the First Few Seconds?

 Even when all matter and energy were their smallest, they expanded.  It’s like a balloon, Lintott says.  Paint it without any air inside - as small as it can be and still exists.  If you blow up a balloon, no matter how big or small it is, it will roughly extend up to a sphere, he explains.  But in the case of our universe, so much mass was concentrated in such a small area that space itself began to expand (as seen above).  That expansion is what we now call inflation because everything starts moving faster than the speed of light, expanding faster after 10 ^ -34 seconds until things start to slow down.  This moment was called cosmic inflation and has been repeated countless times throughout history for fractal inflation.

 What Happened after 10 minutes?

 10-43 seconds - Photons begin to make space.  10-36 seconds - Forms electrons and nuclei, transfers photons to matter and antimatter.  After one microsecond - antimatter and matter destroy each other, returning to the energy that is absorbed by the photons.  After 3 minutes - the primitive soup is formed with equal amounts of substances and antidotes.  After 15 minutes - the quark combines to form protons and neutrons.  300,000 years later - protons and neutrons combine to form the atomic nucleus.  380,000 years later - the first atom appears.  1 billion years later - hydrogen clouds condense into galaxies, stars and planets.  13 billion years later - the present day has arrived!

Time stages

 What happened to our baby universe?

 Even the question we can ask is proof of how far cosmology and astronomy have come in recent decades.  Many discoveries in this field can be found in the groundbreaking work of Edwin Hubble, especially his observation that many galaxies are moving away from us.  The farther away a galaxy is, he realized, the faster it is moving;  Every three kilometers per second (about two miles per second) through which an object moves away from us, its speed increases by two more kilometers per second.  This relationship between distance and velocity is known as Hubble's law, and it was an incredible discovery in his time.
 Where did all the mass come from?
 Believe it or not, we have actually observed galaxies with redshifts greater than z = 1.8 (which corresponds to a cosmic period about 700 million years after the Big Bang).  These high-redshift objects are called high-z galaxies and expand our understanding of how large and old space they can be.  A popular hypothesis suggests that high-Z galaxies are formed by combining smaller, lower-redshift galaxies.  So the question is how did these low-red shift galaxies form in a universe of so little mass?  It is possible that huge black holes in galactic centers are responsible for accelerating gaseous clouds formed in the stars at a very early time in the history of the universe.

 Is dark matter even real?

 The biggest challenge in astronomy today is not finding the answer — finding out what we need to ask.  For decades, scientists have looked deep into space and observed light from objects that do not appear to have an obvious source.  Now, researchers at Italy's National Institute for Astrophysics believe they have discovered a new type of quasar বা or supermassive black hole যেখানে where particles of dark matter are destroying each other.  This will help explain how these dark galaxies came to be, but it also raises more questions about what dark matter is - and how much of it there is in our universe.

 Why does time run forward?

 We are all aware that we feel like time is moving in one direction.  So what about our world does it make us realize this way?  We look back on events that happened at a different time from now, but why do we feel the difference between the past and the future?  It seems surprising to think that we may be lagging behind over time, yet there doesn’t seem to be any obvious reason why this can’t happen.  The only answer is to accept that we have something fundamental in the universe - so fundamental and engaging in its construction - that it allows us to move forward with time.

 Dark Energy, Dark Matter, and Dark Radiation

 What is Dark Energy?  By dark energy, physicists mean a kind of invisible, yet-unknown force that is responsible for two-thirds of our universe.  We cannot see it directly because it does not interact with ordinary matter and light.  Why is the power of darkness not visible to us?  Physicists do not know, but they have some ideas.  Some people think that space itself expands faster and faster because of the dark energy (thus explaining its name).  Others believe that dark energy is related to a mysterious subatomic particle called a neutrino.  Why is Dark Matter not visible to us?  At least some types of dark matter do not seem to be able to interact with ordinary matter.

 What's next for physics?

 One possible future development is to try to identify the signature of primary inflation by finding a wound from space time in which our own universe collides with another bubble universe.  At extremely high power, it is possible that collisions between multiverse could occur frequently and leave an impression on our cosmic microwave background.  These collisions will also create gravitational waves whose signature can be found in today’s data.  Of course, there are other extensions of inflation outside of perpetual inflation, such as modulated instability, which may point to physics outside of GR.  The next big thing for cosmology might be to identify the evidence for what happened before our Big Bang.