The Worlds Beyond

Since  time immemorial, people were fascinated by what they saw in the sky. They mapped the sky,measured time, and prepared calenders based on there  observations  and  recordings ;which led  to  the birth of of the oldest branch of science-astronomy.As the time moved  on  many scientists all around the world contributed to it  . Today  we  know a lot more about our universe.And  i  found it interesting to know about them.
In  this blog  you can learn about the past,present, the uncertain future,and the unimaginable phenomena  taking place  in it .I welcome you to the thrilling worlds and spaces beyond.
         We  will start our tour from within an atom to the extends of the universe

CONTENTS

The contents of this blog is as follows.
Click on the links below to display the posts

• The Atom
• More About The Nucleons 
• The Elementary Particles
• The Big Bang Theory
• What Happened After The Big Bang
• The Big Bounce Theory
• The Big Crunch Theory
• Stars-Introduction
• Stars-Birth
• Stars-Life
• Stars-Death 
• Black Hole
• Quasars 

The Atom

To learn about the vast universe we live in ,we  must learn about the smallest particles in it -the atom. To put it simply an atom is the fundamental unit of  matter. The internal structure of an atom is pretty much interesting. It consists of a dense central  nucleus surrounded by negatively charged electrons. These electrons
keep rotating around the nucleus at a fixed  velocity.The electrons of a single atom rotate at different distances from the nucleus  thus forming different orbits or shells.Hydrogen has only a single shell while carbon has two shells.
The number  of electrons each shell can accommodate also varies.The number of electrons in a particular shell is given by the equation 2nsq(ie. 2*n*n)where n is the shell number.
          The nucleus of an atom consist of positively charged protons and neutrons which has no charge.They are collectively called nucleons.The radius of a nucleus is approximately equal to , where A is the total number of nucleons.
         Generally an atom has equal number of protons and electrons,thus nullifying each others charges. The nucleons are bound together by a short-ranged attractive potential called the residual strong force. At distances smaller than 2.5 fm this force is much more powerful than the electrostatic force that causes positively charged protons to repel each other.

Atoms of the same element have the same number of protons, called the atomic number. Within a single element, the number of neutrons may vary, determining the isotope of that element. The total number of protons and neutrons determine the nuclide. The number of neutrons relative to the protons determines the stability of the nucleus, with certain isotopes undergoing radioactive decay.

The structure of an atom

More About The Nucleons

Neutrons and protons,which constitutes the atomic nuclei  are collectively called nucleons. Until the 1960s, the nucleons were thought to be elementary particles. Now they are known to be composite particles, each made of three quarks bound together by a force called the strong force.Protons and neutrons are most important and best known for constituting atomic nuclei, but they can also be found on their own, not part of a larger nucleus.Both the proton and neutron are made of three quarks. The proton is made of two up quarks and one down quark, while the neutron is one up quark and two down quarks. The quarks are held together by the strong force. It is also said that the quarks are held together by gluon s, but this is just a different way to say the same thing (gluons mediate the strong force).

To know more about the theories related to the beginning of the universe it is necessary to understand  the principle  of  the  elementary particles. 

The Elementary Particles

In particle physics, an elementary particle or fundamental particle is a particle believed not to have substructure; that is, it is believed not to be made up of smaller particles. If an elementary particle truly has no substructure, then it is one of the basic building blocks of the universe from which all other particles are made.

 The elementary particles can be divided into two;the bosons and the fermions.Particles which satisfy the Bose-Einstein law  are  called bosons,those which satisfy the Fermi-Dirac law are called  fermions. 

Elementary particles of the Standard Model include:

• Six "flavors" of quarks: up, down, bottom, top, strange, and charm;
• Six types of leptons: electron, electron neutrino, muon, muon neutrino, tau, tau neutrino;
•  Bosons (force carriers): the graviton of gravity, the photon of electromagnetism, the  W and Z bosons of the weak force, and the eight gluons of the strong force.

Out of this leptons, and baryons which include protons and neutrons come under the fermions.
{For more info on the elementary particles and the standard model theory click here}

The Beginning With A Bang-The Big Bang Theory

How did it all began?

           Scientists and most astronomers belive that the Universe was born in a massive explosion,which they call the Big Bang,which is belived to have occoured 14 billion years ago.This theory is an effort to explain what happened at the very begining of of our Universe.Discoveries in astronomy and physics have shown that our Universe did in fact have a beginning.Before that moment of the Big Bang,there was nothing.During, and after that momentthere was something- our Universe,which contained space and time.

According to the  Big Bang theory nothing existed before the explosion.The only thing that existed was a tiny point or bubble that was far smaller than an atom,but hotter  and denser than anything we can imagine.This state was coined the term’point singularity’.Then suddenly ,this tiny bubble exploded,and the Universe was born.During the explosion,it let loose a huge amount of energy into a small Universe.Inside the Universe,the energy went zipping around all the place.Within seconds,the Universe gerw from  smaller than a single atom ,to bigger than a galaxy.Time,space and matter were all formed out of that energy.

And it kept on growing at a fantastic rate;infact it is still expanding today.

What Happened After The Big Bang

Right after the big bang,the Universe began stretching like a huge balloon Space and time began to expand at an incredible rate,this phenomenon is called the inflation of space.Later,the Universe became cooler and the particles that make up matter began to form out of the energy.

Right after the Big Bang,a tremendous surge of energy was released,and the universe was born.there was a total turmoil as the elementary particles went crazy.The universe at that time existed as a soup of free-roaming fundamental particles that didn't obey the normal rules  of physics.This is why the early Universe is sometimes referred to as 'Particle Soup'.

the picture explains the step by step formation of the present  universe

As we know the present universe formed as a result of a massive explosion.Only the quarks,leptons and the force particles were present in the Universe just after the Big Bang.But as the universe cooled down(about 1000 billion degree)quarks began to form clusters of quarks with the help of the gluon s and thus form protons and neutrons.(for more info on the structure of protons and neutrons click  here)