The supreme forces of the universe - Dark matter & Dark energy. Why 95.4% of the universe is 'invisible' ?

The Wilkinson Microwave Anisotropy Probe (WMAP) by reading the cosmic microwave background( CMB ) determined that only 4.6% of the total mass-energy constituent of the universe is made of ordinary atoms or baryons( made of neutrons, protons and electrons). 

From the very moment of the big bang till today, some of the visible stuffs that our universe has manifested like dust, gas, planets, stars, galaxies, you and me only accounts for 4.6% of universe. The 95% of the energy density in the universe is in a form that has never been directly detected in the laboratory or was unknown.

What about the rest of the universe ?

Why gravity only attracts but, doesn't repel? How it came into existence? How it has influence over such large distances? How gravity truly works?

What is cosmic microwave background? What is the face of god looks like? What is the 1st light in the universe?

When you are looking at the sky, you can see a lots of starts shining. But as you see them, you are actually looking at the past, not the present. Sounds confusing. isn't it?

What is gravitational lens or gravitational lensing?

Gravity is nothing but, a curve in the space-time. 

So try to imagine that what happens when light travels trough space around a massive object lets say a galaxy.

What is Redshift? Why is it useful to Astronomers?

'Redshift'  is the phenomenon of of the light changing it's color or light shifting it's position in visible spectrum of light.

What is Supersymmetry and how it's related to WIMPs? How do the particles get their masses ?

Blackholes - The masters of the universe

Black hole - from an artist's point of view

Black holes are one of the most powerful and weird developments of our universe. Black holes can consume anything in the universe, starting from stars to entire galaxies. Even light can not escape it. 

Supernovae - The most important piece of puzzle to our universe

"After" and "Before" real images of a supernova by NASA

One of the most energetic and explosive events in the entire universe is known as a supernova. Supernovae are extremely luminous and cause a burst of radiation that can briefly outshine an entire galaxy.

For a better understanding, please go through this post - How stars work ?

This event occur at the end of a star's ( particularly big sized stars = minimum mass 8 times that of the sun ) lifetime, when its nuclear fuel runs out, the star unable to provide necessary resisting force towards the gravity, gravity crushes the star and it's core to itself. Gravity does this so strongly that even the atoms crush together, making the core more and more unstable and intense so at certain point the energy building up overcomes gravity and causes a blast of shock-wave that ejects the star's envelope into interstellar space.

The secrets of the universe. How stars work? Is our Sun ever going to die?

Our universe is almost 14 billions years old and it stretches billions and billions of galaxies across that's why astronomers prefer the term 'observable universe' because the observable universe consists of the galaxies and other matter that can, in principle, be observed from Earth in the present day as light (or other signals) from those objects has had time to reach the Earth since the beginning of the cosmological expansion.

The observable universe is so vast that millions of stars are born and millions of others die everyday, yet our sun has been there for about 5 billion years. The universe created us along with some of the most mysterious objects like black-holes, which defy the laws of physics as we know it. Our understanding of the universe is still incomplete. But there are some things, we have been able to uncover.

Like where did the Universe came from and what is the big bang?

Where did we come from ? Are we really stardust ?

We are in 21st century, with such technological advancements that we can go back in time to the point of creation, when everything started. We are able to understand how everything works around us. Although we can't prevent natural disasters, we can predict them and take necessary precautions. Today we have built skyscrapers to live like kings, we live in luxury houses with technology all around us to make our life simple and easy. We have built cars, ships, underwater-ships and air-planes to satisfy our needs, use wireless cell phones to stay connected with others whenever we want & above all the internet to know about anything anytime. Even we have invaded the space with highly advanced spacecrafts.

But a good designer always know that to transform a good design into a better reality, you need the best building block. Afters thousands of years of evolution man has finally been able to understood the secrets behind the magic material and was able to use it efficiently. Just look around you and you will find it almost everywhere, one of the basic building block of 21st century, steel. Steel is a primary mixture of iron and carbon (carbon content 0.2% and 2.1% by weight depending on the grade) but, the desired physical and mechanical properties of steel can be achieved by adding various metals like Silicon, titanium, vanadium, molybdenum, chromium, manganese etc. That's why steel is suitable for various applications like, building a small needle to a massive and complected mega machines but, it's not the only reason steel is so popular. It is popular because it's an iron alloy and iron is one of the most abundant element of planet Earth. It forms much of earth's outer and inner core.

But ever wondered where does the iron comes from?