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.

Some of the stars bigger than our sun.

                                          Video rights belongs to Discovery channel

There are 2 types of Supernovae found based on presence hydrogen line in their spectrum and these two are further divided into sub categories.

if you wish to know more about how the classification is done then please visit - http://en.wikipedia.org

But actually supernovae are divided into 2 basic physical types depending on the physical mechanism involved that is how they exploded

1. A white dwarf thermonuclear explosion supernova ( type Ia )

2. A core collapsed supernova ( type II )

1. A white dwarf thermonuclear explosion supernova

Unlike our sun, the vast majority of stars orbit in pairs. So when one of the star dies and becomes a white dwarf. If the other star is close enough then the gravity starts drawing materials from the other star. The white dwarf sucks clump of gas and dust to itself.

As the white dwarf sucks more and more materials it gets heavier and denser. Eventually it will acquire too much from the other star and undergo nuclear overload. Increasing temperature and density inside the core will ignite carbon-oxygen fusion to form iron. The moment iron is formed, the white explodes leaving without a trace behind and scatters a lot of iron and other particles into the universe. Almost all the iron in our solar system came from a double star supernova that exploded more than 5 billion years ago.

The peak luminosity of the light curve is extremely consistent across normal Type Ia supernovae, that is astronomers have reason to believe that the peak light output from such a supernova is always approximately equivalent to an absolute blue sensitive magnitude of -19.6 ( like a constant value in a measuring scale ). Thus, if we observe a type Ia supernova in a distant galaxy and measure the peak light output, we can use the inverse square law to infer its distance and therefore the distance of its parent galaxy. This allows them to be used as a standard candle to measure the distance to their host galaxies.

2. A core collapsed supernova

 This kind of supernovae are otherwise known as single star supernovae. These supernovae are the source of all the other heavier elements like gold, silver etc. We know that in massive stars the fusions process continues until iron is produced . When iron is produced and the core goes off balance then the star's gravity will crush the star and it's core to itself at the rate of 1/3rd of the speed of light to the size of a city from the size of a planet. 

Eventually the pressure building up inside the core will overcome gravity and will be blasted away with a huge shockwave ripping the star apart. While the shockwave is ripping through the inner layers of star it creates all the heavier nuclei like gold,silver,platinum... all the way towards uranium. These elements are blasted trillion of miles into space and responsible for creation.

Single star supernova

Chain of events just before supernova

Like the mid sized stars, supernovae leaves a corpse behind.

A supernova explosion sometimes gives rise to very small, dense (high density) core called a 'neutron star'. A neutron star has the mass of a star but the size of a few miles in diameter. The name "neutron star" comes from the fact matter is compressed so tightly that protons and electrons are squeezed together inside atomic nuclei to form neutrons. It is so dense that a teaspoon of of a neutron star would weight 100 million tons. So if this teaspoon of material is drooped on earth, it would fall right through it.

Neutron star

Inside a neutron star 

When a mass as great as our sun's, is packed into a space which is about the size of a city, the conserved angular momentum causes the resulting neutron star to spin very rapidly and emit a ray of high-energy light that sweeps around like a lighthouse beam. It is a neutron star called 'pulsar'.

The name 'pulsar' derives from the fact that the beam appears to be a pulse that it can be only observed when the beam is pointed in the direction of earth. Pulsars usually spin between .1 to 60 times per second. The newly discovered PSR J1311-3430, which is located in the constellation Centaurus could be the fastest spinning pulsar discovered till today.

Pulsar

Inside a pulsar

When supenovae having mass greater than 30 times that of the sun collapses they gives rise to a type of neutron star that is only 12 miles in diameter and called a 'magnetar'. Magnetars generate powerful magnetic fields. The fields can be 100 trillion (10^15) times more powerful than the magnetic field of the earth. It is is so powerful that it is capable of sucking the iron right out of the blood from thousands of miles away. But their life us short, the strong magnetic fields decay after about 10,000 years. SGR 1806-20, is a magnetar located 50,000 light-years from Earth on the far side of our Milky Way galaxy in the constellation of Sagittarius.

Magnetar

But these neutron stars are not the weirdest remains of a supernova. When stars having mass over 100 times the mass of our sun explodes, it does't just crushes the electrons and protons together but, the comparable gravity crushes space and time itself and creates one of the most dangerous and mysterious developments in our universe, a 'blackhole'.

Blackhole

This exploding star explodes with such enormous energy, scientists call it a 'hypernova'.

Hypernova

During a hypernova explosion when the core produces iron and nuclear fusions stops, the gravity is so dominating that it crushes the the core of the star to a blackhole.

The blackhole instantly starts to eat the star from inside at a rate of a million earth masses a second. But a million earth masses per second is too much to go into a tiny space so the black hole spits a lot of it back out in opposite directions with nearly the speed of light.

This creates two beams of pure energy blasting it's way through the stars inner layers ripping it apart. When the jet breaches the star's surface, it produces a pulse of gamma rays typically lasting a few seconds. Satellites like Swift and Fermi can detect this emission if the jet is approximately directed toward us. This is called 'gamma ray bursts'. These gamma ray bursts are so energetic that they light up the entire universe. Any point in the universe will eventually pick up this radiation. They are the most illuminating things of the universe.

Gamma ray bursts

Hypernovas can recognized by picking up gamma ray bursts. So when ever a super massive star undergoes a hypernova, it's leaves a monster behind, a blackhole.

A monster capable of destroying space and times itself.