What is a Supernova? Pt.II

Now what makes the supernova explode, well strangely enough, it is not that well understood Though it is known that neutrinos are a major particle that plays a role in the super nova explosion. Though incidentally neutrinos don’t interact with matter or anything physical, almost behaving as a massless particle free-Roaming the universe. But a major percentage of the explosion is from neutrinos escaping to the surface of the dying star and then causes a massive explosion pushing all the out remnants of the dead star, flinging across the cosmos. Though the parts that get shot across space from the explosion is actually a small percentage of the star.

Essentially a typical star would need to be 8+ Solar Masses (O), so it needs to have a certain threshold of mass before it would be able to explode into a super nova. But, it there is a process where the star could lose its weight and essentially, it’s mass, then a supernova explosion would be averted. An example of such a thing would be the interaction of other star, solar flares (Coronial Mass Ejection). Though the opposite can be said as-well, where other explosions (Supernova) can add to the mass of a star, making its total mass even larger, thus making stars that are just below the Chandrasekhar limit, being made supernova eventually. Currently the star that is more close to us and is in chance of actually detonating into a supernova is Betelgeuse in the Orion constellation and currently the 8^th brightest star in the Night Sky.

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What is a Supernova? Pt.1

So…What is a supernova? What are these intense energy explosions that radiate and emanate throughout the Universe? To answer this question In this instance well focus on the type II supernovae SNII as this is the start that died. But your probably wonder what a supernova Class I is (SNI).  In this instance the classifications that are used to describe supernovae and their properties bear no real physical significance. But to generalise, what the classifications mean, boils down to their spectra (Spectrometric properties), So for example would be that when a dying star is ready to explode, the explosion and the remnants from the explosion are analysed spectrometric ally. It is these precise chemical characteristics that determine which bracket to place the particular supernova into. Like whether an absorption line is shown in a spectral analysis. Though normally when you discover a type I SN. Normally it is similar in most ways to that of a white dwarf, though still accreting matter and slowing perishing in the cold voids of space eventually collapsing into itself. The SNI has to hit a certain threshold, a mass threshold called the Chandrasekhar limit. The maximum mass allowed for a white dwarf to be at, to avoid going supernova. A SNII is a final death phase, where the star has reached the end of its life.

 

 Fig.1 A extra terrestrial nebula that habits around Wolf-Rayet star (WR124)

Credit: van der Sluys, M,; Lamers, H. J. G. L. M. (2003).

 *Note: This Nebula is 21,000 light years across

So, now you probably asking, why and how does a star collapse in on itself? At first thought, it would seem like a difficult answer, but actually is quite the contrary.  Gravity as usual, tries to pull anything down towards the particle or object with most matter/density. For us to let go of a cup of tea in free space only for gravity to intervene and pull it straight down to the ground, likely breaking it and causing a mess. In that situation there is nothing stopping the cup from falling to the Earth, no force or energy to keep it in check. With Stars its similar, though there is a difference, energy! Energy is actually a factor with a star and gravity. With the hydrogen and helium inside burring away in a nuclear fusion reaction, intense energy is keeping gravity from crushing the star into oblivion. Now, when the star dies, meaning when it has no more hydrogen to burn and the fusion reaction is essentially gone, gravity steps in to do its business, crushing the star into its inner most core. Then the centre of the star then collapses on itself.

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Necessary Ingredients Detected in the Milky Way for the formation Black Holes Pt.I

In certain parts of the Milky Way galaxy habit molecular clouds, these thick and massive clouds of chemicals are good birth places for new stars for which nuclear fusion can commence. Scientists are searching in these regions which contain the most massive and the most densest molecular clouds. These are known to habit and surround our galaxy near the center, which has be suggested that a Super Massive Black Hole is in the centre, dictating our gravitation interaction with the galaxy and everything within it. This Super Massive Black Hole mentioned before in pervious topics, named Sagittarius A* or Sgr A*) is the lynch pin of the galaxy, making everything in and around it form in to a swirl of immense gravitational force.  This Black hole is the suns mass of about 4 millions of our Suns! That’s pretty big and you can imagine the gravitational forces that are associated with this stellar mass.

 

Fig.1 illustration of a large stellar cluster habituated near the Milky Way.

Credit: Keio University

These clouds that scientists are looking for are good places to start looking for evidence for forming stars. To analyse what is going on in these places, the use of radio telescopes are to determine the make up of these clouds and to compile a map of the density and temperatures of the molecular nebula in the center of the Galaxy. The discovery of 4 massive gas clouds that appear to be the seeds of small medium black holes. These voids in space or ultimate density. 100,000’s time more denser than the Sun are suggested to be the building blocks of SMBH’s that are thought to be in the centre of the galaxy.  

 

Fig.2 Molecular gas at the center of the Galaxy. 

Credit: Keio University

Legend: + : Sagittarius A* (SMBH)

Though these clouds are really big, they are 30,000 light years away from Earth. Though we are able to see them now. Why is that?  Well the simple answer is that light travelled to us. I have asked a few times, why if its 30,000 light years and that means that light would take 30,000 years to reach that nebula then another 30,000 light years back, wouldn’t that mean we couldn’t, realistically do anything about it. Light travelled from the nebula 30,000 years ago to reach Earth Today.

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