What makes supernova explode?

[alpha2cen]

I,m interested in supernova.

Supernova explosion is well known.

Why it should have to be exploded?

There are many steps, but it can be simply explained like this.

One star -----> mass loss ---->gravity decrease ------> supernova ------>explosion.

 

What I don' t understand well is gravity decrease and supernova explosion phenomena.

If gravity decreased, the nuclear reaction rate would decrease, and inside star energy would be decreased.

There is no reason it should have to be bigger.

Are there any unknown star phase exist?

Edited December 2, 2010 by alpha2cen

[steevey]

I,m interested in supernova.

Supernova explosion is well known.

Why it should have to be exploded?

There are many steps, but it can be simply explained like this.

One star -----> mass loss ---->gravity decrease ------> supernova ------>explosion.

 

What I don' t understand well is gravity decrease and supernova explosion phenomena.

If gravity decreased, the nuclear reaction rate would decrease, and inside star energy would be decreased.

There is no reason it should have to be bigger.

Are there any unknown star phase exist?

 

Here's what's going on.

A star forms, it has a large mass. Because of it's large mass, it compresses the core, and after that happens, the core is dense enough to fuse hydrogen atoms and helium. After time, the star becomes more dense, but more energy is released when fusion occurs and there is gravity to pull matter inwards, so the star grows. But, eventually, once a star fuses elements in the core into iron, the core becomes too dense and requires too much pressure for fusion. At this point, there is nothing more to generate outward heat in the star, which is now has a way more dense core. And because there is no more heat pushing outward, the only main force left is gravity. The center starts to condense, however, because of some laws of density and Newton's laws, when the core condenses past a certain point, it creates a tremendous resistance force to collapsing, a little like pushing down a spring and then letting it go. However, the core is too dense to itself get flung outward, so instead, shock waves travel through the outer gas of the star, and send that gas flying at millions of miles per hour, leaving only the core to collapse under gravity.

 

 

 

It isn't that gravity decreases at all, it's that after a certain point, there's no longer any force to balance or counteract gravity.

 

If the star isn't massive enough, there won't be enough gravitational force to collapse it into a black hole, but the core will get so dense, that atoms will become so close together and dense, that all the protons and electrons fuse to form neutrons, and any left over electrons are forced outward if the force is great enough, or form a super-ultra dense liquid of electrons to leave small cracks ion the neutron star.

If it's not massive enough to do that, it will form a white dwarf, which is dense, but not dense enough to be formed of only neutrons.

If it's too heavy for the strong force of neutrons, then the material will collapse even further, and after that point, there is no known cause for the material to stop collapsing, so condenses to such a small point, that it severely warps the fabric of space time as to not allow even light to escape. Scientists call this a singularity. It's unclear whether the singularity actually stopped decreasing in size and density at some point, but my logic is a singularity has to stop somewhere, otherwise it's gravitational pull would be exponentially stronger with every second that passes, which means block holes would not just be at the center of our galaxy, but be as big as our galaxy, and would continue to grow. Some scientists just think that a singularity just phases out of existence because its too small, but I think that's silly because otherwise, what's warping the fabric of space-time? It can't be a hole in the fabric of space time because as some math and simulations predict, there couldn't be gravity, since there would be no fabric to warp if it was a hole into nothingness.

Edited December 2, 2010 by steevey

[lemur]

Are there any unknown star phase exist?

If a star phase existed and was not known, how would anyone be able to know it to answer the question?

[steevey]

how do I delete this?

Edited December 2, 2010 by steevey

[alpha2cen]

About explosion.

The speed is too fast.

I think inside the stellar every particles are plasma state, or free particle state( assumption).

Think about the state before explosion.

If gravity is enough, the fusion reaction occur.

The heat would be released into light or ionized photon ....

The heat release is not no problem, because gravity is so high not to escape high energy particles or electro magnetic waves.

 

Supernova explosion procedure (assumption)

In the supernova some causes makes very high density core condition.

---->The core attract surround matter.

---->The core become more dense.

---->The reaction condition is over the common nuclear reaction. Gravity broken phenomena ------> other state (anti-gravity, assumption)

---->explosion happen.

[between3and26characterslon]

About explosion.

The speed is too fast.

I think inside the stellar every particles are plasma state, or free particle state( assumption).

Think about the state before explosion.

If gravity is enough, the fusion reaction occur.

The heat would be released into light or ionized photon ....

The heat release is not no problem, because gravity is so high not to escape high energy particles or electro magnetic waves.

 

Supernova explosion procedure (assumption)

In the supernova some causes makes very high density core condition.

---->The core attract surround matter.

---->The core become more dense.

---->The reaction condition is over the common nuclear reaction. Gravity broken phenomena ------> other state (anti-gravity, assumption)

---->explosion happen.

 

 

As fusion occurs in the star it makes ever heavier elements up untill the point iron is made. Iron either does not fuse under stella conditions or does not release energy when it fuses, I think it's the former. As the mass of iron at the stars core increases and its fuel gets used up the star will start to cool. As it cools it gets more dense and when the density reaches a certain point it will collapse under its own gravity (probably to a white dwarf). The collapse of the core releases energy which blows the outer layers of the star off in what is a supernova.

 

 

(I've just gone back and read the other post before adding my reply and realised I've just repeated what steevey said, though not in as much detail.)

Edited December 2, 2010 by between3and26characterslon

[Arch2008]

When a star fuses iron, it takes more energy than is released from the fusion. So the star essentially reaches a dead end by making iron. When the core loses energy to make iron it cools. Then gravity is no longer balanced by thermal energy being radiated from the core, so the outer layers of the star collapse at something like a quarter of the speed of light. These outer layers then crash into the core. The core is compressed and the outer layers reverberate, causing the star to rip itself apart.

Sometimes, supermassive stars undergo matter-antimatter chain reactions in its core that totally destroy the star in what has been called a hypernova.

Edited December 2, 2010 by Arch2008

[lemur]

When a star fuses iron, it takes more energy than is released from the fusion. So the star essentially reaches a dead end by making iron. When the core loses energy to make iron it cools. Then gravity is no longer balanced by thermal energy being radiated from the core, so the outer layers of the star collapse at something like a quarter of the speed of light. These outer layers then crash into the core. The core is compressed and the outer layers reverberate, causing the star to rip itself apart.

Interesting, I wonder if such endothermic fusion was prevalent in the energy-dense early universe and the formation of iron+ heavy atoms contributed to the formation of spacetime between early stars by causing condensation around the endothermic reaction-centers.

[steevey]

Interesting, I wonder if such endothermic fusion was prevalent in the energy-dense early universe and the formation of iron+ heavy atoms contributed to the formation of spacetime between early stars by causing condensation around the endothermic reaction-centers.

 

uh

 

no

 

The universe was WAY WAY WAY too hot to even form the most basic of elements at first, and there certainly wasn't stars right away to make iron.

Edited December 3, 2010 by steevey

[lemur]

uh

 

no

 

The universe was WAY WAY WAY too hot to even form the most basic of elements at first, and there certainly wasn't stars right away to make iron.

 

At what point, then, would the primordial energy begin to differentiate into gravity wells and why?

[alpha2cen]

 

In the supernova some causes makes very high density core condition.

 

 

Assumption

Stellar resonance phenomena?

If star is more bigger, it causes a big stellar wave resonance phenomena .

Its not proved yet.

But, Some papers recently published said the Sun has its own sound.

Similarly stellar has its own sound.

When its own sound meet with the stellar size , it would repeatedly contract and expand.

At sometime it could be very contracted, its energy state is beyond common nuclear reaction.

It will explode.

The other possibility is the resonance phenomena of the gravity waves and big stellar size.

This could make very big contraction. Gravity waves comes from other space region.

[steevey]

At what point, then, would the primordial energy begin to differentiate into gravity wells and why?

 

After the shock waves from the big bang. The universe is still pretty close together at this point after the big-bang, and most of the gas can come into contact with one another, like one giant solar system. So, remnant shock waves can pass through nearly all the gas, since its still dense enough, and these shock waves cause the denser and collapse gas to bump into each other and form lumps, which then over time grow and begin to attract more amounts of gas.

 

Assumption

Stellar resonance phenomena?

If star is more bigger, it causes a big stellar wave resonance phenomena .

Its not proved yet.

But, Some papers recently published said the Sun has its own sound.

Similarly stellar has its own sound.

When its own sound meet with the stellar size , it would repeatedly contract and expand.

At sometime it could be very contracted, its energy state is beyond common nuclear reaction.

It will explode.

The other possibility is the resonance phenomena of the gravity waves and big stellar size.

This could make very big contraction. Gravity waves comes from other space region.

 

It's more just that once the star got massive or dense enough, it wants to collapse, but it can't because of heat pushing outward. So after heat stops pushing outward, all that's left is gravity wanting to pull everything in.

The core starts to contract, but because of the strong force and electro-magnetic force, when the core contracts, all the atoms try to push against it once they are forced close enough together, and as the other gas collapses into the core, it feels the shock-waves of that strong force/electro-magnetic force resistance, and is thrown outward. But non the less, gravity continues to pull the core together closer and closer, and any remaining gas would be pulled to the core and then blasted away by more shock-waves. A supernova is actually repeated explosions, but the core is so massive, and there's so much energy involved, that it happens really fast, as a series of gas collapsing into the core and getting pushes out as the core tries to resist gravity's pull.

Edited December 3, 2010 by steevey

[alpha2cen]

Important thing is how to make more massive point. If iron atom is existed, it would be existed homogeneously in the star atom existing area. The more massive point is made of repeatedly contract and expand. Is the core same as less massive star in the supernova? It is not well known. But I think the core is more dense than less massive star. When explosion happen,the nuclear reaction is not common proton - neutron reaction. It wold be quark related fusion-my assuming.

 

Which one makes repeatedly contract and expand? Resonance, which is its own sound meet with the stellar size. Or gravity wave from other space -assumption.

Edited December 3, 2010 by alpha2cen

[lemur]

After the shock waves from the big bang. The universe is still pretty close together at this point after the big-bang, and most of the gas can come into contact with one another, like one giant solar system. So, remnant shock waves can pass through nearly all the gas, since its still dense enough, and these shock waves cause the denser and collapse gas to bump into each other and form lumps, which then over time grow and begin to attract more amounts of gas.

This explanation makes sense, but the idea I've been contemplating lately is that the early universe was so dense that gravitation would be indistinguishably intense from other kinds of force, including strong and weak. Thus, I have been wondering if the development of the universe is not characterized by a differentiation of forces early on, and how this progression of force-differentiation could have taken place. I realize that this idea is quite different from the theory that energy first coalesced into small particles and the small particles fused into larger ones later due to gravity. My sense is that the extreme density of the early "soup" was such that all force was unified and that it eventually expanded to the point where fission became possible, which would accelerate the expansion and push the fragmenting force-fields to the point where they could actually move relative to each other insofar as gravitation differentiated from the electromagnetic force that would have governed the earliest particles as they separated. Probably you will just dismiss this as deviating from consensus, but if you have any rational reasons my thinking is flawed, I'd like to hear them.

 

Before you totally dismiss my logic, however, please just consider one question: why would energy coalesce first into small particles and only later fuse into larger ones if it was extremely dense to start with? Wouldn't heat and pressure levels higher than the largest star cause it to fuse at a level that would far exceed iron due to the excessive levels of energy-density present?

[alpha2cen]

Sometimes, supermassive stars undergo matter-antimatter chain reactions in its core that totally destroy the star in what has been called a hypernova.

 

This explanation is reasonable to explain reaction condition before explosion.

n particle + m particle -------- >p particle + q antiparticle

q particle + q antiparticle -----> energy

 

This reaction can be occurred in the particle accelerator.

If it consisted of the matter-antimatter chain reactions, it would be more powerful than common nuclear reaction.

To prove this, any gamma wave or mass loss data which represent before and after reaction is required.

Particle-particle fusion concept.

[steevey]

This explanation makes sense, but the idea I've been contemplating lately is that the early universe was so dense that gravitation would be indistinguishably intense from other kinds of force, including strong and weak. Thus, I have been wondering if the development of the universe is not characterized by a differentiation of forces early on, and how this progression of force-differentiation could have taken place. I realize that this idea is quite different from the theory that energy first coalesced into small particles and the small particles fused into larger ones later due to gravity. My sense is that the extreme density of the early "soup" was such that all force was unified and that it eventually expanded to the point where fission became possible, which would accelerate the expansion and push the fragmenting force-fields to the point where they could actually move relative to each other insofar as gravitation differentiated from the electromagnetic force that would have governed the earliest particles as they separated. Probably you will just dismiss this as deviating from consensus, but if you have any rational reasons my thinking is flawed, I'd like to hear them.

 

Before you totally dismiss my logic, however, please just consider one question: why would energy coalesce first into small particles and only later fuse into larger ones if it was extremely dense to start with? Wouldn't heat and pressure levels higher than the largest star cause it to fuse at a level that would far exceed iron due to the excessive levels of energy-density present?

 

 

Matter in the universe was only extremely dense only when the entire universe was a single point. But, there was so much energy in that point, all the energy of the universe in fact, that it projected all matter outward as fast as it possibly could. Particles were still fairly close together and dense, but they weren't close enough together after the big bang to form stars and heavier particles right away because they were so energetic. The universe for some of its early life was hotter than anything you could have imagined, and it wasn't too dense as it was expanding at the same time into a vacuum. Particles DID fuse into some particles, but they were far to energetic and without pressure to hold them down in order to fuse into something like iron right away. A star holds these particles in a specific area though, which they can't escape, especially due to the fact that gravity is now a separate force and is holding them down, which means as all the particles are super hot, they are also forced close together, where they can fuse.

 

 

Sometimes, supermassive stars undergo matter-antimatter chain reactions in its core that totally destroy the star in what has been called a hypernova.

 

What the hell? That's like never happened in the history of the universe. There's NO WAY that anti matter could last that long in a star without being destroyed to make it to a supernova. There isn't even any measurable anti-matter in the universe at all anyway. I don't know where you got that idea from. Some stars are just way more massive than the sun, there's stars literally 100 times more massive than the sun, and THEY go out with a giant bang because they are far more massive, which means gravity pulls on the core inward more, which means there will be a bigger resistance from newton's law of "for every action, there is an equal and opposite reaction" which is caused by resistances of the strong and electro-magnetic force. There is just way more energy involved in a star that massive.

Edited December 4, 2010 by steevey

[Martin]

When a star fuses iron, it takes more energy than is released from the fusion. So the star essentially reaches a dead end by making iron. When the core loses energy to make iron it cools. Then gravity is no longer balanced by thermal energy being radiated from the core, so the outer layers of the star collapse at something like a quarter of the speed of light. These outer layers then crash into the core. The core is compressed and the outer layers reverberate, causing the star to rip itself apart.

Sometimes, supermassive stars undergo matter-antimatter chain reactions in its core that totally destroy the star in what has been called a hypernova.

 

 

 

 

 

What the hell? That's like never happened in the history of the universe. There's NO WAY that anti matter could last that long in a star without being destroyed to make it to a supernova. There isn't even any measurable anti-matter in the universe at all anyway. I don't know where you got that idea from.

 

 

Be careful about dismissing people if you don't always know what you are talking about, Steevey. Nobody knows it all (not me anyway.)

 

Arch gave a fairly clear (if very brief) mention of the pair-instability hypernova mechanism. Indeed it is believed to proceed by a kind of chain reaction which in effect traps increasing numbers of gamma photons once they reach a certain threshhold energy---so they no longer help to support the outer layers by radiation pressure.

 

The gamma photon reacts with an atomic nucleus to produce an electron positron pair. The particles and antiparticles in the core then annihilate to produce more gamma photons with the required energy to repeat the interaction.

 

This can happen in a massive (>150 solar) star long before she has run out of fuel. The core full of good stuff ready for a runaway thermonuclear explosion if the temperature gets high enough.

 

All that needs to happen is the temperature reaches the threshhold where photons are diverted by the pair-production reaction from their job of supporting the outer layers. Then there is an abrupt drop in pressure. The outer layers come crashing. Temperature rises. More gamma photons are absorbed by the pair-production. More outer layer crashes down. And the remaining fuel in core experiences runaway detonation.

 

In a pair-instability hypernova you don't even necessarily get a neutron-star or black hole remnant, at least according to the theoretical model.

 

It's cool. I think that was what Arch was trying to say in a few words.

Edited December 4, 2010 by Martin

[lemur]

Matter in the universe was only extremely dense only when the entire universe was a single point. But, there was so much energy in that point, all the energy of the universe in fact, that it projected all matter outward as fast as it possibly could. Particles were still fairly close together and dense, but they weren't close enough together after the big bang to form stars and heavier particles right away because they were so energetic. The universe for some of its early life was hotter than anything you could have imagined, and it wasn't too dense as it was expanding at the same time into a vacuum. Particles DID fuse into some particles, but they were far to energetic and without pressure to hold them down in order to fuse into something like iron right away. A star holds these particles in a specific area though, which they can't escape, especially due to the fact that gravity is now a separate force and is holding them down, which means as all the particles are super hot, they are also forced close together, where they can fuse.

First, I assume by "particles" you mean fields of strong nuclear force. My question is at whether such force was distinguishable from gravitational force at the level of strength it would have had in an extremely dense early universe. In other words, I think that we typically think of gravity as a relatively weak force because of how non-dense the universe we observe is currently. If gravitation was as strong, however, as strong nuclear force in the early universe, how would strong-nuclear force-fields separate into "particles" at all? After all, for multiple particles to exist separately from each other, they have to be able to pull away from each other, and I would think this would only be possible within a gravitational field with weaker binding-force than the strong nuclear force itself. See my point?

 

Thus, I think that all forces were basically have to be the same in the very early universe. This would basically translate into the universe existing as a single enormous particle and eventually splitting into smaller particles as gravitation became weak enough to allow for spatial separation. Then, at the still very high levels of gravity and energy-density that would have been present after initial fragmentation into smaller particles began, fusion among the particles would have been as common as fission, in that enormous amounts of available energy would have expended themselves in endothermic fusion-reactions, which could have been the first impetus for vacuum-producing densification unless expansion happened so fast as to release expansionary pressure to its full potential.

 

I guess the question would be whether the early universe was able to expand freely or was it to constrained under its own gravity and other attractive force? My guess would be that it was too constrained, just because the speed of light is an absolute limit that would cause early matter to be very turbulent and energy-abundant as it moved forward. This energy abundance would be enough to result in a trend of endothermic fusion for some time before it cooled down enough to make endothermic reactions scarcer, no?

[alpha2cen]

Some papers recently published said the Sun has its own sound.

Similarly stellar has its own sound.

 

 

It's related to stellar stability.

Stellar is a big object.

When nuclear reaction happens in the stellar, huge amount of mass and energy transfer is required.

In order to reaction proceeds smoothly without big unbalance, certain harmony is required.

 

**mass input -----------------------------> reaction ----------------> product (plasma ion, high molecules, neutrino...)

**fluid transfer.......heat emission(gamma way emission..).....electromagnetic balance.......gravity

 

That is the stellar sound or the stellar music.

If it did not exist, stellar behavior would be very irregular.

When the star becomes more bigger and bigger , the big size breaks the harmony or increases the wave period and wave intensity - my assumption.

Edited December 5, 2010 by alpha2cen

[swansont]

It's related to stellar stability.

Stellar is a big object.

When nuclear reaction happens in the stellar, huge amount of mass and energy transfer is required.

In order to reaction proceeds smoothly without big unbalance, certain harmony is required.

 

**mass input -----------------------------> reaction ----------------> product (plasma ion, high molecules, neutrino...)

**fluid transfer.......heat emission(gamma way emission..).....electromagnetic balance.......gravity

 

That is the stellar sound or the stellar music.

If it did not exist, stellar behavior would be very irregular.

When the star becomes more bigger and bigger , the big size breaks the harmony or increases the wave period and wave intensity - my assumption.

 

!

Moderator Note

Please keep speculative science in the speculations forum

[steevey]

Be careful about dismissing people if you don't always know what you are talking about, Steevey. Nobody knows it all (not me anyway.)

 

Arch gave a fairly clear (if very brief) mention of the pair-instability hypernova mechanism. Indeed it is believed to proceed by a kind of chain reaction which in effect traps increasing numbers of gamma photons once they reach a certain threshhold energy---so they no longer help to support the outer layers by radiation pressure.

 

The gamma photon reacts with an atomic nucleus to produce an electron positron pair. The particles and antiparticles in the core then annihilate to produce more gamma photons with the required energy to repeat the interaction.

 

This can happen in a massive (>150 solar) star long before she has run out of fuel. The core full of good stuff ready for a runaway thermonuclear explosion if the temperature gets high enough.

 

All that needs to happen is the temperature reaches the threshhold where photons are diverted by the pair-production reaction from their job of supporting the outer layers. Then there is an abrupt drop in pressure. The outer layers come crashing. Temperature rises. More gamma photons are absorbed by the pair-production. More outer layer crashes down. And the remaining fuel in core experiences runaway detonation.

 

In a pair-instability hypernova you don't even necessarily get a neutron-star or black hole remnant, at least according to the theoretical model.

 

It's cool. I think that was what Arch was trying to say in a few words.

 

It's scientifically impossible that any anti-matter could ever survive in a star at all. ANY anti matter that appears is a result of some weird quantum mechanics thing, and appears of the seeming nothingness of space with another normal particle, and then the pair annihilates itself. These matter-anti-matter pairs are very small and usually can't be observed. I can prove with simple physics and some complex math that the only reason a supernova happens, is because fusion ceases. There is no longer a constant regenerating force pushing outward, only inward. Because all the matter is being compressed and pushed into each other, its like Newton's law which describes "if you push on a wall, it pushes back with the same amount of force". Since there's so much gravity and its relentless, the resistance is huge. This is also why bigger stars have bigger supernove, because there is stronger gravity to pull the core to a more dense state faster. If gradually the star increased in energy, it wouldn't supernova, it would just keep growing until it ran out of fuel anyway.

Edited December 6, 2010 by steevey

[D H]

It's scientifically impossible that any anti-matter could ever survive in a star at all. ANY anti matter that appears is a result of some weird quantum mechanics thing, and appears of the seeming nothingness of space with another normal particle, and then the pair annihilates itself. These matter-anti-matter pairs are very small and usually can't be observed. I can prove with simple physics and some complex math that the only reason a supernova happens, is because fusion ceases. There is no longer a constant regenerating force pushing outward, only inward. Because all the matter is being compressed and pushed into each other, its like Newton's law which describes "if you push on a wall, it pushes back with the same amount of force". Since there's so much gravity and its relentless, the resistance is huge. This is also why bigger stars have bigger supernove, because there is stronger gravity to pull the core to a more dense state faster. If gradually the star increased in energy, it wouldn't supernova, it would just keep growing until it ran out of fuel anyway.

Try again, but only do so after you have googled the phrase "pair instability supernova".

 

 

 

[Arch2008]

Here's a link to Wolf-Rayet stars which are the culprit in hypernovae, with further links.

http://en.wikipedia.org/wiki/Wolf%E2%80%93Rayet_star

These stars are really rare (only a few hundred in the galaxy). I recall that I did a post about the pair instability mechanism about a year ago.

[steevey]

Try again, but only do so after you have googled the phrase "pair instability supernova".

 

 

 

 

Except it's completely theoretical in nearly every way. Have any astronomers even found a super massive tar after it's supernova-ed without a black hole or neutron star remnant? If so, give me a link.

[D H]

Except it's completely theoretical in nearly every way. Have any astronomers even found a super massive tar after it's supernova-ed without a black hole or neutron star remnant? If so, give me a link.

You are moving the goal posts here. You previously disputed that antimatter could have anything to do with a star going supernova. Now you are disputing the concept of a true pair instability supernova, which is lesser claim. That said, here is what you asked for:

 

Gal-Yam, A. et al, "Supernova 2007bi as a pair-instability explosion," Nature 462, 624-627 (3 December 2009)

Full-text at nature.com: http://www.nature.com/nature/journal/v462/n7273/full/nature08579.html

Pre-print at arxiv.org: http://arxiv.org/abs/1001.1156

 

Ofek, E.O. et al, "SN 2006gy: An Extremely Luminous Supernova in the Galaxy NGC 1260," ApJ 659:1 L13 (2007 April 10)

Abstract at iop.org: http://iopscience.iop.org/1538-4357/659/1/L13/

Pre-print at arxiv.org: http://arxiv.org/abs/astro-ph/0612408