Naked Science Forum
Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: Dr. Praetoria on 18/08/2005 22:51:02
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Just what do we really know about the sun and the possibility that it could explode or become a supernova? How sensitive is this balance between its massive, inward force of gravity and the outward pressure from its fusion reactions?
Doc
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I think it is pretty much self regulating until it runs out of fuel; if the sun contracts under gravity the density of the core increases, increasing the rate of hydrogen fusion and therefore temperature so that it expands again.
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I'm by no means the expert here..butI'm pretty sure the sun is not big enough to go supernova......in about 5 billion years it'll grow big enough to envelop us and the inner planets ....so we'll have a barbeque of a time !!....gsmollin hopefully will put you at ease with an answer.
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The inner fire in the core of the sun produces a flux of photons of unimaginalble force that keeps the outside of the star in place. The outside seems to have higher concentrations of iron and silicon that play a roll in the electrical storms (iron) on the surface, and in slowing the temperature loss (silicon) and insulating the core of the star. There has been some recent published data on this.
The Hydrogen to Helium reaction produces a lot of energy. With enough pressure/temperature and helium, the second reaction is helium to carbon. This produes far less energy and the star begins to shrink. When the concentration of carbon is high enough, a third reaction sets in and carbon is fussed to iron. This reaction produces almost no energy, and the photon pressure drops so low that the star begins a collapse and turns into a Nova. The outer gasses are blown away and the star settles down to being a dwarf star with very little heat or light given off.
Larger stars may turn into a Super Nova, and produce larger dwarfs or even neutron stars. Very few stars have the mass to turn into a singluarity or black hole. Our star is slated to be a small dwarf.
David
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the most likely way for the sun to pop tommorrow is a problem with the magnetic fields that hold the corona stable as i understand it the feilds are most suseptible to disruption during solar storms the kind that produce electrical problems hereon earth if a body of suficent size and density and iron heavy strikes the pole opposite of where the storm is magnetic fiels around the suns equator will be weakend and the corona will start to disperse if this happens the sun will start to burn far more fuel at some points than others this may set of a cyclic burn atwhich point the center of the burn will start pushing energy out creating a star wide inbalance which could shear the poles and start a core explosion. the chanes of this happening are hundreds of trillions to one so i wouldnt worry and the object hitting it would have to be about the size of earth so we would see it coming.
i think thats all right but anyone who knows better feel free to correct me.
Giggidy Giggidy Goo
The philosopher Q man
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So there is really nothing to say that the sun could actually blow up then?
Do we know how long left the sun has to burn because eventually it will run out of gas to burn.
Oh and did you know that because the suns light takes 8½ minutes to get to earth when we look at the sun we are seeing the sun as it was 8½ minutes ago. So imagine if it blew up now while you are reading this, we wouldn't know till 8½ minutes later.
Y'all probably knew that already but hey
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But since there is no way of getting information from the sun faster than that we should live each 8.5 minutes as though it were our last!
Actually, is that true? If the Sun blew up, would the gravitational changes propogate at the speed of light or instantaneously?
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quote:
Originally posted by Simmer
But since there is no way of getting information from the sun faster than that we should live each 8.5 minutes as though it were our last!
Actually, is that true? If the Sun blew up, would the gravitational changes propogate at the speed of light or instantaneously?
Gravitational changes would propagate at the speed of light. Actually, unless the explosion were un-symmetrical, there would be no gravitational changes here, until ejecta reached earth's orbit.
The original question is somewhat vague. Do you mean explode now, or at any time. The anytime question is easy. There will be an event known as a helium flash when the sun runs out of hydrogen, and falls off the main sequence. The helium flash is quite powerful, and would probably incinerate life on earth, long before the sun became a red giant and burned the earth to a crisp.
The chance of becoming a supernova is nearly zero, at any time. The sun is not massive enough.
The other possibility is that the sun would vary its burn-rate, and become a variable star. It actually does this now, with the release of solar flare energy. The explosive change is too low to kill us outright, but I wonder if a large flare happened at a time of low magnetic shielding on the earth.
More massive stars include variables like Cepheids and RR Lyrae variable stars. These stars have an oscillating pressure wave in them that causes the variability. If the sun developed such an oscillation, we would all fry here on earth. However, the sun is too small to support the feedback mechanism that gets variable stars oscillating.
I think we are pretty safe from this sort of problem. At least the weak-anthropic principle states that if the sun were to become lethal to life, it would have done that already, and we wouldn't be here.
"F = ma, E = mc^2, and you can't push a string."
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If it explodes, it's probably for the best![:)]
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First off as qsmollin said, the hydrogen will run out. So Helium will begin to fuse. This is when you get the Red Giant bit starting. Then all the helium runs out and you get Carbon appearing in this period the Sun shrinks quite a bit and releases even more ionised gas. After the Sun will end up as a White Dwarf slowly simmering held up by electron degeneracy pressure (the electrons fill every energy state and the atoms can’t be pushed closer together)… over a very long time (longer than the age of the universe) the Sun will turn in to a Black Dwarf… just a hunk of invisible matter doing nothing in particular.
David Sparkman said that the Carbon will then be used to form Iron. I’m not so sure this will happen with the Sun is it massive enough, it certainly wont last long fusing Iron before the core cools? I figured you would just get a gigantic crystal of Carbon and Oxygen, a super size diamond! BLING! BLING! Plus if the Sun got as far as fusing down to lots of Iron you would end up with a Type II Supernova wouldn’t you???
I wonder is it possible if the Sun siphons off all the matter from the giant gas planets after becoming a White Dwarf would there be enough mass to overcome the degeneracy pressure, leading to a Type I Supernova and a Neutron Star being formed??
wOw the world spins?
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I thought the sun was too small to become a supernova but I had hoped that perhaps, as suggested by some researchers, if the sun's particle ejections were to take place (during its final burnout) at a higher rate, humans could escape from Earth using spacecrafts fitted with large sails that could be propelled by such an explosive solar "winds". A bit too scifi?
Doc
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I didnt think there was such thing as instantanious.
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quote:
Originally posted by gsmollin
Gravitational changes would propagate at the speed of light. Actually, unless the explosion were un-symmetrical, there would be no gravitational changes here, until ejecta reached earth's orbit.
Blast! So much for my scheme for FTL communication by blowing up unwanted stars in a coded sequence[:(]
Never mind - if gravity propagates at light speed that means it must be related to electromagnetism - we could be on the verge of a breakthrough here!
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don't worry.the sun won't blow apart while I'm holding it together. though it's making my hands a bit hot.
I am GOD..You are Not..I don't exist !!
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Since God likes to toss dice (quantum reality) how do you know the Sun will not blow-up?
Doc
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Well people can just base all of their theories on the facts that they have.
And I think personally everything happens for a reason too
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Yeh spose there is the chance anything can happen. But the more massive a system and the lower the probability of each individual event occurring means it's not likely. Same reason why you don't see people randomly tunnelling through solid objects, it's possible but doesn't happen.
wOw the world spins?