What exactly is the Sun made up of?

[§rv]

I know there is hydrogen and its being converted to helium thats why we get all this heat but what exactly is the sun made of? When people speak about the core of the sun.....well....what is it?



I apologise for wasting your time with this stupid question

[Diamond]

I know there is hydrogen and its being converted to helium thats why we get all this heat but what exactly is the sun made of? When people speak about the core of the sun.....well....what is it?



I apologise for wasting your time with this stupid question

The Sun is basically a plasma held together by mutual gravity. The dominant element is hydrogen with about a quarter of the rest being helium, and other elements being a trace.

The core has hydrogen nuclei (protons) under incredible pressure and heat energy overcoming their natural electrostatic repulsion and fusing together to forum Helium nuclei.

[Brady Yoon]

The core of the sun is a plasma also. However, it's density is much greater than anything naturally found on Earth.

[Tobin Dax]

To nitpick Diamond's answer a little, the entire sun started out having about 3/4 hydrogen, 1/4 helium, and 1% heavier stuff. The core started out with this ratio of elements, but the ratio of hydrogen to helium decreases as helium is formed.

The core (as has been said above) is the region in the center of the sun that is hot enough and dense enough that hydrogen can (and does) fuse into helium.

[Manchurian Taikonaut]

we don't understand everyting and sometimes it is difficult to describe the Sun

Sometimes we use a layer structure to describe what is happening in the Sun

like the lava coming through the mantle, lower mantle, core, outer-core...

but in the Sun it is different

the diametre of the sun is about 1400 million Km so its volume is well over a million times that of our Earth, there is a hot dense plasma energy core where energy is generated, it extends about 180,000Km from the centre of the Sun's globe structure..

Above this is another high energy radiative layer which is succeeded by a convective layer.

The Suns visible surface know as the photosphere and is only about 400km deep

Then we have the cromosphere after that, rarefied area where the absorption lines of spectrum are made

Beyond this comes the high energy corona which sometimes appears to have no definite boundary

nuke reaction in the sun creates huge energy, it can take 4 hydrogen nuclei to form one nucleas of helium, in these types of process a little energy is released. But with millions of reactions in nuclei comes temperatures radiating to the surface making the sun 6000 K
in the process from hydrogen reactiuion to helium a little mass is lost, this is the energy which keeps the sun shining..this mass loss amounts to 4 million tonnes vanished per second

you can read another article about the Sun here

http://www.thespacesite.com/communit...?showtopic=734

[HypersonicMan]

The sun is a mass of incandescent gas. A gigantic nuclear furnace where hydrogen is turned into helium at a temperature of millions of degrees.

:wink:

[tracer]

welike the lava coming through the mantle, lower mantle, core, outer-core...

If lava came out of the core, we'd have to seriously revise our models of the Earth's interior.

[eburacum45]

Incidentally the diameter of the Sun is 1.39 million kilometers not 1400 million kilometers.

The Sun also contains oxygen, carbon, and nitrogen and other so-called 'metals'-
from here-
http://www.astronomynotes.com/starsun/s2.htm

Spectroscopy shows that hydrogen makes up about 94% of the solar material, helium makes up about 6% of the Sun, and all the other elements make up just 0.13% (with oxygen, carbon, and nitrogen the three most abundant ``metals''---they make up 0.11%). In astronomy, any atom heavier than helium is called a ``metal'' atom. The Sun also has traces of neon, sodium, magnesium, aluminum, silicon, phosphorus, sulfur, potassium, and iron. The percentages quoted here are by the relative number of atoms. If you use the percentage by mass, you find that hydrogen makes up 78.5% of the Sun's mass, helium 19.7%, oxygen 0.86%, carbon 0.4%, iron 0.14%, and the other elements are 0.54%.

[Excelsior]

The sun is a nuclear bomb going off slowly.

[dvb]

Isn't iron the heavest metal and also the final stage of conversion in the sun?

I don't know, just askin.

[AstroSmurf]

Isn't iron the heavest metal and also the final stage of conversion in the sun?

Uh, it's not the heaviest metal, just the heaviest that can be produced through stellar fusion as we understand it. The Sun isn't producing iron yet; it won't be doing that until it's nearing the end of its life. The reason is that iron production takes far higher temperatures and pressures than the core has at this point.

[dvb]

Isn't iron the heavest metal and also the final stage of conversion in the sun?

Uh, it's not the heaviest metal, just the heaviest that can be produced through stellar fusion as we understand it. The Sun isn't producing iron yet; it won't be doing that until it's nearing the end of its life. The reason is that iron production takes far higher temperatures and pressures than the core has at this point.

Thank you for the quick reply AstroSmurf. I have no idea where I remembered that from.

[drhex]

Also, our sun is too light to produce any iron even in its end stages.

[Hamlet]

Also, our sun is too light to produce any iron even in its end stages.

Correct. Our sun will produce elements up to carbon and oxygen. It doesn't have enough mass to fuse elements beyond this. The sun will end up as a white dwarf after expelling its outer layers during its Red Giant and planetary nebula phases.

[Excelsior]

Our sun is also not destined to explode as a supernova. Howeve when the sun reaches its red giant stage it will consume Earth and the inner planets.

[Morrolan]

The sun is a nuclear bomb going off slowly.

hmm... i thought our current nuclear weaponry was all based on splitting atoms whilst the process in the sun is fusion, which is the opposite.

[Mainframes]

Isn't iron the heavest metal and also the final stage of conversion in the sun?

Uh, it's not the heaviest metal, just the heaviest that can be produced through stellar fusion as we understand it. The Sun isn't producing iron yet; it won't be doing that until it's nearing the end of its life. The reason is that iron production takes far higher temperatures and pressures than the core has at this point.

Also Iron is the last element that gives a net release of energy when formed by fusion. Elements with a larger nucleus actually absorb energy overall when formed by fusion.

[AGN Fuel]

The sun is a nuclear bomb going off slowly.

hmm... i thought our current nuclear weaponry was all based on splitting atoms whilst the process in the sun is fusion, which is the opposite.

Most nuclear weapons are fission, but the Hydrogen bomb is a fusion device.

(PS Morrolan - I e-mailed your spider description to a friend of mine in WA and am waiting to hear back. I'll revive the old thread when I do! ).

[tracer]

Actually, uncontrolled fusion is so much more efficient than straight fission that nearly all nuclear weapons on the planet today, even the smaller ones, are fusion-based.

Of course, the hydrogen isotopes used in nuclear fusion bombs are deuterium (²H) and tritium (³H), while the hydrogen isotope that undergoes fusion in the sun's core is good old-fashioned regular hydrogen (¹H). And the sun didn't require a small nuclear fission bomb to set it off.

[Manchurian Taikonaut]

welike the lava coming through the mantle, lower mantle, core, outer-core...

If lava came out of the core, we'd have to seriously revise our models of the Earth's interior.

where did I say lava came out of the core? So my English isn't so good, but I didn't mean lava comes from the core
I think you know that anyway.

People have learnt many things about the Sun in the past years. They don't say the Sun's core is just 'old fashioned Hydrogen'. The Suns' core is believed to be a superhot extremely dense mass of atomic nuclei and electrons. It is here inside the Sun that the temperature and pressure is so intense that nuclear reactions take place. This reaction causes four protons to fuse together to form one alpha particle or helium nucleus. The alpha particle is about .7 percent less massive than the four protons. Many scientists at NASA have said the solar core is made up of an extremely hot and dense material in the plasma state, fusion reactions release energy both in the form of electromagnetic energy like gamma rays and other exotic particles such as neutrinos.

[AGN Fuel]

Actually, uncontrolled fusion is so much more efficient than straight fission that nearly all nuclear weapons on the planet today, even the smaller ones, are fusion-based.

Wow, thanks Tracer - I wasn't aware of that. I knew that many nuclear weapons incorporated a combination of fission & fusion elements, but I did think that overall fission weapons dominated.

Thanks for the correction!

[Excelsior]

The sun is a nuclear bomb going off slowly.

hmm... i thought our current nuclear weaponry was all based on splitting atoms whilst the process in the sun is fusion, which is the opposite.

I should have phrased my post better. The sun uses fusion like a hydrogen bomb.

[§rv]

Thanks for the replies. Just one more question: Are all other stars considered to have the same structure as the Sun?

[Hamlet]

Thanks for the replies. Just one more question: Are all other stars considered to have the same structure as the Sun?

I'm not sure what you mean by same structure, but other Main Sequence stars like the Sun also fuse hydrogen at their cores to produces helium and energy. There may be differences in overall chemical composition depending on where the star formed. However, once fusion begins, stars follow a fairly predictable evolution that is primarily determined by their initial mass.

There are thought to be differences in the radiative and convective zones between high mass stars and low-mass stars. The high mass stars are thought to have convective zones that go deep into the core and radiative zones nearer the surface. For a star like our Sun the radiative zone sits above the core with the convective zone in the outer layers.

[Tobin Dax]

IThere may be differences in overall chemical composition depending on where the star formed.

Actually, "when" makes significantly more difference than "where" in most cases (or it's at least as significant). Stars are the only things to change the chemical composition of the universe since they started to form. Older stars must die and inject these elements into the interstellar medium before stars can form with the appropriate composition. Proximity to old, dead stars does help, but the older stars still must die first.

[Hamlet]

IThere may be differences in overall chemical composition depending on where the star formed.

Actually, "when" makes significantly more difference than "where" in most cases (or it's at least as significant). Stars are the only things to change the chemical composition of the universe since they started to form. Older stars must die and inject these elements into the interstellar medium before stars can form with the appropriate composition. Proximity to old, dead stars does help, but the older stars still must die first.

Correct. I didn't explain my statement very well. Thanks!