Specifically a Yellow G2 Dwarf star. Stars have 7 fundamental classes - O, B, A, F, G, K and M.
Our Sun is nothing special with respect to others but it does (like all other stars though) "make" fuel which sustains an outward force that prevents Gravity from killing our star. In actual fact it is Gravity that is responsible for the birth of every star you see.
Now, the temperature of the core of our Sun is an intense 15,000,000 degrees Celsius - HOT HOT HOT! Unimaginably hot.
It's these temperatures that allow the important part to be carried out by a star during its life - NUCLEAR FUSION - and this is their boring middle-age part.
Every second the Sun converts 600,000,000 tonnes of Helium into 596,000,000 tonnes of Hydrogen - the 4,000,000 tonnes that is missing is lost as is done.
To help explain - we convert this:
To this:
Now, you may look at these two pictures and wonder where the blue-balls come from - these are called Neutrons as they are the same size as Protons but have no charge.
Charges:
Proton = +1
Neutron= 0
Electron= -1
The temperature of the core is due to how dense it is, atoms are tiny but yet the Sun boasts enough Hydrogen to carry on Nuclear Fusion for another 4 billion years (approx - thank goodness!).
Protons don't like each other, by that I mean they can't just be stuck together on their own (due to the +1 charge), this is where the Neutron comes into play as it has no charge so it can act as a barrier between Protons and bring stability to the nucleus (the centre) of the atom.
So are Neutrons present in the Sun? - probably but not exactly.
This where atoms get clever in my opinion.
STABILITY is key, every atom pretty much wants to be stable and carry no overall charge (e.g 12 Protons and 12 Electrons) but it can't get anywhere without Neutrons to help build from the most basic atom - Hydrogen (see above diagram).
So it makes a Neutron, out of a Proton!
Proton - internal structure:
Protons are made up of Quarks! Specifically:
2 x Up-Quarks
1 x Down-Quark
Quarks are held together by Gluons (the wavy lined parts)
Neutron - internal structure:
Neutrons are also made of Quarks:
2 x Down-Quarks
1 x Up-Quark
You can see that the difference is minimal as a Proton has the exact opposite to a Neutron.
This is the clever part:
An Up-Quark will DECAY into a Down-Quark - ON PURPOSE FOR STABILITY.
Now the Proton is a Neutron.
To be continued........
When this decay occurs, a Positron and a Neutrino will be emitted by the nucleus of the atom.
A Positron is the exact opposite to an Electron (it carries a positive charge).
A Neutrino is a massless particle that has no charge (think a tiny Neutron).
Now we have an atom that is not your usual Hydrogen because there is a Neutron present.
The atom is now known as Deuterium (1P and 1N).
Now this Deuterium atom can accept a second Proton into the nucleus and now that we have a Neutron, we have a little bit of STABILITY.
So, the Deuterium atom can accept/capture a Proton but this process results in energy being given off and we're talking a lot of energy in the form of a GAMMA WAVE. A gamma wave is a Photon that has a very short wavelength and a lot of energy.
Now we're faced with an Isotope of Helium.
Our atom now contains:
2P
1N
Not quite your usual Helium atom of:
2P
2N
So we have an isotope. An isotope is a variation of a specific atom - I.E a certain number of Protons (e.g Helium = 2), but a different number of Neutrons than the correct stable state that you would expect to find the atom in. An isotope is an atom that contains a different number of Neutrons - you can usually get variations where by there is 1 less or 1 more than normal.
Now our Helium isotope is ready to undergo the FINAL STAGE of fusion.
It will combine with another Helium isotope, an exact replica of itself.
You may be thinking that this would give us:
4P
2N
and it does, temporarily, before 2 Protons are ousted from the nucleus, leaving us with:
2P
2N
HELIUM!!!
Now, you may be wondering:
Why doesn't a proton decay into a neutron and give us Lithium-3?
What happens to the ejected Protons?
The first question I cannot answer, sorry. My best postulation would be that the temperature of the core is not quite hot enough for this to happen - we should be glad as if this weren't the case then the burn rate wouldn't be another 4 billion years.
The second question I can answer and I pick up from the last sentence I wrote as these 2 Protons will be able to join the party once more and will eventually fuse into Helium (they could, for example, take part in the first phase).
To round off I shall explain what happens to;
The Positron
The Neutrino
The Gamma wave
The Positron is the opposite to an Electron (what we call antimatter) and when the two are able to combine they annihilate each other (both explode) and a lot of energy is given off - a Photon of a very short wavelength (i.e a Gamma wave).
The Neutrino, due to being massless will travel away (close to the speed of light (186,000 mph)) and not interact with anything and I mean anything. Neutrinos pass through the most solid of objects - buildings, land and PLANETS!! In fact they are passing through you right this second as you are reading this!!
The Gamma wave(s) - we now have prospectively 2 - these will probably be absorbed by electrons and then released by electrons over and over gain until they are able to leave the sun completely. They then travel at the speed of light to our earth and provide LIFE with energy to LIVE. An important aspect of Photons is that they can alter their wavelength (only get longer with less energy) the more they are absorbed by electrons. Effectively they get diluted due to losing energy through the absorption meaning they arrive at Earth as any of lower energy wavelengths thjat can penetrate Earths atmosphere - UV-3 and lower.
It can take a Photon up to a MILLION YEARS to get from our Suns core to the surface of our planet!!
I hope this helps.
Adam King
15/4/2012
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