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The proton-proton chain reaction that fuses hydrogen into helium begins at a threshold of about 10 million degrees Kelvin. The fusion of helium doesn't begin until a temperature of about 100 million degrees Kelvin is reached. All the hydrogen must be exhausted and then a star must undergo further collapse for the new, higher threshold temperature to be reached to cause the initiation of helium fusion. Shazam! Now that's hot! Use the link below to our friends at Wikipedia for details.
Wiki User
∙ 16y ago
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∙ 12y agoFusion reactions need a certain amount of energy to get started. The energy, as indicated by the temperature, is simply too low in the sun's core (at THIS time) to fire up a helium fusion reaction. Wait a few billion years, and the amount of helium will build up so that the core will contract (thus compressing it and raising its temperature) to the temperature that He fusion can start.
Wiki User
∙ 13y agoIn order to yield energy, the nuclear fusion must be used on an element which has fission fragments that will be less massive than when combined to form the element. Since mass is directly proportional with energy (remember the equation E=mc2), the fragments will release energy in order to match the loss in mass. However, since helium's two neutrons and two protons are more massive in their free states than when combined to form helium, they do not yield any energy.
Wiki User
∙ 11y agoHelium fusion, or the triple alpha process produces very unstable isotopes of beryllium which then form stable carbon, however the latter does not happen as much.
This means that the star can barely maintain itself, as the beryllium's rate of decay now approximately equals the rate of fusion of helium.
The stable carbon can then rarely form oxygen, and as the production of carbon is already low, the amounts of carbon and oxygen are fairly low, and beyond that, a fairly small amount of any further elements occur.
Obviously, this doesn't necessarily mean that it would less likely occur, but philosophical arguments for the anthropic principle state that the Universe may somehow make it so that there are high amounts of carbon and oxygen in the Universe, so as to progenate life.
Wiki User
∙ 14y agoIt is because the sun is not large enough and therefore the core does not get hot enough to fuse carbon nuclei.
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What fusion in stars occurs to create the element helium?
Hydrogen undergoes nuclear fusion in the core of the sun to form helium.
What is the site of nuclear fusion on the sun?
If you are asking where does solar nuclear fusion take place, then that would be at the core of stars.
Where in the sun is hydrogen fused into helium?
in stars and fusion bombs.
What is the sun's source of enegry?
The Sun's energy is generated by nuclear fusion, the fusion of hydrogen into helium in the core of the Sun.
Hypothesize what will happen when the sun exhausts it's supply of hydrogen?
When a main sequence star, such as our sun, exhausts it's supply of Hydrogen, fusion of Hydrogen to Helium ceases in the core. This results in cooling of the core and therefore causes it to contract. As the core contracts, the layers surrounding the star gain kinetic energy until the fusion of Hydrogen is possible in the outer layers. As these layers undergo fusion, they increase in temperature dramatically. The outer layers expand due to heat, and the star becomes massive; the main sequence star has evolved into a red giant. Fusion of Hydrogen to Helium continues in the outer layers, whilst the fusion of heavier elements such as carbon occurs in the core.
Why doesnt the helium curently in the suns core under go fusion?
The Sun's core is not yet hot enough, or under enough pressure, for helium fusion. Which is probably just as well, since when helium fusion begins, the Sun will swell into a red giant which will incinerate the Earth.
How does the sun create energy it is core?
Nuclear Fusion from hydrogen in it core and helium
What fusion in stars occurs to create the element helium?
Hydrogen undergoes nuclear fusion in the core of the sun to form helium.
What is the site of nuclear fusion on the sun?
If you are asking where does solar nuclear fusion take place, then that would be at the core of stars.
Is the sun made out of core?
No, it is formed by fusion of hydrogen and helium molecules.
Where in the sun is hydrogen fused into helium?
in stars and fusion bombs.
What does helium have to do with a star?
Helium is formed in the core of the star (like the sun) by the nuclear fusion of hydrogen isotopes.
Why is the sun's temperature so high?
Because of the Thermonuclear fusion that goes on inside the core. Hydrogen nuclei undergo this process to form helium nuclei, giving out massive amounts of heat and light.
All of the sun energy is produced in its core through?
Through nuclear fusion of hydrogen to form helium
What is the sun's source of enegry?
The Sun's energy is generated by nuclear fusion, the fusion of hydrogen into helium in the core of the Sun.
What element is transformed in nuclear fusion in the sun's core?
We understand that hydrogen atoms are fused into helium in the sun's core.
Where does fusion take place in the sun?
Around the core of helium that been formed from hydrogen fusion.
