think of it, this way, it's a positive of a black hole. Meaning that this singularity has achieved enough mass to support nuclear fusion caused but extreme gravitational pull of the singularity. but much is thoerized by Stephen Hawking, and his notes on the hawking molecule that should give you the information you need.
Because no one has been able to produce a continuous fusion reaction so far.
The first work on nuclear fusion was performed in 1933 by Ernest Rutherford. The first nuclear fusion "reactor" was built in 1947 by teams in the UK and USSR. To this day no nuclear fusion "reactor" has been able to produce more energy than had to be put into it to get the reaction started, despite many different experiments on many different designs.
Nuclear fusion is unsure now at industrial scale.
Sure, you can get a tan from it, since the Sun is a big fusion power reactor. In the near future we will be able to build fusion reactors here on Earth. Google "ITER" to see how it's going. In the meantime I suppose you can say the fusion power is actually solar energy.
All current nuclear reactors are fission reactors, tritium has no function in a fission reactor, in standard water moderated reactors deuterium also has no function, in heavy water moderated reactors deuterium is the moderator. If we are ever able to make a fusion reactor, deuterium/tritium mix will be used as fuel.
It gets the energy from nuclear fusion. It is able to carry out this nuclear fusion because of its mass, which pulls the Sun together, and keeps its core hot and dense.
So far, it takes so much more power to generate fusion than it produces. No one's been able to produce it on an industrial scale, i.e. for a sustainable length of time. A Nobel prize or three would surely follow that feat.
It may be possible one day but it will be many years before fusion plants are developed.
Thermonuclear fusion is the process of nuclei joining together with the release of energy. This is the process which powers the stars, including our sun, and also the H-Bomb. Scientists hope to be able to make this work in a controlled way to produce energy which could then produce electric power. The most likely process for controlled use is between nuclei of deuterium and tritium, which are isotopes of hydrogen.
For fusion, the main disadvantage is that nobody has been able to make it work. However it does have promise and if it can be developed it will not produce the dangerous fission products that fission does. For fission, see reply to question 'What are the disadvantages of nuclear fission power'
At the moment it's not because nobody has been able to get it to work for the sort of duration necessary for power production. There are, however a couple of nice advantages over fusion: - No radioactive waste products (the product is helium-4) - No radioactive raw material (need heavy hydrogen) - Theoretically large energy gain per reaction On the down side it is technically very challenging, requiring extremely high pressure. Getting the inital reaction to start requires a lot of energy.
The source of the sun's energy, as well as that of every star, is nuclear fusion in its core. The only way we're able to use nuclear fusion consistently on Earth so far is in the explosions of large nuclear weapons, but we're working on the ability to control other applications.