In 1979, scientist Eddy and Boornazian cautiously the sun is shrinking. Its diameter was decreasing at a rate of almost six feet per hour. Consequently, very good arguments and data that contradicted this result came forth.
The sun is a big ball of gas and plasma. Most of the gas present in sun is hydrogen (91%). It is converted into energy in the sun’s core. The energy moves outward through the interior layers, into the sun’s atmosphere, and is released into the solar system as heat and light. In the sun’s core, gravitational forces create tremendous pressure and heat. The temperature of the sun in this layer is about 27 million degrees Fahrenheit. Hydrogen atoms are compressed and fuse together, creating helium. This process is called nuclear fusion. As the gases heat up, atoms break apart into charged particles, turning gas into plasma.
Scientists believed that once the core hydrogen is exhausted, the sun will expand into a subgiant phase and slowly double in size over about half a billion years. This will then start the red-giant branch (RGB) phase where the sun will spend around a billion years and lose around a third of its mass.
After RGB, the core ignites the helium flash, and the sun shrinks back to around 10 times its current size. The sun is not massive enough to fuse carbon or oxygen to neon or magnesium.
Still, there is number of arguments and data against this observation. It is believed that the sun was the same in 1716, as it is today.