Your My Hy-Vee account provides access to your history, allows you to print records, submit multiple prescriptions at once and more. Learn more. This healthy lifestyle program emphasizes eating for good health, weight loss and being physically active. Beginâ¢ is not a âdietâ- Beginâ¢ is a plan to help with lifelong wellness.
Given sufficient temperature and pressure, 4 hydrogen nuclei fuse to produce helium, at the same time giving off energy in the form of heat and light and other forms of radiation. This means that stars, with a few exceptions such as super-massive stars, last for many billions of years.
Once all the hydrogen in the core has been converted to helium by nuclear fusion, there is no energy outflow to counter the inward force of gravity and the star rapidly collapses. This in turn heats the core and the region around it to such an extent that hydrogen fusion begins in the outer layers.