A giant ball of hot gas mainly hydrogen and helium is a star.
Star is a celestial body that shines its own light. It is a spheroidal form in a state of plasma (high ionized gas at high temperature), and it consists mostly of hydrogen and helium, and only a small part of other elements. The star generates energy in its nucleus by thermonuclear reactions. This energy is transferred to the surrounding space by convection and electromagnetic radiation and particles.
The closest star to the Earth is the Sun, the source of light, heat, and life for our planet. Other stars (with the exception of certain supernovae) are visible only during the night, as bright points in the sky that blink due to the effect of the Earth's atmosphere.
