If a sun can let go of gases with its intense gravity why cant the earth let go of its gases?

The sun does not let go of gases, it repels ions because of its electric charge. Gravity is puny compared to electric charge. Astronomers have no training in electric physics, so they make up baloney instead. They say the sun is powered by fusion. That implies it should be hotter inside than outside, and the reverse is true.

An ion moving is an electric current, and that makes gases in Earth's atmosphere glow, which we call northern lights. Scientists are forced to admit that is an electric effect, but they call it a "solar wind" and speak of "collisions", rather than an electric current making gases glow like a neon light. They completely miss that an electric current plus a magnetic field makes a motor, and we call that motor the jet stream. There is no other clue to what powers the jet stream.