What is the sun and how does it relate to other objects in the solar system?

Answer 1

The sun is a star.

It's the only self-luminous body in the solar system.

The gravitational force of mutual attraction between the sun and everything in a closed orbit
around it is what makes the closed orbits possible.

One focus of the elliptical path of everything in closed orbit around the sun is at the center of the sun.

The orbits of the planets are so nearly circular (small eccentricity) that the center, as well as both foci,
of every planetary orbit is inside the sun. This isn't true of most repeating cometary orbits.

Answer 2

The sun is a star at the center of our solar system, providing heat and light to all the planets including Earth. It is the largest object in the solar system and its gravity holds all the planets in orbit around it. The sun's energy drives the climate and weather on Earth and is essential for supporting life.