The sun is much closer to Earth than any other star. The average distance between the sun and Earth is about 149.6 million kilometers, while the nearest star, Proxima Centauri, is about 4.24 light-years away. This means that Proxima Centauri is about 270,000 times farther away from us than the sun.

As a result of its proximity, the sun appears much larger in the sky than other stars. The apparent size of an object is determined by the angle it subtends at the observer's eye. Since the sun is so much closer to us than Proxima Centauri, the angle it subtends is much larger.

The apparent diameter of the sun is about 32 arcminutes, while the apparent diameter of Proxima Centauri is only about 0.00001 arcminutes. This means that the sun appears about 1,800,000 times larger in the sky than Proxima Centauri.

Brightness

The sun is also much brighter than other stars. The apparent brightness of a star is determined by two factors: its intrinsic brightness and its distance from Earth.

The intrinsic brightness of a star is determined by its luminosity, which is the total amount of energy it emits per second. The sun is a very luminous star, and it emits more energy than any other star in our solar system.

The brightness of a star also decreases with its distance from Earth. This is because the light from a star spreads out as it travels through space, so the farther away a star is, the less light reaches our eyes.

The sun is so close to Earth that its brightness is not significantly affected by its distance. However, Proxima Centauri is so far away that its brightness is reduced by a factor of about 10^-27. This means that Proxima Centauri is about 10^27 times fainter than the sun.

In summary, the sun appears bigger and brighter than other stars because it is much closer to Earth and much more luminous.