What defines a star's 'surface' when considering its wispy, ever-thinning layers of gas?

Answer

The point where gas becomes thin enough for light to escape relatively freely

A star's surface is fundamentally different from a solid world like Mars or Venus because it has no ground to stand on. The 'surface' is defined purely by optics and density gradients. It is the specific altitude or layer within the star where the gaseous material thins out sufficiently that the photons generated internally can escape into space without being significantly scattered or absorbed by overlying layers. If an observer were to attempt standing on the photosphere of any star, they would immediately pass through the wispy, ever-thinning layers of gas, encountering only a continuous gradient of increasing heat and pressure as they moved inward.

What defines a star's 'surface' when considering its wispy, ever-thinning layers of gas?

#Videos

First Close-up Picture of a Star Outside Our Galaxy - YouTube

Related Questions

What texture characterizes the Sun's visible surface, the photosphere, upon close inspection?What defines a star's 'surface' when considering its wispy, ever-thinning layers of gas?What process suppresses convective flow, causing dark patches known as sunspots to appear on the Sun?What astronomical technique was necessary to resolve the surface details of the red supergiant Betelgeuse?How large can a single convective feature on Betelgeuse be compared to a major solar system boundary?Stars are fundamentally composed of what superheated state of matter, where light is emitted?What visual description characterized Betelgeuse when astronomers captured its first resolved close-up image?For the vast majority of stars not named the Sun or Betelgeuse, how is their surface appearance understood?How many times larger is the angular size subtended by a dime held at arm's length compared to Proxima Centauri as seen from Earth?What mission provided empirical close-up data showing the turbulent plasma surface of our Sun?What are the bright, irregularly shaped patches within the Sun's granular photosphere texture specifically called?
Spaceastronomyappearancestarup close