The Limb of the Sun

The video explains the brightness variations in flames and the sun, focusing on limb darkening and brightening effects. It describes how the sun's edges appear darker and redder due to temperature differences and viewing angles. The reverse effect is seen in some flames, where edges are brighter due to optimal oxygen and fuel mixture. The video also touches on similar effects in nebulas, explaining the geometrical reasons behind these phenomena.

Why do flames sometimes appear brighter at the edges?

• Because the edges are cooler

• Due to the mixture of oxygen and fuel

• Because the center is cooler

• Due to the lack of oxygen

What is the term used to describe the sun's darker and redder edges?

• Sunset effect

• Edge fading

• Limb darkening

• Solar dimming

Which of the following is NOT a reason for the sun's limb darkening?

• The sun's edges are closer to Earth

• Viewing angle across a sphere

• The sun is cooler near its surface

• Hotter materials glow brighter and yellower

What effect does looking at the edge of a sphere have on visibility?

• The sphere appears smaller

• The sphere appears larger

• You see less deep into the sphere

• You see deeper into the sphere

How does the concept of limb darkening apply to certain nebulas?

• They are hollow expanding shells of glowing gas

• They are solid objects

• They are completely opaque

• They are made of liquid