General Astronomy Lecture - The Sun and Fusion

Flashcards covering key concepts about the Sun and its fusion processes from the General Astronomy lecture on October 15, 2025.

What is the approximate age of the Sun according to the lecture notes?

The Sun is approximately 4.5 billion years old.

What two forces are in a state of Dynamic Equilibrium in the Sun?

Gravity and pressure are in Dynamic Equilibrium, where gravity pulls inward and pressure from heat pushes outward.

What is required for fusion to occur in the Sun?

Fusion requires high temperature and pressure, specifically about 15 million degrees Celsius at the core.

What are the four fundamental forces mentioned in the lecture?

The four fundamental forces are Gravity, Weak Force, Electromagnetic Force, and Strong Force.

What is the equation relating mass and energy mentioned in the lecture?

The equation is E=mc², showing the relationship between mass and energy.

How long does it take for energy to radiate out from the core of the Sun?

It takes approximately 100,000 to 1,000,000 years for energy to escape from the Sun's core to the surface.

What particle provides almost real-time information about the Sun?

Neutrinos provide almost real-time information because they can escape the Sun easily.

Describe the structure of the Sun as outlined in the lecture.

The Sun has three main layers: the Core (where H+ fusion occurs), the Radiative Zone (where energy emerges as light), and the Convective Zone (where H+ can move in convection cells).

What evidence is provided in the notes for the existence of convection cells on the Sun?

Granules on the surface of the Sun show patterns where hot gas rises and cooler gas sinks, supported by Doppler shift data.

What is the main product of the fusion process in the Sun?

The main product of fusion in the Sun is helium (He₂) along with energy and neutrinos.