Chapter 14

10 Pages
Unlock Document

Astronomy & Astrophysics
Clifford Orwin

Chapter 14: Our Star Why does the sun shine? 2 Using Einsteins famous formula E = mc it was able to show that the suns mass itself contains an enormous amount of potential energy through the process of nuclear fusion. The Stable Sun Nuclear fusion requires high temperatures and high densities, which is found in the core. Core must always be kept hot and dense for steady shine Maintains these conditions through a balance of two forces, gravity pulling inward and pressure pushing outward, aka gravitational equilibrium How Fusion Started: Sun was formed from a collapsing cloud if interstellar gas. The contractions released gravitational potential energy Most of the energy was radiated away from the surface as thermal radiation, the rest remained inside causing the temp and pressure inside to spike. When the core was hot, and dense enough to sustain nuclear fusion, the energy in the suns interior was balanced with the energy lost in the form of radiation. This balance in turn stabilized the size of the sun achieving gravitational equilibrium. Basic Properties of the Sun Radius just under 700,000 km and sunspots can be even larger than earth 300,000 times the mass of earth and nearly 1000 times the mass of all the planets put together. Sun does not rotate at the same rate. Solar equator completes one rotation in 25 days, and the rotation period increases with latitude to about 30 days at the poles. 26 The suns power output or luminosity, is 3.8 x 10 watts.
More Less

Related notes for AST101H1

Log In


Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.