ALWAYS SHOW YOUR WORK; Keep track of units!
1. When the Sun dies, it will swell into a "red giant", with a diameter around the
size of the orbit of Mars. What will be the surface area of the red giant shell of the Sun then?
2. Assuming that the Sun's surface temperature goes down by a factor of 2.5 from its
present temperature of 6000 K,
what will that surface temperature be?
3. What will the wavelength of the peak of the solar spectrum at that time?
_________ nm. Use Wien's law λ = (0.3 / T) (cm/K).
4. What will the amount of energy radiated per m2 of the red giant surface?
_____________W/m2 . Use Stephan-Boltzman law J = σ T4
where σ = Stephan-Boltzman constant = 5.67 10-8 W/(m2 K4)
5. What will be the total amount of energy radiated from the Sun then?
How does that compare to the Sun's total energy output now? (3.84 x 1026 W)
6. (Back to today's Sun): If a Coronal Mass Ejection has an average speed of
1000 km/s on its way to Earth from the Sun, how long will it take to arrive?
Last updated 9/9/2014