1. It is thought that Venus once had a habitable global climate that eventually succumbed to a runaway greenhouse effect, which now supports surface temperatures hot enough to melt lead. Can you speculate whether such a scenario could happen to Earth's climate? Why or why not? What mechanisms could prevent such a catastrophe both on short and long time scales?
2. Using the inverse square law, find the solar flux at perihelion (0.983 AU) and at aphelion (1.017 AU). Recall that the solar flux at 1 AU is 1370 Watts/m2. How much higher is the solar flux at perihelion than at aphelion today? How much warmer is the effective radiating temperature of Earth at perihelion than at the aphelion?
where σ=5.67*10-8 W/m2K4
3. List out the various eras and epochs in Earth's history in chronological order and mention their time periods.