Week 4, clip 6

Timepoint:  05:57.8

1) Why do sunspots appear black?

- They are shadows cast on the Sun's surface by massive convective cells within the Sun's interior.
- They are small astronomical objects, like asteroids, that pass in front of the bright Sun's surface, blocking out light as they transit across the solar disk.
- They are cooler regions of the Sun formed because solar storms create low pressure areas which are cooler due to expansion of the hot plasma.
- They are cooler regions of the Sun formed because strong local magnetic fields prevent convection of hot inner plasma up to the surface.

Timepoint:  12:19.5

2) As Ronen states in the video, it takes about 3 days for the mass of hydrogen from a coronal mass ejection to reach Earth from the Sun.  How fast are these particles traveling?  Give your answer in meters per second rounded to two significant digits.

Answers:
1) They are cooler regions of the Sun formed because strong local magnetic fields prevent convection of hot inner plasma up to the surface.

2) [5.7e5,5.9e5] is the preferred range.  [5.3e5,6.3e5] is the extended range.