1. active prominences - solar prominences that change in a matter of hours
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3. active Sun -
• unpredictable aspects of the Sun’s behavior; sudden, explosive prominences and flares
6. convection zone -
• area of Sun’s interior where material is in constant convection, extends from photosphere to depth of 200,000 km
8. coronal hole -
• large regions of solar atmosphere 10 times denser than normal; here gas streams freely into space, escaping the Sun’s gravity
12. fusion -
• light nuclei are ‘fused’ into heavier ones, releasing energy; generates energy in the Sun’s core
15. Helioseismology -
• study of ‘sound’ waves that cross solar interior, reveals interior conditions
18. limb darkening -
• light from edge is cooler since it is from particles that are not as deep, so edge is darker
20. Maunder minimum -
• period between the years 1645 and 1715 with little solar activity, sunspot cycle apparently stopped
22. neutrino oscillation -
• possible solution to missing solar neutrino problem, some neutrinos may ‘oscillate’ (be transformed into other particles between the Sun and the Earth)
25. positron -
• the antiparticle of the electron, one of the products in the first step of the proton-proton chain
26. prominence -
• loop or sheet of glowing gas ejected from the surface of the Sun and moving through the inner corona
27. proton-proton chain -
• chain of fusion reactions, from hydrogen to helium, that powers most stars
28. quiescent prominences -
• stable prominence, lasting days or weeks, held by Sun’s magnetic field
30. radiation zone -
• photons travel through this region of the Sun’s interior with relative ease because atoms are stripped of electrons by the high heat
33. solar cycle -
• 22-year period required for Sun’s average number of spots and magnetic polarity to repeat
42. Supergranulation -
• large scale granules on the surface of the Sun, cells up to 30,000 km across
• Core - nuclear fusion occurs here.
• Interior - gaseous layer.
• Convection zone - constant convective motion.
• Photosphere - surface that we see.
• Chromosphere - bright lower atmosphere.
• Corona - upper atmosphere.
• Solar Wind - escaping particles.
2. How massive is the Sun, compared with the Earth?• 300,000 times greater than the mass of the
Earth.
4. Why does the Sun appear to have a sharp edge?
• The temperature of the sun increases with depth. Photons coming from the center of the observed disk are more energetic and therefore brighter than those coming from the edge of the disk.
5. What is the solar wind?
• Fast moving particles escaping the Sun. Produced by high temperature coronal gas.
6. What is a sunspot?
• A cooler, and therefore darker region of the Sun’s photosphere.
• Typically areas of concentrated magnetic fields.
7. What is thought to be the cause of sunspots, flares, and prominences?
• It is believed that the strong magnetic fields in these areas are the causes of all the disturbances in the photosphere.
10. Why are scientists trying so hard to detect solar neutrinos?
• Finding the correct output of neutrinos would confirm that the model of the fusion reactions on the Sun is correct.