Transcript 1. active prominences -

1. active prominences • solar prominences that change in a matter of
hours
2. active region • photosphere around a sunspot group, can
erupt violently and unpredictably
3. active Sun • unpredictable aspects of the Sun’s behavior;
sudden, explosive prominences and flares
4. chromosphere • the Sun’s lower atmosphere, just above
photosphere
5. conservation of mass and
energy • the sum of mass and energy must remain
constant
6. convection zone • area of Sun’s interior where material is in
constant convection, extends from
photosphere to depth of 200,000 km
7. corona • outer atmosphere of Sun, at great distances
becomes solar wind
8. coronal hole • large regions of solar atmosphere 10 times
denser than normal; here gas streams freely
into space, escaping the Sun’s gravity
9. deuteron • hydrogen isotope, produced in the first
fusion reaction that powers most stars
10. effective temperature • average temperature of a star’s photosphere,
6000K for our Sun
11. flare • explosive event on the Sun, usually occurs
near sunspots
12. fusion • light nuclei are ‘fused’ into heavier ones,
releasing energy; generates energy in the
Sun’s core
13. GONG • Global Oscillations Network Group
14. granule • topmost part of a solar convection cell, just
below photosphere
15. Helioseismology • study of ‘sound’ waves that cross solar
interior, reveals interior conditions
16. isotope • nuclei with the same number of protons but
different number of neutrons
17. limb • edge of the Sun
18. limb darkening • light from edge is cooler since it is from
particles that are not as deep, so edge is
darker
19. luminosity • total energy radiated by a star each second
20. Maunder minimum • period between the years 1645 and 1715
with little solar activity, sunspot cycle
apparently stopped
21. neutrino • virtually massless and chargeless particle
produced by fusion in the Sun
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)
23. penumbra • outer region of a sunspot, not as dark or
cool as the central umbra
24. photosphere • visible surface of the Sun, lies just below
chromosphere
25. positron • the antiparticle of the electron, one of the
products in the first step of the protonproton 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
29. quiet Sun • predictable elements of Sun’s behavior
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
31. solar constant • amount of energy reaching Earth per unit
area per unit time
32. solar core • center of Sun, where nuclear reactions occur
33. solar cycle • 22-year period required for Sun’s average
number of spots and magnetic polarity to
repeat
34. solar disk • surface of Sun that we see
35. solar interior • region between solar core and convection
zone
36. solar maximum • part of cycle where sunspot number is at its
highest
37. solar minimum • starting point of sunspot cycle, number is at
its minimum
38. Standard Solar Model • most accepted picture of the way the Sun
behaves
39. star • glowing ball of gas held together by its own
gravity and powered by nuclear fusion
40. sunspot • dark area on Sun’s surface, cooler than
surrounding area
41. sunspot cycle • fairly regular pattern the number of
sunspots follows
42. Supergranulation • large scale granules on the surface of the
Sun, cells up to 30,000 km across
43. transition zone • region of rapid temp. increase, separates
chromosphere from the corona
44. umbra • darkest, coolest, innermost portion of a
sunspot
45. WIMP • Weakly Interacting Massive Particle
1. Name and briefly
describe the main
regions of the Sun.
• 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.
3. How hot is the solar surface?
The solar core?
• 6000K at the surface.
• 15,000,000K at the core.
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.
8. What fuels the Sun’s enormous
energy output?
• Nuclear fusion.
9. As mass decreases in the
proton-proton chain, where does
it go?
• It is converted into energy.
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.
11. What are some possible
explanations for the scarcity of
detected neutrinos?
• 1. The Sun could be pulsating, requiring less
energy from fusion that would produce
neutrinos.
• 2. Other material might be present in the core
that is not accounted for.
• 3. Neutrinos could transform into other
particles.