QUIZ - 3.28.13

1. Why does the Sun shine?

• The Sun shines steadily because nuclear fusion in the core maintains both gravitational equilibrium between pressure and gravity and energy balance between thermal energy released in core and radiative energy lost from the Sun's surface. The chemical and gravitational energy sources could not explain how the Sun could sustain its luminosity for more than about 25 million years.

2. What is the Sun's structure?

• The Sun's structure is:
• From inside out, the layers are.....
• Core
• Radiation Zone
• Convection Zone
• Photosphere
• Chromosphere
• Corona

3. How does nuclear fusion occur in the Sun?

• The nuclear fusions occurs in the Sun when the graviational equilibrium and energy balance together act as a thermostat to regulate the core temperature because the fusion rate is very sensitive to temperature. The core's extreme temperature and density are just right for the nuclear fusion of hydrogen to helium through the proton-proton chain.

4. How does the energy from fusion get out of the Sun?

• The energy from fusion gets out of the Sun by randomly bouncing photons carrying it through the radiation zone. The rising of hot plasma carries energy through the convection zone to the photosphere.

5. What is nuclear fission?

• Nuclear fission is either a nuclear reaction / radioactive decay proccess in which a heavy nucleus (such as uranium) splits into two equal and lighter nuclei, either spontaneously or as a result  of the impact of a particle, often producing free neutrons and photons (in the form of gamma rays) and releasing a very large amount of energy. (and possible some other radioactive particles as well) The two nuclei produced are most often of comparable but slightly different sizes, typically with a mass ratio  of products of about 3 to 2.
• Most fissions are binary fissions, producing two charged fragments, but occasionally 2 to 4 times per 1,000 events.
• Three positively charged fragments are produced in a ternary fission. The smallest of these fragments in ternary processes ranges in size from a proton to an argon nucleus.

6. Are neutrinos formed in nuclear fusion?

• YES, neutrinos are formed in nuclear fusion.

7. Are photons created in nuclear fusion?

• YES, photons are created in nuclear fusion.

8. Does the Sun have the same temperature throughout?

• NO, the Sun does not have the same temperature throughout.

9. Which element is created in the Sun?

• The element, Helium, is created in the Sun.

10. What fraction of mass is converted into energy in the Sun's core?

• At the absolute most, only 0.7% of the mass is converted into energy, in the Sun's core. The actual expected amount of mass, to get converted into energy, is around 0.07%.