Post on 27-Mar-2015
Exploring the Universe
Chapter 26
26.1 Energy From the Sun
Since you read the chapter
• We won’t be spending time on these vocab words that were part of your reading guide.
Review of Vocabulary
• Core - central region, where nuclear fusion occurs.
How does the sun produce energy?
Energy is produced in its central region by the fusion of hydrogen nuclei into helium nuclei.
Question: What new isotope is produced by this fusion reaction?
1. hydrogen-1
2. helium-4
3. oxygen-16
4. none
What new isotope is produced by this fusion reaction?
1. hydrogen-1
2. helium-4
3. oxygen-16
4. none
26.1 Forces in Balance
May the force be with you!
Why does the sun remain stable over time?
• Inward pull of gravity balances the outward push of thermal pressure from nuclear fusion.
Question: What would happen to the sun if it began to run out of fuel?
1. It would become cooler very quickly.
2. The force of gravity would decrease.
3. Its core would expand as thermal pressure increased.
4. Its core would shrink as thermal pressure decreased.
What would happen to the sun if it began to run out of fuel?
1. It would become cooler very quickly.
2. The force of gravity would decrease.
3. Its core would expand as thermal pressure increased.
4. Its core would shrink as thermal pressure decreased.
26.1 The Sun’s Interior
Sunny’s pretty on the inside?
Interior facts
• The sun’s interior consists of 3 parts.– Core– Radiation zone– Convection zone
• Energy moves through the sun in two main ways:– Radiation– Convection
Review of Vocabulary
• Radiation zone - region of highly compressed gas where energy is transferred by the radiation.
Review of Vocabulary
• Convection zone - the outer layer of the sun's interior, where energy is transferred mainly by convection currents.
Remember how convection currents move…..
26.1 The Sun’s Atmosphere
Very unlike Earths!
Exterior facts
• The sun's atmosphere consists of three layers.– Photosphere– Chromosphere– Corona
These regions are outside the convection zone.
Photosphere
• Innermost layer
• Visible surface of the sun
• 500 kilometers thick
• Temp: approximately 5800 K
Chromosphere
• Middle layer
• Temp: increases to nearly 10,000 K
• At high temperatures, hydrogen gas emits a reddish light.
• This light gives it its name, which means “sphere of color.”
• Can see this during a total solar eclipse.
Corona
• Outermost layer
• Gases in the corona are thin
• Temp: Gases super hot (about 1 million K)
• Thermal energy in it is relatively small.
• Usually seen only during solar eclipses.
26.1 Features of the Sun’s Atmosphere
You will use your notes and text to compare and contrast these features after
lecture with table partner.
Sunny’s got a magnetic personality!
• The sun's magnetic field produces striking features on and above its surface
• Such as:– Sunspots– Prominences– Solar flares.
Sunspots
• Areas of gas in the photosphere that are cooler than the surrounding gases.
• Spots can be larger than Earth• Associated with intense magnetic fields on the
sun. • Last from a few hours to a few months. • Numbers varies in cycles, with about 11 years
separating one sunspot peak from the next.
Prominences
• Huge loops of gas that erupt from sunspot regions.
• Extend from the photo S into the chromo S and sometimes into the corona.
• Travel along the magnetic field lines that connect sunspots.
• Heights can be more than 100,000 kilometers above the sun's surface.
Solar Flares
• Sudden release of energy • Surface erupts dramatically, producing X-rays and hurling
charged particles into space.• Heat the corona to a temps near 20 million K and produce
solar wind. • High-energy particles and radiation can reach Earth• Cause magnetic storms in Earth's upper atmosphere. • Storms disrupt electric power transmission, radio, TV, and
phone signals.
Question: How can sunspots be recognized on the sun's surface?
1. Sunspots appear darker than the surrounding photosphere.
2. Sunspots appear lighter than the surrounding photosphere.
3. It is hard to distinguish sunspots from the surrounding photosphere.
4. Sunspots always appear in definite groups.
How can sunspots be recognized on the sun's surface?
1. Sunspots appear darker than the surrounding photosphere.
2. Sunspots appear lighter than the surrounding photosphere.
3. It is hard to distinguish sunspots from the surrounding photosphere.
4. Sunspots always appear in definite groups.
Let’s play…….
Name that feature!!
Great Job!You win
200,000,000,000,000,000
Joules of ultraviolet radiation
View clip for review
Inside the Sun (6:16)