Chapters 29 & 30 Test review: The Sun & Stars

1. First, list & describe the effects that geomagnetic storms caused by solar winds from the Sun can

have on Earth. Then, explain how each of the negative effects you mentioned can be avoided.

Descriptions of effects / Ways effects can be avoided
Positive effects / Auroras are caused when solar winds of a geomagnetic storm cause the gasses in our atmosphere to get excited and glow. / (No answer needed here b/c positive things don’t need to be avoided!)
Negative effects / à damage caused to power grids and electrical equipment such as satellites and transformers as the charged particles from solar winds over load them with energy and short out/damage them.
à disruption of Earth’s magnetic field causes the flow of electricity and movement of radio waves to be disrupted.
**This causes communication & entertainment satellites (like TV, internet & cell phone satellites) to not function properly.
**Radio waves between towers
will not work correctly (cell
phones, radio signals, TV
signals, & CB radios).
** It also means that GPS systems
that depend on the magnetic
field for accuracy do not work
correctly. / à Power down satellites/put them to sleep and reduce the load on power grids so they can’t be overloaded and damaged by the excess charged particles from the solar wind.
à use “space forecasts” to predict a severe event and be aware that these items may not function temporarily so you don’t panic and aren’t stranded. (prepare to be a little inconvenienced)

2. First, explain how the Hertzsprung-Russell diagram can be used to determine the amount of nuclear fusion occurring in a star.

à This graph shows the color of stars and this is related to their temperature.

Blue = hottest, Red = coolest

à Temperature shows how much fusion is happening b/c the hotter the star is, the more fusion is happening, since heat energy is a product of this process.

Then, use the chart provided to compare the relative percentages of hydrogen and helium in 3 stars at different locations on the H-R diagram (like a blue one, yellow one & red one).

Star color / % H / % He / Reason for the difference in %?
Blue / 90% / 10% / As the star ages it uses up hydrogen to fuel nuclear fusion & increase helium as a product of this reaction. The older the star is, the less hydrogen it has left for fusion = less heat being produced = the color changes with the temp.
Yellow / 50% / 50%
Red / 10% / 90%

3. Describe, in detail, the lifecycle of an average sized star. Begin with the original cloud of gas it formed from and end with the final stage it goes through as a “burnt out” star.

Name of stage / Description of stage
Nebula / A large cloud of gas and dust in space where stars are born; as the cloud is compressed, some of the particles move close together and are pulled together by gravity.
Protostar / A central core formed inside a spinning, shrinking region of gas and dust as it begins to flatten into a disc.
Main Sequence Star / The longest stage in the lifecycle of an average sized star- collisions in the star cause friction which causes heat & fusion begins in the core when it reaches 10,000,000°C & it produces a great amount of energy .
Red Giant / When almost all of the hydrogen in the core is used up, the star’s shell of gases grows cooler as it expands and it glows with a reddish color.
Planetary Nebula / As the star’s outer gases drift away, the remaining core heats these expanding gases and the cloud of gas begins to glow around the dying star.
White Dwarf / A hot, extremely dense core of matter is all that is left after gravity causes the remaining matter in the star to collapse inward until it cannot be pressed further together.
Black Dwarf / This is the final stage of an average sized star and it occurs when a white dwarf cools completely & no longer gives off light.

4. First, name the color shift shown by each of the following types of stars AND explain why each shift occurs. Then, below the chart, explain what the Doppler shift shown by most stars in our universe may tell us about its formation.

Direction of star movement / Shift that occurs / Reason that shift occurs
Stars moving toward Earth: / Blue
Shift / B/c as the star moves toward us, the light waves we see are being compressed and the perceived wavelength we see is shorter = a blue tint when viewed over a long time.
Stars moving away from Earth: / Red
Shift / B/c as the star moves away from us, the light waves we see are being stretched out and the perceived wavelength we see is longer = a red tint when viewed over a long time.

à Because most stars in our universe show a red shift, this means that most of them are moving away from us (and each other). This supports the main component of the Big Band theory because it shows that the universe is expanding.