Chap 15 and 16 Flashcards
Describe the main differences between the composition of Earth and that of the Sun.
The Earth is rocks and metals whereas the sun is gaseous and made up of helium and hydrogen
Why do sunspots look dark?
The sunspot’s area of gas has a lower temperature compared to surrounding gas.
Which aspects of the Sun’s activity cycle have a period of about 11 years?
Which vary during intervals of about 22 years?
The sunspot cycle peaks every 11 years.
The solar magnetic cycle is every 22 years and the polarity of the sunspots reverses.
What is the Zeeman effect and what does it tell us about the Sun?
The magnetic field of the Sun causes spectral lines to split, which tells us about the strength of the magnetic field of the Sun.
Compare and contrast the four different types of solar activity above the photosphere.
- Plages: Higher temperature region around sunspots
- Prominence: Loops of ionized gas
- Coronal Mass Ejection: Flare that reaches escape velocity
- Flare: Violet explosion of gas
How does activity on the Sun affect human technology on Earth and in the rest of the solar system?
It can affect wave signals, satellites, and electronics on Earth and in space.
What are the two sources of particles coming from the Sun that cause space weather? How are they different?
- Solar wind: a constant stream of charged particles (plasma) that flow from the sun’s outermost atmosphere (the corona) into space
- Coronal mass ejection: a large eruption of plasma and magnetic fields from the Sun’s corona
The key difference is that solar wind is a continuous flow while CMEs are powerful, sporadic events with significantly higher particle density and speed
How does activity on the Sun affect natural phenomena on Earth?
Solar wind causes the northern lights to form.
Starting from the core of the Sun and going outward, the temperature decreases. Yet, above the photosphere, the temperature increases. How can this be?
The Sun’s magnetic field lines are accelerating the gases, causing their temperatures to increase.
Since the rotation period of the Sun can be determined by observing the apparent motions of sunspots, a correction must be made for the orbital motion of Earth. Explain what the correction is and how it arises.
We know how fast Earth rotating/orbiting and can observe the motion of sunspots to conclude on the rotational period.
How can the prominences, which are so big and ‘float’ in the corona, stay gravitationally attached to the Sun while flares can escape?
The flares are going faster then escape velocity and the Sun’s has a lot of gravity.
Suppose you observe a major solar flare while astronauts are orbiting Earth. Use the data in the text to calculate how long it will before the charged particles ejected from the Sun during the flare reach them.
400km/s = 400,000 m/s
1AU = 1.5 x 10^11m
time = distance/speed
time= 1.5 x 10^11/ 400,000 = 375,000 secs
How do we know the age of the Sun?
Since the solar system should of formed at the same time, we can use meteorites and lunar rocks to date the Sun.
Explain how we know that the Sun’s energy is not supplied either by chemical burning, as in fires here on Earth, or by gravitational contraction (shrinking).
Chemical burning isn’t possible without oxygen, which the Sun barely has. The sun also is not shrinking so gravitational contraction isn’t a contributor. These would also be too small of sources to sustain the Sun’s energy.
What is the ultimate source of energy that makes the Sun shine?
Nuclear Fusion
