Astronomy Chapter #5: The Sun, Quiz Study Guide

Coronal Mass Ejections

_____________ (CMEs) are huge bubbles of gas ejected into space from the corona. They contain billions of kilograms of matter traveling at 1 to 2 million miles per hour. These eruptions are relatively unpredictable. Although the solar magnetic field is clearly involved, the details are elusive. If a CME happens to be aimed in our direction, it can take only a couple of days for a blast to reach Earth. During minimum activity, only one CME may occur in several days, while at the peak of the cycle many may be observed on a single day. Once a CME reaches Earth, it can create geomagnetic storms in Earth's magnetosphere. They can produce unusually strong auroras. You may never have heard the term aurora, but you have probably heard about the "northern lights". Due to the Earth's magnetic poles in the northern and southern hemispheres, it is common to see a light show of spectacular colors as charged particles spiral around these magnetic fields. CMEs can result in this spectacular light show being visible at much lower latitudes than usual. CMEs can also hamper radio communications, disrupt electrical power delivery, expose airline crews on polar flights and astronauts to harmful radiation, and damage the electronic components in satellites. olar storms can powerfully affect Earth and our technological society. Solar flares and ____________ (CMEs) can damage satellites, power grids, and temporarily disrupt cell phone communications, not to mention threaten the life of astronauts. CMEs and solar flares are generally observed at the start of a space weather event that leads to a large magnetic storm on Earth.

Magnetic Fields

_____________ are responsible for depositing energy above the Sun's surface into the chromosphere and corona. The _______________ also trap the hot coronal plasma (charged particles) in loops that tower up to tens of megameters (Mm) over the surface of the Sun. __________ trigger solar flares, prominences, and coronal mass ejections in general, particularly during solar maximum.

Proton-Proton Chain

Nuclear fusion is the source of the Sun's energy. The overall hydrogen fusion reaction transforms four individual hydrogen nuclei (proton) into a helium nucleus (two protons and two neutrons) releasing energy in the process. The sequence of steps that occurs in these reactions is called the _____________ because it begins with collisions between individual protons (hydrogen nuclei). A helium nucleus has a mass slightly less (by about 0.7%) than the combined mass of four hydrogen nuclei. A little bit of mass disappears in the end.

Sunspots

Occasionally regions of the photosphere appear darker than the rest, these are called the _____________. They are cooler regions (4,200 K) and thus appear darker than the hotter surroundings. They usually have a darker inner region - the umbra - surrounded by a lighter outer region - the penumbra. _____________ are caused by strong local magnetic fields, which slow the convection near the surface, allowing the patch with strong field to cool and darken. They generally appear in groups and the larger ones can span many times the size of Earth. They can last for days or even months and they move across the surface of the Sun as the Sun rotates.

Geomagnetic Storms

Once a CME reaches Earth, it can create _______________ in Earth's magnetosphere. They can produce unusually strong auroras. You may never have heard the term aurora, but you have probably heard about the "northern lights". Due to the Earth's magnetic poles in the northern and southern hemispheres, it is common to see a light show of spectacular colors as charged particles spiral around these magnetic fields. CMEs can result in this spectacular light show being visible at much lower latitudes than usual. CMEs can also hamper radio communications, disrupt electrical power delivery, expose airline crews on polar flights and astronauts to harmful radiation, and damage the electronic components in satellites.

Solar Activity

Slight changes in __________ directly affect life on our planet. like weather: sunspots, solar flares, solar prominences, all related to magnetic fields, (also known as Solar Weather).

A.

The Sun converts 600 million tons of hydro- gen into 596 million tons of helium every second, which means that _________ tons of matter is turned into energy each second. A. 600 million, 596 million, 4 million B. 596 million, 600 million, 4 million

B.

The Sun has a magnetic activity cycle of 11 years. During maximum activity the number of sunspots increases, _________ occur, and ________ erupt from its surface. A. prominences, huge solar flares and coronal mass ejections B. solar flares, huge prominences and coronal mass ejections

C.

The Sun has a magnetic activity cycle of _______. A. 10 years B. 22 years C. 11 years D. 20 years

Rigid Body

The Sun is gaseous and does not rotate as a ___________ like Earth. Some parts of the Sun rotate faster than other parts. The Sun's equator rotates in about 25 days while near the poles the rotation period is about 30 days.

Hydrostatic Equilibrium

The Sun is in _________, also called "gravitational equilibrium." Inside stars like our Sun, the force of gravity inward is balanced by the outward push of internal gas pressure.

D. (Both (They are the exact same number))

The Sun's luminosity, energy output, is 3.8x1026 watts which means 3.8x1026 Joules of en- ergy released each second. The Hiroshima bomb in Japan released 20,000 tons of TNT, the energy equivalent to 84 TJ (terajoules; 1 TJ = 1x1012 Joules). How does the energy released by the Sun in one second compare with the release of energy of the atomic bomb released in Hiroshima? 1 second's worth of the Sun's luminosity = _________________ Hiroshima nuclear bombs in one second. A. 4.5*10^12 B. 45 trillion C. Neither D. Both (They are the exact same number)

B.

The Sun's mass is about __________ times the mass of Earth. A. 200,000 B. 300,000 C. 800,000 D. 500,000

B. (How much hydrogen does the Sun fuse in a year? 1.89 x 10^17 kg of hydrogen per year How much hydrogen does a star like our Sun have (in kilograms)? 1.5 x 10^30 kg of hydrogen How much hydrogen available for fusion does a star like our Sun have (in kilograms)? 1.95 x 10^29 kg of hydrogen ready to fuse)

The Sun's total mass is equal to 2x1030 kg. The Sun fuses about 600 billion kilograms of hydrogen each second. Even though 75% of the Sun's mass is hydrogen only about 13% of this hydrogen is available for fusion in the core. A. The Sun's total mass is equal to 2x10 kg. The Sun fuses about 600 billion kilograms of hydrogen each second. Even though 75% of the Sun's mass is hydrogen only about 13% of this hydrogen is available for fusion in the core. How much hydrogen does the Sun fuse in a year? 1.95 x 10^29 kg of hydrogen per year How much hydrogen does a star like our Sun have (in kilograms)? 1.5 x 1030 kg of hydrogen How much hydrogen available for fusion does a star like our Sun have (in kilograms)? 1.89 x 1017 kg of hydrogen ready to fuse B. How much hydrogen does the Sun fuse in a year? 1.89 x 10^17 kg of hydrogen per year How much hydrogen does a star like our Sun have (in kilograms)? 1.5 x 10^30 kg of hydrogen How much hydrogen available for fusion does a star like our Sun have (in kilograms)? 1.95 x 10^29 kg of hydrogen ready to fuse

Sun

The _____, like other stars, is a nuclear furnace, a hot ball of gas composed mainly of hy- drogen and helium.

Corona

The ________ is the Sun's faint outer atmosphere where temperatures rise to more than 1 million degrees. It is the source of most of the X-ray light coming from the Sun. Since heat flows from hot to cool regions, the heating of the ____________ has remained a mystery for many decades. Even though astronomers do not yet understand all the aspects of this heating mechanism, a general explanation has been formulated.

Solar Wind

The ___________ is the stream of charged particles (plasma) that is continually blown from the Sun and can be considered an extension of the corona. The ___________ blows past Earth at about 1 million miles per hour with gusts as high as 2 million miles per hour! The Sun looses about 107 tons of mass each second through this outward flow of gases, but that is only a very small fraction of its total mass.

Umbra

Sunspots usually have a darker inner region - the _______ - surrounded by a lighter outer region - the penumbra.

Penumbra

Sunspots usually have a darker inner region - the umbra - surrounded by a lighter outer region - the ___________.

Photosphere

The ___________ is the visible surface of the Sun where sunspots are observed. Most of the sunlight received by Earth comes from the ___________, the layer of the Sun's atmosphere through which photons escape into space. The ___________ is the bright apparent surface of the Sun, though it is not a solid sur- face. The Sun is gaseous from its outer atmosphere all the way to its center. The temperature of the _____________ is 5,800 K and the density of the gas is 3,000 times less than the air we breathe. Occasionally regions of the ____________appear darker than the rest, these are called the sunspots.

Flares

Solar ________, also associated with sunspots, are intense bursts of radiation that appear to our instruments as bright flashes. They occur when magnetic field lines become so stretched and twisted due to differential rotation that they break and reconnect. The energy released in the process heats the gas and produces X-rays. Some of the particles are accelerated to nearly the speed of light. Particles from ________ reach Earth hours or days later as gusts in the solar wind. _________ are classified according to their intensity, and X-class ________ are the most powerful ones. These high intensity ________ can trigger dramatic solar storms and radio blackouts on Earth. Solar _______ and Coronal Mass Ejections (CMEs) can damage satellites, power grids, and temporarily disrupt cell phone communications, not to mention threaten the life of astronauts. CMEs and solar ________ are generally observed at the start of a space weather event that leads to a large magnetic storm on Earth.

Auroras

Solar storms can powerfully affect life on Earth. Besides beautiful _________ they can generate an enormous amount of damage to our technological society and even threaten the life of astronauts.

Coronal Holes

Some regions of the corona emit far less X-rays than their surroundings. We call these ______________. The magnetic field lines in ____________ are open and project out into space allowing particles to escape, leaving less material to emit X-rays and giving rise to the solar wind.

A.

The ________________ are very hot layers of the Sun's atmosphere, and the source of most of the ultraviolet and X-ray light emitted by the Sun. A. chromosphere and corona B. photosphere and chromosphere

Solar Thermostat

The amount of nuclear reactions occur- ring inside the Sun is controlled by gravity in a feedback process that acts as a ___________ keeping steady the rate of hydrogen fusion.

Helioseismology

Seismologists use earthquakes to learn about Earth's interior. An earthquake at one location on Earth results in seismic waves that move at different speeds and in different directions depending on the type and density of material that they are travelling through. In a similar way, ___________, the study of 'sunquakes', can provide information about temperature, density, and magnetic fields, at different places within the Sun to improve our models of the Sun's interior.

A. (50, 5,357)

The image in Figure 5.22 from the SOHO spacecraft shows an enormous coronal mass ejection (CME) that occurred on December 2, 2003. CMEs like this one can blast billions of tons of gas and travel at speeds over 3 million km/h. This particular CME was not aimed toward Earth. If it was aimed toward Earth, how long would it take for particles of the bubble to arrive at Earth? (Recall the Earth-Sun distance = 150,000,000 km) ___ hours Compare this speed with a fast jet plane (600 miles/h) and the space shuttle (28,000 km/h) Can the space shuttle out-race the bubble? (1km = 0.6 miles) No, the space shuttle would take ___________ hours to reach Earth from that distance A. 50, 5,357 B. 100, 7,535

Chromosphere

The irregular layer above the photosphere, where the temperature rises to about 10,000 K, is referred to by astronomers as the _____________. This region radiates most of the ultraviolet light produced by the Sun. At these higher temperatures hydrogen emits light with a reddish color. That is the reason why this layer was so named - the Greek word 'chroma' means color. Like the corona, the ______________ can only be observed with unaided eyes during a total solar eclipse when the Moon cov- ers the photosphere.

Plasma

The magnetic fields also trap the hot coronal ___________ (charged particles) in loops that tower up to tens of megameters (Mm) over the surface of the Sun.

Core

What makes our Sun shine are the fusion nuclear reactions occurring in its ______. Nuclear fusion occurs in the Sun's _______ under conditions of extreme high temperature and pressure. The temperature inside the Sun's _______ reaches 15 million K (27 million F) and the pressure is 200 billion times the atmospheric pressure on the surface of Earth. The Sun's _______ extends out to a distance of 25% of the solar radius and the density (150 g/cm3) is about 10 times the density of lead. The energy produced in the ______ gradually moves out- wards to the radiative zone.

A. True

When the temperature in the core rises slightly, the fusion rate rapidly increases generating an increase in pressure that causes the core to expand and cool. A. True B. False

Granules

__________ cover the Sun as can be observed in Figure 5.6. These __________ are the tops of convection cells where hot gas rises up, cools and sinks in- ward along the dark contours. Each ___________ can range from about the size of Texas to the size of our Earth and last for about 10 to 20 minutes before being replaced by new ones.

Solar Storms

___________ can powerfully affect life on Earth. Besides beautiful auroras they can generate an enormous amount of damage to our technological society and even threaten the life of astronauts.

Gamma Rays

___________ in the form of photons lose energy on their way out of the Sun because they have been in a random walk, bouncing around in the Sun for hundreds of thousands of years.

Nuclear Fusion

___________ is the source of the Sun's energy.

Prominences

____________ are charged particles (plasma) suspended above the Sun's surface by magnetic field lines. They intrude into the corona but are about 100 times cooler and denser. Strong flows are often observed along ________________ field lines. Sometimes the gas falls back onto the Sun and other times it erupts into space, carrying the magnetic field with it. _____________ can last for days or even months.

A. (The reaction occurs as a sequence of steps and not randomly. Because the energy generated the energy generated is a minuscule fraction of the Sun's total mass. If the temperature in the core rises slightly, the fusion rate rapidly increases generating an increase in pressure the causes the core to expand and cool.)

The nuclear reactions occurring inside the Sun are an example of controlled fusion reactions. A Hydrogen bomb is an example of an uncontrolled fusion reaction. What makes the fusion reactions in the Sun a controlled process? Why doesn't the Sun explode as a gigantic H-bomb? Describe the Sun's thermostat. A. The reaction occurs as a sequence of steps and not randomly. Because the energy generated the energy generated is a minuscule fraction of the Sun's total mass. If the temperature in the core rises slightly, the fusion rate rapidly increases generating an increase in pressure the causes the core to expand and cool. B. The reaction occurs randomly and without sequence and/or pattern. Because the energy generated is a minuscule fraction of the Sun's total mass. If the temperature in the core rises slightly, the fusion rate gradually increases generating a minimal increase in pressure that has no effect on the core's state whatsoever.

Hydrogen Fusion Reaction

The overall _________ transforms four individual hydrogen nuclei (proton) into a helium nucleus (two protons and two neutrons) releasing energy in the process.

A.

The percentage of the Sun's radius that the Core takes up is... A. 25%. B. 20% C. 30% D. 35%

Maunder Minimum

The solar variable activity has some correlation with variations in temperature at the Earth's surface, even though scientists are still trying to understand the influence of the Sun in climate change. During a period between 1645 and 1715, known as the _____________, the Sun produced virtually no sunspots. This period coincides with a period of unusually cold temperatures on the Earth, called the Little Ice Age, when in regions of Europe and North America glaciers expanded and even summers were no longer warm.

A.

The three major zones of the Sun's internal structure are: A. the core, the radiative zone and the convection zone. B. the core, the corona, and the photosphere

Differential Rotation

This difference in rotation speed with latitude is called _____________. It causes magnetic lines to become twisted and stretched. Sunspots occur where loops of tangled magnetic field burst through the Sun' s surface.

D.

Through____________, astrono- mers can gather information about what is going on inside the Sun. A. computer models B. helioseismology C. detection of neutrinos D. All of the above E. None of the above

Luminosity

A measure of a star's brightness (magnitude) that measures the amount of energy (light) that a star emits and/or radiates from its surface. The Sun is a middle age star, near the mid-range in mass and _________ compared with the upper and lower extremes among nearby stars, but it is not a typical star in the sense that most stars are smaller and dimmer than our Sun. The actual brightness of an object such as a star.

B.

About ___________ of the Sun's mass is hydrogen and ____________ is helium. There are also small amounts of other elements such as carbon, nitrogen, and oxygen. A. one fourth, three fourths B. three fourths, one fourth

Mass

About three fourths of the Sun's ________ is hydrogen and one fourth is helium. There are also small amounts of other elements such as carbon, nitrogen, and oxygen.

E=mc^2

According to Einstein's equation __________, where E is energy, m is mass, and c is the speed of light, the 'missing' mass does not really disap- pear but is transformed into energy.

B.

Although our Sun is 150,000,000 km (93 million miles) away from us, a ray of light from the Sun takes only ________to reach Earth. A. 170,000,000 km (106 million miles), 10 (light) minutes B. 150,000,000 km (93 million miles), 8 (light) minutes C. 130,000,000 km (81 million miles), 5 (light) minutes

Random Walk

Although photons travel at the speed of light, inside the Sun they bounce randomly among electrons in a zig- zag path called a _________.

Radiative Zone

In the ___________ energy is carried outward primarily by photons of light. The journey of photons, beginning as gamma rays at the core to the surface takes a very long time. Although photons travel at the speed of light, inside the Sun they bounce randomly among electrons in a zig-zag path called a random walk.

Convective Zone

In the ____________ the transport of energy is done through convection which makes the Sun's surface churn like a pot of boiling water. Granules cover the Sun as can be observed in Figure 5.6. These features are the tops of convection cells where hot gas rises up, cools and sinks in- ward along the dark contours.

Gravity

Inside stars like our Sun there is a balance between _______ that exerts a force inward and inter- nal gas pressure that pushes outward.

A.

Light from the next closest star, Proxima Centauri, takes over 4 years to reach the Earth. A. 4 years B. 7 years C. 3 years D. 5 years

Proxima Centauri

Light from the next closest star, __________, takes over 4 years to reach the Earth.

A. (3.1536x10^14 tons, 2.20752x10^16 tons, 0 percent (0.01585520362%), 0 percent (0.01585520362%))

Because of the solar wind, the Sun is slowly losing mass. The Sun loses about 107 tons per second. a). How much mass does the Sun lose through the solar wind in a year? 107x60x60x24x365= ___________ b). How much mass has the Sun lost in a persons' lifetime? (Use a typical lifetime of 70 years). What percent of the Sun's mass does this represent? 3.1536x1014x70= ____________ The Sun itself is 1.989 × 1030 kg Which is 1.989 × 1027 in tons (2.20752x1016 ÷1.989 × 1027)x 100%= (1.10986425x10-11)x 100% Nearly ____________ c).How much mass does the Sun loose in a billion years (suppose the solar wind does not vary with time)? What percent of the Sun's mass does this represent? 3.1536x1014x1000000000= 3.1536x1023 tons (3.1536x1023 ÷1.989 × 1027)x 100%= (1.585520362x10-4)x 100% Nearly _________ A. 3.1536x10^14 tons, 2.20752x10^16 tons, 0 percent (0.01585520362%), 0 percent (0.01585520362%) B. 3.1635x10^16 tons, 2.20725x10^14 tons, 10 percent (10.0585520362%), 15 percent (15.085520362%)

Dynamo Effect

Because the gas in the Sun is highly ionized (the electrons are free to move), the gas is a very good conductor of electricity. Turbulence in the convection zone generates electric currents which generate magnetic fields. This process is called the _____________. Another important ingredient in this process is differential rotation.

Space Weather

CMEs and solar flares are generally observed at the start of a ________________ event that leads to a large magnetic storm on Earth. This term, _____________, refers to conditions on the Sun and in the solar wind that can affect our technological systems, either on space or on the ground, and perhaps endanger human life

( )

Look at Review question 5.8 and its diagram either in chapter five of the textbook or on the finals review PowerPoint to see the diagram and to label the correct answers (layers and features) of the Sun. Each of the terms are Vocab words in the quiz. You can look at each word individually as well as their corresponding definition to further approximate where they are located in the Sun. This is a free point.

Solar Cycle

During parts of the ____________ our star can be very dynamic, constantly producing solar flares, prominence eruptions, and huge coronal mass ejections. All these features are triggered by magnetic fields. The breaking and reconnecting of magnetic field lines generate intense activity on the Sun's surface. North and South poles flip every 11 years (New cycle every 22) 11 years, 4 year rise to solar maximum, 7 year decline to solar minimum sunspot and flare activity changes from year to year; rise and fall every 11 years. (Also known as the "Sun's Magnetic Cycle.") Nevertheless, even though the Sun's luminosity does not vary much during the ___________, it radiates considerably more energy in ultraviolet and X-ray light during maximum activity.

Placid

During solar minimum there is placid quietness and a relatively constant solar wind

Radiate

Emit (energy, especially light or heat) in the form of rays or waves, in this scenario from our Sun. Ex. Even though the Sun's luminosity does not vary much during the solar cycle, it __________ considerably more energy in ultraviolet and X-ray light during maximum activity.

D.

Energy created in the proton-proton chain is carried off and/or released in the forms of... A. gamma rays B. subatomic particles (neutrinos and positrons). C. None of the above D. All of the above

Sun-Climate Connection

Even though the _________ is still not well understood, the variability of the Sun's activity seems to have some effect on the Earth's climate.

Neutrinos

Even though there is no way of sending a probe below the Sun's surface to give us direct information of what is going on, there are other ways of unveiling what is happening in the Sun's interior. As- tronomers can gather information about the Sun's interior through astrophysical models, observations of the Sun's vibrations, and detection of solar ___________, tiny, nearly massless (ghost) particles that rarely interact with matter.