Astronomy: Chapter 5

Question 1

Describe the chief characteristics of the sun.

Answer 1

• The sun’s diameter is 109x the Earth’s diameter.
• The sun is very large and very massive but it is low density and high temperature. it’s properties are those of a gas.
• the process which fuels the sun is nuclear fusion. nuclei collide and fuse together, producing helium.
• Has a Photosphere
• The sun has a magnetic field.
• Chemical Composition: mostly hydrogen and helium.
• Above the Photosphere lies the Chromosphere.
• Outer most layer is the Corona.

Question 2

Describe the Photosphere

Answer 2

• Photosphere: a layer in the sun’s atmosphere that is dense enough to emit plenty of light but not so dense that the light can’t escape; so the photosphere is the source of most of the sunlight recieved by earth. It is less than 300 miles deep. temperature of the photosphere is about 5,800 K. Very low density gas, 3,000 times less dense than the air you breath.
• Sunspots
• Granulation

Question 3

Describe Sunspots

Answer 3

• Sun spots are regions of the photosphere that appear darker than the rest. they produce less light than equal sized pieces of the normal photosphere, and their color is redder than the average. they are usually about 1,000 to 1,500 K cooler. Each sun spot cycle last about 11 years.

Question 4

Describe Granulation

Answer 4

• Granulation: The Fine structure of bright grains with dark edges covering the sun’s surface
• each granules are about the size of texas and last for only 10 to 20 minutes before fading away.
• faded granules are continuously replaced by new ones.
• the center of granules are rising columns of hot gas, and the edges of the granules are cooler, sinking gas presence of granulation is clear evidence that energy is flowing upward through the photosphere by a process known as convection.
• Convection: circulation is a fluid driven by heat. hot material rises and cool material sinks.

Question 5

Describe the Chromosphere

Answer 5

• roughly 1,000 times fainter than the photosphere.
• has a pinkish light produced by combined light of three bright emission lines–the red, blue, and violet balmer lines of hydrogen.
• produces an emission spectrum.
• low density gas viewed with a dark, cold background.
• density is about 10^8 times less than that of the air you breathe.
• atoms in the lower chromosphere are ionized, and atoms in the higher layer of the chromosphere are even more highly ionized.
• the temperature falls to a minimum of about 4,500 K and then rises to the extremely high temperatures of the corona.
• Filament: solar eruption, seen from above, silhouetted against the bright photosphere.
• spicule: a small, flamelike projection in the chromosphere of the sun. last between 5 to 15 minuets.

Question 6

Describe the Corona

Answer 6

• the outer most part of the sun
• Solar Wind: rapidly moving atoms and ions that escape from the solar corona and blow outward through the solar system.
• Coronagraph: special telescope used to capture images of faint objects, such as the corona, that are near bright objects.
• there are high temperature gasses in the corona.
• because the density is very low, the corona doesnt produce much light even though it is very high temperature.

Question 7

Draw a labeled sketch of the interior structure of the sun.

Answer 7

.core, radiative envelope, convective envelope, photoosphere, chromosphere.

sunspots, prominences, solar flare

corona.

Question 8

Discuss the structure and components of the atom.

Answer 8

• an atom has a massive compact nucleus containing positively charged protons, usually accompanied by electrically neutral neutrons. The nucleus is embedded in a large cloud of relatively low-mass, negatively charged electrons.

Question 9

Discuss and compare the four fundamental forces of nature.

Answer 9

1. ) Gravity - the force acts between all mass in the universe and it has infinite range.
2. ) Electromagnetic - this acts between electrically charged particles. Electricity, magnetism, and light are all produced by this force and it also has infinite range.
3. ) The Strong Force - this force binds neutrons and protons together in the cores of atoms and is a short range force.
4. ) Weak Force - This causes beta decay (the conversion of a neutron to a proton, an electron and an antineutrino) and various particles (the “strange” ones) are formed by strong interactions but decay via weak interactions. Like the strong force, the weak force is also short range.

Question 10

Explain the formation of spectral emission lines in terms of atomic structure and electron energy levels.

Answer 10

.

Question 11

Describe what the continuous, emission, and absorption spectra look like, and discuss the circumstances under which each is formed.

Answer 11

Continuous: A solid, liquid, or dense gas excited to emit light will radiate at all wavelengths and produce the continuous spectrum.

Emission: When photons are emitted by an excited gas, they produce Emission lines, or bright-line spectra.

Absorption: When radiation passes through a cool gas, this creates absorption lines, or dark-line spectra.

Question 12

How can you estimate the temperature of a star with your unaided eye? How does this work?

Answer 12

The brighter stars are hotter. If the star appears blue it is hotter because it has shorter wavelengths and is at the end of the spectrum. The longer the wavelength the duller the star will appear.

Question 13

8. What can the doppler effect tell us about stars and galaxies? How does this work?

Answer 13

Well if the galaxy appears red it means the galaxy is moving away from us but if the galaxy appears blue it is moving towards us. This happens because the light rays get bunched up to make a bluish light while when they are red they are being stretched.