| A | B |
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| Define star | a body of gases that gives off a tremendous amount of radiant energy in the form of light and heat |
| How do astronomers determine the composition and temperature of stars | They direct starlight through a spectrometer. This produces a display of colors and lines called a spectrum. Using the dark-line spectra, you can tell which elements make up a star. Every element has a certain composition and temperature. |
| Why do stars appear to move? | The apparent motion of stars is due to the rotation of the earth on its axis. |
| Name and describe the way astronomers measure the distance from the earth to the stars | Parallax-as the earth circles the sun, we are able to study the stars from different angles. A star is photographed at the beginning and end of a six - month period and its position in relation to other stars is studied each time. |
| What is apparent magnitude ? | the brightness of a star as it appears from the earth |
| What is absolute magnitude ? | the true brightness of a star. |
| What is a H-R diagram? | Hertzsprung-Russell:Plotting the surface temperature of stars against their absolute magnitude. The brightness of most stars increases as their surface temperature increases. |
| How does a protostar develop into a star? | Particles collide at the center and produce heat. When the temperature gets to over 10,000 C, nuclear fusion begins. As this happens the protostar generates energy and is considered a star. |
| What are main sequence stars? | star with characteristics that place it within a band running through the middle of the H-R diagram |
| What is a nebula? | a cloud of gas and dust |
| What is a white dwarf? | a small, hot, dim star |
| What is a black dwarf? | a dead star |
| What is a nova? | a white dwarf star that explodes as it cools, temporarily becoming thousands of times brighter |
| What is a supernova? | a star that blows apart with a tremendous explosion |
| What is a black hole? | a hole in space with a gravity so great that not even light can escape |
| What is a constellation? | a fixed pattern of stars |
| What are the three main types of galaxies? | Spiral, Elliptical, and Irregular |
| What generates the sun's energy? | Hydrogen fusion |
| What are sunspots? | Cool, dark areas of gas within the photosphere that are caused by powerful magnetic fields. |
| How often do sunspots occur? | Every 10-11 years |
| What is a prominence? | a cloud of glowing gases that arches high above the sun's surface |
| What is a solar flare? | a sudden eruption of electrically charged atomic particles |
| What are auroras? | sheets of colored light produced by a magnetic storm in the earth's upper atmosphere |
| What are planetesmals? | small bodies of matter in the solar nebula |
| What are protoplanets? | some planetesmals join together through collisions & through the force of gravity, form these larger bodies |
| What happens in a red shift of a star? | the star is moving AWAY from us |
| What happens in a blue shift of a star? | the star is moving TOWARD us |
| Through Parallax we know that the bigger the shift of stars means.... | the closer the star is |
| What is the model of the solar system that Ptolemy proposed? | Geocentric- earth centered |
| What is the model of the solar system that Copernicus proposed? | Heliocentric- sun centered |
| What was Kepler's First Law? | Law of Ellipses |
| What is the Law of Ellipses? | each planet orbits the sun in a path |
| What is the Law of Equal Areas? | the speed at which planets travel at different points in their orbits |
| What is the Law of Periods? | the relationship between the average distance of a planet from the sun and the orbit period of the planet |
| If something is more eccentric, it is.... | more oblong, flat |
| If something is less eccentric, it is.... | less oblong or flat |
| The formula to find the eccentricity of an ellipse is..... | LOOK IN YOUR REFERENCE TABLES. The distance between foci divided by the length of the ellipse. |
| What is a maria? | dark areas on the moon- plains of dark solidified lava that reflect little light |
| What are rilles? | long, deep channels, that look somewhat like a dry riverbed, that run through the maria |
| What are craters? | bowl-shaped depressions |
| What are rays? | streaks of displaced rock material radiating from a crater |
| What happens in a solar eclipse? | the moon is directly between the sun and the earth and it casts it's shadow on a certain spot on earth |
| What happens in a lunar eclipse? | the earth is inbetween the sun and the moon, the shadow of the earth blocks out the sun's light and casts a shadow on the moon |
| How is a day determined on earth? | the time required for the earth to make one rotation on its axis-24 hours. |
| How is a month determined on earth? | the time required for the moon to go through one cycle of phases as it orbits the earth- 29.5 days |
| How is a year determined on earth? | the time required for the earth to make one orbit around the sun, about 365.24 days |
| How many phases does a moon go through? | Eight |
| If the moon is waxing, it is getting...... | bigger |
| If the moon is waning, it is getting...... | smaller |
| What is a new moon? | When the moon is between the sun and the earth and it is not able to reflect any light from the sun. |
| What causes tides? | the moon's gravitational pull on the oceans |
| What is a Spring Tide? | When the moon is at its full and new phases, the earth has higher high tides and lower low tides than at other times. |
| How often do spring tides happen? | twice a month |
| What are neap tides? | During the first and last-quarter phases, the moon's gravitational pull on the oceans is partially canceled out by the sun's gravitational pull. Results in tides that are not very high or low. |
| How often do neap tides happen? | Twice a month |
