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134 Cards in this Set
- Front
- Back
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What is the meaning of the word cosmos |
The sum total of all matter and energy, that is, everything within and between all galaxies |
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Which of the following has your "address" in the correct order? |
you, Earth, solar system, Milky Way, Local Group, Local Supercluster |
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About where is our solar system located within the Milky Way Galaxy? |
About two-thirds of the way from the center of the galaxy to the outskirts of the galactic disk |
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Roughly how many stars in the Milky Way Galaxy |
100 Billion |
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Modern telescopes are capable of seeing bright galaxies up to about |
10 Billion Light-years away |
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Suppose we imagine the Sun to be about the size of a grapefruit. How big an area would the orbits of the eight planets of the solar system cover? |
The size of a typical campus |
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What do we mean when we say that the universe if expanding? |
Average distances are increasing between galaxies |
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The age of the universe is... |
Between 10 million and 16 million years
(14 Million years)
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How are galaxies important to our existence? |
Galaxies recycle heavy elements produced in stars into future generations of stars. |
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Earth is made mostly of metals and rocks. Where did this material come from? |
It was produced by nuclear fusion in stars |
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What is nuclear fusion? |
The process of combining lightweight nuclei to make heavier nuclei |
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Why did Carl Sagan say that we are all star stuff? |
Nearly every atoms from which we are made once (before the solar system formed) was inside of a star. |
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Which of the following statements does not use the term light-year in an appropriate way? |
It will take me light-years to complete this homework.
(Because light-year measures distances NOT time) |
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One light-hour is the distance that light tavels in an hour. How far is this, in kilometers?
(Recall that the speed of light is 300,000 km/s) |
1.08 Billion km |
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Suppose we look at a photograph of many galaxies. Assuming that all galaxies formed at about the same time, which galaxy in the picture is the youngest? |
The one that is farthest away. |
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What do we mean by the observable universe? |
The part of the universe that could be observed in the principle, including things that may require future technologies. |
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Suppose we imagine the Sun to be about the size of a grapefruit. Which of the following describes the size and distance of Earth on the same scale? |
Earth is the size of a point about 15 meters away from the Sun. |
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WHat is the Sun mainly made of? |
hydrogen and helium |
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Which of the following is smallest? |
The size of a typical planet -
smaller than 1 light second smaller than 1 AU smaller than the size of a typical star |
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Which of the following is largest? |
The size of a typical galazy
smaller than the size of Pluto's orbit smaller than the distance to the nearest star smaller than 1 light-year |
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On the 1-to-10-Billion scale, about how far is it to the nearest stars besides the Sun? |
4,400 Kilometers
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Suppose we imagine the Sun to be about the size of a grapefruit. How far away are the nearest stars? (the three stars of Alpha Centauri) ? |
2,500 Miles |
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If we use 1 millimeter to represent 1 light-year, how large in diameter is the Milky Way Galaxy? |
100 Meters |
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Describe the Milky Way Galaxy |
A spiral galaxy with a disk about 1 billion kilometers in diameter and containing between 100 million and 1 billion stars |
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How long would it take to count all the stars in the Milky Way Galaxy at a rate of one star per second? |
several thousand years |
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How many galaxies are there in the observable universe? |
Roughly (within a factor of 10) the same as the number of stars in our galaxy |
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If you represented each star by a grain of sand, how much sand would it take to represent all the stars in the universe? |
MORE than all the sand on all the beaches on Earth |
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On the scale of the cosmic calendar, in which the history of the universe is compressed to 1 year, how long has human civilization existed? |
a few seconds |
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On a cosmic calendar, in which the history of the universe is compressed into 1 year, when did the dinosaurs become extinct? |
In late December |
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On a cosmic calendar, in which the history of the universe is compressed into 1 year, when did Kepler and Galileo first discover that we live on a planet in a solar system? |
1 second ago |
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On a cosmic calendar, in which the history of the universe is compressed into 1 year, how long is the average human life span? |
0.2 Second |
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Approximately how fast are you moving with the rotation of Earth? |
1,300 kilometers/hr |
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What is an astronomical unit? |
the average distance from Earth to the Sun |
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What is NOT true about the ecliptic plane? |
It is the plane of the Moon's orbit around Earth. |
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Patterns of stars in constellations hardly change in appearance over times of even a few thousand years. WHY? |
The stars in our sky actually move rapidly relative to us - thousands of kilometers per hour - but are so far away that it takes a long time for this motion to make a noticeable change in the patterns in the sky. |
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How long does it take our solar system to complete ONE ORBIT around the Milky Way Galaxy? |
230 million years |
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What is NOT true about the Milky Way Galaxy? |
Our solar system is located very close to the center of the Milky Way. |
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Speeds slowest to fastest: |
Earth's speed of rotation on its axis (slow), Earth's speed of revolution about the Sun, typical speeds of stars in the local solar neighborhood relative to us, the speed of our solar system orbiting the center of the Milky Way Galaxy, the speeds of very distant galaxies to us (fast). |
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Most of the mass in the Milky Way Galaxy is located: |
in the HALO (above/below the disk) |
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The distribution of the mass of the Milky Way Galaxy is determined by: |
studying the rotation of the galazy |
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From the fact that virtually every galaxy is moving away from us and more distant galaxies are moving away from us at a faster rate than closer ones, we conclude: |
The universe is EXPANDING |
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By studying distant galaxies in the 1920s, Hubble made which discovery that led us to conclude that the universe is expanding? |
All galaxies outside the Local Group are moving away from us, and farther away they are, the faster they're going. |
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Imagine that we put a raisin cake into the oven, with each raisin seperated from the others by 1 cm. An hour later, we take it out and the distances between raisins are 3 cm. If you live in one of the raisins and watched the other raisins as the cake expanded, what would you conclude? |
More distant raisins would be moving away from you faster. |
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Which scientist played a major role in overturning the ancient idea of an Earth-Centered universe, and about when? |
Copernicus, Kepler, and Galileo : About 400 years ago. |
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How many stars can you see with your naked eye on a clear, moonless night from a dark location? |
a few thousand |
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Describe the definition of constellation? |
a region of the celestial sphere |
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What about the celestial sphere is NOT true |
The 'celestial sphere' is just another name for our universe. |
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What about the celestial equator is TRUE at ALL LATITUDES? |
It represents an extension of Earth's equator onto the celestial sphere |
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What is an ecliptic? |
the sun's apparent path along the celestial sphere |
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When we look into the band of light in our sky that we call the Milky Way, can we see distant galaxies? |
NO! because the stars, gas and dust of the Milky Way block us from seeing them. |
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Describe the meridian in your sky |
A half-circled extending from your horizon due NORTH, through you ZENITH, to your horizon due SOUTH |
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If it is midnight in New York, it is... |
daytime in Sydney, Australia |
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How many arcseconds are in 1˚? |
3,600 |
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What term does NOT use the term angular size or angular distance correctly? |
The angular distance between those two bright stars in the sky is about 2 meters. |
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What is circumpolar star? |
A star that always remains above your horizon |
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What is true about circumpolar stars at ALL Latitudes? |
They always remain above your horizon |
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We describe a position on Earth's surface by stating its... |
latitude and longitude |
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What makes the North Star, Polaris, special? |
It appears very near the north celestial pole. |
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You are standing on Earth's equator. Which way is Polaris, the North star? |
on the northern horizon |
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By locating the north celestial pole in the sky, how can you determine your latitude? |
The altitude of the NCP is the same as your latitude |
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Orion is visible on winter evenings but not summer evenings because of.. |
the location of Earth in its orbit |
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Why do we have seasons on Earth? |
As Earth goes around the Sun and Earth's axis remains pointed toward Polaris, the Northern and Southern hemispheres alternately receive more and less direct sunlight. |
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Why is it summer in the Northern Hemisphere when it is winter in the Southern Hemisphere? |
The Northern Hemisphere is titled toward the Sun and receives more direct sunlight |
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What is true about the Northern and Southern hemispheres: |
Both Northern and Southern hemispheres receive the same amount of sunlight to the equinoxes.
The Northern Hemisphere receives the most direct sunlight on the summer solstice. |
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What is false about constellations? |
Most constellations will be unrecognizable hundreds years from now. |
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What is true about Lunar phases? |
It is possible to have two full Moons during January, but not during February |
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What is not a phase of the Moon? |
HALF moon |
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When someone on Earth observes the Moon in the first-quarter phase, someone on the Moon facing Earth observes Earth in the... |
third-quarter Earth phase |
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If the Moon is setting at 6. A.M. the phase of the Moon must be: |
FULL
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If the Moon is setting at noon, the phase of the Moon must be: |
third-quarter |
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If the Moon is setting at midnight, the phase of the Moon must be: |
third-quarter |
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At approximately what time would a full Moon be on your meridian? |
midnight |
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At approximately what time would a first quarter Moon rise? |
Noon |
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If the Moon rises around 3.A.M. its phase must be: |
waning crescent |
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In which direction does a quarter Moon rise? |
East |
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Why do we see essentially the same face of the Moon at all times? |
because the Moon's rotational and orbital periods are equal. |
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What is true about the Moon? |
The Moon's distance from Earth varies during its orbit. |
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Suppose you live on the Moon. How long is a day? |
a year |
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Ashen light is: |
sunlight reflected by Earth that illuminates the 'dark' portion of the Moon. |
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What explains the reason why there is not a solar eclipse at every new Moon? |
The orbital plane of the Moon is tilted by about 5˚to the ecliptic point |
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What effect or effects would be most significant is the Moon's orbital plane were exactly the same as the ecliptic plane? |
Solar eclipses would be much more frequent |
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What conditions are required for a solar eclipse? |
The phase of the Moon must be new, and the nodes of the Moon's orbit must be nearly aligned with Earth and the Sun |
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What conditions are required for a lunar eclipse? |
The phase of the Moon must be full, and the nodes of the Moon's orbit must be nearly aligned with the Earth and the Sun. |
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In addition to the conditions required for any solar eclipse, what must also be true in order for you to observe a total solar eclipse? |
The Moon's umbra must touch the ares where you are located. |
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If part of the full Moon passes through Earth's umbra, we will see a: |
Partial lunar eclipse |
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If the Moon is relatively far from Earth, so that the umbra does not reach Earth, someone directly behind the umbra will see: |
an annular eclipse |
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When are the eclipse seasons? |
When the nodes of the Moon's orbit are nearly aligned with the Sun. |
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The precession of the Moon's nodes means that: |
the eclipse seasons occur less than 6 months apart |
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What is the Saros cycle? |
the 18-year cycle over which the pattern of eclipses repeats |
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Ancient people who knew Saros cycle could: |
predict when an eclipse would happen, but not necessarily what type and where it would be visible |
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What happens during the apparent retrograde motion of a planet? |
The planet appears to move westward with respect to the stars over a period of many nights. |
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Why are lunar eclipses more commonly seen than solar eclipses? |
The Earth casts a bigger shadow than the Moon |
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What causes the apparent retrograde motion of the planets? |
As Earth passes another planet, the other planet appears to move backward with respect to the background stars, but the planet's motion does not really change. |
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Which of the following never goes in retrograde motion? |
the SUN |
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What about a parallax is false |
The technique of stellar parallax was used by Hubble to determine that the andromeda Galaxy is about 2 million light-years away |
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What is true about stellar parallax |
The closer the star is to us, the more parallax it exhibits |
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We can't detect stellar parallax with naked-eye observations. What would make parallax easier to observe? |
Increasing the size of Earths orbit |
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Why were ancient peoples unable to detect stellar parallax? |
They did not have the ability to measure very small angles. |
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People of central Africa predicted the weather by: |
Observing the orientation of the crescent Moon relative to the horizon |
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The names of seven days of the week are based on: |
Seven naked-eye objects that appear to move among the constellations |
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Suppose the planet Uranus were much brighter in the sky, so that is was easily visible to the naked eye as Jupiter or Saturn. What would most likely be true? |
A week would have eight days instead of seven |
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Compared with the standard hour of 60 minutes used today, the hour of ancient Egypt: |
Was longer than 60 minutes in the summer and shorter than 60 minutes in the winter |
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In order to tell time at night, the ancient Egyptians used: |
star clocks, which measured time based on the positions of stars at particular times of night and particular times of year |
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Historians trace the origins of a 24-hour day to: |
the ancient Egyptians |
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What do the structures of Stonehenge, the Templo Mayor, and the Sun Dagger all have in common? |
They were all used by ancient peoples for astronomical observations |
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At the Sun Dagger in New Mexico, a dagger-shaped beam of sunlight pierces a spiral: |
at noon on the summer solstice |
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The Muslim fast of Ramadan occures: |
during the ninth month of a 12 month lunar calendar |
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The Metonic cycle is the: |
19-year period over which the lunar phases occur on about the same dates |
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The Jewish calendar is kept roughly synchonized with a solar calendar by: |
adding a thirteenth lunar month to 7 our of every 19 years. |
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Which ancient culture had the greatest known success in predicting eclipses? |
Mayans |
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The path that led to modern science emerges from ancient civilizations in which part of the world? |
the Mediterranean and the Middle East |
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When and where did the Library of Alexandria exist? |
from 300 B.C. to A.D 400 Egypt |
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How did Erostosthenes estimate the size of Earth in 240 B.C? |
by comparing the maximum altitude of the Sun in two cities at different latitudes |
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What is true about scientific models? |
A model can be used to explain and predict a real phenomena |
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Ptolemy was important because: |
He developed a model of the solar system that made sufficiently accurate predictions of planetary positions to remain in use for many centuries. |
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When did Ptolemy live? |
about 2000 years ago |
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How did the Ptolemaic model explain the apparent retrograde motion of the planets? |
It held that the planets moved along small circles that moves on larger circles aroudn Earth |
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Why did Ptolemy have the planets orbiting Earth on "circles upon circles" in his model of the universe? |
To explain the fact that planets sometimes appear to move westward, rather than eastward, relative to the stars in our sky. |
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Where was the Sun in Ptolemy's model? |
Between the orbits of Venus and Mars |
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During the Dark Ages, the scientific work of the ancient Greeks was preserved and further developed primarily by scholars in: |
Baghdad |
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The controversial book of this former person, published in 1543 suggested that Earth and other planets orbit the Sun |
Copernicus |
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He developed a system for predicting planetary positions that remained in use for some 1,500 years: |
Ptolemy |
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He was the first to prove that comets lie beyond Earth's atmosphere: |
Tycho Brahe |
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He discovered that the orbits of planets are eclipses: |
Kepler |
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He discovered that Jupiter has moons |
Galileo |
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He discovered what we now call Newton's first law of motions: |
Galileo |
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When Copernicus first created his Sun-centered model, it did not lead to substantially better predictions of planetary positions than the Ptolemaic model. Why not? |
Copernicus used perfect circles for the orbits of the planets |
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When did Copernicus live? |
about 500 years ago |
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What was not observed by Galileo |
Stellar parallax |
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One of the 'nails in the coffin' for Earth-centered universe was: |
Galileo's observations of the moons of Jupiter |
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When we see Venus in its full phase, what phase would Earth be in as seen by hypothetical Venetian? |
full |
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What is not one of Kepler's Laws: |
The force of attraction between any two objects decreases with square of the distance between their centers |
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Kepler's third law, p^2 = a^3, means that: |
a planets period does not depend on the eccentricity of its orbit. all orbits with the same semimajor axis have the same period the period of a planet does not depend on its mass planets that are farther from the Sun move at slower average speeds than nearer planets |
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From Kepler's third law, a hypothetical planet that is twice as far from the Sun as Earth should have a period of: |
more than 2 years |
