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28 Cards in this Set
- Front
- Back
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What type of galaxy has the greatest range of size?
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Elliptical
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Life on Earth is based on...
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NONE OF THESE
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Which of the following forces was not present during the inital stages of the Big Bang?
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ALL - The weak force wiould be another one. Gravity was the first of those forces to freeze out after the Big Bang.
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What is the temperature of the cosmic background microwave radiation?
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2.7 K
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Star forming regions are a characteristic of what region of the galaxy?
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disk
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Why can't we travel out to other star systems?
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All of them are limitations. The best way ofr us would be to communicate using radio waves or developing a worm hole.
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Why did only a few of the simplest elements from during the Big Bang?
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The universe expanded too rapidly for heavier elements to form
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Cepheid variable stars are good indicators of...
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distance
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Where is dark matter found in a galaxy?
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halo
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Dark matter is believed to be composed of mostly...
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WIMP's
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What would be the fate of the universe if the shape was spherical?
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The universe would collapse and another Big bang would occur.
In a hyperbolic and flat shaped universe it would expand forever eventually creating a Big Chill. |
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The Drake Equation predicts...
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the number of communicative civilizations in the galaxy right now.
The number of communicative species is limited by the survival of the technological socieities. |
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It is believed that a supermassive black hole exists at the center of the Milky Way galaxy. Which of the following is not true about this energy source?
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must be greater than 100 AU in diameter
The energy source is less than 10 AU in diameter. |
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What type of galaxy has very young stars, and lots of gas and dust?
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Irregular
Elliptical galaxies have old stars and little gas and dust. Normal and Bar Spirals have older stars in the bulge and older and younger stars in the disk. |
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Where would a good place be to look for life in our solar system?
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All of these may have life.
Life would most likely be microscopic on these worlds. |
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The newest force in physics that we have discovered in the universe is...
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dark energy
Dark energy causes the universe to accelerate. We know very little about it at this time. |
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What spectral type stars are most likely to harbor planets that have life?
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G to K main sequence stars.
O to F type stars produce too much harmful UV radiation and don't live long enough for life to develop. M type stars are generally too cool and the planet would be locked into orbit so one side would be continuously hot and the other side cold. |
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What is the current theory of the state of the universe?
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flat and accelerating in its expansion.
We believe that the acceleration is caused by dark energy. |
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The region around a star where a planet's temperature would permit the existence of liquid water is called the...
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life zone.
Water is the key to looking at planets for signs of life. Essentially we want a planet where water exists in a triple state- solid, liquid, and gas |
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What value determines the shape and fate of the universe?
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Density.
Space time would be flat if the average density of the universe is equal to the critical density. It will be open if the average density is greater than the critical density, and closed if it is less than the critical density. |
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How do astronomers know that dark matter exists?
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Stars rotate faster than expected in the outer region of the galaxy.
The faster star rotation is the clue. If there was no dark matter the galaxy's arms would have wound themselves tight over time because of the rotational speed of the galaxy. They haven't so we can deduce that there is a larger unseen mass outside the galaxy that slows this process down. |
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The Milky Way is part of the...
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Local Group.
The Local Group is considered a poor cluster with dozens of galactic members. A rich cluster would contain 1000's of galaxies pulled together by large elliptical galaxies. |
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The Hubble Constant helps us to determine...
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The age of the universe.
We determine the Hubble constant from the recessional velocity of distant galaxies. |
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Irregular galaxies form from...
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the merger of two galaxies.
When galaxies collide vigorous star birth takes place. Huge clumps of material eventually turns into an irregular galaxy forming from the gas "tails" of these collisions. |
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Which of the following galaxies is a bar spiral?
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Milky way
Our own galaxy has been found to be a bar spiral. Andromeda and the Whirpool galaxy are normal spirals and the Large Magellanic Cloud is an irregular galaxy. |
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According to the Hubble law, if you know the recessional velocity and the ________ of groups of galaxies, you can determine the age of the universe.
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Distance.
The Hubble Law is a relation between a galaxy's recessional velocity and distance. |
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Rich star clusters are quite dense and contain many giant...
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elliptical galaxies.
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The center of the Milky Way galaxy lies in the direction of the constellation of...
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Sagittaruis
We are located in the Orion arm and and the center of the galaxy is in the direction of Sagittarius. |
