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135 Cards in this Set
- Front
- Back
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What is meant by a geocentric universe?
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One where the Earth is the center.
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List the 5 basic astronomical objects in the universe:
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1. star
2. planet 3. moon(satellite) 4. asteroid 5. comet |
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What is the term given to a large, glowing ball of gas that generates heat and light through nuclear fusion in its core?
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A Star
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What is the term given to a moderately large object that orbits a star and shine primarily by reflecting light from its star?
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A Planet
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List the 3 characteristics that are now required by the IAU to be considered a planet:
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1. orbits a star
2. large enough for its own gravity to make round 3. has cleared most other objects from its orbital path |
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T or F
Based on the IAU's new definition of a planet, does Pluto still qualify? Why? |
No, because it hasn't cleared its orbital path
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According to the IAU, what is Pluto now considered?
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Dwarf planet
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What is the term given to an object that orbits a planet?
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A moon or satellite
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What is the term given to a relatively small and rocky object that orbits a star?
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Asteroid
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According to the IAU, asteroids are officially considered part of a category known as what?
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Small solar system bodies
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What is the term given to a relatively small and ice-rich object that orbits a star?
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A comet
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According to the IAU, comets are part of what category?
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Small solar system bodies
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Name the 7 collections of astronomical objects:
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1. solary system
2. star system 3. galaxy 4. cluster 5. supercluster 6. universe 7. obervable universe |
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What is the term given to the Sun and all the material that orbits it, including the planets, dwarf planets and small solar system bodies?
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Solar system
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T or F
Although the term "solar system" technically refers only to our own star sysem, it is not applied to other star systems. |
False,
The term is often used with other star systems. |
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What is the term given to a star and any planets and other materials that orbit it?
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Star system
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T or F
Roughly half of all star systems contain 2 or more stars. |
True
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What is the term given to a great island of stars in space, containing from a few hundred million to a trillion or more stars, all held together by gravity and orbiting a common center?
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Galaxy
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What is the term given to a collection of galaxies bound to gether by gravity?
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Cluster or group of galaxies
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What are small collections of galaxies called?
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Groups
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What are large collections of galaxies called?
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Clusters
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What is the term for a gigantic region of space where many individual galaxies and many groups and clusters of galaxies are packed more closely together than elsewhere in the universe?
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Supercluster
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What is the term give to the sum total of all matter and energy-that is all galaxies and everything between them?
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Universe
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What is the other term given to the Universe?
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Cosmos
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What is the term given to the portion of the entire un iverse that can be seen from Earth, at least in principle
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Observable Universe
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What is the term that is the average distance between Earth and the Sun which is @ 150 million kilometers
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Astronomical Unit (AU)
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What is the length of the semimajor axis of Earth's orbit?
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1 AU
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What is the term for the distance that light can travel in one year?
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light year
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What is the distance of 1 light year in kilometers?
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9.46 trillion kilometers
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What is the term given to the spinning of an object around its axis?
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rotation
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How often does the Earth rotate around its axis?
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once each day
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What is the term for the orbital motion of one object around another?
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Orbit
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What is the other term used instead of orbit?
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Revolution
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How often does the Earth orbit the Sun?
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Once a year
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What is the term for the increase in the aveerage distance between galaxies as time progresses?
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Expansion of the Universe
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What is the easiest way to catalgue in your brain the measurement of 1 lightyear?
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10 trillion kilometers
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How fast does light travel?
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300,000 km/s
or 300,000 kilometers per second or 186,000 miles per second |
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Who coined the phrase "star stuff"?
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Carl Sagan
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What is "star stuff"
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we are all part of star stuff, that is to say that star stuff is made of material that was manufactured in stars from the simple elements born in the Big Bang
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How long ago from our observations do we calculate that the Big Bang occurred?
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14 billion years ago
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What is the term for the process in which lightweight atomic nuclei smash together and stick (or fuse) to make heavier nuclei?
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nuclear fusion
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How do stars live?
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From nuclear fusion
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How do stars die?
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When it exhuasts its usable fuel
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What happens when a massive star dies?
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in titanic explosions called supernovae
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What is a supernovae?
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When a massive star dies through titanic explosions
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Explain, "The farther away we look in distance, the further back we look in time"?
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Because it takes time for light to travel through space
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T or F
Any snapshot of a distant galaxy is a picture of both space and time? |
True, because the light we see from the far side of a galaxy must have left on it journey before the light we see from the near side.
That is to say that the light we see is older from the far side than from what we see on the near side |
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What is meant by the observable universe?
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Because the universe is @ 14 billion years old, we cannot observe light coming from anything more than 14 billion lights years away
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Describe our solar system on the 1: 10 billionth scale?
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1.Sun is the size of a large grapefruit;
2.Earth is the size of a ball point in a pen |
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Describe one way to put the scale of the Milky Way Galaxy into perspective
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1:10 billionth scale becomes useless,
use 1: 10 to the 19 and the diameter of the Milky Way becomes @ the length of a football field |
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On a scale how many stars are there in the Universe
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Using a grain of sand to equal a star, the number is comparable to the number of every grain of dry sand on every beach on Earth or 10 to the 22 power
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Based on the cosmic calendar when did you and your friends show up?
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0.05 seconds ago
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What is the Earth's ecpliptical plane?
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The Earth's orbital path
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What is the axis tilt?
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only in relation to the ecliptic plane, the Earth's axis tilt is 23.5 degrees from the EArth's ecliptical plane.
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What is the shape of the Milky Way
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A huge disc shaped collection of stars with a central bulge with a spehrical halo that surrounds the entire disk
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Where is our solar system located in the Milky Way?
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@ 28,000 light years from the center of the Milky Way, sort of on the fringe
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What is meant by our "cosmic address"?
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When describing our place in the universe
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What is the term for the the Sun and all of the objects that orbit it?
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Our solar system
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T or F
Asteroids and comets are included as part of our solar system. |
True
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What is the term for the huge, disk-shaped collection of stars called which our solar system is located?
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Milky Way
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T or F
The Milky Way is a solar system. |
False,
It is the Milky Way Galaxy |
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What is the term for a great island of stars in space, containing from a few hundred million to a trillion or more stars.
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Galaxy
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T or F
The Milky Way is relatively large. |
True
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Approx. how many stars are in the Milky Way Galaxy?
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100 Billion
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Where is our solar system located in the Milky Way Galaxy?
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little over halfway from the galactic center to the edge of the galactic disk
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T or F
The Milky Way is one of the 2 largest among @ 40 galaxies in the LOCAL GROUP. |
True
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WHat is the term for groups of galaxies with moe than a few dozen members?
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Galaxy Clusters
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On a large scale how do galxies and galaxy cluster appear?
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In giant chains and sheets
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What is the term for galaxies and galxy clusters that are more tightly packed in some places?
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Superclusters
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What is the term for the supercluster that our Local Group belongs to?
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Local Supercluster
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What is the term for the sum total of all matter and energy, encompassing the superclusters and voids and everything within them?
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The Universe
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T or F
The Universe is expanding? |
True
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What is the term for the event that was the start of the Universe?
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The Big Bang
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Approx. how old is the Universe?
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14 Billion years old
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T or F
Individual galaxies and their contents do not expand. |
True
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When is it estimated that most galaxies including the Milky Way were formed?
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within a few years of the Big Bang
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What is the term used to describe the evolution of a star?
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Life cycle
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What is the result when gravity compresses the material in a cloud to the point where the center becomes dense enough and hot enough to generate energy by nuclear fusion?
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A star is born
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T or F
In its final death throes a star blows much of its content back out into space. |
True
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What is the term for the titanic explosions that occur when stars die?
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Supernovae.
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What is the term for the large glowing ball of gas that generates heat and light through nuclear fusion in its core?
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A staR
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wHAT IS THE TERM FOR A MODERATELY LARGE OBJECT THAT ORBITS A STAR and shines primarily by reflecting light from its star?
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A planet
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What are the 3 criteria for an object to be considered a planet?
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It:
1. orbits a star 2. is large enough for its own gravity to make it round 3. has cleared most other objects from its orbital path. |
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Why isn't Pluto considered a planet any longer?
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It has not cleared its orbital path.
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What is Pluto considered now?
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A dwarf planet
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What is the term for an object that orbits a planet?
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Moon or satellite
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What is the term for a relatively small and rocky object that orbits a star?
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asteroid
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What is the term for a relatively small and ice-rich object that orbits a star?
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Comet
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What is the term for the Sun and all the material that orbits it, including planets, dwarf planets, and small solar system bodies?
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Solar System
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What is the term for a star, sometimes more than one star, and any polanets and other materials that orbit?
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Star System
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How many star systems contain 2 or more stars?
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1/2 or one half
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What is the term for the portion of the ntire universe that can be seen from Earth, at least in princi[;e?
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Observable Universe
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What is the distance that light can travel in 1 year?
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A light year
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In kilometers, how long is a light year?
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9.46 trillion kilometers
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T or F
A light year is a measure of time? |
False,
It is a measurement of distance, 9.46 trillion km (kilometers) |
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What is the term for the increase in the average distance between galaxies and their contents
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Expansion of the Universe
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What is the formula for distance?
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distance= speed x time
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What is the speed of lightin kilometers?
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300,000km/second
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What is the speed of light in miles?
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186,000 miles/second
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T or F
Galaxies funciton as cosmic recycling plants |
True
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What elements did the Universe contain in its earliest stage?
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Hydrogen and helium
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Name the 4 elements that make up primarily us and the Earth?
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1. Carbon
2. Nitrogen 3. Oxygen 4. Iron |
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What is thought to be manufacturer of the additional elements?
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The stars, either through nuclear fusion
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How long ago is it thought that our solar system was formed?
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4.5 Billion years ago
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What is the distance of a light year in miles?
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6 trillion miles.
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T or F
THE FARTHER AWAY WE LOOK IN DISTANCE, THE FURTHER BACK WE LOOK IN TIME. |
True
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Name the brightest star in the night sky?
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Sirius
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How far away is Sirius?
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8 light years away.
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T or F
When we look at Sirius, we are seeing it in real time. |
False,
we see it as it was @ 8 years ago. |
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How many light years away from us is the Andromeda Galaxy?
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2.5 million light years
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What is the other name for the Andromeda Galaxy?
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M31
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Approx. how large is the Andromeda Galaxy?
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100,000 light years in diameter
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What is the term for the smaller objects that orbit the Sun, including asteroids and comets?
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Small solar system bodies
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Name the only other world man has stepped onto?
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Our Moon
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What is the nearest star system to our own?
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Alpha Centauri @ 4.4 light years away.
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Name the space probe that the US launched in 1977, that flew past Jupiter, 1979, Saturn in 1981, Uranus in 1986 and Neptune in 1989 and is now bound for the stars?
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Voyager 2
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What is the rough est. of the toal number of stars in the o servable universe?
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22
10 or 10 to the 22nd power |
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On a cosmic calendar on which the Big Bang takes place on the in the first instant of January 1, how long is approximately 1 month?
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1.16 Billion years
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How long did the death of the dinosaurs take place?
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65 million years ago
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What is the term for the flat plane that defines the Earth's orbital path?
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Ecliptical plane
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What is the degree of tilt for the Earth's axis?
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23.5 degrees from a line perpendicular to the ecliptic plane
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In what direction is the Earth's axis tilt pointed?
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Towards Polaris aka the North Star
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What is the other name for the star Polaris?
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North Star
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T or F
The Earth orbits the Sun in the same direction that it rotates on its axis. |
True
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In what direction does the Earth rotate and orbit the Sun?
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Counter clockwise as viewed from above the North Pole
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What is the term for the region of the Sun and its nearby stars?
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Local solar neighborhood
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How fast are we moving relative to nearby stars?
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70,000km/hr or 40,000mi/hr
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T or F
We are moving 3x as fast as the Space Station orbits the Earth in relation to neaby stars. |
True
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T or F
In 10,000 years, the constellations will be noticeabaly different from those we see today. |
True
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Approx. what is the distance from the galactic center of the Milky Way is our solar system?
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28,000 light years
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What are the 2 astonishing facts discovered by Hubble @ about outside our Local Group
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1. Virtually every galaxy outside the Local Group is moving away from us.
2. The more distant the galaxy, the faster it appears to be racing away. |
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Name the example that is often cited to explain how the universe is expanding?
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Raisins in a cake
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How fast do we spin around Earth's axis?
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1,000 km/hr
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How fast does the Earth orbit the sun?
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100,000 km/hr
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T or F
We are latecom ers on the scale of cosmic time. |
True
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