vocabulary the words are in lesson order with the lesson the word is from written as: – l # 1
TRANSCRIPT
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CHAPTER 3: STARS, GALAXIES, AND THE UNIVERSE
VocabularyThe words are in lesson order with the lesson the word is from written as: – L #
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light-year – L 1
The distance that light travels in one year, about 9.46 trillion kilometers
Is a unit of distance NOT time
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parallax – L 1
The apparent change in position of an object when you look at it from different places
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scientific notation – L 1
Uses powers of 10 to write very large numbers in shorter form
Example: 37,000,000,000,000 3.7 x 1013
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universe – L 1
All of space and everything in it
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binary star – L 2
• Star systems that have 2 stars, called double stars
• Often 1 of the stars is much brighter & more massive
• solarsystem.nasa.gov• solarsystem.nasa.gov
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elliptical galaxy – L 2
• It looks round and flattened• Billions of stars• They don’t have much gas or dust between
the stars• Contains old stars
• solarsystem.nasa.gov
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galaxy – L 2
A huge group of single stars, star systems, star clusters, dust, and gas, bound together by gravity
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irregular galaxy – L 2
• They are not regular shapes; smaller• Contains you, bright stars• Includes a lot of gas & dust to form new stars
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planet – L 2
• An object that orbits a star• Large enough to have become rounded by its
own gravity• Has cleared the area of its orbit
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quasar – L 2
• Active, young galaxies with black holes at their center
• Gas spins around the black hole• Heats up, & glows
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solar system – L 2
• Contains a star and the planets and other objects that revolve around the star
• solarsystem.nasa.gov
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spiral galaxy – L 2
• Looks like a pinwheel• Its arms are full of young stars & new stars
form there
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star – L 2
• A giant ball of gas in a small volume• Primarily composed of hydrogen and helium,
which undergoes nuclear fusion (combining)
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accretion – L 3
The process of building something up gradually by the gathering together of smaller pieces
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force – L 3
A push or a pull
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gravity – L 3
The force that pulls objects towards each other
The strength of the force of gravity between 2 objects depends on the masses of the objects & the distance between the 2 objects
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inertia – L 3
The tendency of an object to resist a change in motion
Example: when a car stops suddenly, you keep moving forward
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Law of universal gravitation – L 3
Every object n the universe attract every other object
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Newton’s first law of motion – L 3
An object at rest will stay at rest and an object in motion will stay in motion; unless acted upon
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orbit – L 3
The path of an object as it revolves around another object in space
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absolute brightness – L 4
• Also known as luminosity• It is the brightness that a star would have if it
were at a standard distance from Earth
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apparent brightness – L 4
• Also known as apparent magnitude• It is a star’s brightness as seen from Earth
• solarsystem.nasa.gov
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Hertzprung-Russell diagram (H-R) diagramL 4
• A graph of stars’ surface temperature versus their absolute brightness
• Astronomers use H-R diagrams to classify stars and to understand how stars change over time.
• solarsystem.nasa.gov
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main sequence – L 4
• A diagonal area of the H-R diagram where most of the stars are located
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spectrograph – L 4
• A device that breaks light into colors and produces an image of the resulting spectrum
• solarsystem.nasa.gov
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black hole – L 5
An object with gravity so strong that nothing, not even light, can escape
Image Credit: NASA, ESA, H. Teplitz and M. Rafelski (IPAC/Caltech), A. Koekemoer (STScI), R. Windhorst (Arizona State University), and Z. Levay (STScI)
Credit: NASA/ESA
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nebula – L 5
A large cloud of gas and dust that is spread out in an immense (large) volume
Image Credit: NASA, ESA, H. Teplitz and M. Rafelski (IPAC/Caltech), A. Koekemoer (STScI), R. Windhorst (Arizona State University), and Z. Levay (STScI)
Credit: NASA/ESA
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neutron star – L 5
The remains of a supergiant explosion
Smaller and denser than white dwarfs
May be 3 times the mass of the sun
Image Credit: NASA, ESA, H. Teplitz and M. Rafelski (IPAC/Caltech), A. Koekemoer (STScI), R. Windhorst (Arizona State University), and Z. Levay (STScI)
Credit: NASA/ESA
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Protostar – L 5
The first stage of a star’s life A contracting cloud of gas and
dust with enough mass to form a star
Image Credit: NASA, ESA, H. Teplitz and M. Rafelski (IPAC/Caltech), A. Koekemoer (STScI), R. Windhorst (Arizona State University), and Z. Levay (STScI)
Credit: NASA/ESA
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pulsar – L 5
Rapidly spinning neutron stars May spin hundreds of times per
second
Image Credit: NASA, ESA, H. Teplitz and M. Rafelski (IPAC/Caltech), A. Koekemoer (STScI), R. Windhorst (Arizona State University), and Z. Levay (STScI)
Credit: NASA/ESA
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supernova – L 5
When a supergiant runs out of fuel – it can explode
The explosion blazes millions of times brighter
Image Credit: NASA, ESA, H. Teplitz and M. Rafelski (IPAC/Caltech), A. Koekemoer (STScI), R. Windhorst (Arizona State University), and Z. Levay (STScI)
Credit: NASA/ESA
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white dwarf – L 5
When a star runs out of fuel, it is the blue-white core of the star that is left behind
Image Credit: NASA, ESA, H. Teplitz and M. Rafelski (IPAC/Caltech), A. Koekemoer (STScI), R. Windhorst (Arizona State University), and Z. Levay (STScI)
Credit: NASA/ESA
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chromosphere – L 6
The middle layer of the sun’s atmosphere
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Convection zone – L 6
The outermost layer of the sun’s interio
Energy moves toward the sun’s surface by convection
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core – L 6
It is the central region of the sun
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corona – L 6
The outer layer of the sun’s atmosphere
It extends far into space It gradually thins into streams of
solar wind
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nuclear fusion – L 6
A process where hydrogen atoms join together to form helium;
Requires extremely high temperature and pressure
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photosphere – L 6
The inner layer of the sun’s atmosphere
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prominence – L 6
Huge loops of gas that link different parts of sunspot regions together
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radiation zone – L 6
A region of very tightly packed gas where energy moves mainly in the form of electromagnetic radiation
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solar flare – L 6
When loops in sunspot regions connect, it releases energy and causes gas to erupt into space
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solar wind – L 6
Electrically charged particles Can enter the Earth’s
atmosphere near the North and South poles – causes auroras
They can also cause magnetic storms
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sunspot – L 6
Areas of gas on the sun’s surface
They are cooler than the gases around them
They give off less light – so they look dark
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