Transcript Unit 1: Chemical Building Blocks Chapter 1: Introduction to Physical

Unit 4: Astronomy
Chapter 15: Stars, Galaxies, &
the Universe
Big Idea: Astronomers learn about the
structure & evolution of the universe
by studying stars, galaxies, & other
objects in space
5 Sections
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2.
3.
4.
5.
Telescopes
Characteristics of Stars
Lives of Stars
Star Systems & Galaxies
The Expanding Universe
Mrs. Lee - Ch 15
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Sec 1: Telescopes
KEY CONCEPTS
• The electromagnetic spectrum includes:
1) radio waves
2) infrared radiation
3) visible light
4) ultraviolet radiation
5) X-rays
6) gamma rays
Mrs. Lee - Ch 15
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Sec 1: Telescopes (cont’d)
• Telescopes are instruments that collect &
focus light & other forms of
electromagnetic radiation
• Many large observatories are located on
mountaintops or in space
Mrs. Lee - Ch 15
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Sec 1: Key Terms
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Visible light
Wavelength
Spectrum
Optical telescope
Electromagnetic
radiation
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Refracting telescope
Convex lens
Reflecting telescope
Radio telescope
Observatory
Mrs. Lee - Ch 15
5
Sec 2: Characteristics of Stars
KEY CONCEPTS
• Characteristics used to classify stars include:
1) color
2) temperature
3) size
4) composition
5) brightness
• The brightness of a star depends upon both its
size & temperature
Mrs. Lee - Ch 15
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Sec 2: Characteristics of Stars
(cont’d)
• Astronomers use a unit called the lightyear to measure distances between the stars
• Astronomers often use parallax to measure
distances to nearby stars
• Astronomers use H-R diagrams to classify
stars & to understand how stars change
over time
Mrs. Lee - Ch 15
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Sec 2: Key Terms
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Constellation
Spectrograph
Apparent brightness
Absolute brightness
• Light-year
• Parallax
• Hertzsprung-Russell
diagram
• Main sequence
Mrs. Lee - Ch 15
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Sec 3: Lives of Stars
KEY CONCEPTS
• A star is born when gas & dust become so dense
& hot that nuclear fusion stars
• How long a star lives depends on its mass
• After a star runs out of fuel, it becomes a:
1) white dwarf
2) a neutron star
or 3) a black hole
Mrs. Lee - Ch 15
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Sec 3: Key Terms
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Nebula
Protostar
Planetary nebula
White dwarf
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Supernova
Neutron star
Pulsar
Black hole
Mrs. Lee - Ch 15
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Sec 4: Star Systems & Galaxies
KEY CONCEPTS
• Most stars are members of star systems
• Astronomers classify most galaxies into
the following types:
1) spiral
2) elliptical
3) irregular
Mrs. Lee - Ch 15
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Sec 4: Star Systems & Galaxies
(cont’d)
• Our solar system is located in a spiral
galaxy called the Milky Way
• Astronomers often use scientific notation
to describe sizes & distances in the
universe
Mrs. Lee - Ch 15
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Sec 4: Key Terms
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Binary star
Eclipsing binary
Open cluster
Globular cluster
Galaxy
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Quasar
Spiral galaxy
Elliptical galaxy
Irregular galaxy
Universe
Scientific notation
Mrs. Lee - Ch 15
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Sec 5: The Expanding Universe
• According to the big bang theory, the universe
formed in an explosion billions of years ago
• About 5 billion years ago, a giant cloud of gas &
dust collapsed to form our solar system
• New observations lead astronomers to conclude
that the universe will likely expand forever
Mrs. Lee - Ch 15
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Sec 5: Key Terms
• Big bang
• Hubble’s law
• Cosmic background
radiation
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Solar nebula
Planetesimal
Dark matter
Dark energy
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