Chapter 24.1
SC912N11, SC912E58
SC.912.P.10.16/18,
Describe the waves that compose the electromagnetic spectrum
Describe what the different types of spectra reveal about stars
Explain how the Doppler effect is applies to the motion of stars in
relation to Earth.
Essential Questions
What types of radiation make up the
electromagnetic spectrum?
2. How do scientist determine the elements in a star?
1.
Vocabulary Words
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2.
3.
4.
5.
6.
7.
Electromagnetic spectrum
Photon
Spectroscopy
Continuous spectrum
Absorption spectrum
Emission spectrum
Doppler Effect
Electromagnetic
Radiation
 Electromagnetic radiation includes gamma rays, X-
rays, ultraviolet light, visible light, infrared light,
microwaves, and radio waves.
 The arrangement of these waves according to their
wavelengths and frequencies is called the
electromagnetic spectrum.
 All energy, travels through the vacuum of space at the
speed of light, or 300,000 kilometers per second.
 Over a 24 hour day, this equals 26 billion kilometers.
Waves
Measured from
crest to crest
Vary in size
from
kilometers to
less than a
billionth of a
centimeter
Colors and Wavelengths
Photons
 A stream of particles
 Resemble bullets fired from machine gun.
 Push on matter.
 Shorter wavelengths have more energetic photons.
 Blue light has more than red light.
Developed by Sir Isaac Newton when he divided light into
components.
Spectroscopy
 Spectroscopy is the study of the properties of light that
depend on wavelength.
 Newton produced a rainbow of colors which included
all wavelengths of visible light.
Spectroscopy
Continuous Spectrum
Absorption Spectrum
 Produced by an incandescent
 Produced when visible light is
solid, liquid, or gas under
high pressure.
 Incandescent means to emit
light when hot.
 Spectrum consists of an
uninterrupted band of color.
 Visible light from light bulb is
a result
passed through a relatively
cool gas under low pressure.
 Appears continuous, but has
a series of dark lines running
through it.
 The radiation most stars
produce.
Spectroscopy
Emission Spectrum
 Produced by a hot gas under low pressure.
 A series of bright lines of particular wavelengths
(depending on gas)
 When the spectrum of a star is studied, the spectral
lines act as “fingerprints.” These lines identify the
elements present and thus the star’s chemical
composition.
Who introduced the field of spectroscopy?
Doppler Effect
 Refers to the perceived change in wave length of a wave
that is emitted from a source that is moving away or toward
an object.
 Tells astronomers whether a star is moving towards or away
from Earth.
Essential Questions
1.
What types of radiation make up the
electromagnetic spectrum?
2. How do scientist determine the elements in a star?
Cooler, darker spots on sun are called___________
2. Squeezing together of H atoms to create He is ____________
3. H atoms ripped apart, create electrically charged particles
called ______________
4. How is the sun similar to a bar magnet on Earth?
1.
Ch.24.2
SC.912.N.1.1,
SC.912.E.5.7, SC.912.E.5.8
Explain how refracting, reflecting, and radio telescopes work.
Explain the advantages that space telescopes have over Earthbased telescopes.
Vocabulary
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2.
3.
4.
5.
6.
Refracting telescope
Chromatic aberration
Reflecting telescope
Radio telescope
Interferometer
Resolving Power
Essential Questions
1.
How does a refracting telescope produce an image?
2. What advantage does the space telescopes have over
the Earth-based telescopes?
Refracting Telescopes
 Galileo considered first person to use a telescope for
astronomical observations.
 Uses a lens to bend or refract light
 Most important lens in a refracting telescope, the
objective lens, produces an image by bending light
from a distant object so that the light converges at an
area called the focus
 Focus = central point
Refracting Telescopes
 How it works is that light from an object enters the
telescope and passes through the objective lens, which
bends the light rays so that they converge at the focus.
The rays then travel to the eyepiece, which magnifies
the image for the observer.
Chromatic Aberration
 Chromatic (chroma = color) aberration (aberrare = to
go astray)
 Optical defect, short wavelengths bend more so than
long wavelengths of refracting telescopes
 When a refracting telescope is in focus for red light,
blue and violet light are out of focus.
 Problem for astronomers because it weakens the image
and produces a halo of color around it.
Reflecting Telescope
 Use a concave mirror that focuses light in front of a
mirror, rather than behind it, like the lens.
Is a telescopes ability to produce sharper images and finer detail.
Properties of
Optical telescopes
 Both reflecting and refracting telescopes have 3
properties that aid astronomers:
Light-gathering power
2. Resolving power
3. Magnifying power
1.
Radio Telescopes
 Are huge dishes used to gather and focus radio waves
 A radio telescope focuses the incoming radio waves on an
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antenna, which absorbs and transmits these waves to an
amplifier, just like a radio antenna.
Used to measure the galactic distribution of hydrogen
Radio telescopes have poor resolution, when grouped
reduces problem.
Several radio telescopes wired together, is called an
interferometer.
Measure the galaxy’s distribution of hydrogen from which
stars are made from.
Advantage
 Major advantage of space telescopes versus Earth-
based telescopes is they do not have interference from
the atmosphere.
Essential Questions
1.
How does a refracting telescope produce an image?
2. What advantage does the space telescopes have over
the Earth-based telescopes?
Create a Bingo Board using the vocabulary words
provided in the chapter.
4x4
Ch. 24.2
SC912N11, SC912N14, SC912N24, SC912N25, SC912N41
SC912E54
Explain the structure of the sun.
Explain how the sun produces energy.
Essential Questions
1.
What is the structure of the sun?
2. How does the sun produce energy?
Structure of
the Sun
We can divide the
sun into four parts:
1. The solar interior
2. The visible
surface or
photosphere
3. 2 atmospheric
layers –
chromosphere
4. corona
Photosphere
 Photo = light
sphere = a ball
 Radiates most of the sunlight we see and thought to be
the “visible” surface
 Grainy texture is the result
of numerous relatively small,
bright markings called
granules, which are
surrounded by narrow,
dark regions.
Photosphere/granules
 Granules are normally the size of Texas
 Owe brightness to hotter gases that are rising from
below. As gas spreads, cooling causes it to darken and
sink back into the interior.
 Each one only survives for 10-20 minutes
 The combined motion of new granules replacing old
ones gives the photosphere the appearance of boiling.
Photosphere/granules
 The up and down movement is called convection.
 Convection is responsible for the transfer of energy in
the uppermost part of the sun’s interior.
 Energy is transmitted inside the sun through the
processes of radiation and convection.
 The sun’s energy is created in and around the core.
Photosphere
-revealed by dark
lines of its
absorption
spectrum.
-90% of suns
surface atoms are
hydrogen, almost
10% helium
Chromosphere
Lies just above the
photosphere
Relatively thin
layer of hot gases a
few thousand
kilometers thick.
Only observed
during solar
eclipses or with
special
instruments
corona
 Corona = crown
 Outer most portion of the solar atmosphere
 Only visible when the brilliant photosphere is covered.
 Outer fringe, ionized gases have speeds great enough
to escape the gravitational pull of the sun.
 The streams of protons and electrons that flow from
the corona constitute the solar wind.
Sun Spots
 Dark regions on the surface of the photosphere
 An individual spot contains a black center rimmed by
lighter region.
 Sunspots appear dark because of their temperature,
which is about 1500 K less than that of the
surrounding solar surface. They are cooler than the
rest of the surface.
 Sunspots increase and decrease in a cycle of 11 years.
Sun Spots
Solar Flares
 Most explosive event associated with sunspots
 Are brief outbursts that normally last about an hour
and appear as a sudden brightening of the region
above a sunspot cluster.
 During their existence, solar flares release enormous
amounts of energy, much of it in the form of
ultraviolet, radio, and X-ray radiation.
Solar
Flares
Most
spectacular
effects of solar
flares on Earth,
are the auroras,
also called
northern and
southern lights.
Nuclear Fusion
 The process in which the
sun produces energy.
 The nuclear reaction
converts four hydrogen
nuclei into the nucleus
of a helium atom.
 During nuclear fusion,
energy is released
because some matter is
actually converted to
energy.
Nuclear Fusion
 The sun consumes an estimated 600 million tons of
hydrogen each second
 About 400 million tons are converted to energy.
 As hydrogen is consumed, the product of this reactionhelium-forms the solar core, which continually grows
in size.
 The sun’s energy is created in the area in and around
its core.
The Sun
 In the stable present
stage the sun is expected
to exist 10 billion years.
 The sun is 4.5 billion
years old.
 “Middle-Aged”
 It has 5.5 billion years
left at present stage.
Essential Questions
1.
What is the structure of the sun?
2. How does the sun produce energy?
Chandra X-Ray Observatory
 Studies black holes.
Savage Sun Part 2 Quiz
Streams of particles coming out of sun that disrupt
communications on Earth are
2. What forms when electrons from the solar wind
cascade down Earths magnetic field lines and
interact with gases in Earth’s atmosphere?
3. What part of the sun can a person on Earth observe
during a solar eclipse?
4. At the Solar Neutrino Observatory, what is used to
capture neutrinos?
1.
Part 2 (25 min)
You may use your notes from Part One and Part Two to
complete the quiz. This is an individual assignment. No talking
or sharing of answers. Anyone who talks will receive a 0% on
the quiz.