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Fall 2018: Chapter 4 ASTR/PHYS 1060: The Universe
Chapter 4: Light
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Fall 2018: Chapter 4 ASTR/PHYS 1060: The Universe
Light is a wave
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Tacoma Narrows Bridge, 1940
https://www.youtube.com/watch?v=XggxeuFDaDU
Chapter 4: Light ASTR/PHYS 1060: The Universe Fall 2018: Chapter 4 - - PowerPoint PPT Presentation
Chapter 4: Light ASTR/PHYS 1060: The Universe Fall 2018: Chapter 4 - - PowerPoint PPT Presentation
Chapter 4: Light ASTR/PHYS 1060: The Universe Fall 2018: Chapter 4 1 Tacoma Narrows Light is a wave Bridge, 1940 https://www.youtube.com/watch?v=XggxeuFDaDU ASTR/PHYS 1060: The Universe Fall 2018: Chapter 4 2 ASTR/PHYS 1060: The
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Fall 2018: Chapter 4 ASTR/PHYS 1060: The Universe 3
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Fall 2018: Chapter 4 ASTR/PHYS 1060: The Universe
Light is an “electromagnetic wave”
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Fall 2018: Chapter 4 ASTR/PHYS 1060: The Universe
Chapter 4: Light
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Grab an ABCD page from me if you don’t have one
C D B A
HW2 posted to website under: http://www.physics.utah.edu/~wik/courses/astr1060fall2018/ homework.html due on Monday, September 17th NOTE: requires internet connection and flash installed Reading assignment Ch. 5 due this Friday (not yet available) (P .S. - spectra lab in class tomorrow, don’t skip!)
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Fall 2018: Chapter 4 ASTR/PHYS 1060: The Universe 6
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Fall 2018: Chapter 4 ASTR/PHYS 1060: The Universe
Speed of Light
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Fall 2018: Chapter 4 ASTR/PHYS 1060: The Universe
A light-year is a unit of…
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A) Energy B) Time C) Distance D) Time and Distance
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Fall 2018: Chapter 4 ASTR/PHYS 1060: The Universe
A light-year is like a parsec, but 3.26 times shorter
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Fall 2018: Chapter 4 ASTR/PHYS 1060: The Universe
Light is “quantized” Its energy is proportional to frequency
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Fall 2018: Chapter 4 ASTR/PHYS 1060: The Universe
Electromagnetic Spectrum
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Fall 2018: Chapter 4 ASTR/PHYS 1060: The Universe
What type of emission do we see only from the most energetic events?
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A) Visible Light B) Radio Waves C) Ultraviolet Light D) Gamma Rays
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Fall 2018: Chapter 4 ASTR/PHYS 1060: The Universe
What is a spectrum?
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Wavelength [nm] Intensity/Brightness
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Fall 2018: Chapter 4 ASTR/PHYS 1060: The Universe
Which object would look bluer? Which object would look brighter?
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Wavelength [nm] A B Intensity/Brightness
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Fall 2018: Chapter 4 ASTR/PHYS 1060: The Universe
Emission and Absorption Lines
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Emission sticks up Absorption sticks down
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Fall 2018: Chapter 4 ASTR/PHYS 1060: The Universe
Our eyes are telescopes!
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Works like a refractor amount of refraction depends on the wavelength of light — cannot focus red and blue light at the same time!
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Fall 2018: Chapter 4 ASTR/PHYS 1060: The Universe
Astronomical Sources are “infinitely” far away
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Fall 2018: Chapter 4 ASTR/PHYS 1060: The Universe
Use reflecting telescopes due to less chromatic aberration and easier to build large ones
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Fall 2018: Chapter 4 ASTR/PHYS 1060: The Universe
Chapter 4: Light
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Grab an ABCD page from me if you don’t have one
C D B A
HW2 posted to website under: http://www.physics.utah.edu/~wik/courses/astr1060fall2018/ homework.html due on Monday, September 17th NOTE: requires internet connection and flash installed MAY HAVE TO ENABLE FLASH IN YOUR BROWSER SETTINGS Reading assignment Ch. 5 due this Friday
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Fall 2018: Chapter 4 ASTR/PHYS 1060: The Universe 22
xkcd.com
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Fall 2018: Chapter 4 ASTR/PHYS 1060: The Universe
Why do astronomers keep making telescopes
bigger?
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A) Increase the field of view of a single
- bservation
B) Resolve finer details (better image resolution) C) Collect more light D) Astronomers need to compensate for something
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Fall 2018: Chapter 4 ASTR/PHYS 1060: The Universe
Telescope Resolution
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Fall 2018: Chapter 4 ASTR/PHYS 1060: The Universe
Making Images
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Charged Coupled Devices (CCDs)
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Fall 2018: Chapter 4 ASTR/PHYS 1060: The Universe 26
Filters
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“True” Color “False” Color
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False color images can be made using light at any wavelength, from radio to gamma ray “True” Color
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Fall 2018: Chapter 4 ASTR/PHYS 1060: The Universe
Brief Tour of the Universe at Different Wavelengths
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low energy high energy
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Fall 2018: Chapter 4 ASTR/PHYS 1060: The Universe
Radio (broad band)
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Jupiter Captured charged particles from the Sun Centaurus A Galaxy Jets accelerated by a supermassive black hole
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Fall 2018: Chapter 4 ASTR/PHYS 1060: The Universe
Radio (narrow band)
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Hydrogen gas through emission line at 21 cm Visible light (stars - images at the same scale) Spiral Galaxy
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Fall 2018: Chapter 4 ASTR/PHYS 1060: The Universe
Infrared - Dust Clouds
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Visible Light Infrared Light (1-2 μm)
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Fall 2018: Chapter 4 ASTR/PHYS 1060: The Universe
Ultraviolet - Massive Stars
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M81
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Fall 2018: Chapter 4 ASTR/PHYS 1060: The Universe
X-ray - Dead Stars
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X-ray (Chandra) Infrared (Hubble)
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The Crab Nebula
(Remains of a supernova, with a pulsar at the middle)
Crab Nebula supernova explosion left a pulsar at the center that energizes surrounding gas
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Fall 2018: Chapter 4 ASTR/PHYS 1060: The Universe
Radio/X-ray - Million Degree Gas in Galaxy Clusters
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Red = Radio Yellow = Visible Blue = X-ray
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Fall 2018: Chapter 4 ASTR/PHYS 1060: The Universe
Andromeda Galaxy - Our Nearest Neighbor
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