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A Trip Through the Light Fantastic
Dr. Frank Summers
Space Telescope Science Institute
September 1, 2015
Contact, Warner Bros 1997
Visible Light
InfraredVisible
Hotter Star
Cooler Star
Sun-like Stars
Ultraviolet
Red
Orange
Yellow
Green
Blue
Violet
ROYGBV
Red
Orange
Yellow
Green
Blue
Violet
ROYGBV
Increasing FrequencyIncreasing Energy
Increasing Wavelength
Energy is proportional to Frequency
E = h * ν
Energy: Joules, E
Planck’s constant: 6.626 * 10-34 Joule-sec
Frequency: oscillations per second (Hz), ν [nu]
Frequency * Wavelength = Speed of Light
ν * λ = c
Frequency: oscillations per second (Hz), ν [nu]
Wavelength: distance between crests (m), λ [lambda]
Speed of Light: 300,000 km/s = 186,000 mi/s, c
Electromagnetic Spectrum
Electromagnetic Spectrum
Shorter wavelength
Higher frequency
Larger energy
Longer wavelength
Lower frequency
Smaller energy
Radio Waves
wavelength > 1 meter
frequency < 300 MHz
Radio Bands
• AM radio– Amplitude modulation– 540 to 1600 kHz– WABC-AM 770 = 770 kHz = 770,000 Hz
• FM radio– Frequency modulation– 88 to 108 MHz– WPLJ 95.5 = 95.5 MHz = 95,500,000 Hz
Microwaves1 millimeter < wavelength < 1 meter
300 Ghz > frequency > 300 MHz
Microwave Oven
• Dielectric heating– 2.45 GHz
(12.2 cm)– 915 MHz
(32.8 cm)
Planck
Infrared Light700 nanometers < wavelength < 1 millimeter
Night Vision is not Infrared
Enhanced low light vision
SOFIA – Stratospheric Observatory for Infrared Astronomy
Visible Light
400 nanometers < wavelength < 700 nanometers
Electromagnetic Spectrum
Ultraviolet Light
10 nanometers < wavelength < 400 nanometers
X-rays0.01 nanometers < wavelength < 10 nanometers
Action Comics #20 by Joe Schuster and Paul Cassidy
Gamma Rayswavelength < 0.01 nanometers
Multi-wavelength Montages
Hubble Space Telescope
Spitzer Space Telescope
Chandra X-ray Observatory
Hubblevisible
Spitzerinfrared
Chandrax-ray
Supernova 1604 - Kepler
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