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