William Herschel Discovery of Infrared Radiation 1800 Build

William Herschel Discovery of Infrared Radiation - 1800

Build your own Herschel demo

The full electromagnetic spectrum … Making Light of it All!

The Electromagnetic Spectrum Our eyes see only part of the electromagnetic spectrum…

Riding the Wave u u Light is a transverse wave of electromagnetic energy The wavelength (and, reciprocally, the frequency) of light defines its radiation band (X-ray, or Visible, or Infrared, or …)

Light has a dual nature: It exhibits both wave-like and particle-like properties

FORMULA CONNECTING WAVE & PARTICLE PROPERTIES OF EM RADIATION: E=hc/l E h c l = = energy per photon (joules, J) Planck’s constant speed of light (m s-1) wavelength (m)

Low-energy Light u Infrared • Thought of as “heat, ” common in daily lives u Microwaves • Used for communication, cooking u Radio • Wavelengths of centimeters to kilometers • Great for transmissions that need to go far and penetrate buildings

High-energy Light u u u Gamma Rays • Radioactive atoms, nuclear power plants X-Rays • Penetrate soft tissue Ultraviolet • Tans and sunburns, mostly stopped by atmosphere

Temperature determines the main type of radiation emitted … (left to right: Compton, Chandra, Hubble, and Spitzer space observatories)

“Invisible” Light in Astronomy Each part of the spectrum provides a piece of the puzzle in understanding our universe.

The Pinwheel Galaxy – M 101 http: //hubblesite. org/newscenter/archive/releases/2009/07

Multi-wavelength astronomy An object can appear radically different depending on the type of light collected from it: Constellation Orion left: visual-wavelength view right: far-infrared view

Visible: dark nebula, heavily obscured by interstellar dust u Near-IR: dust is nearly transparent, embedded proto-stars can be observed u Mid- and far-IR: glow from cold dust is directly observable u Visible Near Infrared Mid-Infrared

EARTH ATMOSPHERIC OPACITY VERSUS WAVELENGTH

There’s a problem for IR astronomy. . . u u Earth’s atmospheric water vapor absorbs almost all incoming infrared radiation Even mountain-top observatories get a limited view of the infrared universe

thermal-IR image of Earth from a weather satellite

View of troposphere / stratosphere boundary from above

And a Solution. . . u u NASA’s Kuiper Airborne Observatory (KAO) C-141 with a 36 -inch telescope onboard, based at NASA-Ames near San Francisco, flew from 1975 - 1995 , High-flying aircraft -above 40, 000 ft -can observe most of the infrared universe Airborne infrared telescopes can be more versatile -- and much less expensive -than space infrared telescopes

Further information: u u SOFIA Science Center home page • http: //www. sofia. usra. edu Spitzer Space Telescope’s award-winning infrared tutorial • http: //coolcosmos. ipac. caltech. edu (includes instructions for home-made Herschel demo)

“Invisible” Light in Society Each part of the spectrum impacts our daily lives… Sunscreen Communications Microwave ovens Remote controls X-rays

The Tools of Our Search We collect light from distant objects, and bring together researchers from many disciplines.

Where did we come from? What is our destiny? Are we alone?

Our Place in the Universe

Searching for Life Are we alone?

JUPITER – heat from formation still escaping

The Orion M 42 star-forming region (left to right: visible-l, near-IR, mid-IR)

Looking Back in Time To find the earliest galaxies, we will need to explore the universe in the infrared.

Active Astronomy (“AA”) classroom kit Middle School physical science, High School physics • • 4 activities comparing and contrasting visual & infrared light Teachers’ guide including curricular material, pre-/post-tests, parts list available at: www. sofia. usra. edu/Edu/materials/edu_materials. html

Resources SOFIA Active Astronomy http: //www. sofia. usra. edu/Edu/materials/active. Astronomy/active. Astrono my. html u Stanford Solar Center Spectrascopes and Colors of the Sun video http: //solar-center. stanford. edu/posters_spec_bulk. html u The Dynamic Sun http: //www. hightechscience. org/the_dynamic_sun. htm u Project Spectra http: //lasp. colorado. edu/home/education/k-12/project-spectra/ u

Further information: • SOFIA Science Center home page http: //www. sofia. usra. edu • Spitzer Space Telescope’s award-winning infrared tutorial: http: //coolcosmos. ipac. caltech. edu • (includes instructions for home-made Herschel demo)