Multiwavelength Milky Way: The Nature of Light
The visible spectrum
The Multiwavelength Milky Way images show us a view of our sky that our eyes cannot give us. Why? Well, for one thing, we see the world in visible light. Visible light comes to our eyes as colors ranging from deep red to deep violet. Light also comes in the form of radio waves, microwaves, infrared light, ultraviolet light, X-rays, and gamma rays. These represent light that our eyes cannot see - invisible light. The continuous range of this light is what we call the Electromagnetic Spectrum.
Light is often called electromagnetic radiation because it has electric and magnetic properties. Light has both wave and particle-like characteristics. In that light is like a wave, it has a wavelength (the distance between two successive wave peaks). Light is particle-like in that it is made up of tiny packets of energy (photons).
Every form of light is associated with a wavelength and an energy. Energy, in turn, is associated with temperature. The following topics will help you and your students learn more about light (the electromagnetic spectrum), and its association with energy and temperature. The topics also cover how different forms of light are detected. Finally, you can discover how one astronomical object can look when seen in different forms of light, and what can be learned about that object.
I. Discovering the visible and invisible rainbow
II. The laws of light, energy, and temperature
A. Stefan-Boltzmann law
B. Wien's law
C. Planck's law
III. Different telescopes for different wavelengths
IV. Seeing across the spectrum
Lesson plans available on-line from other sources:
1. From Amazing Space:
K-12 grade. "Star Light, Star Bright" -
Web-interactive lessons on light, energy, and the colors of stars. Can be adapted for printing out.
4. From NASAs Spacelink:
5-8 grade. "Space Based Astronomy" -
Teacher activity guide which includes lessons on the Earth's filtering atmosphere, the
electromagnetic spectrum, detecting electromagnetic radiation, and transmitting data back to Earth.
Guide in PDF form.