Astronomical Images in Different Wavelengths

Visible light is just one portion of the electromagnetic spectrum that a telescope may detect. This collection of images produced for Teachers' Domain features radio wave, infrared, visible light, and X-ray images of distant stars and galaxies as well as images of the telescopes designed to detect the various wavelengths of radiation.

Evidence for the Big Bang Theory

This video segment adapted from NOVA tells the story of two scientists who inadvertently discovered microwave radiation that is now believed to be heat left over from the Big Bang.

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How Big Is Our Universe?

This interactive resource from Harvard Smithsonian Center for Astrophysics uses images and activities to understand the scope and scale of our universe. Featured are technologies used by generations of explorers.

Hubble's Expanding Universe

This adapted video segment, using footage from NOVA and NASA, examines Edwin Hubble's work and how his findings laid the foundation for the Big Bang theory.

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Hubble Telescope: Looking Deep

This video segment adapted from the Space Telescope Science Institute shows what the Hubble telescope found when it stared at a single, nearly empty spot in the sky for 10 days in 1995. The unexpected result was a picture of a multitude of galaxies stretching into the distance.

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Infrared Search for Origins

This interactive resource from NASA illustrates how infrared technology has advanced space exploration and can offer insight into questions about star formation, planetary systems, brown dwarfs, and the origins of the universe.

Monster Black Hole in Galaxy M84

This animation by Thomas Goertel of the Space Telescope Science Institute is an artist's conception of a spiral galaxy harboring a super-massive black hole. Observe how the material rotates faster the closer it is to the nucleus.

Relativity and the Cosmos

This illustrated essay from the NOVA Web site introduces the basic concepts of Einstein's General Theory of Relativity and what we know about cosmology as a result.

Spin a Spiral Galaxy

This interactive activity from NOVA Online lets you spin a spiral galaxy, including our own Milky Way. It demonstrates that what you can learn from visible light observations of a galaxy is largely determined by the angle from which you are observing it.

Stellar Velocity: The Doppler Effect

This interactive activity from the NOVA Web site illustrates the Doppler effect and shows how it applies to measuring the direction and speed of stellar objects.