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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Explore the Moon

See what it is like to walk on the Moon by viewing this collection of QuickTime images from NOVA Online. Stunning 360-degree panoramas from each of the six successful Apollo Moon landings are featured.

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.

How Big Is the Universe?

In this media-rich essay from the NOVA Web site, astronomer Brent Tully of the University of Hawaiʻi walks you through the latest scientific theories about the size of the universe.

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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Light Years

This video segment adapted from Shedding Light on Science describes how astronomical distances can be measured in units of light-years, and how the finite speed of light allows astronomers to study how the universe looked long ago.

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Observe One Place at Many Scales

These satellite images and the companion animation from McDougal Littell/TERC begin at a scale that covers the whole Earth and zoom in to a view of the Capitol building in downtown Atlanta, Georgia.

Speed of Light: How Fast Is That?

How fast is 300,000 kilometers per second? This text from the NOVA Web site offers a few real-world comparisons for the speed of light.

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.

WMAP: "Baby Picture" of the Universe

View the Wilkinson Microwave Anisotropy Probe (WMAP) image from NASA to see the first detailed map of the oldest light in the universe, from 379,000 years after the Big Bang, over 13 billion years ago. A second image offers a visual timeline to put the WMAP image in perspective.