All Planet Sizes

This illustration from the Lunar and Planetary Laboratory shows the approximate sizes of the planets relative to each other. Note that the planets are not shown at appropriate distances from the Sun.

Characteristics of the Sun

This video segment adapted from NASA describes the basic characteristics of our star, the Sun.

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Eve: Extreme Ultraviolet Variability Experiment

In this NASA video, scientists describe how the Extreme Ultraviolet Variability Experiment will sample and track the Sun's ultraviolet irradiance, providing a detailed time sequence of extreme ultraviolet output -- data that can provide advance warning for potentially disruptive energy bursts.

Expedition 8 Crew Talks to Students in Japan

In this video segment adapted from NASA, students in Matsuyama City, Japan, interview Expedition 8 Commander and NASA Science Officer Mike Foale and Flight Engineer Alexander Kaleri about life and work aboard the International Space Station.

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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.

Extreme Temperatures on the Moon

In this video segment adapted from Interactive NOVA, astronaut John Young experiences extreme temperatures on the Moon that are a result of the Moon's low gravity and lack of atmosphere.

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Galileo: Discovering Jupiter's Moons

This video segment adapted from NOVA shows how Galileo, using his newly developed refracting telescope, observed four of Jupiter's moons, the first astronomical bodies to be discovered since ancient times.

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Galileo on the Moon

Watch Apollo 15 astronaut David Scott perform Galileo's falling objects experiment on the Moon in this video segment from NASA.

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Galileo: Sunspots

This video segment adapted from NOVA shows how Galileo used his telescope to carefully observe and study sunspots.

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Gallery of Auroras

View this stunning collection of auroral displays from NOVA Online to find out why auroras appear in different colors and shapes and whether they occur on other planets.

Gamma Ray Telescope Senses High-Energy Radiation

This video from NASA describes the GLAST satellite, which is equipped with a gamma-ray telescope, and shares some background about the kinds of extreme universal phenomena indicated by the presence of gamma rays.

The Habitable Zone

This illustration is an approximate representation of the planets in our solar system and their relation to what scientists call "The Habitable Zone." The planet distances from the sun are measured in Astronomical Units (AU) and are not to scale.

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.

Ingredients for Life: Water

This video segment adapted from NOVA goes on a whimsical journey in search of life forms thriving in extreme conditions on Earth and in outer space. Animations show ice on Jupiter's moon, Europa, and signs that water once existed on Mars.

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James Webb vs Hubble

Compare two space telescopes—the Hubble Space Telescope and its planned successor, the James Webb Space Telescope —in this interactive activity from NASA.

LAMP: Peering into the Lunar Dark

In this video from NASA, learn more about the Lyman-Alpha Mapping Project (LAMP), an instrument on NASA's Lunar Reconnaissance Orbiter mission to map and study the Moon.

The Lunar Cycle

Students learn about the Moon's changing appearance and how orbital motion causes the Moon’s phases.

Mass Spectrometry 101

Learn how mass spectrometry can identify the chemical composition of matter in this video from NASA.

Meet Carrie Anderson: Taking on Titan

In this video from NASA, astronomer Carrie Anderson studies Saturn's moon, Titan, using data transmitted from the Cassini space probe.

Meteor Showers

This video segment adapted from NASA uses animation to illustrate the properties of meteor showers and comets. Included is are visualizations of a comet's tail and of Earth passing through a debris stream left behind by meteoroids.