Topic: Introductory Astronomy

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.

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.

Birth of a Supernova, Type Ia
In this interactive activity from NOVA Online, learn about a type of exploding star — a Type Ia supernova — that is so bright that astronomers can measure the distance to the galaxy in which it resides, and even learn which elements make up the star.

The Elements: Forged in Stars
The story of how elements from lithium to uranium are created by stars is illustrated through animation and a hands-on periodic table in this video segment adapted from NOVA.

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.

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.

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.

Galileo's Thought Experiment
How can Earth move through space without our feeling its motion? This video segment adapted from NOVA answers this question by dramatizing one of Galileo's thought experiments.

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

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.

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 Do You Get to the Moon?
This video, adapted from NOVA, showcases the competing engineering plans designed for landing a person on the Moon for the first time.

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.

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.

Jupiter: Earth's Shield
Jupiter's immense gravity protects Earth from asteroids. In this video segment adapted from NOVA, scientists searching for signs of life in the universe identify solar systems with Jupiter-like planets that may be shielding smaller nearby Earth-like planets from comets and asteroids.

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.

Newton's Third Law of Motion: Astronauts in Outer Space
In this video segment adapted from NOVA, NASA learns hard lessons from the first American attempt to do work while "walking" in space. The video also explores Newton's third law of motion.

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.

The Search for Another Earth
This NASA video provides an overview of technology under development to explore the planets and stars outside our solar system. These will be the most sensitive instruments built to date.

Solar Magnetism
This video segment adapted from NOVA describes how the Sun's magnetism can have an effect here on Earth, from dramatic auroras to a mini-Ice Age in the 1600s.

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.

A Strange New Planet
This video segment adapted from NOVA features the first planet to be discovered outside our solar system. Its surprisingly large size and short orbit sent scientists back to their data and led them to discover similar planets.

The Wall of Time
This illustrated timeline from the Lunar and Planetary Institute provides a journey through four-and-a-half billion years of time from the birth of our solar system to its current existence today.

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.