NASA
Nasa Space Place: What Is a Light Year?
Brief description of light-years with examples and images.
PBS
Pbs Teachers: Math Space Odyssey: How Long Is a Light Year?
This lesson helps students to demonstrate the ability to use a light year as a standard of measurement to calculate time and distance from the earth. They will also solve problems based on light years.
NASA
Nasa Star Child: What Is a Light Year and How Is It Used?
This is a definition and example of how distance is measured in astronomy, such as the distance between our earth and the stars.
TED Talks
Ted: Ted Ed: Sunlight Is Way Older Than You Think
It takes light a zippy eight minutes to reach Earth from the surface of the Sun. But how long does it take that same light to travel from the Sun's core to its surface? Oddly enough, the answer is many thousands of years. Sten Odenwald...
TeachEngineering
Teach Engineering: Navigating at the Speed of Satellites
For thousands of years, navigators have looked to the sky for direction. Today, celestial navigation has simply switched from using natural objects to human-created satellites. A constellation of satellites, called the Global Positioning...
PBS
Pbs Learning Media: Einstein: How Smart Was He?
This essay from the NOVA Web site explores the impact Einstein made on physics and most everything we know about the cosmos.
NASA
Nasa: Imagine the Universe: "Nasa Detects One of Closest"
Site provides the article, "NASA Detects One Of Closest And Brightest Gamma Ray Bursts." Provides links to learn more about gamma rays and black holes as well as other resources.
TED Talks
Ted: Ted Ed: What Are Gravitational Waves?
In September 2015, scientists witnessed something never seen before: two black holes colliding. Both about 30 times as big as our Sun, they had been orbiting each other for millions of years. A fraction of a second before the crash, they...