Discovering the Universe

Explore the concepts that underlie the study of the stars and other heavenly bodies, and how astrophysicists analyze their distant light for clues to their physical and chemical properties. This Special Collection sets out the fundamentals and demonstrates them in a set of articles, activities, and reference lists for all ages.

Light: Its Secrets Revealed

Article

Light: Its Secrets Revealed

Did you know that when you look at a star, your eyes are capturing light that traveled all the way from the star to your eye? Learn more about how light carries information from distant objects.

Detecting UV Light

Curriculum Materials

Detecting UV Light

You can't see the Sun's ultraviolet rays with your eyes—you just see their results on your freckled, tanned, or sunburned skin. Build a bracelet that immediately detects these invisible rays.

White Light and Colored Light

Curriculum Materials

White Light and Colored Light

When does mixing every color under the rainbow create pure white rather than a murky brown or black? When light, not paint, is the medium—and you're subtracting, not adding, color.

Building a Spectroscope

Curriculum Materials

Building a Spectroscope

White light is a mixture of all colors of visible light, but it doesn't always include every color of the rainbow. Build a spectroscope, and view the spectral fingerprints of different light sources.

Telescopes: Super Views from Space

Curriculum Materials

Telescopes: Super Views from Space

It probably comes as no surprise that telescopes do a better job of collecting light and observing outer space than your eyes. But do you know why? (Hint: the answer is NOT magnification!)

Gathering Light

Curriculum Materials

Gathering Light

While refracting and reflecting telescopes use different means of collecting light, the same principle applies to both—the bigger the aperture, the more light collected.

Building a Simple Refracting Telescope

Curriculum Materials

Building a Simple Refracting Telescope

What could Galileo see when he looked through his telescope? Build a refracting telescope with lenses similar to the ones he used, and see the answer for yourself.

Focal Point

Activity

Focal Point

What is a telescope's focal point, and why is knowing its location so important to astronomers? Grab a flashlight, an empty soda bottle, and a few other supplies; then find out.

Digital Images: The Universe Exposed

Article

Digital Images: The Universe Exposed

For most of human history, recording a star meant describing it with words or drawing a picture. The 19th-century invention of photography changed that—only to be revolutionized by digital imaging.

Pixel This!

Curriculum Materials

Pixel This!

No doubt you've received—or even sent—a digital image. But do you know how these pixel-based photographs work? You will after you decode one yourself.

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