This activity uses slime making as a tool to talk about why we need X-ray and infrared observatories to "see" through the dust in a galaxy.
Colored glitter glue: about 5 ounces each out of each 6 ounce bottle (our example uses purple, blue & green.)
1/3 to 1/2 cup of liquid starch for each color
A few drops of food coloring
Small packet of silver confetti stars (to help demonstrate the “seeing through the dust”)
Fine white glitter (a teaspoon or more in each color to make it a little “dustier”)
3 Glass bowls for mixing
1 Measuring cup
3 Large popsicle sticks for stirring
1 Medium plastic container for storage
Newspaper or tablecloth to protect your work surface
*There are many recipes for slime, so experiment! Some people prefer contact lens solution over liquid starch, others like acrylic paints instead of food coloring, etc.
We created the slime shown here by making purple, blue and teal slimes with silver star confetti and glitter mixed in, then combining the three slimes into one. The slime colors and look were inspired by the NASA Chandra X-ray Observatory image of our Milky Way’s galactic center (shown below, right).
1. Spread a newspaper or protective tablecloth.
2. Add the 5-6 ounces of glue of the three colors you’ve chosen, one color glue per mixing bowl.
3. Then add a few drops of food coloring to darken the colors, if desired.
4. Next, add the silver star confetti (a teaspoon or two to each bowl)
5. Add more glitter, about a teaspoon to each bowl, if desired.
6. Mix each bowl well with your popsicle stick.
7. Next, add the liquid starch, about 1/3 cup to each of the colored glues.
8. Mix well until you have the consistency you like. If it’s too sticky, add a bit more liquid starch.
9. Next, knead each slime (separately) to help the slime come together.
10. Let the 3 colors of slime sit for about 15 minutes. As a final step, combine your 3 slimes together. Be careful not to over mix/knead the 3 colors as they can eventually blend into one color if you do.
Step by step guide:
Since different types of light can help us understand objects in the Universe, astronomers have built telescopes and detectors that can see far beyond the type of radiation we can detect with the human eye. This ranges from long radio and infrared waves to shorter wavelengths of ultraviolet, X-rays, and gamma rays that reveal the hottest parts of the Universe. Scientists, for example, can use X-ray light and infrared light to see through the obscuring dust of a galaxy, such as our own Milky Way, or those farther beyond our galaxy. The different colors in our slime represent the various kinds of light emitted by objects near our Galactic Center.
In the image to the above, the center of our Milky Way galaxy is located within the bright white region to the right of and just below the middle of the image. The entire image width covers about one-half a degree, about the same angular width as the Full Moon.
After you’ve made your galactic slime, look at it clumped together as a large ball. How easy is it to see through to the center, or to one of the edges? Can you make out all the many stars that are in the ball? Could there be something interesting in the middle of the ball that you can’t see?
The sensitive detectors and equipment on board observatories such as NASA’s Chandra X-ray Observatory, and Spitzer Space Telescope help us see through the dust of a galaxy to where the action is. The supernovas (exploding stars), the neutron stars (dense cores of leftover stars), the black holes, even the stellar nurseries, much would be blocked if we could only look at a galaxy in visible light.
Learn more about this image at
The Milky Way is our home galaxy - a vast rotating spiral of gas, dust, and hundreds of billions of stars. Our Sun and its planetary system formed in the outer reaches of the Milky Way about 4.5 billion years ago. This mosaic of photographs of the Milky Way shows some of the billions of stars that make up our galactic neighbourhood, along with clouds of gas and a dark obscuring lane of interstellar dust. Credit: Eckhard Slawik