Have you ever looked at the night sky and wondered why some stars look a bit blurry? That is because Earth’s atmosphere bends and blocks some of the light from space.
To get a clearer view of the universe, scientists built space telescopes that orbit high above our atmosphere. Two famous ones are the Hubble Space Telescope and the James Webb Space Telescope.
How Hubble helps us observe the universe
Launched into space aboard the Space Shuttle Discovery in 1990, the Hubble Space Telescope orbits about 540km above Earth.
From up there, the telescope takes sharp pictures of stars, galaxies and colourful clouds of gas called nebulae. It has been capturing and sending back these photographs for over 35 years.
Before this space telescope existed, astronomers studied stars, galaxies and nebulae using ground-based telescopes, long-exposure astrophotography and careful measurements of how celestial objects moved over time.
These observations revealed a great deal about the universe, but Earth’s atmosphere and urban light pollution often blurred the view and limited how clearly scientists could study the night sky.
Not only can Hubble see much farther than the human eye, but it can also detect invisible light such as ultraviolet and near-infrared wavelengths. This helps scientists learn how stars are born, how galaxies form and how the universe changes over time.
One example is the stunning photograph of the Pillars of Creation, taken by Hubble.
The Pillars of Creation are where new stars are born. They are a small part of a space cloud called the Eagle Nebula. The pillars are about 4 to 5 light years long, while the entire Eagle Nebula is 70 light years wide and 55 light years tall.
Understanding telescopes up close
Capturing images of things so far away requires perfect engineering. To understand the technology behind these discoveries, you can build a refracting telescope model.
All you need are two cardboard tubes, tape and two convex lenses. For the convex lenses, buy them online or ask your parents to help remove lenses from a pair of reading glasses.
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Cut one tube the long way, and wrap it a bit more tightly so that it fits inside the other tube.
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Pull the inner tube out slightly. Tape one lens to the end of the inside tube so that the curve faces inside.
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Flip the tubes to the other side, and tape the other lens to the outside tube so that the lens’ curve faces outward.
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Look through the inside tube’s lens, and try to look at things in the distance. Move the outside tube back and forth until you can see the image clearly.
With a friend, discuss why size, lens shape and alignment affect how sharp the image is.
The tube length matters because it helps set the distance between the two lenses. The longer you pull the outside tube forward, the longer the focal length is, which affects the magnification of the image.
Compare your design to the Hubble Space Telescope. Even tiny adjustments to a telescope’s shape, size and alignment affect how clearly we see the universe.
You can also design your own space telescope on Nasa’s website. Scan the QR code to find the link to an interactive online game where you can choose from a combination of wavelengths and tools to study different elements in the universe. This is a great way to explore the technology and science behind a telescope.
Explore more discoveries from the James Webb Space Telescope
Along with Hubble, we now have the James Webb Space Telescope (see table), which has a larger mirror and can see infrared light. Because of this, it can look much deeper into space than Hubble could. Webb helps us see how the universe began.
This leap in technology shows how upgrading tools allows scientists to see the world in a whole new way. How you look at a problem changes what you discover. Science is all about using the right tools and making smart design choices.
Just like the teams that build space telescopes, using curiosity, creativity and teamwork can make learning in the classroom way more fun and meaningful.
