The James Webb Space Telescope for Kids
A golden mirror the size of a giraffe, a sunshield the size of a tennis court, and eyes that see the invisible.
What is the James Webb Space Telescope?
The James Webb Space Telescope, or Webb, is a giant telescope in space. It launched on 25 December 2021 and was built by NASA together with the European and Canadian space agencies. Its job is to look deep into space and far back in time, at the first galaxies, at stars being born and at planets around other stars.
Webb sees a kind of light called infrared, which our eyes cannot see. We feel infrared as warmth, like the heat from a toaster. Seeing infrared lets Webb peek inside dusty clouds and spot galaxies so far away that their light has been travelling for billions of years.
Why is the mirror gold?
Webb’s main mirror is made of 18 hexagons fitted together like a honeycomb. Together they are 6.5 metres across, wider than a giraffe is tall. Each hexagon is about 1.3 metres across, made of a light metal called beryllium.
Every segment wears a coat of real gold, thinner than a hair. Gold is very good at bouncing back infrared light, and infrared is exactly what Webb was built to see. Before Webb could take its first pictures, all 18 pieces had to be lined up so they work as one mirror.
📏 How big is Webb?
- Sunshield (length)about 21 m, a tennis court
- Golden mirror (width)6.5 m
- A tall giraffeabout 5.5 m
- A 7-year-oldabout 1.2 m
Why does Webb need a giant sunshield?
Because Webb sees heat, it has to be incredibly cold, or its own warmth would glow and blind it. A kite-shaped sunshield, about the size of a tennis court and made of five thin layers, always stays between the telescope and the Sun. It keeps the mirror colder than −220°C.
Webb doesn’t circle the Earth like the space station. It flies around a quiet spot in space called L2, about 1.5 million kilometres away, four times farther than the Moon. Because it is so big, it launched folded up inside a rocket, and unfolded itself in space like origami.
Webb Wonder Facts
Infrared slips past space dust.
Ordinary light gets blocked by dust clouds. Infrared slips out, so Webb can see stars still being born inside the Pillars of Creation.
Webb’s pictures use chosen colours.
Our eyes can’t see infrared, so scientists turn it into colours we can see. The pictures are real, but not quite what you’d see out of a window.
Webb photographed Neptune’s rings.
It gave the clearest view of them since a spacecraft flew past in 1989. In infrared, Neptune looks pale and ghostly instead of blue.
Webb looks back in time.
Light takes time to travel. Light from very distant galaxies left them billions of years ago, so Webb sees them as they were long ago.
It unfolded itself in space.
The mirror and sunshield were folded to fit inside the rocket, and opened step by step during Webb’s journey to L2.
Science words to know
- Telescope
- A tool that collects light to help us see faraway things.
- Infrared
- A kind of light our eyes can’t see. We feel it as warmth.
- Galaxy
- A huge group of billions of stars, like our Milky Way.
- Nebula
- A giant cloud of gas and dust in space, where stars can be born.
Quick quiz!
0 / 31. Why is Webb’s mirror coated in gold?
2. How many hexagon segments make Webb’s mirror?
3. Why does Webb have a huge sunshield?
Questions kids ask
Where is the James Webb Space Telescope?
It orbits a point in space called L2, about 1.5 million kilometres from Earth, four times farther away than the Moon.
What does the James Webb telescope look at?
Very distant galaxies, clouds where stars are being born, and planets in our own solar system and around other stars. See the planets in the solar system for kids.
Is Webb better than Hubble?
They are partners. Hubble sees mostly visible and ultraviolet light, while Webb sees infrared, so together they show more than either can alone.
Why is the James Webb telescope so cold?
Webb sees heat (infrared). If it were warm, it would glow in infrared itself and blind its own cameras.
The Infrared Eye
Switch between your eyes and infrared vision to find things hidden in the sky, from stars being born to Neptune’s secret rings.
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