Modern space telescopes like the JWST can see really far into the past because they look at light that has been traveling for a very long time.
Imagine you’re holding a flashlight and shining it toward a friend who is far away. The light from your flashlight takes some time to reach them, maybe even a few seconds if they're super far! Now think of JWST like a really powerful eye, looking at the light that has been traveling for billions of years.
Like Watching a Movie That Started Long Ago
When we look up at stars or galaxies with JWST, we are seeing them as they were in the past, not how they are now. It’s like watching a movie that started a long, long time ago, and you're just now getting to see it.
The farther away something is, the longer its light has been traveling. So when JWST sees a galaxy that's really far away, it means we’re seeing what that galaxy looked like billions of years ago, almost at the beginning of the universe!
It’s not magic, it’s just really clever science and a super strong eye in space!
Examples
- A kid looks at a flashlight in the dark and realizes it’s far away because it takes time for light to reach them.
- Imagine watching a movie that started playing millions of years ago, and you're just now seeing the first scene.
- If your friend shouted from across a big field, you'd hear their voice after some time, light works like that, but over much bigger distances.
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See also
- How are new space telescopes changing our understanding of the universe?
- How are new space telescopes changing our view of the universe?
- How do space telescopes see back in time?
- How will new space telescopes search for exoplanet life?
- How does the James Webb Space Telescope see back in time?