How do we know?
↻ One of the pages with a moving picture
We sent a telescope above the air, and the stars stopped flickering.
- Starlight zooms across space for years and years.
- At the very end of its trip, it passes through Earth’s air.
- Warm and cool air is always moving. It bends the light this way and that.
- So the star seems to jiggle and flicker. It twinkles!
The Hubble Space Telescope circles about 300 miles up, so the air can’t blur its view.
That is the clue: the flicker is added at the very end of the trip, by our own air. Above the air, the light holds still.
The light is also very old. Light from Proxima Centauri, the closest star after the Sun, takes 4.24 years to reach us.
Wow number
4.24 years is how long light from Proxima Centauri, the closest star after the Sun, takes to reach us.
Myth or fact?
Stars blink on and off. Myth. Most stars shine with a steady light. Our air makes them flicker.
Planets twinkle less than stars. Fact. They aren’t tiny points of light like faraway stars.
Think about it
Would an astronaut floating in space see the stars twinkle? Why or why not?
Where in the world?
Maunakea, Hawaiʻi where, at 13,803 feet, telescopes sit above much of the air. On La Palma in Spain, a special law limits outdoor lights to keep the night sky dark — 19.8207° N, 155.4681° W.
Where these facts come from
Every number on page 12, and who measured it
This page explains how moving air makes stars twinkle.
Why do stars twinkle? — NASA StarChild, a NASA science site for kids
starchild.gsfc.nasa.gov/docs/StarChild/questions/question26.html
We checked it on 31 October 2026
This page explains why planets twinkle less than stars.
Why do stars twinkle? — The Hong Kong Observatory, Hong Kong's weather and science agency
hko.gov.hk/en/education/earth-science/optical-phenomena/00356-why-do-stars-twinkle.html
We checked it on 31 October 2026
This page tells us how far away Proxima Centauri is.
APOD: 2016 January 18 — NASA, the U.S. space agency
science.nasa.gov/image-article/apod-2016-january-18-proxima-centauri-the-closest-star
We checked it on 31 October 2026
This page tells us how high the telescopes on Maunakea are.
Science — Maunakea Observatories, the telescopes on Maunakea
maunakeaobservatories.org/science
We checked it on 31 October 2026
This page tells us about La Palma's law that keeps the night sky dark.
Sky protection — The Canary Islands Astrophysics Institute in Spain
iac.es/en/observatorios-de-canarias/sky-protection
We checked it on 31 October 2026
This page tells us how high above Earth the Hubble telescope flies.
About Hubble — NASA, the U.S. space agency
science.nasa.gov/mission/hubble/overview/about-hubble
We checked it on 31 October 2026
Has this changed?
Stars twinkle for the same reason today as they did a thousand years ago, so this answer is not going to change.
What keeps changing is the telescopes. Newer telescopes can correct for the flicker, even from the ground.
Words from this page
- twinkle
- To seem to flicker, because moving air bends the light.
Try it!
Watch moving water wobble a coin, just like moving air wobbles a star.
1. Put a coin in the bottom of a bowl of water. 2. Look at it from above. Ask a helper to tap the water gently. 3. Watch the coin as the water moves.
What happens: the coin seems to wiggle. Moving water bends light, just like moving air bends starlight.
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