But planets vastly closer to us than stars. They’re only light-minutes or light-hours away, in contrast to tens or hundreds or thousands of light-years. Through telescopes, as seen from Earth, planets look like little disks. They don’t twinkle as stars do, because, as their light streams through our atmosphere, the disturbance to light from one side of a planet’s disk is canceled out by a disturbance to light from the other side. So planets appear to shine more steadily than stars.

But they all twinkle when they’re low in the sky. That’s when we’re looking through a lot of atmosphere.

And – even when they’re high in the sky – this effect is really subtle. You can notice it best when you contrast a bright planet to a nearby bright star.

Thanks for visiting! We hope you’ll return often and tell us what you’re viewing in the night sky.

All best,

Deborah

Also, on another post D Byrd said, ‘Stars twinkle—planets don’t—it’s true.’ I dont think so. I think all really far away stuff will ‘twinkle’.