Give Now

A Moment of Science

Blue Sky + Looking Up = Seeing Tiny Dots And Swirls

Have you ever been staring into space, or gazing up at a clear, blue sky and suddenly noticed clusters of tiny dots and swirls?

Blue sky with sun reflecting

Photo: Janielle Beh (Flickr)

Has this "illusion" ever happened to you?

Have you ever been staring into space, or gazing up at a clear, blue sky and suddenly noticed clusters of tiny dots and swirls? Move your eyes and they move as well, seeming to float directly in front of your face. Are you really seeing something, or is it an illusion?

Dots And Swirls

What you see is real, and has to do with the inner workings of the eye. In the back of our eyes is a layer called the retina, which enables us to see. Like most body parts, the retina requires nutrients in the form of blood. Tiny blood vessels lying on top of the retina provide sustenance, but also cast a shadow on the retina.

A bright light shining into your eye from an angle sometimes makes the shadow of the retinal vessels visible, but normally the brain ignores this shadow, allowing us to see clearly.

White Or Light Blue Background

But the blood vessels are not empty, of course: they carry red and white blood cells. Red blood cells are relatively opaque, and therefore contribute to the shadow cast by the blood vessels. White blood cells, however, are transparent to light, and do not simply blend into the shadow. This means that under the right conditions they are visible, and will sometimes appear against a white or light-blue background such as the sky.

Because white blood cells are so small, they can be difficult to see. But the next time you gaze up on a cloudless day and do see a cluster of tiny dots, you’ll know that you’re watching white blood cells in action.

  • Kiri Pileta

    Can they be seen even on cloudy days?

  • Amanda Rules

    yes

  • Matt Leary

    When you see them at different times everywhere against variously colored and textured surfaces, that is not the norm. It is a phenomena that millions of people experience and is due much further investigation. Or at least more awareness so that we don’t think there is something fundamentally wrong with our experience of reality.

  • aditya

    uffff…. i got scared for no reason…. i though something was wrong with my eyes, and quickly thought of visiting a doctor……

    Glad i read this post first before making a fool out of myself…..

  • Erohiel

    I don’t buy that they’re white blood cells, because they’re brighter than the sky I’m looking at.

  • http://www.jaimeflor.com Jaime Flor

    Erohiel, I’ll give you an alternative answer, which some people will find hard to believe, but there are ongoing studies about subtle energy, & I believe you’re referring to a specific type nature energy. So I don’t think the “Blue Field Entoptic Phenomena,” is incorrect, but I just learned about it this year. However, in 2013, I was taught that I was looking at something else. After reading your comment, I think you may have clarified things for me. So you already know about the white blood cells. However, I believe that I’m seeing 2 different things. The white blood cells look like pieces of transparent dust that give off a feint whitish glow, as they lazily float about. However, I’m also seeing these rapid moving little lights, which are also whitish, but brightly lit. Sometimes, these lights can have a golden look to me. This is what Taoist’s would call Air Prana, which can be used to energize you through various breathing exercises, & techniques that involve the chakra points. Other nature energies include Solar Prana, (Ground) Earth Prana, & you can even receive energy from trees.

Stay Connected

What is RSS? RSS makes it possible to subscribe to a website's updates instead of visiting it by delivering new posts to your RSS reader automatically. Choose to receive some or all of the updates from A Moment of Science:

Support for Indiana Public Media Comes From

About A Moment of Science

Search A Moment of Science