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What is heiligenschein?
Heiligenschein – which means holy light in German – is a phenomenon that appears when you look down at your shadow and see a glowing light surrounding your head. This can happen when the ground is wet, such as when there is dew on the grass. But it can also happen when the ground is bone dry. It can even happen on other worlds!
The phenomenon of heiligenschein also goes by many other names, including shadow hiding, opposition surge and also the Seeliger effect.
The most common form of heiligenschein occurs when you look down at your shadow on a day when the grass is wet with dew. You might see a slight brightening around your head, like a halo reflected back up at you. So what’s happening? In this case, the sun is behind you, and bright sunlight is passing through those dew droplets and reflecting back the way it came, at the observer.
In the video below, notice the shadow of the videographer’s head and camera below the golfer. There’s a brightening around their head, giving them a subtle halo. This is an example of heiligenschein.
Dry heiligenschein
So how can you see a similar effect of a halo around your head when you’re looking at your shadow on dry ground? A more precise term for this is dry heiligenschein. In the book Weather by Storm Dunlop, he describes the effect as follows:
A similar effect occurs on dry grass, trees and other rough surfaces. Looking in the same direction as a ray of sunlight, a blade of grass (for example) hides its own shadow, but looking to the side, the shadows of other blades of grass (or leaves) begin to be visible. This hot spot may often be seen from an aircraft, apparently gliding over the surface of the fields and woods below.
What this means is that when there is a source of light directly behind you, like the sun, the ground in front of you is devoid of shadows. But just a bit farther away, objects start to have shadows again. So the spot straight out from your point of view without any shadows is brighter, creating a halo-like phenomenon.
If this sounds a bit like the phenomenon of a glory, that’s because they are created similarly. Glories are not just a bright spot but a rainbow-hued ring around the antisolar point.
I’ve seen both the dry heiligenschein and glories from airplanes. The first time I saw the dry heiligenschein, I was flying over Chicago and noticed how a sparkle would reflect back at my eye from cars and buildings and other objects below. This sparkling spot traveled along with me.
More images
Halos on other worlds
But you can even see the heiligenschein phenomenon on other worlds! That’s because, of course, the physics of light works the same throughout our solar system.
As seen above, astronauts on the moon took images in which the dry heiligenschein appeared. And the Japanese spacecraft Hayabusa2 captured a remarkable image of its own shadow on the asteroid Ryugu during its visit, along with heiligenschein. These are places in the solar system with no or nearly no moisture. But the source of light behind the observer and the dry, dusty soil still produces the halo effect.
Bottom line: Have you ever looked down at your shadow and noticed it looks like you have a bright halo around your head? That’s heiligenschein.
Read more: Airplane glory: What is it and how to spot one?
Read more: Can you see a full circle rainbow? All you need to know
The post Heiligenschein is the halo around your head’s shadow first appeared on EarthSky.
from EarthSky https://ift.tt/gvpQEjV
EarthSky’s 2026 lunar calendar is available now. Get yours today! Makes a great gift.
What is heiligenschein?
Heiligenschein – which means holy light in German – is a phenomenon that appears when you look down at your shadow and see a glowing light surrounding your head. This can happen when the ground is wet, such as when there is dew on the grass. But it can also happen when the ground is bone dry. It can even happen on other worlds!
The phenomenon of heiligenschein also goes by many other names, including shadow hiding, opposition surge and also the Seeliger effect.
The most common form of heiligenschein occurs when you look down at your shadow on a day when the grass is wet with dew. You might see a slight brightening around your head, like a halo reflected back up at you. So what’s happening? In this case, the sun is behind you, and bright sunlight is passing through those dew droplets and reflecting back the way it came, at the observer.
In the video below, notice the shadow of the videographer’s head and camera below the golfer. There’s a brightening around their head, giving them a subtle halo. This is an example of heiligenschein.
Dry heiligenschein
So how can you see a similar effect of a halo around your head when you’re looking at your shadow on dry ground? A more precise term for this is dry heiligenschein. In the book Weather by Storm Dunlop, he describes the effect as follows:
A similar effect occurs on dry grass, trees and other rough surfaces. Looking in the same direction as a ray of sunlight, a blade of grass (for example) hides its own shadow, but looking to the side, the shadows of other blades of grass (or leaves) begin to be visible. This hot spot may often be seen from an aircraft, apparently gliding over the surface of the fields and woods below.
What this means is that when there is a source of light directly behind you, like the sun, the ground in front of you is devoid of shadows. But just a bit farther away, objects start to have shadows again. So the spot straight out from your point of view without any shadows is brighter, creating a halo-like phenomenon.
If this sounds a bit like the phenomenon of a glory, that’s because they are created similarly. Glories are not just a bright spot but a rainbow-hued ring around the antisolar point.
I’ve seen both the dry heiligenschein and glories from airplanes. The first time I saw the dry heiligenschein, I was flying over Chicago and noticed how a sparkle would reflect back at my eye from cars and buildings and other objects below. This sparkling spot traveled along with me.
More images
Halos on other worlds
But you can even see the heiligenschein phenomenon on other worlds! That’s because, of course, the physics of light works the same throughout our solar system.
As seen above, astronauts on the moon took images in which the dry heiligenschein appeared. And the Japanese spacecraft Hayabusa2 captured a remarkable image of its own shadow on the asteroid Ryugu during its visit, along with heiligenschein. These are places in the solar system with no or nearly no moisture. But the source of light behind the observer and the dry, dusty soil still produces the halo effect.
Bottom line: Have you ever looked down at your shadow and noticed it looks like you have a bright halo around your head? That’s heiligenschein.
Read more: Airplane glory: What is it and how to spot one?
Read more: Can you see a full circle rainbow? All you need to know
The post Heiligenschein is the halo around your head’s shadow first appeared on EarthSky.
from EarthSky https://ift.tt/gvpQEjV
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