EarthSpace

How to see Earth’s shadow at sunrise and sunset


EarthSky’s Kelly Whitt explains how to see Earth’s shadow and the Belt of Venus, in this video.

Earth’s shadow is easy to see

Like all worlds orbiting a sun, Earth casts a shadow. It extends some 870,000 miles (1.4 million km) into space. And like all shadows, the shadow of Earth is always opposite the sun. You can see the shadow of Earth cast onto Earth’s atmosphere twice daily as a bluish band adjacent to the horizon. It’s easy to see in the sky. Just look east after sunset or west before sunrise.

Plus, the pretty band of pink that lies on top of Earth’s bluish shadow is called the Belt of Venus. More on that below!

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What to look for to see Earth’s shadow

You’ll see Earth’s shadow as a deep blue-gray. It’s darker than the blue of the twilight sky.

The shadow of the Earth is big. It helps to be on a hill or somewhere you have a long view to the horizon. You might have to turn your head this way and that – along the arc of the horizon opposite the sun – to see the whole thing. And, just so you’ll recognize it more easily, remember that the shadow is curved, in exactly the same way that the whole Earth is curved.

Once you spot it, don’t go back inside just yet. Wait a while, and watch Earth’s shadow ascending or descending at exactly the same rate that the sun is rising or setting on the opposite horizon.

And here’s a fun thought … night itself is a shadow. When night falls, you’re standing within the shadow of Earth.

Long blue shadow at horizon with long pink band above it, over clouds with trees in the foreground.
View at EarthSky Community Photos. | Mohsen Salehi captured this image on October 17, 2019, in the Alimastan jungle in Iran’s Chelav Rural District. Known for its scenery and nicknamed “Iran Green Gold,” the area attracts nature photographers. Mohsen wrote: “Earth’s shadow and Belt of Venus over an ocean of cloud.” Thank you, Mohsen!

What exactly is the Belt of Venus?

The Belt of Venus, that pink band of sky above Earth’s shadow, also has the name of the anti-twilight arch. So, for example, during sunset, the colors of twilight will be happening in the west, and when you turn to the opposite horizon, you’ll see the anti-twilight arch. You’ve probably noticed that sometimes the whole sky seems colorful at sunset. There’s a good chance that what you’re seeing opposite the sunset is Earth’s shadow and the Belt of Venus.

When the sun is below the horizon, some of the sun’s rays of light still reach our atmosphere. The light passes through our atmosphere and – at the antisolar point – it backscatters. That light then reaches back to us in shades of pink.

You might think that the Belt of Venus got its name from the planet Venus. Venus, orbiting inside Earth’s orbit, never strays far from the sun in our sky. So we often see it around sunrise and sunset. But, of course, the sun is on the opposite side of the sky from the Belt of Venus. So if Venus is visible in the sky, it’s near the sun, not on the opposite horizon.

Instead, like many other objects we know in the sky, it gets its name from ancient myth. The Belt of Venus is named for the Goddess of Love’s pink girdle.

Branches in the foreground with dark blue band over hilly landscape and hot pink band above it.
View at EarthSky Community Photos. | Kamala Venkatesh in Julian, California, captured this image on November 2, 2023. Kamala wrote: “I shot this post-sunset pointing my camera to the east.” She caught the blue band of Earth’s shadow and the pink band called the Belt of Venus. Thank you, Kamala! Learn how to see Earth’s shadow, plus the pink band above Earth’s shadow known as the Belt of Venus.

Our shadow is why we see lunar eclipses

Earth’s shadow extends so far into space that it can touch the moon. That’s what a lunar eclipse is. It’s the moon within Earth’s shadow.

When the sun, Earth and moon align in space (nearly or perfectly), with the Earth between the sun and moon, then Earth’s shadow falls on the moon’s face. That’s when people on Earth see the shadow gradually turn a bright full moon into a dark lunar eclipse.

As seen from Earth’s surface, there are typically two or more lunar eclipses every year. Some are total, some are partial, some are a subtle kind of eclipse known as penumbral.

During a lunar eclipse, a very small amount of light from the sun filters through Earth’s atmosphere onto Earth’s shadow on the moon. It’s why – at the middle part of a total lunar eclipse – the shadow on the moon looks reddish.

Diagram of sun, Earth and moon, with Earth's shadow extending into space, falling on the moon.
A lunar eclipse takes place when the sun, Earth and full moon line up in space. The full moon passes through Earth’s shadow. Image via Wikimedia Commons (CC0 1.0 Universal Public Domain).

The view from space

Another way to get an awareness of Earth’s shadow is simply to think about it as seen from space.

The image below provides a beautiful global view of Earth at night. It’s a composite image, assembled from data acquired by the Suomi National Polar-orbiting Partnership (Suomi NPP) satellite over nine days in April 2012 and 13 days in October 2012.

The dark part is, of course, in Earth’s shadow.

Full Earth at night, mostly very deep blue with small, wispy patches of light.
Global view of Earth at night. Image via NASA.

Photos of Earth’s shadow

EarthSky’s global community shares amazing photos with us every day. Here are some of their images of Earth’s shadow. Do you have a great photo to share? Send it to us!

A panorama of a flat countryside with a few houses and on the far horizon is a curved band of blue with pink above.
View larger. | Jan Curtis captured this view of the full moon rising in Earth’s shadow with the pink Belt of Venus above on November 30, 2020, from Wyoming. In this image, you can see the curve of the blue shadow that mimics the curve of Earth. Image via Jan Curtis. Used with permission.
Looking down a hill past houses to horizon, where a darker blue band fades into a pink band, under yellow and light blue.
View at EarthSky Community Photos. | EarthSky’s own Kelly Kizer Whitt captured this image of Earth’s shadow and the Belt of Venus on November 13, 2023.
Blue rays radiating from an orange and blue sunset, with distant mountain, all reflected in calm lake.
View at EarthSky Community Photos. | Dennis Schoenfelder captured this sunset image on October 7, 2023. Dennis wrote: “We were out walking our dog and just happened to see these anticrepuscular rays. We moved to a spot for a nice reflection.” Thank you, Dennis! In this image, you can also see the dark blue of Earth’s shadow and the pink Belt of Venus.
An observatory in a desert with the full moon in a pink band and dark blue below near the horizon.
View at EarthSky Community Photos. | Mohamed Farouk at Kottamia Astronomical Observatory in Egypt captured this image on August 2, 2023. Mohamed wrote: “The 1st supermoon of August 2023 is setting through the Belt of Venus.” Thank you, Mohamed!
Earth's shadow: Snowy mountain rising from foggy lowland, against blue sky with a horizontal fuzzy pink stripe.
View at EarthSky Community Photos. | Stephanie Longo captured this image of Earth’s shadow (on the right side) and the pink Belt of Venus before sunrise on February 2, 2020. Thank you, Stephanie!
Large, nearly full moon rising behind blue and pink horizontally striped sky over deep blue water.
View at EarthSky Community Photos. | Cissy Beasley captured the moon from Rockport, Texas, in September 2020. She wrote: “As a longtime fan of the original StarDate radio show when I was a student at UT Austin, I have since been intrigued with nature photography. As a professional nature photographer, I eagerly embrace opportunities to capture scenes of sunrises and sunsets, and the moon. Last night, I found a nice spot for documenting the rising moon amid the Belt of Venus. Here is what I saw!” Gorgeous, Cissy. Thank you!

During Starship launch

When SpaceX attempted its second launch of Starship on November 18, 2023, it was during morning as the sun was rising. In some of the early images, you could see Earth’s shadow and the Belt of Venus behind the rocket.

Blue band topped with pink band on the horizon with rocket on the launchpad and billowing steam fog near the ground.
On November 18, 2023, as Starship waited for launch, we could see Earth’s shadow and the Belt of Venus along the horizon. Image via SpaceX.

Bottom line: You can see Earth’s shadow in both the evening and morning sky. It appears as a bluish band opposite the sun. At sunset, face east and look for a dark blue line along the horizon. Above that you may see a pink band, which carries the pretty name of the Belt of Venus.

Posted 
November 26, 2023
 in 
Earth

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