SDO's Crazy-Looking Sun Due to Syzygy

By Nancy Atkinson - April 1, 2011 at 10:20 PM UTC | Solar Astronomy
SDO-eclipse.jpg

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It looks like something is eating the Sun in recent pictures from the Solar Dynamics Observatory -- and in recent SDO videos, the Sun suddenly disappears! What is going on? Could it be aliens, Planet X, or the Great Galactic Ghoul? Nope, just orbital mechanics and syzygy (an alignment of three celestial objects). At this time of year the Sun, Earth, and the SDO spacecraft in geosynchronous orbit line up, creating syzygencially spectacular Sun-Earth eclipses. The folks from SDO explain it this way:

"Twice a year, SDO enters an eclipse season where the spacecraft slips behind Earth for up to 72 minutes a day. Unlike the crisp shadow one sees on the sun during a lunar eclipse, Earth's shadow has a variegated edge due to its atmosphere, which blocks the sun light to different degrees depending on its density. Also, light from brighter spots on the sun may make it through, which is why some solar features extend low into Earth's shadow."

This video shows how the alignment works:

Here's a sped-up video of what SDO sees from space:

See more at

SDO's You Tube page

, and the

SDO website

Nancy Atkinson

Nancy Atkinson

Nancy Atkinson is a space journalist and author with a passion for telling the stories of people involved in space exploration and astronomy. She is currently retired from daily writing, but worked at Universe Today for 20 years as a writer and editor. She also contributed articles to The Planetary Society, Ad Astra (National Space Society), New Scientist and many other online outlets.

Her 2019 book, "Eight Years to the Moon: The History of the Apollo Missions,” shares the untold stories of engineers and scientists who worked behind the scenes to make the Apollo program so successful, despite the daunting odds against it. Her first book “Incredible Stories From Space: A Behind-the-Scenes Look at the Missions Changing Our View of the Cosmos” (2016) tells the stories of 37 scientists and engineers that work on several current NASA robotic missions to explore the solar system and beyond.

Nancy is also a NASA/JPL Solar System Ambassador, and through this program, she has the opportunity to share her passion of space and astronomy with children and adults through presentations and programs. Nancy's personal website is nancyatkinson.com