Astronomy Picture of the Day - Solstice on a Spinning Earth

NASA ^ | 21 Dec, 2025 | Image Credit: Meteosat 9, NASA, Earth Observatory, Robert Simmon

[MtnClimber]

Explanation: Can you tell that today is a solstice by the tilt of the Earth? Yes. At a solstice, the Earth's terminator -- the dividing line between night and day -- is tilted the most. The featured time-lapse video demonstrates this by displaying an entire year on planet Earth in twelve seconds. From geosynchronous orbit, the Meteosat 9 satellite recorded infrared images of the Earth every day at the same local time. The video started at the September 2010 equinox with the terminator line being vertical: an equinox. As the Earth revolved around the Sun, the terminator was seen to tilt in a way that provides less daily sunlight to the northern hemisphere, causing winter in the north. At the most tilt, winter solstice occurred in the north, and summer solstice in the south. As the year progressed, the March 2011 equinox arrived halfway through the video, followed by the terminator tilting the other way, causing winter in the southern hemisphere -- and summer in the north. The captured year ends again with the September equinox, concluding another of the billions of trips the Earth has taken -- and will take -- around the Sun.

[MtnClimber]

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For more detail go to the link and click on the image for a high definition image. You can then move the magnifying glass cursor then click to zoom in and click again to zoom out. When zoomed in you can scan by moving the side bars on the bottom and right side of the image.

Today's image is a video at the source link.

[MtnClimber]

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Today’s image is a video at the source link.

[Hebrews 11:6]

While the NASA image is lovely, it is misleading. It shows the sun moving up and down while earth stays still—just backwards from reality—rather than remaining fixed while the earth’s tilt varies.

Of course, that couldn’t be helped, because the camera was orbitally sychronized with earth. Still, perhaps they could swivel that camera incrementally, to keep the sun “stationary.”