A hauntingly festive image of the Sun, captured by NASA’s Solar Dynamics Observatory (SDO), is spreading a little cosmic cheer just before Halloween. The image, taken on October 28, 2025, shows a vast expanse of the Sun's atmosphere configured to look exactly like a grinning, glowing jack-o'-lantern.
The celestial spectacle is more than just a spooky coincidence; it is a vivid illustration of the Sun's intense magnetic activity, which has real-world effects on Earth.
The Science Behind the Spooky Grin
The "face" is created by the alignment of various features in the Sun’s atmosphere, the corona, as observed in extreme ultraviolet light:
The Bright Features (Eyes and Nose): The bright regions forming the "eyes" and "nose" are active regions on the solar surface. These are areas with intense and complex magnetic fields that concentrate energy, causing them to appear brighter because they emit more light and energy.
The Dark Features (Mouth): The dark patches are coronal holes—cooler, less dense regions where the Sun's magnetic field opens up into space, allowing a high-speed stream of charged particles (known as solar wind) to gush outward. In the recent image, a large coronal hole forms the wide, mischievous "mouth."
The Color: To achieve the distinct, fiery orange-and-yellow Halloween glow, the SDO instrument's data blends two sets of extreme ultraviolet wavelengths: 171 and 193 angstroms.
Potential for Auroras: A Halloween Treat
The alignment of the coronal hole that makes up the "mouth" is currently facing Earth. This has a direct consequence for our planet's space weather:
Solar Wind Stream: The coronal hole is spewing a high-speed stream of solar wind directly toward Earth.
Geomagnetic Storm: This stream of charged particles is expected to interact with Earth's magnetic field, potentially triggering minor (G1) to moderate (G2) geomagnetic storm conditions between October 28 and 29.
Aurora Alert: The resulting geomagnetic storms are known to cause spectacular auroras (Northern and Southern Lights) that may be visible further south (or north) of their usual polar locations. Sky-gazers in mid-latitude regions across the northern hemisphere may be in for a vibrant celestial treat.
This phenomenon is eerily timed and serves as a reminder of the infamous "Halloween Storms" of 2003, which unleashed powerful solar eruptions that caused widespread auroras and disrupted satellites and power systems worldwide.
A Recurring Cosmic Jack-o'-Lantern
While striking, this isn't the first time the SDO has captured the Sun celebrating the holiday. A nearly identical "jack-o'-lantern" visage was captured by the observatory in 2014 and another "smiling" sun was spotted in 2022, illustrating the Sun's recurring patterns of solar behavior, which continue to fascinate scientists and serve as a crucial focus for space weather prediction.