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A NASA observatory captured what appeared to be a jack-o’-lantern-esque smile on the sun’s surface, showing what are actually splotches on the sun’s surface that are cooler than the surrounding areas.
The image, taken by NASA’s space-based Solar Dynamics Observatory, was shared by the space agency on social media last week and prompted an outpouring of responses weighing in on what the pattern of erratic dark spots resembled.
The official Twitter account for NASA’s heliophysics department referred to it simply as a “smiling” sun, while the United Kingdom’s Science and Technology Facilities Council weighed in by photoshopping a pumpkin into the picture, turning it into a jack-o’-lantern.
The dark areas that make up the facial pattern, however, are what are called coronal holes, which appear as irregular black patches when the sun is imaged in ultraviolet light or certain types of X-ray images, according to the space agency.
Coronal holes are not as hot as the surrounding areas and aren’t as dense, making them darker in appearance. They can pop up on the solar surface at any time.
Their magnetic field structure also sets up coronal holes to release streams of solar wind, or charged particles, at speeds of more than 1 million miles per hour (1.6 million kilometers per hour). These winds are powerful enough to reach Earth. Our planet’s magnetic field, which acts as a shield, largely deflects solar wind activity, but it can disturb the atmosphere.
The NASA Solar Dynamics Observatory, or SDO, routinely captures such images of the sun and is monitoring its activity on a nearly continual basis. The orbiting observatory was launched in 2010, and it’s part of the space agency’s Living With a Star Program, which aims to analyze how solar activity impacts our home planet and the space between the Earth and our home star.