It seems the Sun was in a good mood. A photo of the Sun taken from a National Aeronautics and Space Administration (NASA) satellite on Thursday appeared to show a smile on the surface of our nearest star. “Say cheese! Today, NASA’s Solar Dynamics Observatory caught the Sun ‘smiling’. Seen in ultraviolet light, these dark patches on the Sun are known as coronal holes and are regions where fast solar wind gushes out into space,” the American space agency wrote in the caption of the post.
Here’s the science behind the phenomenon in five points:
1. Science.com reported that the amazing picture was caught by NASA’s Solar Dynamic Observatory (SDO) and it showed the Sun spewing vast streams of the solar wind, capable of triggering a mild solar storm on Earth.
2. The three dark patches that made the Sun ‘smiling’ are coronal holes- regions of open magnetic field line structures allowing solar wind to readily escape into space instead of looping back on themselves.
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3. These regions of coronal holes on the Sun’s surface appear dark as they are cooler and less dense than the surrounding plasma regions.
4. According to the Exploratorium, a science museum in San Francisco, torrents of solar material can surge out of coronal holes at speeds of up to 1.8 million mph (2.9 million kph).
5. National Oceanic and Atmospheric Administration (NOAA), an agency under the United States Department of Commerce, has issued a G1 (minor) geomagnetic storm warning for Saturday, as Earth is currently in the firing line of the trio of solar wind streams, which could hit our planet in the next few days.