NASA's Solar Dynamics Observatory has captured an image of the Sun "smiling".

Axar.az reports that the space agency tweeted an image of the Sun in ultraviolet light with dark patches resembling a smile.

"These dark patches on the Sun are known as coronal holes and are regions where fast solar wind gushes out into space," NASA said on Twitter.

The observatory is the first mission to be launched for NASA's Living With a Star program, which is designed to understand the causes of solar variability and its impact on Earth.

NASA says the observatory's goal is to understand the solar variations that influence life on Earth and humanity's technological systems by determining how the Sun's magnetic field is generated and structured and how its magnetic energy is converted and released as solar wind and energetic particles.