The National Aeronautics and Space Administration’s (NASA) Solar Dynamics Observatory (SDO) caught the Sun “smiling”! Yes, you read it right. In the photo, the star which is at the center of our Solar System appears 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 Solar Dynamics Observatory is a NASA mission. Since 2010, it has been observing the Sun. The observatory was launched on 11 February 2010 and is part of the Living With a Star (LWS) program.
The aim of the SDO is to understand the influence of the Sun on our blue planet, Earth. It aims to study the solar atmosphere on small scales of space and time and in multiple wavelengths simultaneously. SDO has been investigating how the Sun’s magnetic field is generated and structured. It has also been investigating how this stored magnetic energy is converted and released into the heliosphere and geospace in the form of energetic particles and solar wind.
The Sun is a star and is a nearly perfect ball of hot plasma. It is hot due to incandescence by nuclear fusion reactions in its core. This huge fireball radiates its energy mainly as light, ultraviolet, and infrared radiation. The Sun is the most important source of energy for life on Earth.
The radius of the Sun is about 695,000 kilometers (109 times that of Earth). Its mass is about 330,000 times that of our planet. It comprises about 99.86% of the total mass of the Solar System. Roughly three-quarters of this star’s mass consists of hydrogen; the rest is mostly helium, with much smaller quantities of heavier elements, including carbon, neon, oxygen, and iron.