The Sun
The Sun is a yellow dwarf star (G2V), about 4.6 billion years old, and the dominant gravitational force in the Solar System. It has a diameter of roughly 1.4 million kilometers and contains around 99.8% of the Solar System’s mass. Nuclear fusion in its core converts hydrogen into helium, producing energy that warms the planets. Above the core lie the radiative and convective zones, followed by the visible photosphere (~5,500 °C), the chromosphere, and the much hotter corona (~2 million °C).
Source: science.nasa.gov
APODs including "The Sun"
Comet Lemmon Beyond Lomnický Peak
04/11/2025
Comet Lemmon has been putting on a show for cameras around the globe. Passing nearest to Earth in late October, the photogenic comet C/2025 A6 (Lemmon) sprouted two long and picturesque tails: a blue ion tail and a white dust tail. The ion tail is pushed away from the coma by the ever-present but ever-changing solar wind, at one point extending over 20 times the diameter of the full Moon -- as captured in this long-duration exposure. The shorter and wider dust tail is pushed away from the coma and shines by reflecting sunlight. The featured picture, captured two weeks ago, framed the comet behind Lomnický Peak of the High Tatra Mountains, home to the Slovakian Lomnický Stit Observatory. Comet Lemmon is now fading as it heads away from planet Earth. The huge shedding snowball will round the Sun later this week.