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"
A Full Plankton Moon
11/03/2024
What glows in the night? This night featured a combination of usual and unusual glows. Perhaps the most usual glow was from the Moon, a potentially familiar object. The full Moon's nearly vertical descent results from the observer being near Earth's equator. As the Moon sets, air and aerosols in Earth's atmosphere preferentially scatter out blue light, making the Sun-reflecting satellite appear reddish when near the horizon. Perhaps the most unusual glow was from the bioluminescent plankton, likely less familiar objects. These microscopic creatures glow blue, it is thought, primarily to surprise and deter predators. In this case, the glow was caused primarily by plankton-containing waves crashing onto the beach. The image was taken on Soneva Fushi Island, Maldives just over one year ago. Your Sky Surprise: What picture did APOD feature on your birthday? (post 1995)