Photosphere but more tenuous corona. Other "surface features" on the photosphere are solar flares and sunspots. Photosphere The photosphere is a star's outer shell from which light is radiated. The term itself is derived from Ancient Greek roots, φῶς, φωτός/"phos, photos" meaning "light" and σφαῖρα/"sphaira" meaning "sphere", in reference to it being a spherical surface that is perceived to emit light. It extends into a star's surface until the plasma becomes opaque, equivalent to an optical depth of approximately 2/3, or equivalently, a depth from which 50% of light will escape without being scattered. In other words, a photosphere is the
What is a Masterpiece? What is a Masterpiece? What is a Masterpiece? is a 1979 non-fiction book by British historian Kenneth Clark. It is a transcribed version of the Walter Neurath memorial lectures given by Clark. The work, initially released on 1 January 1979, received a Thames & Hudson republication on 1 May 1992. Kenneth Clark had already achieved fame with a series of popular books while also serving as, from 1969 on, the writer, producer and presenter of the BBC programme, "Civilisation", a pioneering television documentary series. The prestigious series earned a Peabody Award as well as general commercial success. In the work,