This page is meant to make it easier for you to understand the content of this web site. The glossary contains both astronomical and art terms.
Satellite: This term usually denotes a man made space probe sent to orbit a celestial object. A satellite can also mean a moon orbiting a planet.
Schwarzschild Radius: The radius, at which a body would become a black hole; alternatively, the radius of the event horizon of a spherical black hole, from within which the strength of gravity is so strong that light cannot escape. Named after Karl Schwarzschild.
Semidetached Binary: A binary system in which a star is larger than it's roche lobe. This makes gas fall onto the other companion. This kind of systems can create accretion discs.
Shell burning: When a star evolves (massive stars in particular) it starts to fuse heavier and heavier elements. If a star for example is creating carbon at the center, there may be a shell, an envelope around the core which is hot enough to create helium.
Singularity: A point in a black hole which has an infinite density.
Space art: The art which strives to portray the universe and space exploration. It is sometimes considered the same as astronomical art.
Spectral Type: The spectral type is an indication of the surface temperature of a star since the temperature determines which emission lines will be present and how strong they will be.
From hottest to coolest stars are grouped into categories O, B, A, F, G, K, and M. Each letter is then subdivided into 10 numbers, from hotter to cooler 0, 1, 2, 3, 4, etc.
Link: H-R diagram.
Spectrum: An image of light broken up into its component frequencies, appearing as a rainbow of colours corresponding to the various frequencies.
Spectroscopic Binary: A binary system in which the companions orbit each other so closely that they can only be separated by using spectroscopy. Link: Spectroscopic binaries.
Sunspot: An area on the sun which is cooler than the average, around 4000 K, compared to the average surface temperature of 5 800 K. These areas are thought to be connected to the magnetic field.
Supernova: The explosion of a massive star. Supernovae come in two types: Type I is caused by sudden nuclear burning in a white dwarf star. Type II is caused by the collapse of the core of a supermassive star at the end of its nuclear-burning life.
The star is destroyed and for a moment it shines brighter than the entire galaxy's stars put together. The event of a supernova spawns new stars and spreads heavier elements into space, essential for life.
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