Space Reference Libraries

Page 3 of about 47 Articles
2004-10-19 04:45:44

Terraforming -- Terraforming (literally, "Earth-shaping") is the process of modifying a planet, moon or other body to a more habitable atmosphere, temperature or ecology. The term was first used in a science fiction novel, 'Seetee Shock' (1940?) by Jack Williamson, but the actual concept is older than that. An example in fiction is 'First and Last Men' by Olaf Stapledon in which Venus is...

2004-10-19 04:45:44

Panspermia -- Panspermia is a theory (more directly described as a hypothesis, as there is no compelling evidence yet available to support or contradict it) that suggests that the seeds of life are prevalent throughout the universe and life on Earth began by such seeds landing on Earth and propagating. The theory has origins in the ideas of Anaxagoras, a Greek philosopher. An important...

2004-10-19 04:45:44

Cosmogony -- Cosmogony is the study of the origins of celestial objects. It is most commonly used to refer to the study of the origin of the solar system. Currently, the most widely accepted theory is that the solar system was formed roughly 5 billion years ago with the collapse of a nebula of gas and dust, likely caused by shock waves generated by a nearby supernova. The solar system...

Terrestrial Planet Finder
2004-10-19 04:45:43

Terrestrial Planet Finder -- The Terrestrial Planet Finder is a proposed NASA telescope system capable of detecting extrasolar terrestrial planets. In May 2002, NASA chose two TPF mission architecture concepts for further study and technology development. Each would use a different means to achieve the same goal - to block the light from a parent star in order to see its much smaller,...

X-ray Pulsar
2004-10-19 04:45:43

X-ray Pulsar -- This dramatic artist's vision shows a city-sized neutron star centered in a disk of hot plasma drawn from its enfeebled red companion star. Ravenously accreting material from the disk, the neutron star spins faster and faster emitting powerful particle beams and pulses of X-rays as it rotates 400 times a second. Could such a bizarre and inhospitable star system really exist...

White Dwarf
2004-10-19 04:45:43

White Dwarf -- A white dwarf is a a star supported by electron degeneracy. A star like our Sun will become a white dwarf when it has exhausted its nuclear fuel. Near the end of its nuclear burning stage, such a star goes through a red giant phase and then expels most of its outer material (creating a planetary nebula) until only the hot (T > 100,000 K) core remains, which then settles...

Variable Star
2004-10-19 04:45:43

Variable Star -- Most stars are of nearly constant luminosity. Our own Sun is a good example which goes through practically no measurable variation in brightness. There are, however, stars which do vary in brightness, called variable stars. They fall into two main groups: Intrinsic variables These are stars which have intrinsic variations in brightness, that is the star itself gets...

2004-10-19 04:45:42

Supernova -- A supernova is a star that increases its brightness drastically within a matter of days, making it appear as if a "new" star was born (hence "nova"). The "super" prefix distinguishes it from a mere nova, which also involves a star increasing in brightness, though to a lesser extent and through a much different mechanism. Astronomers have classified supernovae in several...

Spiral Galaxy
2004-10-19 04:45:42

Spiral Galaxy -- Among the galaxies, there are apparently three main categories, according to their appearance: the disk galaxies (`cosmic frisbies' according to P. Murdin, D. Allen, and D. Malin), consisting of a huge disk of stars and interstellar matter, which may form interesting patterns, the elliptical galaxies (`cosmic footballs') which are uniformly looking, ellipsoidal agglomerations...

2004-10-19 04:45:42

Space -- The definition of space in physics is contentious. Various concepts used to try to define space have included: -- the structure defined by the set of "spatial relationships" between objects -- a manifold defined by a coordinate system where an object can be located. -- the entity that stops all objects in the universe from touching one another In classical physics,...

Word of the Day
  • Withering but not falling off, as a blossom that persists on a twig after flowering.
The word 'marcescent' comes from a Latin word meaning 'to wither'.