black-hole phenomenon
21General relativity — For a generally accessible and less technical introduction to the topic, see Introduction to general relativity. General relativity Introduction Mathematical formulation Resources …
22Electron — For other uses, see Electron (disambiguation). Electron Experiments with a Crookes tube first demonstrated the particle nature of electrons. In this illustration, the profile of the cross shaped target is projected against the tube face at right… …
23galaxy — /gal euhk see/, n., pl. galaxies. 1. Astron. a. a large system of stars held together by mutual gravitation and isolated from similar systems by vast regions of space. b. (usually cap.) See Milky Way. 2. any large and brilliant or impressive… …
24Globular cluster — s from the Sun and contains hundreds of thousands of stars. [cite news coauthors =The Hubble Heritage team url = http://hubblesite.org/newscenter/newsdesk/archive/releases/1999/26/ title = Hubble Images a Swarm of Ancient Stars work = HubbleSite… …
25Ball lightning — is an atmospheric electrical phenomenon, the physical nature of which is still controversial. The term refers to reports of luminous, usually spherical objects which vary from pea sized to several meters in diameter. It is sometimes associated… …
26Martin David Kruskal — Born September 28, 1925(1925 09 28) New York City …
27List of astronomy acronyms — This is a compilation of acronyms commonly used in astronomy. Most of the acronyms are drawn from professional astronomy and are used quite frequently in scientific publications. However, a few of these acronyms are frequently used by the general …
28Stargate (device) — For episodes of the television series, see List of Stargate SG 1 episodes, List of Stargate Atlantis episodes, and List of Stargate Universe episodes. A Stargate from Stargate SG 1. A Stargate is a portal device within the Stargate fictional… …
29List of common misconceptions — This incomplete list is not intended to be exhaustive. This is a list of current, widely held, false ideas and beliefs about notable topics which have been reported by reliable sources from around the world. Each has been discussed in published… …
30gravitation — gravitational, adj. gravitationally, adv. /grav i tay sheuhn/, n. 1. Physics. a. the force of attraction between any two masses. Cf. law of gravitation. b. an act or process caused by this force. 2. a sinking or falling …
