Astronomy Flashcards
Define Convection Zone
A region of turbulent plasma between a star’s core and its visible photosphere at the surface, through which energy is transferred by convection. In the convection zone, hot plasma rises, cools as it nears the surface, and falls to be heated and rise again.
Define flare
a brief powerful eruption of particles and intense electromagnetic radiation from the sun’s surface, associated with sunspots and causing disturbances to radio communication on earth
Define nuclear fusion
The nuclear PROCESS whereby several small nuclei are combined to make a larger one whose mass is slightly smaller than the sum of the small ones. Nuclear fusion is the reaction that fuels the Sun, where hydrogen nuclei are fused to form helium.
Define nuclear fission
a nuclear reaction in which a heavy nucleus splits spontaneously or on impact with another particle, with the release of energy.
Define geocentric
having or representing the earth as the center, as in former astronomical systems.
Define chromosphere
a reddish gaseous layer immediately above the photosphere of the sun or another star. Together with the corona, it constitutes the star’s outer atmosphere.
Define sunspot
a spot or patch appearing from time to time on the sun’s surface, appearing dark by contrast with its surroundings.
Define granule
a small compact particle of a substance.
Define red giant
a very large star of high luminosity and low surface temperature. Red giants are thought to be in a late stage of evolution when no hydrogen remains in the core to fuel nuclear fusion.
Define electromagnetic spectrum
the range of wavelengths or frequencies over which electromagnetic radiation extends.
Define ellipse
An ellipse is defined as the locus of all points such that the sum of the distances from two foci to any point on the ellipse is a constant.
Define radius
Solar radius is a unit of distance used to express the size of stars in astronomy equal to the current radius of the Sun
Define corona
A corona (Latin, ‘crown’) is an aura of plasma that surrounds the Sun and other celestial bodies. The Sun’s corona extends millions of kilometres into space and is most easily seen during a total solar eclipse, but it is also observable with a coronagraph.
Define prominence
an eruption of a flamelike tongue of relatively cool, high-density gas from the solar chromosphere into the corona where it can be seen during a solar eclipse or by observing strong spectral lines in its emission spectrum.
Define solar wind
the continuous flow of charged particles from the sun that permeates the solar system.