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Stars & Universe
10 Space
Term | Definition |
---|---|
absolute magnitude | actual brightness of a star |
apparent magnitude | brightness of a star as seen from Earth |
galaxies | very large groups of stars and dust held together by gravity |
supernova | huge explosion that happens at the end of the life cycle of supergiant star. A neutron star or black hole remains. |
parallax | apparent movement of close stars against the background of distant stars when viewed from different positions around the Earth’s orbit |
light year | a unit of astronomical distance equivalent to the distance that light travels in one year |
parsec | a unit of distance used in astronomy, equal to about 3.26 light years |
astronomy | the branch of science which deals with celestial objects, space, and the physical universe as a whole |
star | any massive self-luminous celestial body of gas that shines by radiation derived from its internal energy sources |
The Milky Way | The name of the galaxy that contains our solar system |
black hole | the remains of a star, which forms when the force of gravity of a large neutron star is so great that not even light can escape |
Stella nebula | clouds of dust and gas that may be pulled together by gravity and heat up to form a star |
nuclear fusion | joining together of the nuclei of lighter elements to form another element, with the release of energy |
Red giant | A dying star in the final stages of stellar evolution that originates from an average sized star |
red supergiant | A dying star in the final stages of stellar evolution that originates from a massive star |
White dwarf | a small very dense star that has exhausted all its central nuclear fuel and lost its outer layers as a planetary nebula. |
black dwarf | a theoretical stellar remnant, specifically a white dwarf that has cooled sufficiently to no longer emit significant heat or light. |
planetary nebula | a region of cosmic gas and dust formed from the cast-off outer layers of a dying star |
Neutron star | very small star formed by the gravitational collapse of the remnant of a massive star after a supernova explosion, provided that the star is insufficiently massive to produce a black hole. |
blue shift | shift of lines of a spectral pattern towards the blue end when a light source is moving rapidly towards the observer |
Doppler effect | observed change in frequency of a wave when the wave source and observer are moving in relation to each other |
red shift | shift of lines of a spectral pattern towards the red end when the source is moving away from the observer |
spectrum | light from a source separated out into the sequence of colours, showing the different frequencies |
big bang theory | a theory which states that the universe began about 15 billion years ago with the explosive expansion of a singularity |
cosmology | the study of the beginning and end of the universe |
steady state theory | a theory which states that there was no beginning to the universe and that the universe does not change in appearance |