Paper 2 - Topic 9, Space Physics Flashcards
what are artificial satellites
man-made satellites that have been sent into space for purposes like satellite imaging and communications
what are artificial satellites
man-made satellites that have been sent into space for purposes like satellite imaging and communications
what is the big bang theory
currently accepted model for the origin of the universe, suggests universe has expanded from an initially very small hot and dense point
what is dark energy
hypothesised form of energy that is believed to be responsible for the universe’s increasing rate of expansion
what is dark mass
hypothesised type of mass that cannot be observed by current methods, used to explain why some galaxies rotate faster than they should
what is a main sequence star
the stable state of all stars, gravitational forces pulling the star together and the pressure pushing outwards is balanced
what are natural satellites
the moons that orbit planets
what is a nebula
a cloud of dust and gas
what is a protostar
the first stage all stars go through after forming from a nebula, this stage the star becomes hot enough for hydrogen nuclei to fuse
what is a red giant star
when their hydrogen is used up and larger nuclei are produced by fusion, stars of a similar magnitude to the Sun will expand to form a red giant
what is red-shift
the observed increase in the wavelength of the light emitted by distant galaxies, the more distant the galaxy, the faster it is moving and so the bigger the observed increase in wavelength
what is a sun
a star formed from a cloud of dust and gas being pulled together by gravitational attraction, fusion reactions occur in the sun
what is a supernova
the explosion of a massive star that distributes the elements created by the fusion reactions in the star, throughout the universe
what is a white dwarf
when the fusion reactions in stars of a similar magnitude to the Sun come to an end, the star will contract under gravity and cool down to form a white dwarf
what are the inner planets mainly made of
rock