The Universe Flashcards
(13 cards)
Define Universe.
all existing matter and space considered as a whole.
Define Solar System.
all matter which lies within the gravitational pull of the sun.
Define the main sequence.
Main sequence stars fuse hydrogen atoms to form helium atoms in their cores.
Define red giant.
a star nearing the end of its life, it’s very bright but also very cool.
Define white dwarf.
a small dense star nearing the end of its cycle.
Define supernova.
a star which increases greatly in mass and collapses in on itself creating a huge explosion that ejects most of its mass.
Define planetary nebula.
an expanding, glowing shell of ionised gas ejecting from a red giant late in its life.
Name two theories on how the universe began.
The big bang theory and the steady state theory.
Outline three pieces of evidence for the big bang.
Redshift, when a planet’s frequency becomes lower as it moves away from the earth.
Cosmic Wave Background Radiation, the leftover radiation and energy left over from the big bang which measures to be just above zero.
Expanding universe, by reversing the redshift scientists have come to the conclusion that the universe must have started from some point.
Explain Redshift.
Redshift what it is called when planets are moving away from the earth. It is called this because when the earth gets the frequencies from these planets back, the frequency is moving more towards the red part of the spectrum.
Define CWBR.
Cosmic Wave Background Radiation is radiation coming from everywhere day and night in the universe, measuring the entire sky just above 0. Scientists believe this is left over radiation from the big bang.
What are stellar evolution and list the process?
It is the life cycle of a star.
Nebula, protostar, main sequence star, then to either red dwarf or supergiant, the red dwarf will turn into a white dwarf, and the supergiant will go supernova creating either a black hole or a pulsar.
Why do white giants only have residual heat?
Because the white dwarfs have run out of hydrogen fuel and so are no longer actively burning up.
