Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
23 Cards in this Set
- Front
- Back
Universe |
Everything that exists in time and space :) |
|
Protostar |
A very hot, very dense sphere of condensing dust and gas that's on its way to becoming a star. |
|
Nuclear fusion |
A process where two smaller nuclei join to form one giant nucleus. |
|
Radiation pressure |
Pressure from the photons in the core of a star, which acts outwards to counteract pressure from gravitational force, pulling the matter inwards. |
|
Gas pressure |
The pressure of nuclei in the star's core pushing outwards and contracting the gravitational force pulling matter inwards. |
|
Main Sequence |
The main period on a HR diagram in a stars life, during which is is most stable. |
|
Planet |
An object in orbit around a star with -undergoes no fusion reactions -has cleared its orbit of most other things |
|
Planetary satellite |
A body in orbit around a planet, natural or artificial. |
|
Comets |
A small irregular body made of ice, dust and small pieces of rock in an elliptical orbit around the sun. |
|
Solar System |
A planetary system consisting of a star and at least one planet in orbit around it. |
|
Galaxies |
A collection of stars and interstellar dust and gas bound together by their mutual gravitational force. |
|
Red giant |
An expanding star at the end of its life with an inert core in which fusion no longer takes place, but in which fusion of lighter elements continues in the shell around the core. |
|
White dwarf |
A very dense star formed from the core of a red giant, in which no fusion occours |
|
Electron degeneracy pressure |
A quantum-mechanical pressure created by the electrons in the core of a star due to the pauli-exclusion principle. |
|
Chandra-sekhar limit |
(1.44 solar masses) |
|
Red super giant |
A huge star in the last stages of its life before it explodes in a supernova. |
|
Neutron star |
The remnant core of a massive star after it has gone supernova and the core has collapsed so far that in order to escape and object would need an escape velocity greater that the speed of light. (therefore nothing can escape) |
|
Supernova |
The implosion of a red super giant at the end of its life, which leads to subsequent ejection of stellar matter into space, leaving an inert remnant core. |
|
Hertzsprung Russell diagram |
A graph showing the relationship between the luminosity of stars in our galaxy (y-axis) and their average surface temperature (x-axis) with temperature increasing right to left. |
|
Luminosity |
The total radiant power output of a star. |
|
Energy levels |
A discrete amount of energy that an electron within an atom is permitted to posses |
|
Ground state |
The energy level with the most negative value possible for an electron within an atom - the most stable energy state of an electron |
|
Excited ;) |
(an atom) Containing an electron or electrons that have absorbed energy and have been boosted into a higher energy level |