The Universe


Flashcards on The Universe, created by Hannah Cox on 03/11/2014.
Hannah Cox
Flashcards by Hannah Cox, updated more than 1 year ago
Hannah Cox
Created by Hannah Cox over 9 years ago

Resource summary

Question Answer
Absolute Magnitude A measure of how bright a star would appear if it was 10 parsecs from Earth
Apparent Magnitude A measure of the brightness of a star as it appears to an observer on Earth
Blue Supergiants Stars that are ten or more times more massive than the sun.
Binary Star System When two stars orbit a common centre of mass
Black Dwarf Cold dark remains of a white dwarf
Black Hole Also known as a singularity, a collapsed star so massive that not even light can escape from its gravitational field.
Density Mass per unit volume of a material
Electromagnetic spectrum Different types of electromagnetic radiation ranging from radio waves to gamma rays
Gamma Rays Very high-energy electromagnetic ray
Gravitational lensing The bending of light rays due to the distortion of space caused by a massive object like a black hole.
Gravity The force that causes all matter to collect together
isotope atoms with the same number of protons but different numbers of neutrons
Light-year (l.y.) The distance light travels in a year, approximately 9 500 000 000 000 km
Magnitude A measure of the brightness of a star
Main Sequence A groups of stars lying on a line running from the top left to the bottom right of the H-R diagram.
Neutrino An almost mass-less, neutral particle released during some nuclear reactions
Neutron Star Remnant of a supernova, consisting entirely of neutrons
Nuclear fusion Process in which hydrogen is converted into helium to produce light and heat
Parallax A technique used to measure the distance to other stars
Parsec an astronomical unit of length equal to 3.26 light-years
Plasma State of matter consisting of positively charged ions and free electrons
Positron Positively charged electron
Planetary Nebula A cloud of gas produced when a red giant runs out of fuel
Radiation pressure The force produced by radiation from a hot object
Red Giant a star produced when the core of a Sun-sized star runs out of hydrogen
Spectral class A classification system for stars based on their colour
Spectrometer A device that splits light into a spectrum to show its component wavelengths
Stellar parallax The apparent change in the position of a star throughout the year due to the Earth's motion around the Sun
Supermassive black hole A black hole millions or billions of times the mass of our Sun found at the centre of a galaxy
White Dwarf hot, dense star that is the remains of a red giant
Big Bang Theory that the universe began with an enormous explosion of energy
Blue Shift The compression of light waves due to the motion of stars towards the Earth; blue-shift makes light appear bluer than it should.
Cosmic microwave background radiation the afterglow of the Big Bang; low energy radiation that fills the universe
Cosmology the study of the history and structure of the entire universe
Doppler effect the expansion of waves due to the motion of the object making the waves
Milky Way the galaxy in which the solar system is located
Red-shift The stretching of light waves due to the motion of stars away from the Earth; red-shift makes light appear more red than it should.
Steady state theory Now discounted theory that the universe has always existed in the form that it is today; also known as the 'infinite universe' theory.
Abiogenesis the formation of the living organisms from inanimate material
Accretion process in which particles of dust and rock slowly come together due to gravity to form a larger object
Amino acids organic compounds that can be combined to form proteins
Astrobiology the study of living organisms beyond the Earth's atmosphere
Cyanobacteria also known as blue-green bacteria, microscopic organisms that can store energy from sunlight using the process of photosynthesis.
Gas giant large planet consisting mainly of gases, e.g. Jupiter, Saturn, Uranus and Neptune
Hydrocarbon a compound consisting primarily of hydrogen and carbon
Moon any naturally occurring satellite that orbits a planet
Organic compounds chemical compounds consisting primarily of chains of carbon and hydrogen molecules found primarily in living organisms
Panspermia theory that life did not evolve on Earth but rather came to Earth on a comet or meteorite
Proteins chemical compounds that all living organisms have
Planet a celestial body that is in orbit around the Sun, has sufficient mass for its self-gravity to overcome rigid body forces so that is assumes a nearly round shape, and has cleared the neighbourhood around its orbit
Protoplanetary disk disk of gas surrounding a protostar that will form into planets
Protostar a collapsing cloud of gas that will eventually become a star
Seismic waves waves that carry the energy from an earthquake around the world
Terrestrial planet literally 'Earth-like' planet, planet made primarily of rock and solid material, e.g. Mercury, Venus, Earth and Mars
Supernova a giant explosion that occurs when a star many times larger than our Sun runs our of nuclear fuel
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