Space Science

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light year

the distance light travels in one year

parsec

a unit of measurement used to describe distances between celestial objects, equal to 3.26 light years

parallax

the apparent change in position of an object when seen from different places

nuclear Fusion

a nuclear reaction in which atomic nuclei of low atomic number fuse to form a heavier nucleus with the release of energy

which gas is used as the main source of fuel in stars

Hydrogen

average Star life cycle

stellar nebula, protostar, main sequence, red giant, planetary nebula, white dwarf, black dwarf

massive star life cycle

nebula, protostar, main sequence, red supergiant, supernova, neutron star or black hole

apparent magnitude

the brightness of a star as seen from Earth

absolute magnitude

the actual brightness of a star from a distance of 10 parsecs

The colour of a star depends on

the visible light it emits, due to surface temperature and chemical makeup

red colours

The colour of cooler stars

blue colours

The colour of extremely hot stars

yellow-red colours

The colour of relatively hot stars

spectrometers

instruments that analyse light to determine what gases are present and in what amounts

gravity

the force of attraction between objects that is due to their masses

black hole

an object whose gravity is so strong that nothing, not even light, can escape

how to detect black holes

binary star system or gravitational lensing

red shift

the change in the wavelength of light due to an object moving away from the observer

cosmic microwave background radiation

electromagnetic radiation that has been travelling through space ever since it was created shortly after the Big Bang

the big bang theory

the theory that the universe originated in a huge explosion that released all matter and energy in existance

steady state theory

a theory that proposes that matter in the universe is continuously being created at a rate that allows the density of the universe to remain constant as it expands

doppler effect

an observed change in the frequency of a wave when the source or observer is moving

stars

masses of gas and plasma that burns to produce light and heat

solar system

the sun and all of the planets and other bodies that travel around it

the milky way

a large spiral galaxy that is home to Earth and the rest of our solar system

galaxy

A collection of stars, dust, and gas bound together by gravity

electromagnetic spectrum

All of the frequencies or wavelengths of electromagnetic radiation

satellite

any object that orbits around another object in space

neutron star

the small, dense remains of a high-mass star after a supernova

Hertzsprung-Russell diagram

a graph relating the surface temperatures and absolute brightness of stars