space key words and their meanings

Question	Answer
Asteroid	A dwarf rocky planet, generally orbiting the sun between the orbits of Mars and Jupiter
Big Bang	A huge explosion of a single mass of material. This is the accepted scientific explanation for the start of the universe
Fusion	A nuclear reaction where two small nuclei join, releasing energy. Fusion happens in the centre of the sun.
Light pollution	Light created by humans. It prevents city dwellers from seeing most stars. It also causes problems for astronomers.
Light year	distance traveled by light in a year
Milky way	The galaxy in which we live. It is seen from Earth as a 'milky' stripe in the sky (due to light from all the stars)
parallax	The apparent shift of an object against a more distant background, as the position of the observer changes
Red Shift	When radiation is observed to have longer wavelengths than expected
Solar System	The sun and the objects that orbit it -planets and their moons, asteroids and comets
Universe	All things(including the earth and everything else in space)
nucleus	The central core of the atom involved in nuclear reactions such as the fusion reactions that take place in stars
Galaxy	a collection of thousands of millions of stars
commet	A rocky lump of frozen gasses and water that orbits the sun
Nebula	A cloud of dust and gas found between stars. They are often regions where new stars are formed

Resource summary

	Created by justbuysomemilk over 10 years ago