Universe Mass composition
Life cycle of a star
“The nitrogen in our DNA, the calcium in out teeth, the
iron in our blood, the carbon in our apple pies were made
in the interior of collapsing stars. We are made of star
stuff”
- Carl Sagan
, IMPORTANT TERMS
Protostar – An early stage in the formation of a star
resulting from the gravitational collapse of gases
Thermonuclear fusion – a nuclear fusion responsible for
the energy produced by stars
Main sequence stars – Stars that fuse hydrogen atoms to
form helium atoms in the cores; outward pressure
resulting from nuclear fusion is balanced by gravitational
forces
Light years - the distance light can travel in a year; a unit
of length used to measure astronomical distance
Dark Energy – a source of anti-gravity; a force that
counteracts gravity and causes the universe to expand
Dark matter – matter that has gravity but does not emit
light
Milky way - is the galaxy that includes our Solar System
Galaxy – is a cluster of billions of stars and clusters of
galaxies form super clusters
Life cycle of a star
“The nitrogen in our DNA, the calcium in out teeth, the
iron in our blood, the carbon in our apple pies were made
in the interior of collapsing stars. We are made of star
stuff”
- Carl Sagan
, IMPORTANT TERMS
Protostar – An early stage in the formation of a star
resulting from the gravitational collapse of gases
Thermonuclear fusion – a nuclear fusion responsible for
the energy produced by stars
Main sequence stars – Stars that fuse hydrogen atoms to
form helium atoms in the cores; outward pressure
resulting from nuclear fusion is balanced by gravitational
forces
Light years - the distance light can travel in a year; a unit
of length used to measure astronomical distance
Dark Energy – a source of anti-gravity; a force that
counteracts gravity and causes the universe to expand
Dark matter – matter that has gravity but does not emit
light
Milky way - is the galaxy that includes our Solar System
Galaxy – is a cluster of billions of stars and clusters of
galaxies form super clusters
