Space Flashcards
What is the universe?
Everything you can experience or percieve
The Big Bang theory says that
- the universe is expanding after exploding rapidly from a very small and extremely hot dense region.
- space, time, and matter were created in the Big Bang.
Evidence for the Big Bang
The universe is expanding- galaxies further away are moving faster.
Cosmic microwave background radiation
What is redshift?
the displacement of spectral lines towards longer wavelengths (the red end of the spectrum) in radiation from distant galaxies and celestial objects. This is interpreted as a Doppler shift which is proportional to the velocity of recession and thus to distance.
When do stars become unstable?
When they have no more hydrogen nuclei to fuse together
Life cycle of stars with the same mass as the sun
Protostar> main-sequence star> red giant> white dwarf> black dwarf
Life cycle of stars more massive than the sun
Protostar> main-sequence star> red supergiant> supernova> neutron star or black hole
How are heavy elements formed?
When a massive star collapses and explodes as a supernova
Order of planets
Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune
How did the solar system form?
Gravity formed the sun at the centre of a spinning cloud of dust, gas, and rock. The suns heat evaporated ice and drove away gas from the inner solar system. The rocky planets formed near the sun and the gas giants further away.
The big yawn
When the density of the universe is less than a particular amount, so will expand forever.
The Big Crunch
The density of the universe is more than a particular amount so will stop expanding and go into reverse.
The flat universe
The universe will expand but the rate will decrease until it virtually stops, there must be just the right amount of matter.
