Waves And The Universe Flashcards
What are the planets in our solar system
Mercury Venus Earth Mars Jupiter Saturn Uranus and Neptune
What is a galaxy
A collection of billions of stars
What is a light year
The distance that light would travel through a vacuum in one year
9.5x10power 12 km
What is the job of seti
The search for extra terrestrial intelligence they are looking for narrow bands of radio waves coming into the earth the signals In a narrow band could have come from a transmitter
What do robots and probes do
Carry instruments that can continuously record data
Robots can take photos and collect samples also do experiments the data is then sent to earth by radio waves
What are the advantages of space telescopes
The earths atmosphere can’t absorb any of the waves
There is no light pollution
Or air pollution
What are the advantages of telescopes that detect other types of em waves
X-ray telescopes can detect high temperature events like exploding stars
Radio telescopes can see cosmic microwave background radiation
What is a spectrometer
A tool used to analyse the light given out by stars and galaxies
It works by the telescope directing a beam of light into the spectrometer this splits up the spectrum
The spectra from stars and galaxies contain dark lines
These are caused by the wavelengths being absorbed
Each element has its own absorption spectra so this helps scientists work out what things are made up of
What is the same in the life cycle of all stars
They initially form a cloud of gas and dust called a NEBULA
the force of gravity makes them spin together then gravitational energy is converted to heat energy so the temp rises
When the temp gets high enough the hydrogen nuclei undergo thermonuclear fusion and give out lots of energy and the star is born
Then it reaches a long stable period where the energy from the nuclear fusion punching outward is equal to the gravitational energy pulling inwards this is a MAIN SEQUENCE STAR it can last for 7 billion years
When the hydrogen core runs out the star swells to become a RED GIANT
What happens only in the life cycle of main sequence stars
They then eject their outer layer of dust and gas and become a PLANETARY NEBULA because they are unstable, this leaves behind a hot dense core called a WHITE DWARF which eventually cools down and disappears
What only happens in the life cycle of big stars
More fusion happens and they glow brightly again as they undergo more nuclear fusion to form heavier elements then they eventually explode to make a SUPERNOVA
The explosion throws out layers of dust and gas into space leaving behind a dense core called a NEUTRON STAR of it it is big enough a BLACK HOLE
What is red shift
When we look at light from distant galaxies the frequencies are lower than they should be and shifted towards the red end of the spectrum
This suggests that the galaxies are moving away from us because the more distant the galaxy the greater the red shift
This provides evidence that the universe is expanding which supports the big band theory
What is cosmic microwave background radiation
It is low frequency electromagnetic radiation from all parts of the universe it is strong evidence for the Big Bang as it suggests that the universe is cooling
The Big Bang is the only theory that is supported by the cmb radiation
What is the Big Bang theory
That all of the matter in the universe was packed into a small space and then it exploded
Expansion is still happening and scientists believe the Big Bang was about 14 million years ago
What is the steady state theory
That the universe has always existed as it is now and matter is still being created as the universe expands
