1.2 The Big Bang Flashcards
what is the universe
all of space, time, matter, energy and the physical laws and constant that govern them. It encompasses everything that exists, including all galaxies, stars, planets, moons, asteroids, comets and life
what happens to white light when it enters a glass prism
rainbow spectrum, light refracts
what is the longest wave length
radio waves
what is the shortest wave length
gamma ray
what is the Fraunhofer spectrum
visible light passes through gas/plasma will have dark lines corresponding to particular molecules or atoms of a specific element, useful to study composition and properties of distant objects
what did Edwin Hubble discovery
that there are other galaxies
what is the red shift
the more distant the object, the greater the shift towards the red in the spectral lines, as space expands, it physically stretches wave lengths of the light coming from galaxies
raisin bread expanding, raisin is galaxies, dough is space
what is Hubbles law
redshifts in the spectra of distant galaxies and the apparent speeds they are moving away are proportional to their distance (farther galaxies move away faster)
how fast is the universe expanding today
70.6km/s/mega parsec (one mega parsec away = 70.6km per second)
how old is the universe using Hubbles law
13.77 billion years
sequence of the Big Bang
1) t= 0, universe began 13.8 billion years ago, very dense and hot
2) t = 10 ^ -43, rapid expansion to size of grapefruit, temperature drops to 10^27K
3) t = 10 ^ -12, expansion slows, 4 fundamental forces presentt
4) t= 1 second , university composed of every and fundamental particles such as quarks, electrons, photons and neutrinos, 10^10k
5) t=3 minutes, three light years in diameter, nucleosynthesis occurs, 10^9k
6) t = 380,000 years, universe is around 3000K, cool enough for positively charges atomic nuclei to capture negatively changed electrons, first atoms form (era of recombination), universe is dark (cosmic dark ages)
7) t=400m years, irregularities in gases had collapsed in gravity to form stars and galaxies, light still couldn’t travel very far due to hydrogen fog blocking light
8) T=1b, UV radiation from the first stars ionized hydrogen, universe lights up
9) 13.6b years ago, milky way forms
10) 4.6 billion years ago, solar system forms
11) 200-300 thousand years ago, homo sapiens evolved
what are the four fundamental forces
1) strong nuclear force
2) electromagnetism (100x weaker than snf)
3) weak nuclear force (10,000x weaker than SNF)
4) gravity (10^39x weaker than SNF)
what is nucleosynthesis
neutrons and protons combine to form the first nuclei of H, He and minor LI
what is the significance of quarks in the Big Bang
collide to form protons and neutrons
what is the era of recombination
first atoms form