PSU ASTRO 7N EXAMS TEST PAPER QUESTIONS AND
ANSWERS GRADED A+
✔✔Starburst Galaxy - ✔✔Galaxy with intense star formation triggered by collision
✔✔Galaxy Collision Effect on Stars - ✔✔Individual stars rarely collide
✔✔Redshift - ✔✔Stretching of light to longer wavelengths due to motion away
✔✔Blueshift - ✔✔Shift to shorter wavelengths due to motion toward observer
✔✔Redshift Formula - ✔✔Z = (observed wavelength - rest wavelength) / rest
wavelength
✔✔Velocity from Redshift - ✔✔Velocity = redshift × speed of light
✔✔Hubble's Law - ✔✔Velocity = H₀ × Distance
✔✔Hubble Constant - ✔✔Current expansion rate of the universe
✔✔Standard Candle - ✔✔Object with known luminosity used to measure distance
✔✔Examples of Standard Candles - ✔✔Cepheid variables and Type Ia supernovae
✔✔Universe Expansion - ✔✔Space itself is expanding between galaxies
✔✔Age of Universe - ✔✔About 13.8 billion years
✔✔Big Bang - ✔✔Beginning of universe from extremely hot dense state
✔✔Universe Center - ✔✔There is no center
✔✔Universe Edge - ✔✔There is no edge
✔✔Universe Composition - ✔✔4.6% atoms, 24% dark matter, 71.4% dark energy
✔✔Dark Matter - ✔✔Invisible matter detected through gravity
✔✔Evidence for Dark Matter - ✔✔Galaxy rotation curves, cluster motion, light bending
✔✔Dark Matter Nature - ✔✔Unknown particle that emits no radiation
✔✔Dark Energy - ✔✔Unknown force causing accelerated expansion
, ✔✔Evidence for Dark Energy - ✔✔Type Ia supernova observations
✔✔Dark Energy Effect - ✔✔Causes expansion of universe to accelerate
✔✔Cosmological Constant - ✔✔Einstein's proposed energy density of empty space
✔✔Fundamental Particles - ✔✔Quarks, leptons, bosons
✔✔Quark Types - ✔✔Up, down, charm, strange, top, bottom
✔✔Leptons - ✔✔Include electrons and neutrinos
✔✔Proton Composition - ✔✔Two up quarks and one down quark
✔✔Neutron Composition - ✔✔Two down quarks and one up quark
✔✔Total Fundamental Particles - ✔✔30
✔✔Four Fundamental Forces - ✔✔Gravity, electromagnetism, strong nuclear, weak
nuclear
✔✔Photon - ✔✔Carries electromagnetic force
✔✔Gluon - ✔✔Carries strong nuclear force
✔✔W and Z Bosons - ✔✔Carry weak nuclear force
✔✔Graviton - ✔✔Hypothetical particle carrying gravity
✔✔Planck Time - ✔✔Earliest known period after Big Bang
✔✔Nucleosynthesis - ✔✔Formation of helium nuclei from protons and neutrons
✔✔Recombination - ✔✔Electrons joined nuclei to form atoms
✔✔Cosmic Microwave Background - ✔✔Radiation left from recombination at 2.73 K
✔✔First Stars and Galaxies - ✔✔Formed after gravity pulled matter together
✔✔Heavy Elements Origin - ✔✔Created in stars and spread by supernovae
✔✔Quasars - ✔✔Bright centers of forming galaxies powered by black holes
ANSWERS GRADED A+
✔✔Starburst Galaxy - ✔✔Galaxy with intense star formation triggered by collision
✔✔Galaxy Collision Effect on Stars - ✔✔Individual stars rarely collide
✔✔Redshift - ✔✔Stretching of light to longer wavelengths due to motion away
✔✔Blueshift - ✔✔Shift to shorter wavelengths due to motion toward observer
✔✔Redshift Formula - ✔✔Z = (observed wavelength - rest wavelength) / rest
wavelength
✔✔Velocity from Redshift - ✔✔Velocity = redshift × speed of light
✔✔Hubble's Law - ✔✔Velocity = H₀ × Distance
✔✔Hubble Constant - ✔✔Current expansion rate of the universe
✔✔Standard Candle - ✔✔Object with known luminosity used to measure distance
✔✔Examples of Standard Candles - ✔✔Cepheid variables and Type Ia supernovae
✔✔Universe Expansion - ✔✔Space itself is expanding between galaxies
✔✔Age of Universe - ✔✔About 13.8 billion years
✔✔Big Bang - ✔✔Beginning of universe from extremely hot dense state
✔✔Universe Center - ✔✔There is no center
✔✔Universe Edge - ✔✔There is no edge
✔✔Universe Composition - ✔✔4.6% atoms, 24% dark matter, 71.4% dark energy
✔✔Dark Matter - ✔✔Invisible matter detected through gravity
✔✔Evidence for Dark Matter - ✔✔Galaxy rotation curves, cluster motion, light bending
✔✔Dark Matter Nature - ✔✔Unknown particle that emits no radiation
✔✔Dark Energy - ✔✔Unknown force causing accelerated expansion
, ✔✔Evidence for Dark Energy - ✔✔Type Ia supernova observations
✔✔Dark Energy Effect - ✔✔Causes expansion of universe to accelerate
✔✔Cosmological Constant - ✔✔Einstein's proposed energy density of empty space
✔✔Fundamental Particles - ✔✔Quarks, leptons, bosons
✔✔Quark Types - ✔✔Up, down, charm, strange, top, bottom
✔✔Leptons - ✔✔Include electrons and neutrinos
✔✔Proton Composition - ✔✔Two up quarks and one down quark
✔✔Neutron Composition - ✔✔Two down quarks and one up quark
✔✔Total Fundamental Particles - ✔✔30
✔✔Four Fundamental Forces - ✔✔Gravity, electromagnetism, strong nuclear, weak
nuclear
✔✔Photon - ✔✔Carries electromagnetic force
✔✔Gluon - ✔✔Carries strong nuclear force
✔✔W and Z Bosons - ✔✔Carry weak nuclear force
✔✔Graviton - ✔✔Hypothetical particle carrying gravity
✔✔Planck Time - ✔✔Earliest known period after Big Bang
✔✔Nucleosynthesis - ✔✔Formation of helium nuclei from protons and neutrons
✔✔Recombination - ✔✔Electrons joined nuclei to form atoms
✔✔Cosmic Microwave Background - ✔✔Radiation left from recombination at 2.73 K
✔✔First Stars and Galaxies - ✔✔Formed after gravity pulled matter together
✔✔Heavy Elements Origin - ✔✔Created in stars and spread by supernovae
✔✔Quasars - ✔✔Bright centers of forming galaxies powered by black holes
