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57 Cards in this Set
- Front
- Back
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Frames of reference
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coordinate system to define what we are looking at,
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Principle of relativity
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no experiment performed within a sealed room moving at an unchanging velocity can tell whether you are standing still or moving. Example: inside observer a train, a ball goes up and down, outside observer of train, ball appears to go faster, faster train is moving, faster ball appears.
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Relativistic effects
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not moving fast enough to see any changes, near speed of light to see these
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time dilation
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depending on reference point, time change in real world and speed of light, more time per second closer to speed of light
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length contraction
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closer to speed of light, thinner you get; closer to event horizon, thinner and longer, squeezed and stretched
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mass increase
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faster you go, more you weigh; limiting factor as to why we cannot travel faster than speed of light;
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Twin paradox
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twins, one goes to space, when returns, younger than twin; Earth to Vega, 50 years with rotation of earth, observer sees 2 years
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Principle of mass-energy equivalence (E=MC2)
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Energy has mass; energy has inertia. Mass has energy; mass has the ability to do work. The quantitative relation between energy of the system and the mass of that system is E = mc2
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Theory of relativity
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the theory that space and time are relative concepts rather than absolute concepts.
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gravitational energy
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weight x height; takes energy to overcome gravity (every day experiences, ex: go up a hill); photon energy is related to frequency (photoelectric effect, ex: hen light shines on metal surface, surface emits electrons); photon energies will change due to gravitational fields
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gravity
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is caused by caused by the curvature or space-time
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warped space
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eyes can be tricked, topology
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Tests of relativity
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straight line on paper, what happens when paper is folded; Mercury’s orbit moves in loops; binary pulsars orbiting around each other, same as Mercury’s orbit
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Time travel
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go in wormhole and craw out in an alternate universe,
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Cosmology
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study of the universe
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Ockham’s razor
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that the explanation of any phenomenon should make as few assumptions as possible, eliminating, or "shaving off," those that make no difference in the observable predictions of the explanatory hypothesis or theory; when given to equally valid explanations, go with the less complicated one
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Olber’s paradox
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why is the sky dark at night? Must see a star in every direction we look; Olber thought universe is infinite, it is filled uniformly with stars, it is eternal and unchanging; solution: universe is expanding, finite age of universe
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Steady state universe
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infinitely old, infinitely large, constant density, expanding (Hubble’s law), continuous creation of matter; problems = doesn’t conserve energy, no observations of continuous creation, evolution of galaxies
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Cosmological principal
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the universe is isotropic (the universe is the same in all directions) and homogeneous (we do not occupy a “special position, universe looks the same to any observer anywhere anytime); we are not in a special place
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Hubble constant
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H0; defines the rate at which the Universe is expanding, H0 = 50
100km / s / Mpc |
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Hubble law
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must obey the cosmological principle; everything must be expanding from everything; V = H0D velocity=Hubble constant x distance
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Big bang
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based on the cosmological principle; all galaxies were closer together in the past; in the distant past, the universe would be a point; perhaps everything expanded from a single point in huge explosion
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Early universe
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big bang, dark age
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Temperature
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hotter at beginning, universe expands and cools down
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Planck time
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when did gravity happen 10-43 seconds, Planck length, universe is 10-35 m
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Observable universe
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universe transparent at 3000 degrees K
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GUT
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grant unified theory
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TOE
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theory of everything
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Evidence of big bang
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the universe is expanding (Hubble’s Law), we are bathed in cosmic background radiation, the cooled relic radiation of the B.B., the observed abundances of certain light elements (He, Li, D, Be) all agree incredibly well with detailed calculations
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Dark matter
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a hypothetical form of matter that is believed to make up 90 percent of the universe; it is invisible (does not absorb or emit light) and does not collide with atomic particles but exerts gravitational force
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Dark energy
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A theoretical repulsive force that counteracts gravity and causes the universe to expand at an accelerating rate
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String theory
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a theory that postulates that subatomic particles are one-dimensional strings
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Quantum Physics
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Describes the nature and behavior of matter and radiation, particularly at the microscopic level.
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Theory of radiation
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All electromagnetic fields are quantized. That is, the fields energy must be a simple multiple of the energy increment: E = hf (Energy = Planck’s Constant x frequency)
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Theory of matter
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A new type of field called a matter field exists in nature. Like EM fields, matter fields are quantized.
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Nonlocality
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Quantum theory predicts that entangled particles exhibit behavior that can be explained only by the existence of real nonlocal (that is, instantaneous and distant) correlations between the particles. A physical change in one particle causes instantaneous physical changes in all other particles that are entangled with that particle, no matter how far away those other particles may be.
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Uncertainty
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The position and velocity of every material particle are uncertain. Although either uncertainty can take on any value, it’s product must approximately equal Planck’s constant divided by the particle’s mass.
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Entanglement
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If two particles physically interact with each other, quantum physics predicts that their matter fields usually become intimately connected and remain connected even after the particles have separated.
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ground state energy
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lowest-energy state; zero-point energy of the system
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excited state energy
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any state with energy grater than the ground state
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ionization energy
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describes amount of energy required to remove an electron from the atom or molecule in the gaseous state
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continuous
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when the gas pressures are higher. Generally, solids, liquids, or dense gases emit light at all wavelengths when heated.
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emission
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produced by thin gases in which the atoms do not experience many collisions (because of the low density). The emission lines correspond to photons of discrete energies that are emitted when excited atomic states in the gas make transitions back to lower-lying levels.
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Absorption
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when light passes through a cold, dilute gas and atoms in the gas absorb at characteristic frequencies; since the re-emitted light is unlikely to be emitted in the same direction as the absorbed photon, this gives rise to dark lines (absence of light) in the spectrum.
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Gravity force
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weakest force, unlimited
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weak
force
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operates only on extremely short distance scaled found in an atomic nucleus, responsible for radioactive decay, stronger that electromagnetism
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strong force
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range is limited to subatomic distances, keeps quarks together inside protons an neutrons, and inside of nuclei
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electromagnetic force
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second strongest, attractive and repulsive properties that can combine and cancel each other out
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Quarks
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any of a number of subatomic particles carrying a fractional electric charge, postulated as building blocks of the hadrons
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Ozone depletion
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stratospherix ozone can e easily broken down by the following reaction with chlorine: Cl + O3  ClO + O2
UV radiation at that altitude causes a second reaction: CLO + CLO +sunlight  Cl + Cl + O2 1 chlorine atom can destroy 100,000 ozone molecules! |
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Greenhouse effect
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incoming solar radiation, absorbed in atmosphere by greenhouse gases, infra-red radiation from surface, radiation to outer space
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CO2 concentrations & effects
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causing ride in global temperatures, Melting glaciers & polar ice, Rising sea levels & effects
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Life on earth
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the conditions on Earth are not typical compared to most of the universe: warm but not hot, medium density, lots of complex elements. Likely this type of place is not unique: w see other planets in ou own solar system which are similar
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Miller-Urey experiment
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organic molecules are present in the interstellar space (comets meteorites), fell on earth, formed by Miller-Urey experiment
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Life in the universe
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to have life you need a good star, nice planet, formation of single cells, multicellular organisms, intelligence, civilization and technology
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How to communicate
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send a message or listen for one, send a message in a bottle attached to spacecraft
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UFO’s
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classified by nocturnal lights, daylight disks, radar visual
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