Reality is a self-contained, integrated matter and energy structure {universe}|.
principles
Universe has physical laws, which are probably constant in space and time. Physical laws are deterministic. Physical processes are the same forward and backward in time. Physical processes are the same in any space direction and dimension, so directions are equivalent. Physical processes are the same right-handed or left-handed, so rotation directions are equivalent. Physical processes are the same for positive and negative charges.
Motions have time symmetry, spatial symmetry, and rotational symmetry, which are equivalent to conservation laws of energy, momentum, and angular momentum, respectively [Feynman, 1965]. However, whole universe has time-flow asymmetry, because entropy increases and because processes as a totality only go forward in time. Also, weak nuclear force has slight time asymmetry and parity asymmetry. (When weak force became independent of electromagnetic force, less than one second after universe origin, matter became favored over antimatter.) However, all physical processes have overall symmetry for combined charge, time, and parity symmetries.
Space and time unite into space-time. All motions, including accelerated motions, are relative, so observers in different reference frames, moving and/or accelerating at different velocities, see the same objects at different velocities through time, the same objects with different contractions along velocity direction, and the same events at different times. No physical things travel faster than light speed. However, non-material geometric relations, and so space itself, can expand or contract faster than light speed.
Physical objects and events are both matter-like and wave-like. Quantum-mechanical waves determine object positions, and quantum-mechanical particles determine energies. Observed physical quantities and physical changes have "action" quanta (and so energy, momentum, space, and time quanta). Energy, momentum, space, and time are subject to the uncertainty principle, so small distances and times must have high energies and momenta. In local observable space and time, object and event behaviors appear random and probabilistic, because quantum energy states can fill in different ways. In systems with widely separated parts, events can appear acausal or instantaneous [Feynman, 1965].
beginning
Universe began with maximum energy density, temperature, pressure, and spatial curvature, and minimum volume and entropy. Space then expanded, decreasing energy density, temperature, pressure, and spatial curvature, and increasing volume and entropy.
age
Universe is 13.72 x 10^9 years old (so people can observe universe objects up to 13.72 x 10^9 light years away).
radius
Universe radius is 7.8 x 10^10 light-years or 10^34 meters.
dimensions
Space has three infinite real-number dimensions. Perhaps, space has curled-up real-number dimensions. Perhaps, universe has infinite and/or curled-up imaginary-number dimensions. Time has one real-number dimension. Perhaps, time has one imaginary-number dimension. Time and space dimensions interact to make one unified space-time.
homogeneity
All universe regions are essentially the same.
isotropy
All three real-number infinite dimension are equivalent, so physical laws are independent of direction.
no rotation
Universe and space do not rotate. (Space rotation allows travel to past along rotating space-time dimensions.)
matter
Universe mass is 2 x 10^56 grams. Inertial mass is same as gravitational mass. Matter amount is much more than antimatter amount, so baryon number is positive. Neutrino number is small compared to total radiation, so lepton number is small.
matter: ordinary matter
Visible matter is stars and hot gases, which have detectable electromagnetic radiation. Visible matter is 0.4% of universe mass-energy. One-third of baryons and leptons are in visible matter. Invisible matter is cool gases, planets, dust, dim stars, and black holes, which have low-intensity electromagnetic radiation and so are too dim to detect. Invisible matter is 3.7% of universe mass-energy. Two-thirds of baryons and leptons are in invisible matter. Ordinary matter (visible and invisible) is 99.95% baryons and 00.05% leptons and is 4.1% of universe mass-energy.
matter: dark matter
Dark matter is (unknown) subatomic particles that do not interact with electromagnetic radiation. Dark matter is 25% of universe mass-energy.
energy
Object kinetic energy is a negligible fraction of universe mass-energy. Electromagnetic radiation is 0.9% of universe mass-energy.
energy: dark energy
Dark energy is (unknown) space intrinsic energy that does not interact with electromagnetic radiation. Dark energy is 70% of universe mass-energy.
mass-energy
Universe has matter and energy, and total mass-energy is constant. Universe only exchanges energy between kinetic and potential mechanical, electromagnetic, nuclear, and gravitational energies. Nuclear fission and fusion exchange potential and kinetic energy and release heat, mostly as electromagnetic radiation. Electric charges move, exchanging potential and kinetic energies. Electromagnetic radiation transfers hotter-object kinetic energy to cooler-object kinetic energy. Gravitational collapse changes potential to kinetic energy and makes heat.
Space expansion makes larger volume. Cosmic microwave background radiation redshifts and decreases photon energy, so average random positive kinetic energy decreases. Negative dark energy increases. Gravitational positive potential energy increases. All changes cancel, so total universe energy is constant.
density
Universe average mass-energy density is 10^-29 g/cm^3. At this density, gravity is enough for stars, galaxies, and galaxy clusters to form. At this density, universe expansion continuously slows and stops at infinity, so space has no curvature (is "flat"). Observed cosmic-microwave-background-radiation intensity is same as expected intensity, so light from 13.72 billion years ago traveled in straight (not curved) lines, confirming zero space curvature. (Positive curvature concentrates light, like positive-curvature lenses, making higher intensity. Negative curvature spreads light, like negative-curvature lenses, making lower intensity.)
density: variation
Cosmic microwave background radiation has maximum temperature differences at different points of 1 in 10000. Therefore, 13.72 billion years ago, maximum spatial-region energy-density variations, caused by region random quantum-mechanical states, were 1 in 10000. Energy-density-variations are gravitational differences, which allowed stars, galaxies, and galactic clusters to form.
sound waves
Before 300,000 years after universe origin, universe had free baryons and leptons and was hot dense plasma. Radiation traveled short distance before encountering matter (universe was opaque). Dense matter can carry sound waves, because particles are close enough to interact. Perhaps, because cosmic inflation was rapid, and gravity and internal-radiation pressure synchronized oscillations, sound waves were in phase during inflation. Perhaps, cold dark matter and/or cosmic inflation synchronized oscillations. Sound-wave compressions compressed particles together (and heated plasma), and sound-wave rarefactions spread particles apart (and cooled plasma), causing energy-density variations. In-phase sound waves have harmonics. Maximum and minimum densities were fundamental wavelength apart, one million light-years. Secondary maximum and minimum densities were first-harmonic wavelength apart. Tertiary maximum and minimum densities were second-harmonic wavelength apart, and so on. Fourth-harmonic wavelength was 10,000 light-years.
About 300,000 years after universe origin, free baryons and leptons became neutral-charge atoms. Atom density was lower than plasma density. Radiation traveled far before encountering matter (universe became transparent). That radiation is cosmic microwave background radiation. Because matter and radiation had exchanged freely up to that time, both had same temperature (3000 K), so cosmic microwave background radiation frequency distribution corresponded to temperature 3000 K, which was visible-light frequencies. Atoms were too far apart to interact, and so did not carry sound waves, so no more density variations occurred.
Because universe space-time expansion redshifts source frequencies, cosmic microwave background radiation now has microwave frequencies and frequency distribution corresponding to temperature 2.7 K. Now, cosmic microwave background radiation has same density and temperature variations as at 300,000 years after universe origin, 1 part in 10000. Because universe space-time expansion has increased space distances, fundamental-wavelength density and temperature variations are now over separations of one billion light-years. Fourth-harmonic wavelength is now ten million light-years.
Fundamental, first, second, and third harmonics have same intensity variations, 1 part in 10000 (scale-invariance).
About 300,000 years after universe origin, when neutral atoms formed, average distance between atoms was 10000 light-years. (Space expansion has made that distance ten million light-years.) Fourth-harmonic and higher-harmonic wavelengths were shorter than average distance between atoms, so those distances have almost no density variations.
curvature
Mass-energy density creates gravitational force and field. Mass-energy density determines space-time curvature at space-time points. Space-time curvature is gravitational-energy-field gradient. At universe origin, mass-energy density was maximum, space-time curvature was maximum, and gravitational force was maximum. Space expansion decreases curvature.
entropy
Beginning universe had low entropy, with high symmetry, united forces, and no particles. Beginning universe was in thermal equilibrium, but soon after was not in thermal equilibrium, so entropy transferred among stars, planets, particles, and radiation. Universe entropy always increases. Forces pull things together to make smaller and more complex structures with more motion and more random motion, as potential energy becomes kinetic energy. Motions push things apart to make larger and less complex structures with less motion, as kinetic energy becomes potential energy.
expansion
Milky-Way-like galaxies have similar light-frequency distributions. Earth observers see lower-frequency light {redshift} from distant galaxies than from nearby galaxies. By Doppler effect, observers see that light from objects moving away has lower frequency. Distant-galaxy percent red-shift increase exactly correlates to galaxy percent distance increase, so red shift proves space expansion at all points.
Space expands at same rate in all directions. Like balloon surfaces, space expands at same rate from all points. Because space expands from every point, far objects move away faster than near objects. Moving-away speed {recession velocity} v varies directly with distance d away: v = H * d, where H is Hubble constant (which is constant over space but may not be constant over time). Space expansion makes distances between galaxies increase, but does not move galaxies. Because space itself is expanding, objects are not in motion in space, and special relativity does not apply, so recession velocity can be greater than light speed. Just after universe origin, points 10 centimeters away from a point expanded away at light speed. Now, points 14 trillion light years {Hubble distance} from a point expand away at light speed. Nearest galaxy clusters have frequency 1.5 times lower. Cosmic microwave background radiation, 13.72 billion light-years away, has frequency 1000 times lower, and recession velocity is 1/50th of light speed. (Cosmic microwave background radiation was emitted 13.72 billion years ago, and 13.72 billion light-years away, but by now those radiation sources have expanded to 46 billion light-years away.) Light from 16 billion light years away has frequency so low that photons are not detectable.
Expansion increases volume and cools universe.
At universe origin, expansion rate was maximum, and gravity maximally opposed universe expansion. Soon after universe origin, expansion rate of space itself became constant. From universe origin to five billion years ago, universe expansion made average mass-energy density decrease, so gravity decreased and expansion rate decreased more slowly. Since five billion years ago, expansion rate has been increasing exponentially. Hubble constant is proportional to distance increase ds between objects over time dt, divided by distance s: H ~ (ds/dt) / s.
forces
Universe forces are strong nuclear force, electromagnetism, weak nuclear force, and gravity, in order of decreasing strength. Matter and energy interact through exchange of energy-bearing subatomic particles.
waves
Curvature exerts tidal forces on objects and fields. Changing electromagnetic fields can cause electric-force dipole moments and electromagnetic waves. Changing gravitational fields can cause gravity quadrupole moments and gravity waves.
structures
Universe gravitation clusters particles, forming galactic clouds. Largest space structures are 10^24 meters across. Galactic and intergalactic cloud positions and motions have same distribution as cosmic microwave background radiation. Galactic clouds and their dark matter form galaxies. Galaxy gas motions form stars. Stars generate energy by fusion. During final fusion stages, large stars explode, forming heavy atomic nuclei and dispersing them into space. Some stars have planets. Some planets have carbon, oxygen, metals, phosphorus, and sulfur. Some planets have radioactive nuclei, so they melt and make decreasing-density layers, including surface water and atmosphere. Some planets are in orbits allowing liquid water. Some planets have moons, so they have tides. Some stars last a long time, are not too hot or cool, and do not cool too fast, so planets exist for long enough time that life has time to develop.
gamma rays
Small black holes, supermassive black-hole particle jets colliding with photons, and magnetars emit gamma rays. Perhaps, high-mass supersymmetric-particle collisions emit gamma rays, because they are antiparticles of themselves.
Physical Sciences>Astronomy>Universe
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Date Modified: 2022.0224