speed of light
Universe's velocity ceiling
The speed of light is the velocity at which light travels through a vacuum—approximately 186,000 miles or 300,000 kilometers per second.
Nothing with mass can reach this speed, making it a fundamental limit in physics.
Einstein's relativity established it as constant regardless of the observer's motion.
Figuratively, at the speed of light means extremely fast.
How observers differ
- EinsteinByword for genius
- special relativityTheory uniting space, time
- general relativityGravity as curved spacetime
- E=mc²Energy-mass conversion relationship
mass-energy · time dilation · spacetime · causality · inertia · momentum · kinetic energy · reference frame
Obstruction preventing passage
- thresholdPoint of beginning
- causalityCause-effect connection
- superluminalExceeding light's speed
- FTLExceeding light speed
tachyon · warp drive · unbreakable · insurmountable · ultimate · information transfer · relativistic · impossible
Quality of staying unchanged
- vacuumAbsence of matter
- MaxwellScottish-origin given name
- electromagneticInvolving electric and magnetic fields
- PlanckQuantum theory's founder
exact · defined · SI unit · fundamental · unchanging · absolute · reference standard
Electromagnetic radiation unit
- refractionWave bending between media
- mediumMiddle size or state
- glassTransparent solid from sand
- waterClear essential liquid
diamond · prism · fiber optics · dispersion · wavelength · slowing · transmission · laser
Interstellar length measure
- universeComplete system or domain
- observable universeRegion light has reached us from
- expansionIncrease in scope
- redshiftWavelength stretch from recession
Hubble · starlight · quasar · intergalactic · vastness
Brief burst of light
- blinkRapid lid movement
- instantaneousHappening without any delay
- split-secondFraction of a moment
- nanosecondOne-billionth second unit
fleeting · imperceptible · lightning-fast · blinding · streak · rapid · swift
relativity
How observers differ
- EinsteinByword for genius
- special relativityTheory uniting space, time
- general relativityGravity as curved spacetime
E=mc² · mass-energy · time dilation · spacetime · causality · inertia · momentum · kinetic energy · reference frame
barrier
Obstruction preventing passage
- thresholdPoint of beginning
- causalityCause-effect connection
- superluminalExceeding light's speed
FTL · tachyon · warp drive · unbreakable · insurmountable · ultimate · information transfer · relativistic · impossible · hypothetical
invariance
Quality of staying unchanged
- vacuumAbsence of matter
- MaxwellScottish-origin given name
- electromagneticInvolving electric and magnetic fields
Planck · exact · defined · SI unit · fundamental · unchanging · absolute · reference standard
photon
Electromagnetic radiation unit
- refractionWave bending between media
- mediumMiddle size or state
- glassTransparent solid from sand
water · diamond · prism · fiber optics · dispersion · wavelength · slowing · transmission · laser · beam
parsec
Interstellar length measure
- universeComplete system or domain
- observable universeRegion light has reached us from
- expansionIncrease in scope
redshift · Hubble · starlight · quasar · intergalactic · vastness
flash
Brief burst of light
- blinkRapid lid movement
- instantaneousHappening without any delay
- split-secondFraction of a moment
nanosecond · fleeting · imperceptible · lightning-fast · blinding · streak · rapid · swift
- scientific phrasesbig bang, black hole, natural selection, climate change, genetic code
- speed unitsmph, kph, knots, kilometers per hour, miles per hour
- light physicsphoton, refraction, diffraction, wavelength, polarization
- Physical Constantsh, G, e, atomic mass unit, alpha
- numbersone, two, four, three, 0
- math & science termspi, infinity, zero, billion, million
speed of lightmotionlessness
Total lack of movement
snail's pace · crawl · standstill · rest · stasis
speed of lightinertia
Resistance to altered motion
stagnation · stasis · ground state · immobility · heat death
light, speed, speeding, speeds, speedily, speedboat, speediness, speedometer, speedway