Astrophysics (Index)About

wavelength

(λ)
(distance over which a repeating wave repeats)

Wavelength, the length of a wave, is the distance to the point at which such a disturbance in a medium (that constitutes a wave) begins a repeat of itself. This applies to any waves, such as light waves, sound waves, or ocean waves. Wavelength has this relationship with wave speed and frequency:

wavelength × frequency = wave speed

A wave can be characterized by its wavelength or by its frequency: if you are given its frequency (and know the speed of the waves, e.g., the speed of light), the above relationship yields its wavelength, and vice versa. In the case of electromagnetic waves, the same characteristic can also be specified by its energy per photon (photon energy), which is directly related to its frequency. Which of these three is typically used to specify electromagnetic waves varies over its spectrum: Wavelength is typically used to specify this characteristic of infrared and visible light, Radio is more likely to be specified by frequency (with microwave showing less such preference), and X-rays and gamma rays are more likely to be specified by photon energy.


(EMR,measure,waves)
Further reading:
https://en.wikipedia.org/wiki/Wavelength
https://www.windows2universe.org/physical_science/basic_tools/wavelength.html
https://chem.libretexts.org/Bookshelves/Introductory_Chemistry/Introductory_Chemistry_(CK-12)/05%3A_Electrons_in_Atoms/5.02%3A_Wavelength_and_Frequency_Calculations

Referenced by pages:
1.3-mm observation
2175 angstrom feature
absorption
absorption line
Airy disk
angstrom (Å)
angular resolution
ARCADE
ARO 12m Telescope
asteroseismology
ASTHROS
astronomical quantities
Atacama Large Millimeter Array (ALMA)
atmospheric window
Australia Telescope Compact Array (ATCA)
B
BA supergiant
Baldwin effect
Balmer jump (BJ)
Balmer series (H)
Balmer-break galaxy (BBG)
baseline
beat frequency
biofluorescence
black body (BB)
black hole shadow
black-body radiation
blind survey
blue shift
bolometric luminosity (LBol)
bolometric magnitude (Mbol)
Brackett series
Breakthrough Listen (BL)
brightness temperature (TB)
C-BASS
carbon dioxide (CO2)
carbon monoxide (CO)
CCAT
Chandra Deep Field North (CDFN)
Chandra Deep Field South (CDFS)
Cherenkov radiation
chromatic aberration
circumstellar disk
coherent light
cold gas
collimator
collisional broadening
color index
Compton scattering
Compton wavelength
CONCERTO
confusion limit
continuous absorption
continuum
continuum emission
coronal loop
correlator
cosmic dust
cosmic microwave background (CMB)
cosmic neutrino background (CNB)
cosmological redshift
cosmological time dilation
CRIRES
CUTE
Cygnus-X
data cube
de Broglie wavelength
deuterium (D)
disperser
dispersion measure (DM)
Doppler broadening
Doppler shift
double-line spectroscopic binary (SB2)
DSHARP
dusty galaxy
eclipse mapping
effective temperature (Teff)
Einstein coefficients
electric dipole radiation
electromagnetic radiation (EMR)
electromagnetic spectrum
electron volt (eV)
emission
emission line
emissivity
equation of radiative transfer (RTE)
ESIS
etalon
Euclid
European Southern Observatory Very Large Telescope (ESO VLT)
extinction
extragalactic background light (EBL)
extreme ultraviolet (EUV)
F4
Fabry-Pérot interferometer (FPI)
far infrared (FIR)
Faraday rotation
fiber positioner
filter
filter designator
fine structure
first galaxies
fluorescence
focal plane
foreground subtraction
Fraunhofer lines
frequency (ν)
G band (G)
Galactic All-sky Survey (GASS)
galactic electron density
gamma rays (GR)
gamma-ray burst (GRB)
Gattini-IR
Giant Metrewave Radio Telescope (GMRT)
grating
gravitational redshift
gravitational wave spectrum
gray atmosphere
gray body
Green Bank Telescope (GBT)
greenhouse effect
grism
Gunn-Peterson trough
H-alpha (Ha)
H-beta (Hβ)
HARMONI
HARPS
helium (He)
heterodyne spectrometer
High Energy Transient Explorer (HETE)
high-energy astrophysics (HEA)
high-resolution imaging
Hubble Deep Field (HDF)
Humphreys series
hydrogen (H)
ICRF
imaging Fourier transform spectroscopy (IFTS)
imaging spectrometer
infrared (IR)
Infrared Survey Facility (IRSF)
intensity
interferometer
interferometry
International Ultraviolet Explorer (IUE)
ionized carbon fine structure line ([CII])
ionizing radiation
IRAS
irradiance
Keck Observatory
kilonova (KN)
Kirchhoff's law of thermal radiation
KMOS
Kramers opacity law
LAMBDA
Large Millimeter Telescope (LMT)
Lick indices
light curve
light pollution
line blanketing
line broadening
line shape function
linearly variable filter (LVF)
Long Wavelength Array (LWA)
Lowell Discovery Telescope (LDT)
LSPE-SWIPE
luminosity (L)
Lyman alpha (Ly-α)
Lyman beta (Ly-β)
Lyman break (LB)
Lyman series (L)
Lyman-alpha forest
Lyman-break galaxy (LBG)
magnitude
maser
mass spectrometer
microcalorimeter
microwave
mid infrared (MIR)
Mie scattering
Milky Way Mapper (MWM)
millimeter astronomy
MITgcm
monochromatic luminosity
MORA
multi-messenger astronomy (MMA)
multichroic feedhorn array
NANOGrav
near infrared (NIR)
New Worlds Mission
NIRCam
NIRSpec
observable universe
opacity (κ)
optical depth (τ)
Origins Space Telescope (OST)
P Cygni profile
panchromatic
Parkes Observatory
Paschen series
passband
Pfund series
phase curve
photocathode
photodissociation
photoionization
photometric system
photon energy
photosphere
Planck function
plane of the sky (POS)
planetary nebula (PN)
planetary nebula luminosity function (PNLF)
point source
polarization
post-starburst galaxy (PSB galaxy)
power law
PRIMA
protoplanetary disk (PPD)
proximity effect
pulsar (PSR)
pulsar timing array (PTA)
quantum efficiency (QE)
Radcliffe wave
radiance
radiant flux
radiative transfer (RT)
radio
radio astronomy
Radio Camera Initiative (RCI)
radiometer
rare designator prefixes
Rayleigh scattering
Rayleigh-Jeans law
reddening
redshift (z)
reflection nebula
refractive index
rest wavelength
RMS astronomy
Rosseland mean opacity
Rydberg constant (RH)
Schuster-Schwarzschild model
scintillator
SCUBA
secondary eclipse
self-absorption
sensitivity function (S)
SIMSTACK
software telescope
source function (S)
South Pole Telescope (SPT)
spaxel
specific intensity
spectral band
spectral energy distribution (SED)
spectral flux density (S)
spectral index (α)
spectral line
spectral line designation
spectral line shape
spectral power distribution (SPD)
spectral resolution
spectrometer
spectrometry
spectropolarimetry
spectroscope
spectroscopy
Spektr-R
SPHEREx
SPICA
Spitzer Space Telescope (SST)
standard model of a flare
star formation (SF)
Stark effect
stellar structure
stellar temperature determination
stimulated emission
Strömgren photometric system
Subaru XMM-Newton Deep Survey (SXDS)
submillimeter astronomy
subradio
super low frequency (SLF)
synchrotron radiation
synchrotron self-Compton (SSC)
synthetic aperture radar (SAR)
systematic error
Telescopio Nazionale Galileo (TNG)
Thomson scattering
tip of the red-giant branch (TRGB)
tired light
Tomographic Ionized-carbon Mapping Experiment (TIME)
transit spectroscopy
transiting planet
TripleSpec (TSpec)
U
u-v plane
ultraviolet (UV)
ultraviolet astronomy
UVJ diagram
V
vegetation red edge (VRE)
velocity dispersion (σ)
Very Large Array (VLA)
Very Long Baseline Array (VLBA)
Very Small Array (VSA)
visibility
visible light
wavefront error (WFE)
wavenumber (ν)
waveplate
WEAVE
Wide-field Infrared Survey Explorer (WISE)
Wien approximation
Wien's displacement law
X-ray
XEUV
Y-type star (Y)
young stellar object (YSO)
Yuan-Tseh Lee Array (YTLA)
Zanstra method
Zeeman-Doppler imaging (ZDI)

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