DICTIONARY OF GEOPHYSICS, ASTROPHYSICS, and ASTRONOMY

electromagnetic penetration depth) complicates
somewhat the interpretation (e.g., the Meissner
effect) in usual condensed matter terms.
See Abelian Higgs model, conducting string,
Nielsen–Olesen vortex, spontaneous symmetry
breaking, winding number.
wolf number An historic term for the sunspot
number.
work In Newtonian mechanics, the product
of an applied force and the displacement in the
direction of the force.
work W= F · d = |F||d| sinθ,
where θ is the angle between the force and the
displacement.
Work has units of Joules: 1 Joule =
1 Newton·meter, or of ergs: 1 erg = 1 dyne·cm.
worldsheet charge See electric regime
(string).
worldsheet geometry See fundamental tensors
of a worldsheet.
wormhole A connection between two locations
in space-time. This involves a curvature of
space-time which acts as a bridge between two
distant points that may lie in the same region or
in different regions and which are otherwise inaccessible
to each other. There is currently no
evidence of their existence. See curved spacetime,
Einstein–Roser bridge.
© 2001 by CRC Press LLC
WWSSN (World-Wide Standardized Seismograph Network)
wrinkle ridges Features that occur in the
northern plains of Mars, probably of volcanic
origin. They are classically described as consisting
of a rise, a broad arch, and an associated
narrow sinuous ridge. They may be segmented
to form an “en echelon” arrangement.
Detailed analysis shows that almost all wrinkle
ridges mark a regional elevation offset and so are
asymmetrical. Dimensions are ≈10 km wide,
≈100 m high, with a regional elevation offset
range between ≈10 to 1000 m where detectable.
W Ursa Majoris (W UMa) See contact binary.
WWSSN (World-Wide Standardized Seismograph
Network) In 1960, three-component
Press–Ewing type seismographs and shortperiod
Benioff type seismographs with identical
properties were deployed at about 120 stations
throughout the world by U.S. Coast and Geodetic
Survey (USCGS), mainly aiming at detection
of underground nuclear tests. This world-wide
seismograph network is called WWSSN. Seismic
waveforms recorded by the seismograph network
have contributed substantially to research
on the source process of large earthquakes and
structure of the Earth’s interior using surface
waves. In the 1970s, digital recording type seismograph
networks began to be deployed. To
date, there are IDA, SRO, DWWSSN, RSTN,
and GEOSCOPE as seismograph networks deployed.
Recently, principal observation stations
of WWSSN have been moved to IRIS (Incorporated
Research Institutions for Seismology).
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