Page 349 - NS-2 Textbook

GLOSSARY 345

PULSAR-any of several very short period interstellar TRAJECTORY -the path of a projectile, ntissile, or bomb
radio sources. in flight.
QUASAR-a starlike object, probably clusters of stars, TROPOSPHERE-the lowest region of Earth's atmo-
that emit characteristic visible and radio radiation. sphere, characterized by decreasing ternperature ·with
RADAR-radio detection and ranging; an instrument increasing altitude.
for determining, by radio frequency echoes, the TSUNAl'v1I -an lmusually high and prolonged wave in
presence of objects and their range, bearing, and the ocean cansed by a disturbance such as an under-
elevation. sea eruption, earthquake, or impact of a large body.
REFLECTANCE-the ratio of the total light reflected by TYPHOON -a severe tropical hurricane occurring in
a surface to the total incident on the surface. the \vestern Pacific.
REFRACTION -a change in direction of a wave when ULTRASOUND-acoustic frequencies above the human
passing from one lnedium to another. range of hearing.
RETROGRADE MOTION-backward movement. UNDERSEA WARFARE (USW)-a term encompassing
RIP CURRENT -sh'ong, sea,vard-n1oving ,Yater cur- all aspects of modern ·warfare beneath the sea, in-
rents along a seashore. cluding but not linlited to antisubmarine ·warfare,
SATELLITE-an artificial device or natural body in orbit mine ·warfare, and DDT operations.
around a larger body. VECTOR QUANTITY -a quantity having both magni-
SEA-LANE-a route of travel across an ocean or other tude (size) and direction.
large body of water. VERTEBRATE-animal having a backbone.
SOUND-a long body of water com1ecting larger bodies. VISIBLE SPECTRUM -the range of electromagnetic
SPACECRAFT -a vehicle designed to travel in space. wavelengths visible to the eye as light.
SPACE PROBE-a one-way, Ulunaillled exploratory VOLTMETER-an instrument to measure voltage.
spacecraft. WATERLINE-the line on a vessel's hnll to which it
SPECTRUM -a collection of wavelengths. sinks in the ,vater.
STRATOSPHERE-the relatively isothermal part of the WATT -SI lmit of powel; equal to one joule per second.
atmosphere above the troposphere and below the WEIGHT -force of gravity on an object.
mesosphere.
TELEMETRY -remote h·ansntission of data by radio or
wire.