Delta-V

Impulse (change in velocity) required to accomplish a specific manuever in space

Differentiation

Internal stratification of a body, caused by heating and usually resulting in a core, mantle, and crust


Ecliptic

The plane defined by Earth's orbit around the Sun

Electromagnetic induction heating

Method proposed for asteroid heating, using electric currents induced by variations in a strong solar wind

Emission band

Radiation emitted by an object at a particular range of wavelengths


Interplanetary dust particles

Tiny particles that once orbited in the spaces between planets, normally collected in the stratosphere by high-flying aircraft

Iron meteorite

One composed primarily of iron-nickel alloy

Isotopes

Cosmogenic

Isotope produced by exposure to cosmic rays

Radioactive

Unstable isotope that decays spontaneously

Radiogenic

Isotope formed by radioactive decay


Kuiper Belt

Zone of presumably icy planetesimals located outside the orbit of Neptune


Light curve

Variations in amplitude observed as an asteroid rotates


Metamorphic grade

Relative intensity of heating and recrystallization


Nodes

Two points at which an object's orbit intersects Earth's orbital plane


Oort Cloud

Spherical halo of icy planetesimals located between approximately 1,000 and 50,000 AU from the Sun

Orbital precession

Slow, periodic rotation of the long axis of an orbit


Parent body

Object of asteroidal size from which meteorites were derived

Petrology

Study of the mineralogy, texture, structures, and origin of rocks

Photometry

Measurement of light intensities

Phyllosilicate

Silicate mineral with layered crystal structure

Plutonic

Rocks that crystallized from magma at depth


Radioactive

See Isotopes

Radiogenic

See Isotopes

Radiometric dating

Determining the age of a sample from measurement of its radionuclides



The National Academies | 500 Fifth St. N.W. | Washington, D.C. 20001
Copyright © National Academy of Sciences. All rights reserved.
Terms of Use and Privacy Statement