Test 2

Front 1

Atom

Back 1

The smallest possible unit of a chemical element. When an atom is subdivided, the parts no longer have properties of any chemical element.

Front 2

nucleus

Back 2

a) of an atom, the core, which has a positive charge, contains most of the mass, and takes up only a small part of the volume; b0 of a comet, the chunks of matter, no more than a few km across, at the center of the head; c) of a galaxy, the innermost region.

Front 3

proton

Back 3

elementary particle with positive charge +e, where e is the unit of electric charge, one of the fundamental constituents of an atom.

Front 4

electron

Back 4

A particle of one negative charge, 1?1830 the mass of a proton, that is not affected by the strong force. It is a lepton.

Front 5

wavelength

Back 5

the distance over which a wave goes through a complete oscillation.

Front 6

black-body radiation

Back 6

radiation whose distribution in wavelength follows Planck's law, the black-body curve.

Front 7

Doppler shift

Back 7

The change in wavelenght that arises from the Doppler effect, caused by relative motion toward or away from the observer.

Front 8

Spectra

Back 8

The distribution of a characteristic of a physical system or phenomenon, especially:
The distribution of energy emitted by a radiant source, as by an incandescent body, arranged in order of wavelengths.
The distribution of atomic or subatomic particles in a system, as in a magnetically resolved molecular beam, arranged in order of masses.

Front 9

Refracting telescope

Back 9

A type of telescope in which the primary image is formed by a lens or lenses.

Front 10

reflecting telescope

Back 10

A type of telescope that uses a mirror or mirrors to form the primary image.

Front 11

Spectrograph

Back 11

A device to make and record a spectrum.

Front 12

Radio astronomy

Back 12

The branch of astronomy that deals with the origin and nature of emissions from extraterrestrial sources in the radio wave range of electromagnetic radiation rather than in the visible range.

Front 13

Terrestrial

Back 13

Of or relating to the earth or its inhabitants.
Having a worldly, mundane character or quality.
Of, relating to, or composed of land.
Biology. Living or growing on land; not aquatic: a terrestrial plant or animal.
Terrestrial Planets: Mercury, Venus, Earth and Mars.

Front 14

Jovian

Back 14

Of, relating to, or resembling the planet Jupiter.
Jovian planets (giant planets) Jupiter, Saturn, Uranus and Neptune or even larger extra-solar planets.

Front 15

density

Back 15

Mass divided by volume.

Front 16

Solar System

Back 16

The sun together with the nine planets and all other celestial bodies that orbit the sun.
A system of planets or other bodies orbiting another star.