Glossary of Terms

---

Home | Star Fleet Library | BuPers | SF Engineering | SF Intelligence | SF JAG | SF Marine Corps | SF Medical | SF Records | SF Sciences
UFP Dept. of Colonial Affairs | UFP Educational, Scientific and Cultural Org.

---

Further information

see Substances and Particles Index reference

Alpha rays

Two protons and two neutrons, the nucleus of a Helium atom. Alpha particles have a positive charge. Alpha rays can be stopped by a sheet of paper.

Angstrom

Unit of measurment: one ten-billionth of a meter.

Arc second/minute

There are 360 degrees in a full circle, there are 60 arc minutes in a degree and 60 arc seconds in an arc minute. The arc second or arc minute is used to describe the positions of celestial objects in relation to the horizon.

Asteroid Belt/Field

A ring or group of small chunks of material and dust (often rock and/or ice).

Astronomical Unit (AU)

Measure of distance. Equal to the distance between the Earth and the Sun or 149,600,000km.

Beta rays

High speed electrons, having a negative charge. Beta rays can be stopped by a sheet of aluminum.

Brightness

A systemic evaluation of a star's brightness as it appears from the Earth's surface. The brightness takes in to account galactic dust and gas, the stars actual luminosity, and other factors.

Coronal Mass Injection (CME)

When a large bubble of plasma escapes through a stars corona and travels though space at high velocity.

Deuteron

Nucleus of the deuterium atom.

Deuterium

A form of hydrogen, also called Heavy Hydrogen, whose nucleus contains one proton and one neutron.

Eclipse

When light falling on to a planet or other body is obscured by another planet or body. A solar eclipse occurs when the a moon passes between a star and a planet.

Fission

The breaking apart of an atom to form two completely different new atoms, with the release of energy.

Frequency

The number of occurances per second. In astronomy, usually the frequency of a wave, ie. the number of oscillations per second. Directly related to wavelength. The lower the frequency the longer the wavelength.

Fusion

The joining of two atoms to form a completely new atom, with the release of large quantities of energy.

Gamma rays

The most energetic form of electromagnetic radiation. Very high frequency, and short wavelength. Gamma radiation is produced within the sun when Fusion occurs. Gamma radiation is also produced by certain radioactive materials. Gamma radiation can be shielded using a few inches of lead.

Helioseismology

The study of the surface of a star and how the surface is affected by the interior of the star.

Joule

A measure of energy; the work required to perform a task.

Light-year

A measure of distance. Equal to the distance light travels in one year or 9,461,000,000,000km.

Light-speed

The speed of light, denoted by the letter c. Equal to 300,000 km per second.

Luminosity

A measure of a stars power output, often measured in watts. Sometimes called intrinsic or absolute brightness.

Occulting

Describes the event of an ecclipse. In a solar eclipse of the Earth the moon occults the sun.

Parallax

A star's apparent motion over the celestial sphere, or sky, of a planet. Measured in arc seconds, it is used to determine the distance to the star (a larger parallax indicates the star is closer).

Parsec

A measure of distance. A star would be one parsec from a planet if it had a parallax of 1 arc second. Equal to about 3.26 light years. Kiloparsecs and megaparsecs, thousands of parsecs and millions of parsecs respectively, are also used.

Polarity

The distinction between two poles. For example in the Earth's magnetic field there is a north pole and a south pole.

Tritium

A form of hydrogen, whose nucleus contains one proton and two neutrons.

Watt

A measurment of electrical power, defined as the number of joules per second. One joule per second is equal to one watt.

Wavelength

The distance between two crests of a wave. Directly related to frequency. The longer the wavelength the lower the frequency.

---

Disclaimer

This material was developed for use in ASR and is not intended to apply anywhere outside ASR. You are welcome to bookmark our pages and view them repeatedly without being a player in ASR. No other use of the material contained within the ASR Manual- including copying or altering any of the pages within for one's own use- is permitted. For further information about joining ASR, please click here.