Cosmic Definitions

Astronomical Measurements
Kiloparsec/Kpc 3250 light years

1 Parsec

3.26 ly

1 Light Year/Ly

62,240 AU or 390,363,984,543,616,629,394,560 kms

1 Astronomical Unit/AU

14.968 kms or 6,279,627,051,077,596,944 kms

1 kilometre/km

.6 mile

 

Astronomical Definitions
Universe An immeasurable distance of physical space, the same approximate size as the prime plane. Often this will contain thousands of galaxies.
Galaxy A measurement of space containing the equivalent of anywhere from a few million to several billion stars.
Cluster A measurement of space containing the equivalent of anywhere from a few hundred to a million stars.
System A volume of space large enough to accommodate a sun and several planets or the equivalent.
Planet A volume roughly equivalent to a single world perhaps with some surrounding satellites and space.

 

Scientific Definitions
Energy Energy is a property of a body, not a material substance. When bodies interact, the energy of one may increase at the expense of the other, and this is sometimes called a transfer of energy. This does not mean that we could intercept this energy in transit and bottle some of it. After the transfer one of the bodies may have higher energy than before, and we speak of it as having stored energy. But that doesn't mean that the energy is contained in it in the same sense as water in a bucket.
Heat Heat like work is a measure of the amount of energy transferred from one body to another because of the temperature difference between those bodies. Heat is not energy possessed by a body. We should not speak of the heat in a body. The energy a body possesses due to its temperature is a different thing, called internal thermal energy. The misuse of this word probably dates back to the 18th century when it was still thought that bodies undergoing thermal processes exchanged a substance, called caloric or phlogiston, a substance later called heat. We now know that heat is not a substance.
Inertia A descriptive term for that property of a body which resists change in its motion. Two kinds of changes of motion are recognized: changes in translational motion, and changes in rotational motion. In modern usage, the measure of translational inertia is mass. Newton's first law of motion is sometimes called the 'Law of Inertia', a label which adds nothing to the meaning of the first law. Newton's first and second laws together are required for a full description of the consequences of a body's inertia.

The measure of a body's resistance to rotation is its Moment of Inertia.
Kinetic energy The energy a body has by virtue of its motion. The kinetic energy is the work done by an external force to bring the body from rest to a particular state of motion.
Newton's third law of motion When body A exerts a force on body B, then B exerts and equal and opposite force on A. The two forces related by this law act on different bodies. The forces need not be net forces.

 

Air Composition on Earth
The sea-level composition of air (in percent by volume at the temperature of 15°C and the pressure of 101325 Pa) is given below.
Name Symbol Percent by Volume
Nitrogen N2 78.084 %
Oxygen O2 20.9476 %
Argon Ar 0.934 %
Carbon Dioxide CO2 0.0314 %
Neon Ne 0.001818 %
Methane CH4 0.0002 %
Helium He 0.000524 %
Krypton Kr 0.000114 %
Hydrogen H2 0.00005 %
Xenon Xe

0.0000087 %

 

Temperature Measurements
Kelvin/ 0K Celsius/ 0C Fahrenheit/ 0F Notes
6000 5727 10455 Our sun
5100 4827 8808 Carbon boils
3825 3553 6490 Carbon melts
3023 2750 5032 Iron boils
3000 2727 4990 A red cool star
1808 1535 2823 Iron melts
373 100 212 Water boils
273 0 32 Water freezes
90 -183   Oxygen boils
55 -218   Oxygen melts
0 -273 -459 Absolute zero

 

Index Cosmic Definitions Section 1: Dimensions
Section 2: Galaxies Section 3: Stellar Systems Section 4: Worlds
Section 5: Life Section 6: Civilisation