is the recording and prediction of the relative changes of the earth, its parts and the macrocosmos (the stars)

We record the passing of events relative to 'fixed' patterns i.e. the earth's recurring day and night, and seasons.

All living flora and fuana respond to these events, and humans exploit thier intellectual ability by dividing such changes, for convenience, into hours and minutes and months and weeks.

We inhabit a social system where the day is not so much divided into hours or the year into days, but the day and year are defined by the hourly and dayly rituials we adhere to.

Earth's 'rotations' and 'orbits' are not equal: Days and years differ in space-time.

The year is not 365 days long so every 4 years we add a day to make up for the lost sideral relativity. Then every 400 years we don't do that to make up for the error inherent in adding a day every four years and so on...


is a function of movement and . although it can be expressed in units of time is usually defined by a minimum of three units of 'distance' which are 'straight' lines. However even straight roads or flight paths,between cities etc.may not be straight in all dimensions, given the earth's surface is curved.

Consequently we cannot record the 'off earth' (cosmic) space we travel through except in terms of relativity to the ideas of distance bewtween earth-bound objects.

Distance then becomes a multiple of 'feet' or a factor of the earths circumference 'metre'

When contemplating cosmic distances larger units are used.

The two most common are the

  • Astronomical Unit (AU)
    the 'average' distance of the Earth from the Sun, about 93 million miles roughly 150 million kilometres
  • Light Year
    the approximate distance light travels in an 'average' Earth siderial year .

70,000 light years across the Milky Way.
{Must find another name 'Milky' I don't think so! (Vegan Determination)}

Why a picture of Andromeda you may ask.
Well there's no picture of our Galaxy but it is envisaged as being very similar to Andromeda

A light year is the distance light would travel in year. Light travels approx 186,000 miles per second.

In one year, light should travel (186,000 x 60 x 60 x 24 x 365.25) miles
i.e. 1 light year =5,869,713,600,000 miles or about 6 billion miles.

Units used here are 'OLD' English

Galactic Width = 70,000 light years
this equates to 410,879,952,000,000,000 miles
(5,869,713,600,000 x 70, 000)

The nearest star is 4 light years away ( in our galaxy )

The nearest galaxy is ????

posted on the 02 December, 2004