Page 46 - Modern Spatiotemporal Geostatistics

Spatiotemporal Geometry 27

Table 2.1. Ranges of spatial distances and time intervals.

Meters Seconds
10 25 -I-Size of Universe

10 20 --Distance to galactic 10 20 --
center Age of Universe
Age of Earth
10 15 --Distance to nearest 10 15 --Age of present-day continents
star
Age of man

10 10 - - Distance to Sun 10 10 - - Lifespan of man
Radius of Earth
Orbital period of Earth (1 yr)

10 5 -- 10 5 --Rotation period of Earth (1 day)
Lifetime of free neutron

1 --Man 1 --Reaction time of man

5
5
10~ - - Living cell 10~ - - Lifetime of muon
DNA molecule
10
10
10~ - - Size of atom 10~ - - Response time of electronic device
15
15
10~ - - Size of proton 10~ - - Period of visible light wave
Period of X-ray
10-20__
Period of 7-ray
Lifetime of unstable particle
25
10- +

However, as we shall see later in this chapter, while the rules of Euclidean
geometry are given axiomatically, the rules of spatiotemporal geometry are
statements about the physical world. On the basis of events and world-lines,
other useful space/time entities may be defined, as follows. A position-line
is a set of points in £ representing events associated with P that have the
same spatial position with respect to the reference system (e.g., the world-line