Peter's Science and Religion Pages
Science & Religion
When stars are observed they have a number of features such as colour and brightness.
When these two attributes are plotted on a graph most stars tend to lie along a diagonal.
For example they generally go from dull red (cool) stars to bright blue (hot) stars.
As we look at people we see a pattern from being small with smooth skin to large with wrinkled skin.
This pattern is the result of time.
The observed trend with stars from dull red stars to bright blue has also been patterned to represent the aging or "evolution" of the stars as they sweep up Hydrogen from the surrounding space.
Stars are mostly Hydrogen and they shine because their Hydrogen is being fused into Helium by nuclear reactions.
However other elements have been detected in "older" stars.
It is thought that as a star uses up its Hydrogen, other elements are formed by fusion as far down the Periodic table as Iron.
Fusion stops at Iron.
A star usually performs a balancing act under the competing pulls of gravity and light pressure.
To form elements such as Uranium and Lead, a star would have to be blown apart in the enormous explosion that we call a "supernova".
The elements found naturally on the Earth that are heavier than Iron must have been formed in one or more supernovae, so the Earth was not formed till after the first "generation" of stars.
Another thing that is observed about stars is their "red shift".
This reflects nuclear events such as the conversion of Hydrogen to Helium.
(Helium was first detected in the Sun before it was discovered on Earth hence its name.)
The colours of the farther stars are seen to be shifted more towards the red.
This shift is thought to represent a physical movement (in much the same way that we can tell if a siren is coming towards us or away from us).
It was suggested that the stars are thus all moving away from each other just as if you painted dots on a balloon and blew it up larger and larger.