Bryson, Bill - On galaxies
Type of Spiritual Experience
The actual estimate for the number of galaxies in the Universe is 140 billion. A galaxy is in some ways like an island universe, where the islands are becoming more isolated as each galaxy flies away from its neighbours.
Despite the distance and the number of galaxies, the rules by which they spiral and form appear to be identical across the universe. Although again, we can only go by observations of the physical and again, the time over which we have been able to measure the rules is miniscule in comparison with the time they have been in existence. Nevertheless, the rules for supernova, the rules for galaxy formation and star clusters appear to be common across the universe, to the extent that they can be modelled on a computer – an indication that system exists.
A description of the experience
Bill Bryson - A Short History of Nearly Everything
With a 16” telescope Evans supposes he can see between 50,000 and 100,000 galaxies each containing tens of billions of stars.
These are of course respectable numbers, but even with so much to take in, supernovae are extremely rare.
A star can burn for billions of years, but it dies just once and quickly and only a few dying stars explode.
In a typical galaxy, consisting of 100 billion stars, a supernova will occur on average once every 200 or 300 years