Firmament

One of my major interests is Amateur Astronomy.  My grand children also like to learn new things about ‘Space’  and amaze me with their knowledge.  
The local Horowhenua Astronomical Society to which I belong has made me most welcome. The members have included me in viewing experience’s and helped me to understand the Sky.  The Society produces a monthly members magazine titled ‘IKAROA’ for which I write occasional articles. There is much to learn and understand in Astronomy.  In the endless observable universe which Astronomers have aged at approximately 13.8 billion years the nearest Galaxy to Earth is ‘Andromeda’  which is a spiral galaxy in our Milky Way. The Andromeda Galaxy is quite close at approximately 2.5 million light-years (2.4×1019 km)  or  25,540,000,000,000,000,000 km’s from Earth. 
Andromeda
I am fascinated with Astronomy.  Our Solar System consists of the Sun and those objects bound to it by gravity (the terrestrial planets, Mercury, Venus, Earth and Mars; the gas giants, Jupiter, Saturn, Neptune and Uranus; plus  various dwarf planets, proto-planets and asteroids). However measured, it is less than a light year across. Our Milky Way galaxy is a barred spiral galaxy with a diameter of about 100,000 light-years and containing about 200 billion stars. Our Solar System is located towards the edge of one of the Milky Way’s outer spiral arms, known as the Orion Arm, about 25,000 to 28,000 light years from the galactic centre.  The universe is what we usually think of as the totality of known or supposed objects and phenomena throughout space.  The observable part alone contains over ten billion trillion stars arranged in about 100 billion galaxies, and is estimated to be around 156 billion light years in diameter.   I am told once the eyes have adapted to night vision,   its possible to see a few thousand objects with the naked eye, in dark, clear  conditions.   The number of stars visible is said to be about 2,000 – 4,000.   By definition, we are at the centre of our observable universe, but it is totally unknown where we are in the universe as a whole.     In an effort to encourage other people with disabilities to access and enjoy Astronomy, I have set up a Google site ‘Viewable Sky“… This group is here to simply click and read.  To help and encourage people I have also compiled a set of notes which you can print and talk about with others called.  Just click the title   Astronomy for beginners.