A star , as defined by google is a ‘fixed luminous point in the sky which is a large , remote , incandescent body like the sun’. It has the synonyms : sun , celestial body and heavenly body.
The stars have given humanity many secrets. Stars were used to navigate for direction. Astrology uses birth months to predict characteristics and horoscopes and it may not be an exact science but it’s interesting. We know what elements stars are made of by analysing the light that reaches earth. We know that red shift exists thanks to light from these stars shifting to the red end of the visible spectrum.
The ancient Greeks believed stars were tiny holes in the floors of heaven. We now know that isn’t true obviously but nevertheless it’s a nice thought.
Stars don’t twinkle and that twinkling effect is primarily due to the earth’s turbulent atmosphere. The light passes through many rapidly differing densities and every deflection causes it to change slightly in colour and intensity.
Our sun is approximately 8.3 light minutes away from Earth and is composed of mostly hydrogen at 3/4 and 1/4 is made up of helium with trace heavier elements making up less than 2%. It is known that the sun generates energy by the nuclear fusion of hydrogen in its dense core. The heat moves out of the photosphere and this is the light we see. There is a thin corona that expands outwards and form solar winds, which is an stream of particles that travel out into space.The famous sunspots are nothing but cooler regions where magnetic fields have suppressed heat transfer to the surface. These effects are only temporary.
Our sun was formed from a collapsing gas cloud about 4.57 billion years ago and it is theorised that 5 billion years from now the sun will expand into a red giant and it will engulf Mercury and Venus and possibly Earth. Life on earth will have long gone by then. Eventually the sun will shrink into a hot and dense white dwarf.
Image credits to Google.