The Astronomy Tutor: What do the stars mean?

What have the stars ever done for us? Well for one they have told us when to plant and harvest crops. They can tell us when the river is likely to flood, and when to celebrate an important event. They have been useful to humans for thousands of years helping farmers to keep us fed, as well as guiding explorers by helping them to navigate. All for free, in the beautiful night sky. From the dawn of man, men and women have looked up in wonder at the sky and wondered at its beauty and what it all means. We have only one way to access the sky and that is by receiving the electromagnetic radiation from it. Initially, we could just see visible light, but modern instruments have extended that to include radio waves (particularly useful in the UK where we suffer cloudy skies), Microwaves, Infrared, Ultra violet, X-rays and indeed gamma rays. Observing the brightness, the variability of the brightness, the spectrum and the polarisation of the electromagnetic waves, we have moved from just seeing pretty patterns in the sky, to seeing the echo of the Big Bang, seeing vast galaxies and finding planets like our own circling other stars. We initially put meaning on the stars, different cultures grouping them into different shapes. Popular modern constellations are the Big Dipper, part of the Great Bear, and Orion the hunter. It is hard to make out the original shapes that were defined, and most books struggle to fit the shapes of bears, crabs and twins onto the actual stars, but the layouts are useful. You can use two of the stars in the outside of the pan of the Big Dipper to find the North Pole star (Polaris), which can help you navigate by clearly showing where North is. The stars look very numerous, but in fact, there are only about 8,000 that we can see with the naked eye. (Of which really just about 4,000 because to me in the UK, I can only see half the sky, my cousins in Australia see only the southern sky and so see a mostly different set of 4,000 stars. Using an inexpensive pair of binoculars widens the field dramatically as well as bringing the Moon in a lot closer. An inexpensive telescope further expands what we can see. Tantalising us with the smudge of the rings of Saturn and the moons of Jupiter. Galileo had the world's first telescope and was the first person to see those moons. On realising what they were and seeing that they orbited Jupiter, he was able to think unthinkable thoughts. Here was the clue that not everything orbited the Earth, so indeed maybe (apart from the moon), nothing orbited the Earth, rather everything orbited the Sun. Simple observation, with simple instruments, changed our view of the Universe. It got bigger and more fascinating each time we looked. Better telescopes allowed us to look further, deeper, and indeed back in time! To learn more and to enhance your wonder at all of the creation, it is worth taking a year of study, just about 38 hours of time, to follow the AQA or Edexcel curriculum and earn a GCSE in Astronomy. A GCSE in Astronomy will enhance your ability to do well in Physics. The Astronomy sections straddle the GCSE Physics and the simpler part of the A-Level Physics courses, again enhancing your grades by pre-studying part of the curriculum.    

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