Newton, Isaac (1642–1727)
- an English scientist and philosopher whose influence on astronomy ranged from the highly practical invention of the reflecting telescope to the theoretical insight of the universal theory of gravitation
- English scientist and philosopher. Newton’s influence on astronomy can not be overstated. It ranged from the highly practical invention of the reflecting telescope to the theoretical insight of the universal theory of gravitation. The Newtonian reflector design is still in common use, mainly for small to medium-sized telescopes. It involves a primary mirror sending light back up the telescope tube to a flat secondary, which sends the light to an eyepiece at the side of the tube. Newton also carried out experiments with prisms which demonstrated the nature of light and colour by showing that white light consists of light of the colours of the rainbow, and that heat is a form of light of a wavelength close to that of red light. This was the start of the discovery of the electromagnetic spectrum. Newton was the discoverer of the laws of motion which control all physical objects. The first of these states that objects continue in rest or uniform motion unless some outside force affects them. The second states that a force produces an acceleration in a body in proportion to its size. The third states that all action produces equal but opposite reaction – the basis for all rocketry, since it is the reaction to the gasses emerging from a rocket which drives it in the opposite direction Newton discovered the law of gravitation – that all objects attract each other with a force proportional to the product of their masses and inversely proportional to the square of the distance between them He proved that this result was consistent with Kepler’s laws. Newton was one of a group of influential English scientists which also included Halley, but his interests ran far beyond what we would view as ‘science,’ into biblical chronology and into being Master of the Mint. The Newton is also the standard unit of force in the SystFme International of measurement. The Isaac Newton telescope, first sited in Sussex, England, and relocated in 1984 to Palma in the Canaries, Spain, is the largest optical telescope produced in the UK, with a 2.5m main mirror, and is used mainly by British and Dutch astronomers.