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• Strings theory still string plus#

The idea that randomness is part of the very fabric of nature was revolutionary: it had previously been taken for granted that the laws of physics didn't depend on the size of things. The smaller one looks, the more random things become! This randomness appears when we look at particles at a small enough scale. There simply isn't a "true" value of momentum, but a whole range of values that the momentum can This isn't because your measuring instruments are imprecise. Looking at space at a minuscule scale may allow you to measure position with a lot of accuracy, but there won't be much you can say about momentum. You can never ever measure both its position and its momentum as accurately as you like. The principle states that when you consider a moving particle, for example an electron orbiting the nucleus of an atom, Heisenberg's uncertainty principle is perhaps the most famous example of this. One of the key ideas here is that the smaller the scale at which you look at the world, the more random things become. The other great breakthrough of the 20th century was quantum mechanics. The fact that GPSs work to within five metres in ten years shows just how accurate general relativity is. In fact, most of us will have inadvertently taken part in an experiment that tests general relativity: if it were false, then global positioning systems would be wrong by about 50 metres per day.

The predictions made by general relativity are remarkably accurate. Will roll into, so does a massive body like a planet distort space, causing nearby objects to be attracted to it. Just as a pool ball placed on a trampoline will create a dip that a nearby marble Massive bodies like planets can warp and distort spacetime, and gravity, which we experience as an attractive force, is in fact a consequence of this warping. Einstein realised that space and time are just different aspects of a single object he called spacetime. General relativity is itself a unification. The other equally impressive theory is quantum mechanics. Perhaps the most famous is Einstein's theory of general relativity. There have been two great breakthroughs in the 20th century physics. To understand this, we have to tell another story. It's good, but we'd like to do better, and this is where string theory first enters: it is an attempt to unify further.

Strings theory still string plus#

(See Plus article The physics of elementary particles to find our more.)Īll this is truly impressive: the entire Universe, its matter and dynamics explained by just three forces and twelve elementary objects. Everything we've ever seen in any experiment, here or in distant stars, is made of just these twelve elementary particles. These are known as the elementary particles. Experiments performed with the particle accelerator at CERN in Geneva have shown that there are just twelve basic building blocks That deals with the forces, but what about matter? Many ancient belief systems have postulated that matter - and reality itself - is made from a finite number of elements. This leaves us with three fundamental forces of nature: gravity, the electroweak force and the strong nuclear force which holds protons together. In the process Maxwellĭiscovered electromagnetic waves, which are in fact light - Maxwell had inadvertently explained a further seemingly different aspect of nature.Īnother two hundred years on, in 1984, the Pakistani Abdus Salam and the American Steven Weinberg showed that the electromagnetic force and the weak nuclear force, which causes radioactive decay, are both just different aspects of a single force called the

Maxwell showed that electrostatics and magnetism, by no means similar phenomena at first sight, are just different aspects of a single thing called electromagnetism. The next key unifying discovery was made around 180 years after Newton by the Scottish mathematician James Clerk Maxwell. We take this for granted today, but pre-Newton the connection betweenĪ falling apple and the orbit of the Moon would have been far from obvious and quite amazing. Perhaps the first example of this came from Newton himself, who in his 1687 work Principia Mathematicae explained that the motion of the planets in the solar system, the motion of the Moon around the Earth, and the force that holds us to the Earth are all part of the same thing: the force of gravity. One crucial idea that has driven physics since Newton's time is that of unification: the attempt to explain seemingly different phenomena by a single To understand the ideas and aims of string theory, it's useful to look back and see how physics has developed from Newton's time to the present day.