To explore a region of space you need to send in a probing particle (typically a photon, a particle of light) and observe how that scatters off whatever objects are inside the region. Something curious happens when you try to combine quantum mechanics with relativity. It’s an incredibly small number,īut still, the inequality shows that and cannot simultaneously become arbitrarily small. Here is a constant named after the physicist Max Planck. Writing for the uncertainty in position and for the uncertainty in momentum, the principle is encapsulated by the inequality It’s not that the particle is somewhere definite but you just don’t know where, rather the particle is, in some sense, in many locations at once. If you pin down, say, momentum to a good degree of accuracy your uncertainty about position increases. The uncertainty principle says that the more precise you are about the particle’s position the less precise you can be about its momentum and vice versa. Suppose you have such a "particle" and you’re interested in its position and its momentum (momentum is the particle’s mass times its velocity). A consequence is Heisenberg’s famous uncertainty principle. It is based on the counter-intuitive idea that little particles, like electrons, behave like tiny little billiard balls at some times and like waves at others: they behave like a hybrid of the two. The other great development of early twentieth century physics, quantum mechanics, describes the tiniest building blocks of matter. Seeing inside a black hole from the outside, or of going in and comingīack out again to report what you've seen - whatever happens in Gravitational pull of the mass, the warping of spacetime, becomes so extreme that nothing, not even light,Ĭan escape from its vicinity. Itself, spacetime can curve so much that a black hole forms. Which can happen, for example, when a massive star collapses in on When a lot of mass is concentrated in a very small region of space, Marble rolling around a surface is directed by the bumps and curves of thatĪccording to Einstein's general theory of relativity, massive objects curve spacetime. Massive objects, like the Sun, curve and warp the very fabric of spacetime and this curvatureĭiverts the paths of less massive objects in the vicinity - just like Then became a consequence of spacetime geometry. Gravity, previously thought of as anĪttractive force acting instantaneously across space, He also realised that this spacetime can be curved. Einstein realised that your measurementīe influenced by how you move through space, so spaceĪnd time are inextricably linked in what he called The first blow to Newton'sĪbsolute space came in the early twentieth century whenĮinstein's theory of relativity turned it from a stage into That's a mathematical idea that does not correspond to physics." Space warpĪnd it seems that Ellis may be right. Those fingers, then you believe that there is an uncountable infinity of pointsīetween your fingers. "If you believe that there is a line of points between "Suppose you hold your fingers ten centimetresĪpart," argues George Ellis, a cosmologist and mathematician at the Means admitting that you can hold a frighteningly large infinity in Uncountable infinity, something inherently larger than an as you could label an infinitely long queue of people There are so many points you could not even label A continuous piece of line, no matter how short, is made up of infinitely many Yet from another point of view, the idea of continuity is itself On it to any level you like without seeing it break up into pixels or Given us bridges and spacecraft, is based on another idea that chimes with our intuition: that space is continuous. The maths that has grown from Newton's assumption, and which has Relation-less space, this void, could actually exist in nature. Hypothesis." Because of its power Newton's pronouncement pretty much put a lid onĬenturies' worth of philosophical debate on whether this abstract and Mechanics we can construct bridges, we can goĪssumption was so successful that people forgot it was only a The assumption is so powerful, it allowed Newton to construct his Says Francesca Vidotto, a theoretical physicist at the Radboud University Nijmegen. "He was aware that was just a hypothesis," Newton did not claim he could prove that physical space was really like that. Immovable without relation to anything external," he wrote. "Absolute, true, and mathematical space remains similar and Recently, in historical terms, with Newton's Principia This is how we learn to think of space at school - a rigid box in If it, the Earth and everything else vanished, would space still it exist? Image courtesy NASA.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |