What is the significance of planck time

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Smith Sign up or log in Sign up using Google. Sign up using Facebook. Sign up using Email and Password. Post as a guest Name. Email Required, but never shown. Featured on Meta. On this scale, the entire geometry of spacetime as predicted by general relativity breaks down. Consequently, on such scales, an as yet undiscovered theory that combines general relativity and quantum mechanics is needed to describe the laws of physics.

When we put the two ideas together, we find that there is a scale small enough for virtual black holes to exist. This is the Planck scale. On this scale, a black hole can appear spontaneously — but very briefly — anywhere in space. So, examined on this scale, all of the weird, singular behaviour associated with black holes asserts itself, not just in remote astrophysical peculiarities, but everywhere and at all times. With black holes winking in and out of existence everywhere, space and time as continuous entities cease to have meanings when discussing distances of 10 - 35 metres and times of 10 - 44 seconds.

So relativity, a classical theory of space and time based on a space-time continuum, might run into serious difficulties. Which is perhaps not surprising: the Planck scale is a very, very long extrapolation from our current knowledge. And from our current cosmological era. On this topic, we have so little direct knowledge that there are few hints to guide the development of theories, and few constraints upon those theories.

Currently, there are several different families of theories that aim to produce a consistent theory of quantum gravity. At the moment, however interesting they be, these theories are speculative. Perhaps one of them will turn out to be a good, useful theory, and the others will fall.

At the moment, we cannot put them to the test. Today, we remember Democritus for speculating on the existence of atoms. But the ancient Greek philosophers proposed so many ideas that it is perhaps not too surprising that some of them turned out to be consistent with facts determined much later. Meanwhile, here are a couple of our pages that may interest you:. All matter and all energy in the universe attracts all other energy and matter in the universe via the curvature of 4 dimensional space time.

Again this applies to the entire contents of the universe. Planck Length see planck length. Planck Time see planck time. Planck Energy see planck energy. It is thought to be the scale of the strings of String Theory. So strings are about as long as the Planck length and vibrate on Planck time scales. If the Planck energy is confined to the volume of a cube of size 1 Planck length it will form a black hole. In fact, this is thought to be the smallest possible mass for a black hole and at these "Planck" distances, times and energies it is thought that quantum gravitational effects will be very significant.

The Planck length is the smallest distance scale we can probe with accelerators. High energy accelerators are used to probe small objects, such as the quarks inside protons, so the goal is always to build higher energy accelerators. However, if we could build an accelerator that achieved the Planck energy for a particle like the electron, when the electron interacted with the target, a black hole would form and it would not help to go to higher energies than that since the black hole would just get bigger.

That is why the Planck length is the smallest length scale that we could theoretically probe. The Planck time is the time it takes for light to traverse a Planck length.

At about the Planck time after the big bang, it is thought that gravitation would separate from the three other forces of nature strong, weak and electromagnetic forces.