Does the Planck length expand with the Universe?
Does the Planck length expand with the Universe?
Short answer: no. The Planck units are all fixed in terms of Newton’s constant, G, combined with others like: the speed of light, c, and Planck’s constant h (or ℏ). The “size of things” is set primarily by two constants, the mass of the electron me and the fine structure constant, α.
What is the diameter of the Universe in Planck lengths?
Roughly, the radius of the Universe is 4 x10 ^26 metres and its mass is 10 ^53 kilograms. The Planck mass is around 2.728×10^-8 kilograms and the Planck radius is around 4 x 10^-35 metres. (1) 4×10^26/4×10^-35 = 10^61.
How many Planck units are there in the observable universe?
In cosmology
| Property of present-day observable universe | Approximate number of Planck units |
|---|---|
| Age | 8.08 × 1060 tP |
| Diameter | 5.4 × 1061 lP |
| Mass | approx. 1060 mP |
| Density | 1.8 × 10−123 mP⋅lP−3 |
Does Planck length change?
The size of the Planck length is given by the Planck constant, speed of light and the gravitational constant G. There are hypotheses that these “constants” are not truly constant and thus the Planck units would change, but our current understanding of physics doesn’t do this.
On what scale does the universe expand?
Most recently, by comparing the apparent brightness of distant standard candles to the redshift of their host galaxies, the expansion rate of the universe has been measured to be H0 = 73.24 ± 1.74 (km/s)/Mpc.
How much energy is in the observable universe?
In the case of a universe that is approximately uniform in space, one can show that this negative gravitational energy exactly cancels the positive energy represented by the matter. So the total energy of the universe is zero.”
Is there anything smaller than the Planck length?
Originally Answered: Is there anything smaller than a Planck length? There is no even theoretically possible measuring device that can measure differences between two locations that are closer together than a Planck length. Thus, the Planck length is the smallest possible unit of measurement.
What happens below Planck length?
At distances below the Planck length, we can’t distinguish ‘separate’ objects, so we can’t say there is a length between them. It’s to do with Heisenberg’s Uncertainty Principle. We can think about ‘half a Planck length’ though, just like we can think about ‘infinity squared +1’.
Why does the Planck length exist?
Planck units are special because they are formed from quantities directly found in nature, i.e. speed of light, gravitation constant, etc. Those natural units have dimensions like length and time and such, and when the natural units are combined together they can be expressed directly as a time scale or length scale.