Tagged Questions
0
votes
1answer
67 views
Why Planck scale is so important?
I know that Planck scale is the scale where both, gravity and quantum effects are relevant simultaneously. Are there more reasons?
3
votes
1answer
78 views
Units for physical constants
Someone told me that units for $G$ and $\epsilon_0$ (gravitational constant and Coulomb's constant) are placed there simply to make equations work dimensionally and that there is no real physical ...
2
votes
3answers
71 views
Curious relation between the dependance in ℏ of Planck units and units dimensions
Looking at Planck units, there seems to be a curious rule between the dependance in $\hbar$ of a Planck unit and the unit dimensions of the corresponding physical quantity.
Let the dimensions of the ...
12
votes
5answers
914 views
How can the speed of light be a dimensionless constant?
This is a quote from the book A first course in general relativity by Schutz:
What we shall now do is adopt a new unit for time, the meter. One meter of time is the time it takes light to travel ...
2
votes
3answers
275 views
Planck time, distance, mass? Why do we take those values?
Say we want to make an educated guess for critical values of time, distance and mass, where quantum gravity effects are supposed to be non-negligible. These values are given the prefix "Planck-". Now, ...
9
votes
5answers
966 views
How to get Planck length
I know that what Planck length equals to.
The first question is, how do you get the formula
$$\ell_P~=~\sqrt\frac{\hbar G}{c^3}$$ that describes the Planck length?
The second question is, will any ...
5
votes
1answer
431 views
Why can you remove the gravitational constant from a computer game simulation?
I've seen in a few gravity simulation games (ie. bouncing balls) the equation:
force = G * m1 * m2 / distance^2
shortened to this by removing the gravitational ...
4
votes
1answer
230 views
Deriving or justifying fundamental constants
Is there a fundamental way to look at the universal constants ? can their orders of magnitude be explained from a general points of view like stability, causality, information theory, uncertainty?
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