Planck length
E32679
The Planck length is the fundamental unit of length in quantum gravity, representing the scale at which classical concepts of space and time are expected to break down.
Statements (47)
| Predicate | Object |
|---|---|
| instanceOf |
Planck unit
→
physical constant → unit of length → |
| appearsIn |
black hole entropy calculations
→
generalized uncertainty principle formulations → theories of quantum spacetime foam → |
| approximateValue |
1.616255×10⁻³⁵ m
→
1.6×10⁻³⁵ metres → |
| associatedWith |
Planck energy
→
Planck mass → Planck scale → Planck time → |
| conceptualRole |
fundamental length scale of quantum gravity
→
scale where classical spacetime description breaks down → scale where quantum effects of gravity become significant → |
| definedBy |
ℓ_P = √(ħG / c³)
→
|
| dependsOnConstant |
gravitational constant G
→
reduced Planck constant ħ → speed of light c → |
| field |
cosmology
→
high-energy physics → quantum gravity → theoretical physics → |
| hasDimension |
length
→
|
| implies |
possible discreteness of spacetime at very small scales
→
|
| introducedInContextOf |
Max Planck’s natural units
→
|
| isSmallestMeaningfulScaleIn |
many quantum gravity theories
→
|
| measurability |
not directly measurable with current technology
→
|
| namedAfter |
Max Planck
→
|
| orderOfMagnitude |
10⁻³⁵ metres
→
|
| relatedConcept |
Planck area
→
Planck units → Planck volume → |
| roleInBlackHoles |
sets scale for Bekenstein–Hawking entropy area term
→
|
| roleInQuantumGravity |
candidate minimal measurable length
→
|
| scaleComparison |
far below current experimental reach
→
much smaller than nuclear scale → much smaller than proton radius → |
| SIUnit |
metre
→
|
| status |
theoretical
→
|
| symbol |
l_P
→
ℓ_P → |
| usedIn |
black hole physics
→
loop quantum gravity → models of spacetime discreteness → quantum cosmology → string theory → |
Referenced by (4)
| Subject (surface form when different) | Predicate |
|---|---|
|
Max Planck
→
|
hasNamesake |
|
Fermi (unit)
→
|
largerThan |
|
Planck time
→
|
relatedTo |
|
Newtonian gravitational constant G
→
|
usedToDefine |