Free neutron mean lifetime
Free neutron mean lifetime is the average time a neutron exists outside an atomic nucleus before decaying into other particles.
Also known as: free neutron lifetime
How big is it?
14.67 min · representative mean lifetime
Representative mean lifetime · measured approximate
Typical recorded range: 14.63 min to 14.68 min.
A little perspective
Free neutron mean lifetime vs Earth–Sun distance: duration comparison
The mean lifetime of a free neutron is about 1.76 times the duration of the Earth–Sun distance.
ELAPSED TIME
Free neutron mean lifetime is the average time a neutron exists outside an atomic nucleus before decaying into other particles.
The Earth–Sun distance, or astronomical unit, is the standard measure of separation between Earth and the Sun used in astronomy.
Measurements, assumptions & sources +
Free neutron mean lifetime
Representative mean lifetime: 14.67 min; measured approximate; range 14.63 min–14.68 min.
A free neutron survives for about 880 seconds on average before beta decay. Experimental methods still show a small unresolved discrepancy.
Particle Data Group — Neutron properties
The marked representative mean lifetime is calibrated. Unmeasured illustration details are representative.
Earth–Sun distance
Time: 8.317 min; definition.
One astronomical unit is exactly 149,597,870,700 m. It is a useful Earth–Sun orbital scale, not the separation at every instant. Light takes about 8 minutes 19 seconds to cross it.
NIST — 2022 CODATA fundamental constants
The marked time is calibrated. Unmeasured illustration details are representative.
Use the visual comparison to explore its scale, then check the measurements and sources.
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Why this measurement?
Why we use 14.67 min
We compare the mean lifetime of a free neutron. This is a measured reference value rounded for comparison; check its conditions and uncertainty in the notes. The recorded range is 14.63 min to 14.68 min.
A free neutron survives for about 880 seconds on average before beta decay. Experimental methods still show a small unresolved discrepancy.
The picture identifies the subject; the diagram compares the recorded values. How calibrated comparisons work →
Recorded properties
Dimensions and measurements
| Property | Selected value | Recorded range | Basis |
|---|---|---|---|
| 14.67 min | 14.63 min to 14.68 min | measured approximate |
Around this scale
Explore nearby values.
Compare examples with lower, similar and higher values. Each card names the measurement being compared.
Nearest lower valuePlanets, moons and spaceEarth–Sun distance8.317 minTimeThe Earth–Sun distance, or astronomical unit, is the standard measure of separation between Earth and the Sun used in astronomy.
Nearest higher valueTime and durationA feature film2 hTimeA feature film is a motion picture created to tell a complete story for viewers.Sources and method
Want to check the number?
The source records and measurement method remain available for inspection.
- Particle Data Group — Neutron propertiesRecommended free-neutron lifetime and experimental context.
There’s always another scale
Follow your curiosity.
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PeopleRed-cell circulation time1 minRed-cell circulation time is the typical duration for a red blood cell to complete a full circuit through the human circulatory system at rest.
GravityTen-metre centrifuge at two rpm0.4387 NA ten-metre centrifuge at two rpm is a rotating device used to simulate artificial gravity by spinning samples at a controlled speed.