LISA Pathfinder free-falling test mass
The LISA Pathfinder free-falling test mass is a precisely controlled object in space used to demonstrate technologies for detecting gravitational waves by minimising non-gravitational forces.
Also known as: LISA Pathfinder residual acceleration
How big is it?
5 × 10⁻¹⁵ N · equivalent differential force on a 1 kg test mass
Equivalent differential force on a 1 kg test mass · approximate performance anchor
Typical recorded range: 1 × 10⁻¹⁵ N to 3 × 10⁻¹⁴ N.
A little perspective
LISA Pathfinder free-falling test mass vs Single DNA molecule stretching force: weight comparison
The force stretching a single DNA molecule is about 10,000 times the equivalent differential force on a 1 kg test mass of the LISA Pathfinder free-falling test mass.
FORCE
The LISA Pathfinder free-falling test mass is a precisely controlled object in space used to demonstrate technologies for detecting gravitational waves by minimising non-gravitational forces.
Too small to see at this scale; the bar has not been widened.
Single DNA molecule stretching force is the force required to extend a single DNA strand under controlled laboratory conditions.
Measurements, assumptions & sources +
LISA Pathfinder free-falling test mass
Equivalent differential force on a 1 kg test mass: 5 × 10⁻¹⁵ N; approximate performance anchor; range 1 × 10⁻¹⁵ N–3 × 10⁻¹⁴ N.
A representative LISA Pathfinder residual-acceleration scale expressed as the equivalent differential force on a defined 1 kg test mass near millihertz frequencies. Performance depends on frequency and analysis conditions.
ESA — LISA Pathfinder overview
The marked equivalent differential force on a 1 kg test mass is calibrated. Unmeasured illustration details are representative.
Single DNA molecule stretching force
Representative stretching force: 5 × 10⁻¹¹ N; representative; range 1 × 10⁻¹² N–1 × 10⁻¹⁰ N.
A representative 50 pN single-molecule force in the DNA stretching regime. Measured force depends on construct, contour state, buffer, temperature and pulling protocol; the molecular image is schematic.
NIST — DNA stretching measurements
The marked representative stretching force is calibrated. Unmeasured illustration details are representative.
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Why this measurement?
Why we use 5 × 10⁻¹⁵ N
We compare the equivalent differential force on a 1 kg test mass of the LISA Pathfinder free-falling test mass. This is an estimate; check the notes for its rounding and uncertainty. The recorded range is 1 × 10⁻¹⁵ N to 3 × 10⁻¹⁴ N.
A representative LISA Pathfinder residual-acceleration scale expressed as the equivalent differential force on a defined 1 kg test mass near millihertz frequencies. Performance depends on frequency and analysis conditions.
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 |
|---|---|---|---|
| 5 × 10⁻¹⁵ N | 1 × 10⁻¹⁵ N to 3 × 10⁻¹⁴ N | approximate performance anchor |
Around this scale
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Sources and method
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The source records and measurement method remain available for inspection.
- ESA — LISA Pathfinder overviewMission overview for drag-free proof masses and precision metrology; acceleration performance depends on frequency.
There’s always another scale
Follow your curiosity.
Fundamental physicsPlanck length1.616 × 10⁻³⁵ mThe Planck length is a scale formed from fundamental physical constants.
Fundamental physicsSingle DNA molecule stretching force5 × 10⁻¹¹ NSingle DNA molecule stretching force is the force required to extend a single DNA strand under controlled laboratory conditions.
GravityGravitational attraction between two one-kilogram masses one metre apart6.7 × 10⁻¹¹ NThis is the gravitational force acting between two one-kilogram objects placed one metre apart in a vacuum.GravityEarth-Moon L1 tidal acceleration over one kilometre8.03 × 10⁻⁸ NEarth-Moon L1 tidal acceleration over one kilometre is the difference in gravitational pull experienced across a one-kilometre distance near the Earth-Moon L1 point.GravityGravitational attraction between two people one metre apart3 × 10⁻⁷ NThis is the gravitational force that two people exert on each other when separated by one metre.
Fundamental physicsSnowflake aerodynamic drag1 × 10⁻⁶ NSnowflake aerodynamic drag is the resistive force experienced by a falling snowflake as it moves through air.Fundamental physicsPhoton pressure thrust per kilowatt6.7 × 10⁻⁶ NPhoton pressure thrust per kilowatt is the force generated when one kilowatt of light is absorbed or reflected, due to photon momentum.Fundamental physicsRadiation pressure on a laser mirror7 × 10⁻⁶ NRadiation pressure on a laser mirror is the force exerted by a laser beam as its photons strike and reflect from the mirror.