Feather star
A feather star is a marine crinoid with multiple feathery arms used for filter feeding and movement on the sea floor.
Also known as: crinoid feather star, comatulid
How big is it?
15 cm across
Also 5.906 in
Defined arm-tip span · defined specimen
Typical recorded range: 8 cm to 30 cm.
A little perspective
About the same scale as Human brain.
Human brain: The human brain is the organ that processes sensory information and coordinates thought, memory, movement and many body functions.
Measurements, assumptions & sources +
Feather star
A defined 15 cm feather star measured across its spread arm tips. Species, arm count and posture vary; this span includes the feathery arms and excludes detached cirri.
The marked defined arm-tip span is calibrated. Unmeasured illustration details are representative.
Human brain
A defined adult-brain specimen 15 cm front to back and 1.4 kg. Brain size and mass vary by person; these values are comparison anchors, not health benchmarks.
Defined examples — our methodology
The marked representative front-to-back length is calibrated. Unmeasured illustration details are representative.
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Why this measurement?
Why we use 15 cm
For comparison, this page uses defined arm-tip span. This is labelled defined specimen: an explicit comparison model rather than a claim that every example has the same value. The recorded range is 8 cm to 30 cm.
A defined 15 cm feather star measured across its spread arm tips. Species, arm count and posture vary; this span includes the feathery arms and excludes detached cirri.
The marked horizontal span follows the named feature; transparent margins and unmeasured details do not alter it. How calibrated comparisons work →
Recorded properties
Feather star dimensions and measurements
| Property | Selected value | Recorded range | Basis |
|---|---|---|---|
| 15 cm | 8 cm to 30 cm | defined specimen |
Around this scale
Go smaller. Go bigger.
These links use compatible length records, ordered around the selected value.
Nearest lower value · Living thingsEarthworm12 cmAn earthworm is a segmented invertebrate that lives in soil and aids in decomposing organic material.
Around the same scale · Everyday thingsSmartphone15 cmA smartphone is a portable electronic device that combines mobile phone functions with internet access and apps.
Nearest higher value · Living thingsBasket star20 cmA basket star is a marine echinoderm related to brittle stars, with repeatedly branching arms adapted for filter feeding.Sources and method
Want to check the number?
The source records and measurement method remain available for inspection.
- Smithsonian Ocean — CrinoidsFeather-star anatomy and posture; the atlas uses an explicitly defined arm-tip span.
There’s always another scale
Follow your curiosity.
Living thingsBasket star20 cmA basket star is a marine echinoderm related to brittle stars, with repeatedly branching arms adapted for filter feeding.
PeopleHuman brain15 cmThe human brain is the organ that processes sensory information and coordinates thought, memory, movement and many body functions.
Everyday thingsCantaloupe15 cmA cantaloupe is a round, sweet melon with a netted rind and orange flesh, commonly eaten as a fruit.
SpaceVanguard 116.5 cmVanguard 1 is an early American satellite launched in 1958, notable for being the oldest human-made object still in orbit.
Living thingsGeoduck17 cmA geoduck is a large burrowing marine clam with a comparatively small shell and a very long siphon.
SportClimbing piton15 cmA climbing piton is a metal spike driven into rock cracks to provide protection or anchor points during climbing.
Everyday thingsSweet potato15 cmA sweet potato is the edible, starchy root of the plant Ipomoea batatas, widely grown for food.
PeopleHuman heart12 cmA human heart is a muscular organ that pumps blood through the circulatory system.