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speed of light in vacuum

speed of electromagnetic waves in vacuum
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speed of light in vacuum

Summary

speed of light in vacuum is a physical constant[1]. It ranks in the top 2% of physical_constant entities by monthly Wikipedia readership (14,965 views/month).[2]

Key Facts

  • speed of light in vacuum is credited with the discovery of Ole Rømer[3].
  • speed of light in vacuum's instance of is recorded as physical constant[4].
  • speed of light in vacuum's instance of is recorded as unit of speed[5].
  • speed of light in vacuum's instance of is recorded as fundamental limit[6].
  • speed of light in vacuum's instance of is recorded as constant[7].
  • speed of light in vacuum's instance of is recorded as UCUM constant[8].
  • speed of light in vacuum's instance of is recorded as scalar quantity[9].
  • speed of light in vacuum's instance of is recorded as unit of measurement[10].
  • speed of light in vacuum's measured physical quantity is recorded as speed[11].
  • speed of light in vacuum's Commons category is recorded as Speed of light[12].
  • speed of light in vacuum's said to be the same as is recorded as speed of gravity[13].
  • speed of light in vacuum's topic's main category is recorded as Category:Speed of light[14].
  • speed of light in vacuum's numeric value is recorded as {'unit': 'Q182429', 'amount': '+299792458'}[15].
  • speed of light in vacuum's facet of is recorded as massless quantum particle[16].
  • speed of light in vacuum's facet of is recorded as vacuum[17].
  • speed of light in vacuum's facet of is recorded as special relativity[18].
  • speed of light in vacuum's facet of is recorded as electromagnetism[19].
  • speed of light in vacuum's described by source is recorded as ISO 80000-7:2008 Quantities and units—Part 7: Light[20].
  • speed of light in vacuum's described by source is recorded as IEC 80000-6:2008 Quantities and units—Part 6: Electromagnetism[21].
  • speed of light in vacuum's described by source is recorded as IEC 80000-6:2022 Quantities and units — Part 6: Electromagnetism[22].
  • speed of light in vacuum's different from is recorded as speed of light in a medium[23].
  • speed of light in vacuum's conversion to SI unit is recorded as {'unit': 'Q182429', 'amount': '+299792458.0147178'}[24].
  • speed of light in vacuum's conversion to standard unit is recorded as {'unit': 'Q180154', 'amount': '+1079252848.8'}[25].
  • speed of light in vacuum's conversion to standard unit is recorded as {'unit': 'Q211256', 'amount': '+670616629.384'}[26].
  • speed of light in vacuum's on focus list of Wikimedia project is recorded as Wikipedia:List of articles all languages should have[27].

Body

Definition and Type

Recorded instance of include physical constant[4], unit of speed[5], fundamental limit[6], constant[7], UCUM constant[8], and scalar quantity[9].

Influence

Things named for speed of light in vacuum include Hikari[28], a named passenger train service[29], in Japan[30], founded in 1964[31] and speed of light[32], a rate[33].

Why It Matters

speed of light in vacuum ranks in the top 2% of physical_constant entities by monthly Wikipedia readership (14,965 views/month).[2] It has Wikipedia articles in 30 language editions, a strong signal of global cultural recognition.[34] It is known by 37 alternative names across languages and contexts.[35]

Entities named for it include Hikari[28], a named passenger train service[29], in Japan[30], founded in 1964[31] and speed of light[32], a rate[33].

Related Entities

Geelong Ole Rømer

References

Programmatic citations — every numbered marker resolves to a verifiable graph row below.

Direct Wikidata claims

  1. [4] ↑ . wikidata.org.
  2. [5] ↑ . wikidata.org.
  3. [6] ↑ . wikidata.org.
  4. [7] ↑ . wikidata.org.
  5. [8] ↑ . wikidata.org.
  6. [9] ↑ . wikidata.org.
  7. [10] ↑ . wikidata.org.
  8. [3] ↑ . A Short History of Astronomy. wikidata.org.
  9. [11] ↑ . wikidata.org.
  10. [12] ↑ . wikidata.org.
  11. [13] ↑ . wikidata.org.
  12. [14] ↑ . wikidata.org.
  13. [15] ↑ . 2018 CODATA recommended values. wikidata.org.
  14. [16] ↑ . wikidata.org.
  15. [17] ↑ . wikidata.org.
  16. [18] ↑ . wikidata.org.
  17. [19] ↑ . wikidata.org.
  18. [20] ↑ . wikidata.org.
  19. [21] ↑ . wikidata.org.
  20. [22] ↑ . wikidata.org.
  21. [23] ↑ . wikidata.org.
  22. [24] ↑ . wikidata.org.
  23. [25] ↑ . wikidata.org.
  24. [26] ↑ . wikidata.org.
  25. [27] ↑ . wikidata.org.

Inverse relationships (entities pointing at this one)

  1. [28] ↑ . wikidata.org. → on this site
  2. [32] ↑ . wikidata.org. → on this site

Inline context (facts about related entities)

  1. [29] ↑ . Wikidata. wikidata.org. → on this site
  2. [30] ↑ . Wikidata. wikidata.org. → on this site
  3. [31] ↑ . Wikidata. wikidata.org. → on this site
  4. [33] ↑ . Wikidata. wikidata.org. → on this site

Class ancestry

  1. [1] ↑ . Wikidata. wikidata.org.

Aggregate / graph-position facts

  1. [2] ↑ . Wikimedia Foundation. dumps.wikimedia.org.
  2. [34] ↑ . Wikidata sitelinks. wikidata.org.
  3. [35] ↑ . Wikidata aliases. wikidata.org.

📑 Cite this page

Use these citations when quoting this entity in research, articles, AI prompts, or wherever provenance matters. We aggregate Wikidata + Wikipedia + authoritative open-data sources; the stitched, scored, cross-referenced view is what 4ort.xyz contributes.

APA 4ort.xyz Knowledge Graph. (2026). speed of light in vacuum. Retrieved May 3, 2026, from https://4ort.xyz/entity/speed-of-light
MLA “speed of light in vacuum.” 4ort.xyz Knowledge Graph, 4ort.xyz, 3 May. 2026, https://4ort.xyz/entity/speed-of-light.
BibTeX @misc{4ortxyz_speed-of-light_2026, author = {{4ort.xyz Knowledge Graph}}, title = {{speed of light in vacuum}}, year = {2026}, url = {https://4ort.xyz/entity/speed-of-light}, note = {Accessed: 2026-05-03}}
LLM prompt According to 4ort.xyz Knowledge Graph (aggregator of Wikidata, Wikipedia, and authoritative open-data sources): speed of light in vacuum — https://4ort.xyz/entity/speed-of-light (retrieved 2026-05-03)

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Edit History

Rolling log of changes to this entity's Wikidata record. Values shown reflect the current state of each edited property — follow the history link to see the precise diff for any edit.

  1. 18d ago · Nyuhn · 2026-07-10 view diff on Wikidata ↗
    P14541 → LwoZY
    "/* wbeditentity-update:0| */ QuickStatements 3.0 [[:toollabs:qs-dev/batch/40849|batch #40849]]: ZGBK ID"
  2. 12w ago · Stuchalk · 2026-05-02 view diff on Wikidata ↗
    Instance of → physical constant, unit of speed, fundamental limit +5
    "/* wbremoveclaims-remove:1| */ [[Property:P31]]: [[Q47574]]"
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