Where does “photon sphere” come from?
photon sphere (English) comes from English sphere, from Middle English spere, from Old French sphere, from Latin sphēra, from Ancient Greek σφαῖρα, from Ancient Greek -ειδής, from Ancient Greek -ής, from Proto-Indo-European -ēs — Creates action nouns or result nouns from verbs;...
photon sphere (English): Of a black hole, a spherical limit around a black hole at such distance that any photon meeting it tangentially is constrained to travel in a circular orbit; the region between this limit and the event horizon
Definitions
- Of a black hole, a spherical limit around a black hole at such distance that any photon meeting it tangentially is constrained to travel in a circular orbit; the region between this limit and the event horizon
Ancestry of “photon sphere”, step by step
photon sphere traces back through two separate lines of ancestry.
via English sphere
| Step | Language | Word | Meaning |
|---|---|---|---|
| 1 | English | sphere | A regular three-dimensional object in which every... |
| 2 | Middle English | spere | A spear or lance; The Lance of Longinus; A barb... |
| 3 | Old French | sphere | sphere shape |
| 4 | Latin | sphēra | — |
| 5 | Ancient Greek | σφαῖρα | ball, globe, sphere |
| 6 | Ancient Greek | -ειδής | like, connected to, from the nature of, full of;... |
| 7 | Ancient Greek | -ής | adjective suffix |
| 8 | Proto-Indo-European | -ēs | Primarily forms adjectival bahuvrīhi compounds |
| 9 | Proto-Indo-European | -ess | — |
| 10 | Proto-Indo-European | -os | Creates action nouns or result nouns from verbs;... |
via English photon
| Step | Language | Word | Meaning |
|---|---|---|---|
| 1 | English | photon | The quantum of light and other electromagnetic... |
| 2 | English | photo- | light, electromagnetic radiation; photography |
| 3 | Ancient Greek | φωτο- | — |
| 4 | Ancient Greek | φῶς | Attic form of φᾰ́ος |
| 5 | Proto-Hellenic | pʰáos | — |
| 6 | Proto-Indo-European | bʰéh₂os | — |
| 7 | Proto-Indo-European | bʰeh₂- | to shine, glow light; to speak, say |
| 8 | Proto-Indo-European | bʰeh₂-s-ri- | — |