Greek Alphabet

    Caption: The Greek alphabet of 24 Greek letters: alpha α, beta β, gamma γ, ...

      alpha, beta, ... --- you get it?

    In astronomy, some Greek letters turn up fairly often:

    1. α, β, γ, and δ turn up in Bayer designation system for bright stars and in designating the hydrogen Balmer lines.

    2. θ is the conventional symbol for angle.

    3. λ is the conventional symbol for wavelength.

    4. μ is the metric prefix meaning 10**(-6).

    5. π the letter is the symbol for the irrational number Pi: π = 3.14159265358979 ... (see One Million Digits of Pi).

    6. And others as need arises.

    7. Actually all small Greek letters are used in the aforesaid Bayer designation system to label stars in a given constellation in order of their apparent magnitude (approximately their apparent V magnitude): the brightest one was called α, the 2nd brightest one was called β, etc. The ordering by brightness is NOT always correct. Johann Bayer (1572--1625) and other early implementers of the Bayer designation system did NOT work at modern accuracy/precision. When these implementers ran out of Greek letters they used Roman letters and in later times numbers were used too. So even omicron ο is used astronomy even though it looks almost like o. This is well known to Star Trek fans: see How to Pronounce "Omicron" the Star Trek Way | 0:30.

    Actually, all astronomers and physicists can read Greek---we just don't know what the words mean. But sometimes we do: το δημοσ means "the people" as in "We the people". Indeed,

      ... but, for mine own part, it was Greek to me ...

        ---Casca (c.100--42? BCE) to Cassius (before 85--42 BCE) and Brutus (85--42 BCE), Act I, Scene 2 (scroll down ∼ 40 %) in Julius Caesar (c. 1599), William Shakespeare (1564--1616). See also Julius Caesar (1970 film) | 19:09 mark whereat Casca (Robert Vaughn (1932--2016)) says the same to Brutus (Jason Robards (1922--2000)) and Cassius (Richard Johnson (1927--2015)) (see also Wikipedia: Julius Caesar (1970 film)). Also see also Wikipedia: Greek to me.

    Almost all the Greek letters, upper-case and lower-case, have conventional uses in mathematics, science, and engineering: see Wikipedia: Greek letters used in mathematics, science, and engineering.

    For reference, the complete Greek alphabet: English spelling / upper-case / lower-case, pronunciation of name (NOT sound):

      1) alpha Α α, pronounced alpha, 2) beta Β β, pronounced beta, 3) gamma Γ γ, pronounced gamma, 4) delta Δ δ, pronounced delta, 5) epsilon Ε ε, pronounced epsilon, 6) zeta Ζ ζ, pronounced zeta, 7) eta Η η, pronounced eta, 8) theta Θ θ, pronounced theta, 9) iota Ι ι, pronounced i-ota, 10) kappa Κ κ, pronounced kappa, 11) lambda Λ λ, pronounced lam-da, 12) mu Μ μ, pronounced mu, 13) nu Ν ν, pronounced nu, 14) xi Ξ ξ, pronounced Zi, 15) omicron Ο ο, pronounced omicron, 16) pi Π π, pronounced pi, 17) rho Ρ ρ, pronounced ro, 18) sigma Σ σ, pronounced sigma. 19) tau Τ τ, pronounced tao, 20) upsilon Υ υ, pronounced upsilon, 21) phi Φ φ, pronounced phi, 22) chi Χ χ, pronounced ky, 23) psi Ψ ψ, pronounced sy, 24) omega ω, pronounced omega.

    Additionally, there are archaic Greek alphabets. The only archaic Greek letter that gets a modern conventional use seems to be digamma Ϝ (which looks a lot like F), pronounced digamma (see Wikipedia: Greek letters used in mathematics, science, and engineering: Digamma).

    Credit/Permission: © David Jeffery, 2003 / Own work.
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