Universe Puzzle No. 12

Article written: 3 May , 2010
Updated: 24 Dec , 2015
by

How did you do in last week’s Universe Puzzle? Did you easily find out where the green valley is, but have no clue as to why it’s called a ‘valley’?

Do you enjoy these puzzles? What do you particularly like? Dislike? Would like to see changed? Would like to see more of? Let me know please!

Once again, this week’s puzzle requires you to cudgel your brains a bit and do some lateral thinking (five minutes spent googling likely won’t be enough). But, as with all Universe Puzzles, this is a puzzle on a “Universal” topic – astronomy and astronomers; space, satellites, missions, and astronauts; planets, moons, telescopes, and so on.

Which is the “odd one out”? And why?
α, β, γ, μ, ν, and τ.

In case the Greek symbols don’t display properly, these are (lower case, or small) alpha, beta, gamma, mu, nu, and tau.

UPDATE: Answer has been posted below.

There are, of course, many answers. For example, τ (tau) is alone, because neither of its two neighbors in the Greek alphabet are in the list. But that’s not a particularly good answer, and this week’s puzzle asks for the best answer (which may be τ (tau)!), so the explanation of your choice is what counts.

I think Hon. Salacious B. Crumb’s answer is very good (“tau is the odd one out. The rest are al rings of the planet Uranus by increasing radius from the planet’s disk. alpha, beta, gamma are inner rings, nu and mu are the outmost rings.“)

I also like Navneeth’s (“alpha, because it’s a composite “particle” while the others are truly elementary (as far as we know)“) – gopher65 gave much the same answer, iantresman’s (“alpha particles are the only non-fermions. Neutrinos (nu) are the only ones to come in different flavours“), and the several of you who picked gamma because the photon is massless (though I think iantresman’s “it’s the only gauge boson” is a better reason for choosing it; you could also say it’s the only force carrier particle).

Star designations? If someone had come up with a good answer along those lines, they’d’ve got my vote; but, as far as I know there is nothing “odd” about any of these Greek letters.

My own answer was the tau … it’s the only particle as yet undetected, directly, by any spacecraft or Earth-based facility, originating out in space (Fermi detects gammas; plenty of instruments on spacecraft detect alpha particles, electrons, and muons; and neutrinos from the Sun and SN1987A have been detected; but no taus!)

Check back next week for another Universe Puzzle!


22 Responses

  1. Matthew Burns says

    My guess is gamma.

    ?, ?, ?, ?, and ? are all types of particles.
    (alpha particles, beta particles, muons, neutrons, and tau leptons)

    but ? is a form or radiation. (gamma radiation)

  2. Navneeth says

    Assuming they refer to sub-atomic and elementary particles, I would say alpha, because it’s a composite “particle” while the others are truly elementary (as far as we know).

    But I want to believe that involving the Bayer designation will somehow get me closer to the best answer.

  3. Navneeth says

    Matthew Burns, gamma is used to denote photons.

  4. BillGawne says

    I’ll go with gamma, because gammas are massless. Alphas are helium nuclei (with mass), betas are either electrons or positrons (with mass), and likewise the mu, nu, and tau particles all have mass.

  5. Navneeth says

    Okay, here is my answer with the Bayer Designation in mind: Tau. Tau is the only one in the list of accepted abbreviations of constellation names per the IAU.

  6. gopher65 says

    I see two possible (likely) answers:

    1) ? (gamma) isn’t a separate particle, but rather a frequency of EM radiation.

    2) ? (alpha) is the only one which isn’t comprised of a single particle/wave.

  7. gopher65 says

    hmm. I see that either my browser (FF3.6.3) or this board doesn’t accept Greek letters. Pitty.

  8. gopher65 says

    Huh. Upon reading the other answers I see that other people mentioned mass vs massless. I can’t believe that didn’t occur to me. *headdesk*

    Ah well. It looks like there are multiple valid answers to this question:). I like those ones. It really makes you think.

  9. darthwader says

    Alpha. It typically refers to the first of something, i.e. 1 which is automatically make it odd.

  10. Member
    IVAN3MAN_AT_LARGE says

    Somebody here neglected to close their Italic tag.

  11. Jean Tate says

    Fixed (the closing of the italic tag that is).

  12. vagueofgodalming says

    Going with the elementary particles, is it something to do with the Sun – all of them are produced there, except one of the neutrino types, which is formed spontaneously as they leave?

  13. Member
    IVAN3MAN_AT_LARGE says

    I think that μ (mu) is the “odd one out” because it’s the only letter in the Greek alphabet that’s used as an SI prefix (μ denoting 10^-6).

    (It’s now 07:47 GMT, here in the UK, and it’s past my bedtime!)

  14. grahamw105 says

    Alpha, because it’s composite and the others are elementary.

  15. neoguru says

    I’m with the majority. Gamma has no mass.

  16. Navneeth says

    History

    The neutrino was the only particle to be theoretically predicted before it was observed in the lab. As you may remember, the muon, for instance, rudely barged its way into our world when no one had ordered it.

  17. Hon. Salacious B. Crumb says

    tau is the odd one out. The rest are al rings of the planet Uranus by increasing radius from the planet’s disk.

    alpha, beta, gamma are inner rings, nu and mu are the outmost rings.

  18. thesleepless says

    i am from greece and i know that ? is a fonien in greek gramar and ?,?,?,?,? are simfons so i vote
    alpha

  19. thesleepless says

    i am from greece and i know that alpha is a fonien in greek gramar and beta, gamma, mu, nu, and tau are simfons so i vote
    alpha

  20. Navneeth says

    tau is the odd one out. The rest are al rings of the planet Uranus by increasing radius from the planet’s disk.

    alpha, beta, gamma are inner rings, nu and mu are the outmost rings.

    My nomination for the best answer. I know I don’t get to choose, but still…

  21. Trippy says

    Dam.

    Pipped at the post, just a few minutes too late (I was going to post from home, but ran out of time, and in the time it took me to get to work, the answers were posted).

    Oh well – here’s my answer, and it’s based on Bayer designations.

    My answer is Beta is the odd one out, because Beta Canum Venaticorum is (I believe) the only star with a Bayer Designation that made it into Turnbull & Tarter’s “Top 25 Habstars within 25 Parsecs” list as presented in HabCat2 (pub The Astrophysical Journal Supplement Series, 149:423–436, 2003 December).

  22. Sili says

    “alpha particles are the only non-fermions.

    Photons ain’t fermions.

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