Cancer 7,062 Posted November 26, 2019 Report Share Posted November 26, 2019 The Mathworld page for "Divide and Conquer Algorithm" is blank. Question for the student: Is that fact a deep, haiku-like statement about that kind of algorithm? Quote Link to post Share on other sites
Cancer 7,062 Posted November 28, 2019 Report Share Posted November 28, 2019 Townsend's warbler (male) showed up at the suet feeder. Other winter birds should soon follow. Quote Link to post Share on other sites
L. Marcus 2,467 Posted November 28, 2019 Report Share Posted November 28, 2019 ... Not Pete Townshend? Quote Link to post Share on other sites
Cancer 7,062 Posted November 28, 2019 Report Share Posted November 28, 2019 No, this guy. Quote Link to post Share on other sites
L. Marcus 2,467 Posted November 28, 2019 Report Share Posted November 28, 2019 That's not a singer! Quote Link to post Share on other sites
Old Man 11,648 Posted November 29, 2019 Report Share Posted November 29, 2019 You don't know that. Maybe he could carry a tune just fine. Quote Link to post Share on other sites
Cancer 7,062 Posted November 29, 2019 Report Share Posted November 29, 2019 This is almost as much fun and disruption since the last "Everyone is Thrakazog Day" many, many years ago. Quote Link to post Share on other sites
L. Marcus 2,467 Posted November 29, 2019 Report Share Posted November 29, 2019 Aargh, my brain! Quote Link to post Share on other sites
Cancer 7,062 Posted December 1, 2019 Report Share Posted December 1, 2019 I hear that frying in butter with a little lemon is a good preparation fot that. Quote Link to post Share on other sites
Cancer 7,062 Posted December 1, 2019 Report Share Posted December 1, 2019 Really hard on your cholesterol, though. Quote Link to post Share on other sites
Pariah 8,324 Posted December 1, 2019 Report Share Posted December 1, 2019 On 11/28/2019 at 1:29 PM, L. Marcus said: ... Not Pete Townshend? Who? Quote Link to post Share on other sites
Pariah 8,324 Posted December 1, 2019 Report Share Posted December 1, 2019 14 minutes ago, Cancer said: Really hard on your cholesterol, though. If your brain is being fried in butter with a little lemon, I should think cholesterol would be the least of your worries. Quote Link to post Share on other sites
Cancer 7,062 Posted December 1, 2019 Report Share Posted December 1, 2019 ... No, not by that time, it won't. Quote Link to post Share on other sites
Cancer 7,062 Posted December 1, 2019 Report Share Posted December 1, 2019 The downy woodpecker has been at the feeder quite a bit today. Quote Link to post Share on other sites
Cancer 7,062 Posted December 2, 2019 Report Share Posted December 2, 2019 Of course, those of us who remember teh bunneh, are not at all surprised by any of this. The Bunny Manifesto Quote Link to post Share on other sites
Pariah 8,324 Posted December 2, 2019 Report Share Posted December 2, 2019 Face on Mars now? Quote Link to post Share on other sites
L. Marcus 2,467 Posted December 2, 2019 Report Share Posted December 2, 2019 A face plant. Quote Link to post Share on other sites
Old Man 11,648 Posted December 2, 2019 Report Share Posted December 2, 2019 I knew he was a Cydonian. It all makes sense now. Quote Link to post Share on other sites
Bazza 4,793 Posted December 2, 2019 Report Share Posted December 2, 2019 Men are from Mars Quote Link to post Share on other sites
Cancer 7,062 Posted December 2, 2019 Report Share Posted December 2, 2019 Well, the guys who escape from there, yes. Quote Link to post Share on other sites
Cancer 7,062 Posted December 3, 2019 Report Share Posted December 3, 2019 As we get more and more obscure (as well as red).... Quote Link to post Share on other sites
Pariah 8,324 Posted December 3, 2019 Report Share Posted December 3, 2019 1 minute ago, Cancer said: As we get more and more obscure (as well as red).... Close-up of the previous, perhaps? Quote Link to post Share on other sites
Cancer 7,062 Posted December 3, 2019 Report Share Posted December 3, 2019 No, this is actually a tiny piece out of the solar spectrum ("rainbow") image of a couple of days ago. The very faint absorption line of neutral oxygen at 6300.311Å; it is not an electric dipole transition, hence "forbidden". Quote Link to post Share on other sites
L. Marcus 2,467 Posted December 3, 2019 Report Share Posted December 3, 2019 Forbidden! Quote Link to post Share on other sites
Cancer 7,062 Posted December 3, 2019 Report Share Posted December 3, 2019 That's a term (mostly) from quantum mechanics. An electron in an atom can jump from one level to a different level (by absorbing energy by consuming a photon if the new level is higher in energy , or releasing energy in the form of a photon if the new level is lower energy than the initial one) by a given mechanism (of which there are several) only if the "selection rules" are obeyed. These mostly involve the angular momentum values of the two states involved. "Permitted" lines come from electric dipole transitions, which couple most strongly to electromagnetic waves (and therefore photons). Different mechanisms (these have names like magnetic dipole, electric quadrupole, ...) have different selection rules, and there are electron state changes that can happen according to those other mechanisms, but they have lower probability of happening, by factors of ten-to-the-several. Now, lower probability means it will still happen (if nothing else interferes with the set-up before the jump happens), but you have to wait longer to see it happen. Under terrestrial conditions, you more or less never see anything but the "permitted" transition spectral lines, because collisions between atoms are usually frequent enough that no atom goes unmolested long enough for a detectable number of those "forbidden" transitions to occur. But in conditions that humans call vacuum, that need not be the case, and "vacuums" are pretty common in astrophysical situations, and included in those are the Sun's atmosphere. Quote Link to post Share on other sites
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