OPEN THREAD 20200130

Basically, all legal free speech is allowed. We will assist the authorities in dealing with illegal speech. You are each other’s moderators. Have fun. And don’t forget to MAGA at nuclear levels.

Citizen U

Day 85 – ASTATINE.

47 thoughts on “OPEN THREAD 20200130

  1. Polonium and astatine, as well as the next four elements (radon, francium, radium, and actinium) have in common the fact that were it not by the grace of there still being original uranium and thorium in existence…they wouldn’t exist either.

    The longest lived isotope of any of these elements is 1600 years (only two or three others live longer than a year), which is far, far shorter than the age of our solar system, which in turn formed out of supernova remnants. There is ample evidence that short lived isotopes were present when the solar system first formed (for example, aluminum-26 was present; we can see the effects of its radiation in meteorites, but there is no remaining trace of it). Today they are all gone. (The fact that they were present but are gone now, is evidence for an old earth and solar system, by the way.)

    And yet: we have some polonium-210 in our uranium ores. Similarly for radon, radium, and actinium. (We have NO polonium-209 in our ores, even though it has a much longer half life than polonium-210.)

    So if an isotope has such a short half life, why is it nevertheless still present? And why aren’t they all present?

    The clue is that these isotopes appear only in uranium and thorium ores. They can only exist in the presence of those two elements.

    That’s because they are *created* by those two elements, directly or indirectly.

    OK, so now it’s time to learn a little nuclear bookkeeping.

    An atom consists of a cloud of electrons, which takes up most of the space, but usually contributes less than 1/2000th of the mass. In the center of that cloud is a much smaller nucleus, almost all of the mass and almost none of the space. The electrons matter for chemistry, but don’t matter at all for atomic physics and isotopes, and vice versa for the nucleus, which doesn’t matter at all for chemistry, and is the topic of atomic physics.

    The nucleus consists of some number (1 and up) of protons, positively charged, and some other number (0 or more) neutrons, electricially neutral; the neutron is just a tiny bit more massive than the proton. It is the number of protons that defines the element. 6 protons, is carbon, no matter how many or few neutrons are there. If a proton is lost, it’s not carbon any more, it’s boron, 5 protons. More famously if you have a nucleus of 6 protons and eight neutrons, and one of those neutrons should happen to become a proton, making 7 and 7, you now have an atom of nitrogen.

    The isotope number is simply the total number of protons and neutrons, so carbon-14 has a total number of “nucleons” equal to 14, and is the atom I just talked about; similarly nitrogen-14 has 7 of each.

    So when talking about uranium and thorium, we have three distinct isotopes that live long enough to still be around after 4.5 billion years:

    Th-232 90 protons 142 neutrons
    U-235 92 protons 143 neutrons
    U-238 92 protons 146 neutrons

    These are all unstable, relatively mildly so. Thorium-232 has a half life of over 14 billion years (slightly older than the universe), U-235 has a half life of 700 million years, and U-238 has a half life of about 4.5 billion years.

    They are all most likely to decay by spitting out an alpha particle. An alpha particle is 2 protons and 2 neutrons (it is itself a helium nucleus, and ALL of the helium we get out of oil and natural gas wells is actually alpha particles).

    So what happens to these isotopes when they decay?

    Th-232 loses four units (232-4=228) and two of them are protons, so it’s now element 88 instead of element 90, that’s radium, so it’s now radium-228.

    U-235 loses four units (235-4=231) and two of them are protons, so it’s now element 90 instead of element 92, that’s thorium, so it’s now thorium-231.

    U-238 loses four units (238-4=234) and two of them are protons, so it’s now element 90 instead of element 92, which is thorium, so it’s now thorium-234.

    The OTHER mode of radioactive decay is beta decay, which can involve a neutron turning into a proton, or vice versa (an electron is spat out in the first case, a positron (antimatter electron) in the other so that total charge stays constant). The important thing to note is that the number of nucleons does NOT change, but the element does change. A neutron changing into a proton will increase the element number by one. Thorium-234 does precisely this; one of its 144 neutrons turns into a proton, so now it has 91 protons, 143 neutrons, and is protactinium-234. This atom repeats the trick and becomes uranium-234.

    Each of these three original isotopes has a long chain like this, before they become something stable. That would be a lead isotope of some sort. But note, if the isotope number starts out divisible by four (232, for thorium) it will ALWAYS be divisible by four because the number can only change by spitting out an alpha particle. So whatever might happen to the thorium nucleus as it decays over and over again to become lead, its mass will be 232, then 228, then 224, then 220, then 216, then 212, then finally 208 (lead 208 is stable). So isotopes in this range that have numbers divisible by 4 are called the “Thorium Decay Series” because they’re in the chain that starts with thorium.

    U-238: 238 divides by four with a remainder of 2, so all the daughter isotopes must be the same way: 234 (as we saw already), 230, 226, 222, 218, 214, 210, 206, lead 206 being stable. These isotopes are the “Uranium Decay Series.” (Sometimes called the radium series.)

    Finally U-235: 235 divides by four with a remainder of 3, so all daughter isotopes must be the same way (231, 227, 223, 219, 215, 211, 207, lead 207 being stable). But since the name “uranium decay series” is already taken, it’s called the actinium decay series.

    But…we’ve left something out. Nuclei that divide by four with a remainder of one. Well, a chain like this theoretically exists…but the parent isotope is GONE forever. Neptunium-237 has a half life of 2.14 million years, so 2000 half lives have elapsed since the earth was formed. It’s all gone. The series can only be created artificially today. (We make these isotopes by adding single neutrons to other atoms.)

    As a consequence, no isotope found in nature will have a number like 237, 233, 229, 225, 221, 217, 213, or 209. Thallium 205 is stable, and would be the end of this chain.

    This is why polonium 209, even though it has a fairly long half life, does NOT exist in nature, not even as a trace.

    Decay chains, by the way, have many forks. In many places, an isotope can decay two different ways. Astatine-210, for instance, can either alpha decay to bismuth 206, or can positive-beta-decay to become polonium 210 (same mass, one lower element number).

    Here: you can find pictures of all four series and follow the different branches. Moving down on the diagrams is an alpha decay, while moving up and to the left or right is a beta decay. For example, note that in the uranium series, after U-234, it’s nothing but alpha decays through polonium 218 (U-234, Th-230, Ra-226, Rn-222, Po-218. Po-218 can become lead 214 via alpha decay, or astatine 218. One of the side branches on this series can become Mercury-208, which will undergo a couple of beta decays and settle down as lead 208.

    The amount of a given isotope existing in ore, is directly related to its half life, the half life of the parent isotope, and the odds of that isotope being the route taken. So if the parent has a billion year half life, and the first daughter isotope has a 100 million year half life, you’ll generally see ten times as much of the parent as of the daughter, so if you have 10,000 atoms of the parent, you’d see (100/1000)*10,000 = 1000 atoms of the daughter isotope And if there’s a fork in the road, so that that daughter can decay to either granddaughter A (10 million year half life) or granddaughter B (1 million year half life), but it’s 2-1 odds of becoming granddaughter B, then if your sample has 1000 atoms of the daughter, there will probably be about (10/100*1/3)=0.033 times as many atoms of grandaughter A (33 atoms) or (1/100*2/3)=0.0067 times as many atoms of granddaughter B (6 or 7 atoms).

    So this is why, the shorter lived the isotope, the less of it there is, and it’s compounded if it happens to be on the short end of the stick when the chain forks.

    And that’s why astatine is so doggone rare, that they estimate only an ounce of it exists in the earth’s crust. Because all of its isotopes have a half life of hours (we can ignore astatine 209, because it’s in the neptunium series, but it wouldn’t matter even if it weren’t, because it too is short lived), and it tends to be unlikely to be created in the first place.

    So there’s an ounce of astatine in the earth’s crust right now. Come back next week, and there will be an ounce of astatine in the earth’s crust then, too…but it won’t be the SAME ounce of astatine!

    As a side note, Th-232, U-235, and U-238 aren’t the only primordial isotopes (i.e., ones that are left over from the creation of the earth). Every stable isotope is primoridial too. But even leaving aside that trick-question “gotcha” there are other primordial isotopes, ones that are of elements which we tend to think of as stable. The most famous of these is potassium-40. Every sample of potassium contains almost entirely stable isotopes, but then there’s just a tiny bit of unstable potassium 40, with a half life of a billion years. It was, four billion years ago, sixteen times as common as it is today. Most of the argon in our atmosphere is argon-40, and it was produced by potassium-40 decay. (Stellar nucleosynthesis tends to want to produce argon-36, which is also stable and is more common in the universe; our atmosphere is a special case.)

    Liked by 3 people

    1. One thing to be noted is that the names of the four main decay chains are somewhat arbitrary. As the Wikipedia article expressly states, “In the distant past, around the time that the solar system formed, there were more kinds of unstable high-weight isotopes available, and the four chains were longer with isotopes that have since decayed away. Today we have manufactured extinct isotopes, which again take their former places: plutonium-239, the nuclear bomb fuel, as the major example has a half-life of “only” 24,500 years, and decays by alpha emission into uranium-235. In particular, we have through the large-scale production of neptunium-237 successfully resurrected the hitherto extinct fourth chain.”

      So it’s possible that some of the astatine on the planet today might actually have been primordial Pu-239.

      Liked by 3 people

      1. Yes, they’re named after TODAY’s primordals, and not the actual tops of the chains.

        For that matter, there might still be just a tiny bit of primordial Pu-244 out there (and that would be the true top of the thorium series).

        Liked by 2 people

        1. For a fun next step…..the periodic chart at the top of the page that is provided by our gracious host notes that many of the elements heavier than niobium were substantially produced by merging neutron stars (purple). Here’s the thing, though — last time I checked, there weren’t any neutron stars merging anywhere nearby…..

          Now, one thing about radioactive decay is that it belongs to each particular atom. Irrespective of whether it’s in a group or alone. Doesn’t care if it’s cold or hot. Can happen inside a rock a mile deep inside a planet or as an individual atom travelling through outer space. So, any actual primordial elements at the formation of the earth 4.6B years ago must have been long-lived enough to have made it here from the neutron stars, or were products of decay along the way.

          So, let’s say a pair of neutron stars 100 light-years away merged, and shot a slug of unobtanium our way at .01 lightspeed. Ignoring relativistic effects (which might well come into play at higher velocities), it takes 10,000 years to get here…..and if unobtanium had a half-life of 10,000 years, the primordial elements it would contribute to the earth would be 1/2 unobtanium and 1/2 crapium. If two different neutron stars merged that were 200 light-years away, and sent a similar slug toward the proto-earth, we’d receive 1/4 unobtanium and 3/4 crapium.

          Since each neutron star event would produce its own signature of unobtanium/crapium, and knowing there shouldn’t be that many local ones, a skilled physicist at the formation of our planet could probably say something about recent mergers of neutron stars. The traces are a bit fuzzier 4.6B years later.

          Such are the rabbit-holes of science.

          Liked by 2 people

  2. Astatine is probably the rarest element naturally found in the earth’s crust. At any given time, there exists probably less than a gram in the entire crust. Its longest-lived naturally occurring isotope has a half-life of 8.1 hours.

    Liked by 1 person

  3. Astatine is *probably* a halogen. I’d guess it would be blacker than iodine, if we could see it in bulk.

    We will never know, because even if we create enough of it at once to see its bulk properties, it will be so intensely radioactive it will kill anyone nearby, and the heat will probably vaporize the sample (and you’d not want to be downwind from that!).

    Liked by 3 people

        1. Yeah, I was laughing at some of the descriptions of how they “proved” it would have such-and-such characteristics if they could only get enough of it.

          Liked by 2 people

  4. Second musical interlude — “Hoedown from Rodeo”, Copland (composed 1942)

    I finger-fumbled the first musical interlude and will repost in a bit if management doesn’t give it a swift kick first.

    Liked by 2 people

  5. Third musical interlude. I was going to bring a dance-based orchestral piece from the first half of the 20th century, but I’m writing something in another tab and this little ditty is just too infectious.

    Liked by 2 people

  6. Found at , with some editing.

    (Mind you, I was looking for jokes about Communism and football…. )

    Funny Political Systems

    Every country and every party has its funny political systems, here are some of our favourites researched by Alicia Moss.

    An American Democrat

    You have two cows.
    Your neighbour has none.
    You feel guilty for being successful.
    You vote people into office that put a tax on your cows, forcing you to sell one to raise money to pay the tax.
    The people you voted for then take tax money, buy a cow and give it to your neighbour.
    You feel righteous and Barbara Streisand sings for you.

    An American Republican

    You have two cows.
    Your neighbour has none.


    You have two cows.
    The government takes one and gives it to your neighbour.
    You form a cooperative to tell him how to manage his cow.


    You have two cows.
    The government seizes both and provides you with milk.
    You wait in line for hours to get it.
    It is expensive and sour.

    Capitalism, American style

    You have two cows.
    You sell one, buy a bull, and build a herd of cows.

    Foreign Policy, American style

    You have two cows.
    The government taxes you to the point you have to sell both to support a man in a foreign country who has only one cow, which was a gift from your government.

    Bureaucracy, American style

    You have two cows.
    The government takes them both, shoots one, milks the other, pays you for the milk, and then pours the milk down the drain.

    Democracy, American style

    The government promises to give you two cows if you vote for it.
    After the election, the president is impeached for speculating in cow futures.
    The press dubs the affair “Cowgate”


    You have two cows.
    Your lord takes some of the milk.

    Pure socialism

    You have two cows.
    The government takes them and puts them in a barn with everyone else’s cows.
    You have to take care of all the cows.
    The government gives you as much milk as you need

    Bureaucratic socialism

    You have two cows.
    The government takes them and puts them in a barn with everyone else’s cows.
    They are cared for by ex-chicken farmers.
    You have to take care of the chickens the government took from the chicken farmers.
    The government gives you as much milk and as many eggs as the regulations say you should need.


    You have two cows.
    The government takes both, hires you to take care of them, and sells you the milk.

    Pure communism

    You have two cows.
    Your neighbours help you take care of them, and you all share the milk.

    Russian communism

    You have two cows.
    You have to take care of them, but the government takes all the milk.


    You have two cows.
    The government takes both and shoots you.

    Singaporean democracy

    You have two cows.
    The government fines you for keeping two unlicensed farm animals in an apartment.


    You have two cows.
    The government takes both and drafts you.

    Pure democracy

    You have two cows.
    Your neighbours decide who gets the milk.

    Representative democracy

    You have two cows.
    Your neighbours pick someone to tell you who gets the milk.

    British democracy

    You have two cows.
    You feed them sheep’s brains and they go mad.
    The government doesn’t do anything.

    EU Bureaucracy

    You have two cows.
    At first the government regulates what you can feed them and when you can milk them.
    Then it pays you not to milk them.
    After that it takes both, shoots one, milks the other and pours the milk down the drain.
    Then it requires you to fill out forms accounting for the missing cows


    You have two cows.
    Either you sell the milk at a fair price or your neighbours try to kill you and take the cows


    You have two cows.
    You sell one and buy a bull

    Hone Kong capitalism

    You have two cows.
    You sell three of them to your publicly-listed company, using letters of credit opened by your brother-in-law at the bank, then execute a debt / equity swap with associated general offer so that you get all four cows back, with a tax deduction for keeping five cows.

    The milk rights of six cows are transferred via a Panamanian intermediary to a Cayman Islands company secretly owned by the majority shareholder, who sells the rights to all seven cows’ milk back to the listed company.
    The annual report says that the company owns eight cows, with an option on one more. Meanwhile, you kill the two cows because the feng-shui is bad.


    You have two cows.
    The government bans you from milking or killing them.


    You have two cows.
    They get married and adopt a veal calf.


    You have two cows.
    The government takes them and denies they ever existed.
    Milk is banned.

    Political Correctness

    You are associated with (the concept of “ownership” is a symbol of the phallo – centric, war – mongering, intolerant past) two differently – aged (but no less valuable to society) bovines of non – specified gender.

    Counter Culture

    Wow, dude, there’s like… these two cows, man.
    You got to have some of this milk.

    Clockwork Orange

    The Korova Milk Bar sells Milk Plus: milk plus synthemesc, vellocet, or drencrom, which is what we were drinking. This will sharpen you up and make you ready for a bit of the old ultraviolence.


    You have two giraffes.
    The government requires you to take harmonica lessons.

    Liked by 3 people

      1. We visited Saint Petersburg in 2011. I had flash cards, Nadsat, and 35-year-old memories of poking through translations of Classical Greek. It worked surprisingly well. After the first few days, I was able to transliterate the Cyrillic, and things went more smoothly.

        Liked by 2 people

    1. Good list.

      In all seriousness, foreign aid is such a tiny part of the budget that we’d not notice the change in the budget if we stopped spending that money. It’s not burdensome, but what little there is. is a waste at best.

      Caveat, I am talking about simply handing money to foreign governments so they can flush it down the gold plated toilet we bought them (what is usually meant by foreign aid) rather than defense money spent on (more than) our share of alliance military spending, which is far greater, but at least DOES benefit us as well as them.

      Liked by 1 person

  7. The Vicar spoke to his curate. “I’m going away today, but I’ll be back on Saturday evening in time to conduct matins on Sunday morning. Will you make sure the hymn numbers are put up on Saturday afternoon so that everything is ready when the service begins? They’re all written on this piece of paper apart from the first hymn.”

    “Yes, certainly Vicar, but what are you doing about the first hymn?” asked the curate.

    “It depends”, said the Vicar. “It’s Polling Day for the General Election on Thursday. The first hymn will depend on the result. If the Conservatives have a sufficient majority to form a government, it’ll be 283, ‘Now thank we all our God.’ However, if Labour has most seats and are going to form the next government, then put up number 578, ‘Go labour on, spend and be spent.'”

    “Yes, right”, said the curate. “I’ll see you on Sunday morning.”

    “Oh, there’s just one thing,” said the curate. “Suppose the Liberal Democrats have the majority, what number would you want me to put up in that circumstance?”

    “Oh, in that circumstance, it’ll be 482, ‘God moves in a mysterious way His wonders to perform.'”

    Liked by 3 people

  8. A couple of decades ago, some enironmentalist whacko noticed that a lot of the “nasty” chemicals in the news lately had been chlorine compounds: chloroflurocarbs, PCBs, etc. and figured the problem must be chlorine; he tried to start a crusade to ban all chlorine compounds.

    At least some of these viros were smart enough to realize that sodium chloride is an essential part of our biology, and told this jackass to shut the fuck up.

    But that didn’t stop me from mounting a parody craze to ban ALL of the halogens. And in talking about this with a geek much like myself and Cthulhu, I named them off…fluorine, chlorine, bromine, iodine and astatine. He scoffed, “there’s hardly any astatine out there” and I crowed, “See, our first success!!!!”

    (Well, OK I didn’t think of that line until about ten minutes later and it was too late. Damn.)

    Liked by 3 people

  9. OK…So…I found this and thought appropriate to bring here…LOL😂 as I am getting sent to spam bin at Wolfies…🤷‍♀️🤷‍♀️🤷‍♀️ just started tonight… Want to see if I go to spam here! Hi Steve!!

    Liked by 3 people

      1. Hiya darlin! I am…Still..going in Q tree bin!!! Never happened before!!!!! You better hope I get back on…LOL cuz if WP get’s more bitchy dan dis—Ima bringing my prayers and !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! …TO U!!! LOL! How ya been darlin!!! fence all done?😘

        Liked by 3 people

          1. Not so many parties!!! We..moar…giggles.. and prayers… Plain Jane..had a rough diagnosis…But.. we..could use… Some…Tango!!!!😉💖😘🥰 Miss you, darlin…serious!!!!!!!!!!!!

            Liked by 4 people

              1. Yeah… I kinda thought …this would be…short-lived…but…Our mash unit..Is…Hard…and will..Survive..Gotta keep doing it!!! I told Wolfie…”I just wanted to open a lil window to “mourn PHC” We turned into…a…PLACE…? 🤷‍♀️💖

                Liked by 3 people

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