“And argon, krypton, neon, radon, xenon, zinc and rhodium,
And chlorine, cobalt, carbon, copper, tungsten, tin and sodium.
These are the only ones of which the news has come to Harvard,
And there may be many others, but they haven’t been discarvard.” -Tom Lehrer

Stars fuse hydrogen into helium, then helium into carbon and then it’s up the periodic table to higher and heavier ones via other fusion and neutron-capture mechanisms. But there are three elements in between helium and carbon: lithium, beryllium, and boron. Those three elements can’t be made by conventional fusion, and in fact, aren’t made in stars at all.

Image credit: Wikimedia Commons user MHz`as, with data from Katharina Lodders (2003). The Astrophysical Journal 591: 1220–1247.

Image credit: Wikimedia Commons user MHz`as, with data from Katharina Lodders (2003). The Astrophysical Journal 591: 1220–1247.

Although they’re relatively rare in the Solar System and on Earth, they very much exist, and are essential to everything from plants (which need boron for their cell walls) to cellphones (which need lithium for their batteries). Their origin came not from fusion, but through cosmic spallation, where high energy particles blasted apart these heavy nuclei and created these light elements found on our world.

The nebula from supernova remnant W49B, still visible in X-rays, radio and infrare wavelengths. Image credit: X-ray: NASA/CXC/MIT/L.Lopez et al.; Infrared: Palomar; Radio: NSF/NRAO/VLA.

The nebula from supernova remnant W49B, still visible in X-rays, radio and infrare wavelengths. Image credit: X-ray: NASA/CXC/MIT/L.Lopez et al.; Infrared: Palomar; Radio: NSF/NRAO/VLA.

It’s an incredible story of how these rare, light elements came to be. Go find out the details today.

Comments

  1. #1 eric
    August 18, 2016

    Nice article. I believe 118 is named (or is going to be named) Oganesson, Og, after one of the key Russian scientists in the element discovery business. Not sure whether the odd Z ones have officially been accepted as discovered yet. I really wish they’d just remove the boxes from the undiscovered elements and stop using those IUPAC placeholders. Removing the boxes would more visually communicate to kids that there is stuff to be discovered. Get rid of the ‘un un…’ names because no professional chemist or physicist actually uses them. If you want to teach kids what scientists do, scientists do call the unnamed elements by their number; 115, 117, etc., they don’t use the IUPAC bureaucratically-invented placeholders.

  2. #2 Malakyp
    August 18, 2016

    Your article says that spallation is the “only reason” why Li, Be, and B exist at all, but that’s not strictly accurate. Big Bang nucleosynthesis produced some quantities of 7Li and 7Be:

    3T + 4He -> 7Li + γ
    3He + 4He -> 7Be + γ
    7Be + n -> 7Li + p

    Now, a lot of that has been burned in stars since the Big Bang (and, for that matter, a lot of the primordial 7Li absorbed a proton during Big Bang nucleosynthesis and fissioned off into 2 4He nuclei due to the anomalously low binding energy of lithium). But those primordial nuclides do still exist (and, for 7Li, have been experimentally detected), even if spallation is responsible for much of the elements’ occurrence in the modern universe.

  3. #3 Wow
    August 18, 2016

    But doesn’t that also mean that Li-7 is also created in fusion in the centre of stars, therefore what has been burned off in stars sine the big bang would include that stellar generated Lithium.

    Not to mention only a small % of the matter has been ingested by stars so far. Which would be a small % of primordial Li-7.

    I mean, you have a point, but it’s not really as big as would be implied from your post.

  4. #4 Malakyp
    August 18, 2016

    Well, yes, in fact, stellar nucleosynthesis also produces Lithium-7, but quickly consumes it. In fact, even brown dwarfs not capable of hydrogen fusion can burn lithium, making it one candidate for the dividing lines between large gas giant / brown dwarf / actual star. Some stellar lithium does escape back into circulation, but that’s ot really important, because the process is net-negative under real-world conditions.

    But Big Bang nucleosynthesis of Lithium-7 is still important, and early models (and, arguably, current models) of BBN over-predict the amount of primordial Li-7 present. It’s a significant topic of cosmological research, which is why it’s important, even if the total amount of lithium involved is smallish (although it’s also partially why Lithium-7 is vastly more common than Lithium-6, which pretty much can only be produced by spallation).

  5. #5 See Noevo
    August 18, 2016

    “The rarest light elements in the Universe”

    Another lightweight article.

    I wonder how much play this topic might get in the presidential campaigns and debates.

    Which got me thinking…
    From the recent “Nothing” article by Ethan:
    “General Relativity was formulated in the 1910s; the Standard Model’s predictions were finalized in the 1960s. For the past 50 years, the greatest novel ideas in theoretical physics… have all failed to turn up a direct experimental signature of a new particle or interaction beyond the known forces.”

    From the last hundred years,
    what would be the top two things which people appreciate in their daily lives which resulted from
    General Relativity, the Standard Model, theoretical physics?

  6. #6 eric
    August 18, 2016

    what would be the top two things which people appreciate in their daily lives which resulted from
    General Relativity, the Standard Model, theoretical physics?

    A question to which everyone will have their own opinion. And the last hundred years covers a huge amount of change in society; rocketry, quantum mechanics, integrated circuits, etc. But in the last 30 years or so, I’d say extremely accurate GPS (uses GR corrections) and optical fiber (2009 Nobel award is based on theoretical physics calculations which showed it could function well to transmit signals) have to be pretty close to the top.

  7. #7 Malakyp
    August 18, 2016

    Well, for the last hundred years, I’ll pick just one, because it’s the core of the modern era: the transistor, development of which was based on a then-novel branch of quantum mechanics.

  8. #8 See Noevo
    August 18, 2016

    Ethan,

    Enough of this lightweight stuff.
    Here’s a subject for a future article:

    “… a new and confusing problem for astronomers trying to understand what the heck is going on.
    … No matter how you slice it, this is strange…
    … once again, astronomers are clutching at straws in an effort to explain what is going on.”

    [To me, what’s most shocking is how much intelligent design talk (“alien megastructure”) is coming from members of the astronomical community!]

    http://www.space.com/33674-alien-megastructure-star-just-got-even-weirder.html

  9. #9 Narad
    August 18, 2016

    Enough of this lightweight stuff.

    Oh, dear, changing the subject from comment 5 already? It’s just as well, given that you’ve gotten the same answers before.

    Here’s a subject for a future article

    I’m quite sure the everyone will be eager to check in when you write up this stale dreck on your own blog.

  10. #10 Narad
    August 18, 2016

    ^ P.S.: You can identify the preprint “at issue,” right, S.N.?

  11. #11 Wow
    August 22, 2016

    “Well, yes, in fact, stellar nucleosynthesis also produces Lithium-7, but quickly consumes it.”

    Well, yes, but you’re using the quick consumption to proclaim that the primordial Li-7 is largely gone, which is both circular and begging the question.

    If it must have “eaten” a lot of Li-7, then if that can come from nucleosynthesis in stellar atmospheres, you must deduct this from the volume consumed, or you’re at the very least double-dipping.

  12. #12 Wow
    August 22, 2016

    “But Big Bang nucleosynthesis of Lithium-7 is still important, and early models (and, arguably, current models) of BBN over-predict the amount of primordial Li-7 present. It’s a significant topic of cosmological research,”

    But that’s not what your first point appeared to say.

  13. #13 Akinbo
    August 28, 2016

    This may be the appropriate section of this blog to point out a few things…
    We all know Mother Nature’s gradualist ways and have coined phrases for them: “Rome was not built in a day”; “a journey of a thousand miles starts with a step”, “little drops of water make a mighty ocean”, etc. Unfortunately, some cosmologists would prefer that the universe become wealthy overnight. The universe is now 10^52kg rich (i.e. about 10^69J) and they want to force this wealth, our current mass estimate into the very beginning (time zero), the Planck epoch and the other early times. Of course, Mother Nature has resisted this get-rich-quick attitude and has inflicted such versions of our Big bang model with riddles, like the flatness and singularity problems for example.

    In this post, I quote from Steven Weinberg’s popular book, The First Three Minutes,
    “As the explosion continued the temperature dropped …but the temperature continued to drop, finally reaching one thousand million degrees (10^9K) at the end of the first three minutes. It was then cool enough for the protons and neutrons to begin to form nuclei, starting with the nucleus of heavy hydrogen (or deuterium), which consists of one proton and one neutron”.
    Cosmologists generally admit uncertainty of what the scenario is at time zero, less uncertainty at the Planck epoch but some confidence of the situation at three minutes because knowing what the binding energies of nuclei are, the ambient energies that must be present at three minutes to enable their formation (nucleo-synthesis) can be deduced. For example, the binding energy of the nucleus of heavy hydrogen (deuterium) and that of helium are 2.2 MeV and 28.3 MeV respectively with the corresponding temperatures permitting stability being ~10^10K and 10^11K. These quantitative values are not controversial.
    We can therefore say with confidence that if the ambient energies and temperatures at the end of the first three minutes are above their binding energy values, hydrogen and helium nuclei cannot form. For example, at 10^12K energies are too high and only a quark-gluon plasma can be stable. See Wikipedia: Chronology of the universe, https://en.wikipedia.org/wiki/Chronology_of_the_universe and also Hyperphysics website, http://hyperphysics.phy-astr.gsu.edu/hbase/astro/bbcloc.html#c1 for reference to the timelines.
    Now, there are formulae that help us relate the energy density within a given volume to the temperature using blackbody radiation laws. See for sample reference, “Radiation Energy Density”,
    http://hyperphysics.phy-astr.gsu.edu/hbase/quantum/raddens.html#c1. Same formulae are used to estimate the 10^32K temperature at the Planck epoch from the Planck density.
    From the foregoing, if cosmologists decide to be greedy and acquire all our current material wealth within three minutes, i.e. ~10^52kg (~10^69J), given the standard model expansion rate, our universe will be about 5.4 x 10^10m radius (with volume ~ 6.6 x 10^32m^3), giving us an energy density of ~10^36 J/m^3 (~1019kg/m3) at this time. This energy density translates to temperatures about 6.6 x10^12K and ambient energies of ~669 MeV, which is so much higher than can permit the formation of nuclei for deuterium (binding energy <2.2 MeV, ~10^10K) and helium (binding energy < 28.3 MeV, ~10^11K) and the Big bang nucleo-synthesis model will collapse.
    If however, we allow Mother Nature to build the universe gradually, according to Hypothesis 1 in thee-book, Hypotheses Fingo, (http://www.goodreads.com/book/show/30976852-hypotheses-fingo) to wit;
    The Universe is increasing in mass and radius from an initial zero value in accord with the formula M = rc^2/2G which amounts to about 6.75 x 10^26kg per metre change in radius (and about 2.02 x 10^35kg per second),

    the mass of the universe will be about 3.6 x10^37kg (~ 3.24 x10^54J) at the end of the first three minutes, and not 10^52kg. This being so, given the volume (~ 6.6 x 10^32m^3) the energy density will be 4.9 x10^21J/m3 at three minutes and the corresponding temperatures and ambient energies for the energy density will be ~10^9K and 0.1 MeV (~10^-4GeV) respectively, just the right temperature for Mother Nature to cook us a perfect dinner of hydrogen-helium nuclei soup where both nuclei are stable.
    Or can we cheat Mother Nature?

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