Homestead mailing list

[Bill Jones <billj AT harborside.com>]

Karen L. Black wrote:

> I suggested that a +6 oxidation was not all that unusual.
>  
So the point stands that the only three such elements in sequence by 
atomic number are Np, Pt, and Am.

>  
>
> > B: Only in the higher elements does the shell structure achieve the size
> >    
> necessary to support three elements in a row with the same valance.  The
> first time we notice it is in the transition metals, where lots of
> horizontal neighbors have valance of 2 or 3.
>  

> K: That's particularly noticable in the Group VIIIA triads: 
> iron/cobalt/nickel,
> rubidium/rhodium/palladium, and osmium/iridium/platinum.
>
> On a physical level, what we find in the fourth row is a nucleus shielded by
> three full orbital shells of electrons. That makes the outer-shell electrons
> easily detached, which accounts for metals' reflectivity, malleability, and
> conductivity.
>
> The lanthanides and actinides take this similarity a step further. They all
> act like group IIIA elements. In fact, several of the lanthanides and group
> IIIA elements were found mingled in ore samples from Sweden, which is why
> Ytterby, a small town in Sweden, has four elements named after it (yttrium,
> ytterbium, terbium and erbium).
> ***************************************************
>  
This doesn't seem that relevant, and thus quite a big to do, over my 
amusing speculation.

> > B: Further, neptunium, plutonium, and americium
> >    
> (the 3 sixes in question) became known as elements roughly in order
> shortly after transmutation of elements first occurred (by human
> intervention) in a reactor.
>
> K: The first artifically-produced element was technetium (1937). 
I understand the first priority was to find out why technicium (#43?) 
was missing from the Periodic Table.  And they did.  Technicium, IIRC, 
has such a short half-life that none would have survived long enough to 
have any present in the earth.

> This was
> followed by neptunium (1940), plutonium (1940), 
Indeed, within weeks.

> curium (1944) and americium
> (1944). Np & Pu were produced by cyclotron neutron bombardment of uranium.
> Curium was produced by helium-ion bombardment of plutonium, and americium by
> successive neutron captures by plutonium. (Berkeley had the big gun, and so
> created all of these.)
>
> And to call them "unnatural" begs the question: on what time scale? Were the
> earth considerably younger than it is, radioactive elements like technetium
> and neptunium would be still present from the original formation of the
> planet. Were the earth considerably older, we'd see even fewer radioactive
> elements, especially those that were not themselves decay products.
>  
That's why there are quotes around my use of "natural".  But no humans 
were alive then.  Only the first 92 could be known to any 
pre-technological modern humans (minus technicium).  The significance of 
"transuranic" would be the same as today: the reason there's a special 
word just for that concept.

> ****************************************************************************
> **
>  
>
> > And if it were true, what would be your number of the beast to leave to
> >    
> future generations to ponder?  93, 94, 95 (their atomic numbers)?  It's
> just not as catchy!
>
> I don't believe in numerology or cryptic phrases. If I were to give a
> warning to future generations, I'd make it as clear and as specific as
> possible.
>
>  
To people whose language you would not know?  What would be a better, 
more memorable warning?

My partner and I discussed it at dinner.  It really all depends on how 
confident you are that no such pre-historic human technology existed.  
I'm at least 90% confident that there wasn't, judging by how much money 
I'd put up.

If you believe Sagan, then many nuclear civilizations have likely come 
and gone, in the entire universe.  But as Sagan also pointed out in 
another context, space and time are so vast that it's unlikely their 
warning (if any) could have made it down to us.

The most powerful counterargument is that only Bill would have been 
astute enough to notice the warning, so it likely wouldn't do much good!

Bill