Reply by Rich S October 15, 20212021-10-15
[snip]
> > I recall a show where a guy sat in a field of clover and periodically pulled > > up a four-leaf-clover -- disproving the myth of their scarcity. Maybe it's > > just a matter of BELIEVING that you will find something...? > My wife has this uncanny ability of finding four-leaved clovers > everywhere. She can just casually glance down on a random patch > and pick a handful. Myself, I just don't spot them. I suppose she > must see them in a different colour or something... > > Jeroen Belleman
Maybe she's special :-) https://www.healthline.com/health/tetrachromacy
Reply by Anthony William Sloman October 15, 20212021-10-15
On Friday, October 15, 2021 at 1:55:49 PM UTC+11, wmartin wrote:
> On 10/14/21 1:43 AM, Anthony William Sloman wrote: > > On Thursday, October 14, 2021 at 7:09:23 PM UTC+11, Tom Gardner wrote: > >> On 14/10/21 07:11, Anthony William Sloman wrote: > >>> On Thursday, October 14, 2021 at 4:40:00 PM UTC+11, Ferry wrote: > >>>> On a sunny day (Tue, 12 Oct 2021 04:53:31 -0700) it happened Don Y > >>>> <blocked...@foo.invalid> wrote in <sk3t02$csg$1...@dont-email.me>: > >>>>> I caught the tail end (last 2-3 minutes) of a TV show which depicted > >>>>> a couple of guys hunting for gold deposits with the sorts of metal > >>>>> detectors you'd look for trinkets on a sandy beach. > >>>>> > >>>>> And, apparently, *finding* same! (gold just lying around in > >>>>> surface rock outcroppings? who'd guessed!) > >>>> Obvious, gold is heavy, here in the northern hemisphere it is buried deep, > >>>> while In Australia it sinks to the surface. > >>> > >>> Odd how it did the same thing in California. > >>> > >> We are always being told that California is /odd/. > >> > >> Clearly, since California is at the edge of the world, > >> that's where centrifugal forces are strongest. Ditto > >> Yukon. > > > > So how come John Larkin and Sarah Palin weren't slung off into space? Life would be so much nicer if this had happened. > > > > Of course Tasmania is equally peripheral, and I managed to grow up there. > > The devil you say! :-)
There weren't many around. I lived in a town, and you had to get quite a way into forested areas before you'd have a chance to see one. The only one I can recall seeing (from our car) was making it's way along the over-grown verge of a back-country road through virgin bush about twenty miles in from the coast. -- Bill Sloman, Sydney
Reply by wmartin October 14, 20212021-10-14
On 10/14/21 1:43 AM, Anthony William Sloman wrote:
> On Thursday, October 14, 2021 at 7:09:23 PM UTC+11, Tom Gardner wrote: >> On 14/10/21 07:11, Anthony William Sloman wrote: >>> On Thursday, October 14, 2021 at 4:40:00 PM UTC+11, Ferry wrote: >>>> On a sunny day (Tue, 12 Oct 2021 04:53:31 -0700) it happened Don Y >>>> <blocked...@foo.invalid> wrote in <sk3t02$csg$1...@dont-email.me>: >>>>> I caught the tail end (last 2-3 minutes) of a TV show which depicted >>>>> a couple of guys hunting for gold deposits with the sorts of metal >>>>> detectors you'd look for trinkets on a sandy beach. >>>>> >>>>> And, apparently, *finding* same! (gold just lying around in >>>>> surface rock outcroppings? who'd guessed!) >>>> Obvious, gold is heavy, here in the northern hemisphere it is buried deep, >>>> while In Australia it sinks to the surface. >>> >>> Odd how it did the same thing in California. >>> >> We are always being told that California is /odd/. >> >> Clearly, since California is at the edge of the world, >> that's where centrifugal forces are strongest. Ditto >> Yukon. > > So how come John Larkin and Sarah Palin weren't slung off into space? Life would be so much nicer if this had happened. > > Of course Tasmania is equally peripheral, and I managed to grow up there. >
The devil you say! :-)
Reply by Chris October 14, 20212021-10-14
On Thursday, 14 October 2021 at 23:12:04 UTC+11, Don Y wrote:
> On 10/14/2021 4:08 AM, Martin Brown wrote: > > >>>>> From the bottom of Marianas to the top of Everest is ~ 19.9km vs Earth's > >>>>> radius ~6371km gives ~0.3% - surface features are negligible... > >>>> > >>>> Place a drop of water in a weightless environment. Tell me how much > >>>> variation their is in its shape... > >>> > >>> Depends how big it is. Gravity is an incredibly weak force so it will pretty > >>> much look like an amoeba unless it is small enough for surface tension to be > >>> the most dominant force acting. > >>> > >>> https://www.youtube.com/watch?v=rzytpxtbCzQ > >>> > >>> Water in zero g from the Royal Institution Xmas lectures 2015. > >> > >> Or, for it to "settle" over time. > > > > You might have to wait for geological timescales though. > Um, aren't we talking about geological time scales? :> > > Gravity is really puny. If you put the dimensions of a human into the stellar > > equilibrium equation you find that we ought to fly apart! That is outwards > > radiation pressure must be equal to self gravitating attraction at the surface > > of the body. Luckily we are held together by skin which relies on much stronger > > chemical bonds from electromagnetism. > >
The water drop also isn't spinning like the Earth which gives it (Earth) an oblate spheroid shape bias. -- Cheers, Chris
Reply by Don Y October 14, 20212021-10-14
On 10/14/2021 4:08 AM, Martin Brown wrote:

>>>>> From the bottom of Marianas to the top of Everest is ~ 19.9km vs Earth's >>>>> radius ~6371km gives ~0.3% - surface features are negligible... >>>> >>>> Place a drop of water in a weightless environment. Tell me how much >>>> variation their is in its shape... >>> >>> Depends how big it is. Gravity is an incredibly weak force so it will pretty >>> much look like an amoeba unless it is small enough for surface tension to be >>> the most dominant force acting. >>> >>> https://www.youtube.com/watch?v=rzytpxtbCzQ >>> >>> Water in zero g from the Royal Institution Xmas lectures 2015. >> >> Or, for it to "settle" over time. > > You might have to wait for geological timescales though.
Um, aren't we talking about geological time scales? :>
> Gravity is really puny. If you put the dimensions of a human into the stellar > equilibrium equation you find that we ought to fly apart! That is outwards > radiation pressure must be equal to self gravitating attraction at the surface > of the body. Luckily we are held together by skin which relies on much stronger > chemical bonds from electromagnetism. >
Reply by Clifford Heath October 14, 20212021-10-14
On 14/10/21 7:53 pm, Martin Brown wrote:
> On 14/10/2021 00:27, Don Y wrote: >> On 10/13/2021 3:29 PM, Chris wrote: >>> On Wednesday, 13 October 2021 at 19:35:48 UTC+11, Don Y wrote: >>>> On 10/13/2021 12:52 AM, Tom Gardner wrote: >>>>> On 13/10/21 05:01, Don Y wrote: >>>>>> On 10/12/2021 3:46 PM, Tom Gardner wrote: >>>>>>> On 12/10/21 22:59, Don Y wrote: >>>>>>>> On 10/12/2021 2:28 PM, Martin Brown wrote: >>>>>>>>> On 12/10/2021 20:44, Don Y wrote: >>>>>>>>>> On 10/12/2021 9:23 AM, Joe Gwinn wrote: >>>>>>>>>>> On Tue, 12 Oct 2021 14:15:33 +0100, Martin Brown >>>>>>>>>>> <'''newspam'''@nonad.co.uk> wrote: >>>>>>>>>>> >>>>>>>>>>>> On 12/10/2021 12:53, Don Y wrote: >>>>>>>>>>>>> I caught the tail end (last 2-3 minutes) of a TV show which >>>>>>>>>>>>> depicted >>>>>>>>>>>>> a couple of guys hunting for gold deposits with the sorts >>>>>>>>>>>>> of metal >>>>>>>>>>>>> detectors you'd look for trinkets on a sandy beach. >>>>>>>>>>>>> >>>>>>>>>>>>> And, apparently, *finding* same! (gold just lying around in >>>>>>>>>>>>> surface rock outcroppings? who'd guessed!) >>>>>>>>> >>>>>>>>> They must have known enough about the geology to be in about >>>>>>>>> the right >>>>>>>>> place then. >>>>>>>> >>>>>>>> No doubt! I was surprised that it would be that near the surface. >>>>>>>> And, to wonder how they *knew* it would be there! >>>>>>>> >>>>>>>> (Did someone, someday, just happen to look down and say, "My! >>>>>>>> There's >>>>>>>> a gold nugget by my left foot!" And, thereafter, the area known for >>>>>>>> "gold just lying around"? If so, why is there *still* any left to >>>>>>>> be found -- if it was common knowledge!) > > A common way of doing it is to spike the claim with gold obtained from a > chemicals supplier. I was involved indirectly in gold fingerprinting > case once. The miscreants pleaded guilty after seeing that the mass > spectrum of their claim exactly matched BDH supplied lab reagent gold > leaf. Local gold nuggets had an entirely different signature of trace > elements (and was much less pure). > > A similar one we showed that "grape" juice used to make wine contained > appreciable amounts of cane sugar (C4 metabolism has a much different > isotopic signature). The other one was even more fun determining if the > claimed terroir of high end wines matched their local geology (for > detecting fakes). We needed about 5ml of each and they sent a whole > mixed case! > >>>>>>> According to school geography lessons, the importance >>>>>>> of Kiirunavaara was discovered when someone found his >>>>>>> steel knife was attracted to the ground. >>>>>>> >>>>>>> I've never understood why gold (and similar) elements, >>>>>>> which were produced in supernovae, aren't evenly >>>>>>> distributed lone atoms. > > Initially they pretty much are but when the nebula condenses to form > stars and planets things get pretty toasty during gravitational collapse > and you end up with a blob of hot molten rock (its also a fair bit more > radioactive in the early stages which also generates even more heat). > > The molten material stratifies to some extent according to density with > the most common elements that are immiscible separating out into layers. > Roughly translates to SiAl floating on top and SiMa (Mg) underneath > forming the crust and most of the siderophile metals dissolved in the > NiFe core. That includes most of the platinum group too. > > https://en.wikipedia.org/wiki/Goldschmidt_classification#Siderophile_elements > > > Getting them back out requires vulcanism and/or a lot of time. As one > geology once put it only the youngest or the oldest rocks are rich in > gold - middle aged ones tend to be paupers. > > It is not unlike the way old salad dressing or paint separates. > >>>>>> Why aren't celestial bodies perfectly round (oblate) orbs? >>>>> >>>>> They are good approximations. >>>>> >>>>>> Why Les Alpes and The Mariana Trench? >>>>> >>>>> Plate tectonics. >>>> Why are there plates? That suggests some nonuniformity in composition. > > The composition started out pretty uniform but separated pretty much > according to density with the molten nickel iron core sinking to the > bottom and the lightest elements rising to the top. This includes the > lightest of all water sat on the rocks and the atmosphere above it. >>> Earth's crust is a minor component of the planet: >>> https://www.wowreally.blog/2007/01/earths-crust-thinner-than-apples-skin.html >>> >>> >>> &nbsp;From the bottom of Marianas to the top of Everest is ~ 19.9km vs >>> Earth's radius ~6371km gives ~0.3% - surface features are negligible... >> >> Place a drop of water in a weightless environment.&nbsp; Tell me how much >> variation their is in its shape... > > Depends how big it is. Gravity is an incredibly weak force so it will > pretty much look like an amoeba unless it is small enough for surface > tension to be the most dominant force acting. > > https://www.youtube.com/watch?v=rzytpxtbCzQ > > Water in zero g from the Royal Institution Xmas lectures 2015.
Water has incredibly strong surface tension also. The earth's crust doesn't correspond to that.
Reply by Martin Brown October 14, 20212021-10-14
On 14/10/2021 11:37, Don Y wrote:
> On 10/14/2021 1:53 AM, Martin Brown wrote: > >> Initially they pretty much are but when the nebula condenses to form >> stars and planets things get pretty toasty during gravitational >> collapse and you end up with a blob of hot molten rock (its also a >> fair bit more radioactive in the early stages which also generates >> even more heat). >> >> The molten material stratifies to some extent according to density >> with the most common elements that are immiscible separating out into >> layers. Roughly translates to SiAl floating on top and SiMa (Mg) >> underneath forming the crust and most of the siderophile metals >> dissolved in the NiFe core. That includes most of the platinum group too. >> >> https://en.wikipedia.org/wiki/Goldschmidt_classification#Siderophile_elements >> >> >> Getting them back out requires vulcanism and/or a lot of time. As one >> geology once put it only the youngest or the oldest rocks are rich in >> gold - middle aged ones tend to be paupers. >> >> It is not unlike the way old salad dressing or paint separates. >> >>>>>>> Why aren't celestial bodies perfectly round (oblate) orbs? >>>>>> >>>>>> They are good approximations. >>>>>> >>>>>>> Why Les Alpes and The Mariana Trench? >>>>>> >>>>>> Plate tectonics. >>>>> Why are there plates? That suggests some nonuniformity in composition. >> >> The composition started out pretty uniform but separated pretty much >> according to density with the molten nickel iron core sinking to the >> bottom and the lightest elements rising to the top. This includes the >> lightest of all water sat on the rocks and the atmosphere above it. > > That's exactly the point.&nbsp; Homogeneity is an illusion.&nbsp; You have mixed > substances so expecting uniformity of composition, throughout, is silly. > It ignores time and forces that can be exerted (or encountered) over time. > > Au != Ag != Ni != Fe ... so why would one think that "mixing them" > would lead to them staying mixed?
Actually gold and particularly uranium do have a strong tendency to stay mixed with other things. There is a trace amount of around 2ppm uranium in just about everything but mineable ore is incredibly rare. Silver is 20x rarer than uranium in the Earth's crust but much more easily mined since it does concentrate in ore bodies as sulphides and native metal. Nickel and iron have a very high affinity for each other and the siderophile elements will quite happily stay dissolved in the molten phase - once it starts to cool then things can come out of solution and crystallise or react with (usually) sulphur or oxygen to form ore bodies. Most of our planet's gold content is dissolved in the iron core.
>>>> Earth's crust is a minor component of the planet: >>>> https://www.wowreally.blog/2007/01/earths-crust-thinner-than-apples-skin.html >>>> >>>> >>>> &nbsp;From the bottom of Marianas to the top of Everest is ~ 19.9km vs >>>> Earth's radius ~6371km gives ~0.3% - surface features are negligible... >>> >>> Place a drop of water in a weightless environment.&nbsp; Tell me how much >>> variation their is in its shape... >> >> Depends how big it is. Gravity is an incredibly weak force so it will >> pretty much look like an amoeba unless it is small enough for surface >> tension to be the most dominant force acting. >> >> https://www.youtube.com/watch?v=rzytpxtbCzQ >> >> Water in zero g from the Royal Institution Xmas lectures 2015. > > Or, for it to "settle" over time.
You might have to wait for geological timescales though. Gravity is really puny. If you put the dimensions of a human into the stellar equilibrium equation you find that we ought to fly apart! That is outwards radiation pressure must be equal to self gravitating attraction at the surface of the body. Luckily we are held together by skin which relies on much stronger chemical bonds from electromagnetism. -- Regards, Martin Brown
Reply by Don Y October 14, 20212021-10-14
On 10/14/2021 1:53 AM, Martin Brown wrote:

> Initially they pretty much are but when the nebula condenses to form stars and > planets things get pretty toasty during gravitational collapse and you end up > with a blob of hot molten rock (its also a fair bit more radioactive in the > early stages which also generates even more heat). > > The molten material stratifies to some extent according to density with the > most common elements that are immiscible separating out into layers. Roughly > translates to SiAl floating on top and SiMa (Mg) underneath forming the crust > and most of the siderophile metals dissolved in the NiFe core. That includes > most of the platinum group too. > > https://en.wikipedia.org/wiki/Goldschmidt_classification#Siderophile_elements > > Getting them back out requires vulcanism and/or a lot of time. As one geology > once put it only the youngest or the oldest rocks are rich in gold - middle > aged ones tend to be paupers. > > It is not unlike the way old salad dressing or paint separates. > >>>>>> Why aren't celestial bodies perfectly round (oblate) orbs? >>>>> >>>>> They are good approximations. >>>>> >>>>>> Why Les Alpes and The Mariana Trench? >>>>> >>>>> Plate tectonics. >>>> Why are there plates? That suggests some nonuniformity in composition. > > The composition started out pretty uniform but separated pretty much according > to density with the molten nickel iron core sinking to the bottom and the > lightest elements rising to the top. This includes the lightest of all water > sat on the rocks and the atmosphere above it.
That's exactly the point. Homogeneity is an illusion. You have mixed substances so expecting uniformity of composition, throughout, is silly. It ignores time and forces that can be exerted (or encountered) over time. Au != Ag != Ni != Fe ... so why would one think that "mixing them" would lead to them staying mixed?
>>> Earth's crust is a minor component of the planet: >>> https://www.wowreally.blog/2007/01/earths-crust-thinner-than-apples-skin.html >>> >>> From the bottom of Marianas to the top of Everest is ~ 19.9km vs Earth's >>> radius ~6371km gives ~0.3% - surface features are negligible... >> >> Place a drop of water in a weightless environment. Tell me how much >> variation their is in its shape... > > Depends how big it is. Gravity is an incredibly weak force so it will pretty > much look like an amoeba unless it is small enough for surface tension to be > the most dominant force acting. > > https://www.youtube.com/watch?v=rzytpxtbCzQ > > Water in zero g from the Royal Institution Xmas lectures 2015.
Or, for it to "settle" over time.
Reply by Martin Brown October 14, 20212021-10-14
On 14/10/2021 00:27, Don Y wrote:
> On 10/13/2021 3:29 PM, Chris wrote: >> On Wednesday, 13 October 2021 at 19:35:48 UTC+11, Don Y wrote: >>> On 10/13/2021 12:52 AM, Tom Gardner wrote: >>>> On 13/10/21 05:01, Don Y wrote: >>>>> On 10/12/2021 3:46 PM, Tom Gardner wrote: >>>>>> On 12/10/21 22:59, Don Y wrote: >>>>>>> On 10/12/2021 2:28 PM, Martin Brown wrote: >>>>>>>> On 12/10/2021 20:44, Don Y wrote: >>>>>>>>> On 10/12/2021 9:23 AM, Joe Gwinn wrote: >>>>>>>>>> On Tue, 12 Oct 2021 14:15:33 +0100, Martin Brown >>>>>>>>>> <'''newspam'''@nonad.co.uk> wrote: >>>>>>>>>> >>>>>>>>>>> On 12/10/2021 12:53, Don Y wrote: >>>>>>>>>>>> I caught the tail end (last 2-3 minutes) of a TV show which >>>>>>>>>>>> depicted >>>>>>>>>>>> a couple of guys hunting for gold deposits with the sorts of >>>>>>>>>>>> metal >>>>>>>>>>>> detectors you'd look for trinkets on a sandy beach. >>>>>>>>>>>> >>>>>>>>>>>> And, apparently, *finding* same! (gold just lying around in >>>>>>>>>>>> surface rock outcroppings? who'd guessed!) >>>>>>>> >>>>>>>> They must have known enough about the geology to be in about the >>>>>>>> right >>>>>>>> place then. >>>>>>> >>>>>>> No doubt! I was surprised that it would be that near the surface. >>>>>>> And, to wonder how they *knew* it would be there! >>>>>>> >>>>>>> (Did someone, someday, just happen to look down and say, "My! >>>>>>> There's >>>>>>> a gold nugget by my left foot!" And, thereafter, the area known for >>>>>>> "gold just lying around"? If so, why is there *still* any left to >>>>>>> be found -- if it was common knowledge!)
A common way of doing it is to spike the claim with gold obtained from a chemicals supplier. I was involved indirectly in gold fingerprinting case once. The miscreants pleaded guilty after seeing that the mass spectrum of their claim exactly matched BDH supplied lab reagent gold leaf. Local gold nuggets had an entirely different signature of trace elements (and was much less pure). A similar one we showed that "grape" juice used to make wine contained appreciable amounts of cane sugar (C4 metabolism has a much different isotopic signature). The other one was even more fun determining if the claimed terroir of high end wines matched their local geology (for detecting fakes). We needed about 5ml of each and they sent a whole mixed case!
>>>>>> According to school geography lessons, the importance >>>>>> of Kiirunavaara was discovered when someone found his >>>>>> steel knife was attracted to the ground. >>>>>> >>>>>> I've never understood why gold (and similar) elements, >>>>>> which were produced in supernovae, aren't evenly >>>>>> distributed lone atoms.
Initially they pretty much are but when the nebula condenses to form stars and planets things get pretty toasty during gravitational collapse and you end up with a blob of hot molten rock (its also a fair bit more radioactive in the early stages which also generates even more heat). The molten material stratifies to some extent according to density with the most common elements that are immiscible separating out into layers. Roughly translates to SiAl floating on top and SiMa (Mg) underneath forming the crust and most of the siderophile metals dissolved in the NiFe core. That includes most of the platinum group too. https://en.wikipedia.org/wiki/Goldschmidt_classification#Siderophile_elements Getting them back out requires vulcanism and/or a lot of time. As one geology once put it only the youngest or the oldest rocks are rich in gold - middle aged ones tend to be paupers. It is not unlike the way old salad dressing or paint separates.
>>>>> Why aren't celestial bodies perfectly round (oblate) orbs? >>>> >>>> They are good approximations. >>>> >>>>> Why Les Alpes and The Mariana Trench? >>>> >>>> Plate tectonics. >>> Why are there plates? That suggests some nonuniformity in composition.
The composition started out pretty uniform but separated pretty much according to density with the molten nickel iron core sinking to the bottom and the lightest elements rising to the top. This includes the lightest of all water sat on the rocks and the atmosphere above it.
>> Earth's crust is a minor component of the planet: >> https://www.wowreally.blog/2007/01/earths-crust-thinner-than-apples-skin.html >> >> >> &nbsp;From the bottom of Marianas to the top of Everest is ~ 19.9km vs >> Earth's radius ~6371km gives ~0.3% - surface features are negligible... > > Place a drop of water in a weightless environment.&nbsp; Tell me how much > variation their is in its shape...
Depends how big it is. Gravity is an incredibly weak force so it will pretty much look like an amoeba unless it is small enough for surface tension to be the most dominant force acting. https://www.youtube.com/watch?v=rzytpxtbCzQ Water in zero g from the Royal Institution Xmas lectures 2015. -- Regards, Martin Brown
Reply by Anthony William Sloman October 14, 20212021-10-14
On Thursday, October 14, 2021 at 7:09:23 PM UTC+11, Tom Gardner wrote:
> On 14/10/21 07:11, Anthony William Sloman wrote: > > On Thursday, October 14, 2021 at 4:40:00 PM UTC+11, Ferry wrote: > >> On a sunny day (Tue, 12 Oct 2021 04:53:31 -0700) it happened Don Y > >> <blocked...@foo.invalid> wrote in <sk3t02$csg$1...@dont-email.me>: > >>> I caught the tail end (last 2-3 minutes) of a TV show which depicted > >>> a couple of guys hunting for gold deposits with the sorts of metal > >>> detectors you'd look for trinkets on a sandy beach. > >>> > >>> And, apparently, *finding* same! (gold just lying around in > >>> surface rock outcroppings? who'd guessed!) > >> Obvious, gold is heavy, here in the northern hemisphere it is buried deep, > >> while In Australia it sinks to the surface. > > > > Odd how it did the same thing in California. > > > We are always being told that California is /odd/. > > Clearly, since California is at the edge of the world, > that's where centrifugal forces are strongest. Ditto > Yukon.
So how come John Larkin and Sarah Palin weren't slung off into space? Life would be so much nicer if this had happened. Of course Tasmania is equally peripheral, and I managed to grow up there. -- Bill Sloman, Sydney