I bet you didn't know that this thread would have a part 2

Wibbs

Nixonbot wrote: »

Sparked conversation and knowledge about the Romans!

On that score; in Rome there is a hill called Monte Testaccio that's today 120 feet/35m tall and covers a few acres. It's made up almost entirely of broken pottery from discarded amphora that were used to carry olive oil.



The ancient Romans consumed billions of litres of the stuff and used it in cooking and oil lamps and perfumery and cleaning the body(cover yourself in the stuff and then scrape it off and it carries the dirt with it). It was a massive business back then. It was shipped from across the empire in amphora which were the classical world's bottles, cans, wrapping for all sorts of stuff.



They each contained between 50-80 litres of oil.

So when they were empty they decided to make an area where people could discard them. A city dump for amphora as it were. Particularly olive oil amphora. They reused and repurposed amphora that carried wine, grains, dates and the like. Used them for making drains, flower pots, cooking vessels, foundation material etc. The olive oil ones weren't of use because of the rancid oil residue.

They didn't just drop them though, it was organised. They built up terraces held back by intact amphora walls where you'd bring yours in and smash them up behind the walls. They would then scatter ash and lime over things to neutralise the whiff of rotten olive oil. It would have been much higher back then and would have been more like a pyramid.



Because of the thermal peculiarities of the site many centuries later it was used as a cool house for storing wines and cheeses by cutting shafts into the bottom.

Realt Dearg Sec

partyguinness wrote: »

Jesus I'm sorry. What have I done..

A man of genius makes no mistakes; his errors are volitional and are the portals of discovery.

-James Joyce

New Home

Back to "Salary" for a second.

Soldiers, like previosly mentioned, but magistrates, too, were paid in kind with grains, wine, oil, and especially salt. As time went on, "Salary" (i.e. salarium) was the name given to the coin used to pay them.

Wibbs

New Home wrote: »

Back to "Salary" for a second.

Soldiers, like previosly mentioned, but magistrates, too, were paid in kind with grains, wine, oil, and especially salt. As time went on, "Salary" (i.e. salarium) was the name given to the coin used to pay them.

Later on NH, but not in classical Rome. There's also no record from Rome of soldiers being paid in salt as a thing. They do mention coinage after they became professional soldiers and of course spoils of war and how they were divvied up.

New Home

Wibbs wrote: »

Later on NH, but not in classical Rome. There's also no record from Rome of soldiers being paid in salt as a thing. They do mention coinage after they became professional soldiers and of course spoils of war and how they were divvied up.

See, when I read that first, I thought they were ONLY paid in salt which they then had to barter, but it seems that the salt was only part of their benefits in kind. I don't have any dates/periods for that, though.

JupiterKid

Leaving Dromoland Castle this evening after a bite to eat, my OH and I passed Pete Townshend and Roger Daltrey of The Who who walked in with two ladies.

Place must be popular with the rock star set. Maybe next time I'll see Bono...

Realt Dearg Sec

JupiterKid wrote: »

Leaving Dromoland Castle this evening after a bite to eat, my OH and I passed Pete Townshend and Roger Daltrey of The Who walked in with two ladies.

Place must be popular with the rock star set. Maybe next time I'll see Bono...

You can get the guy with him to take your picture and he'll turn out to be Bruce Springsteen

partyguinness

JupiterKid wrote: »

Leaving Dromoland Castle this evening after a bite to eat, my OH and I passed Pete Townshend and Roger Daltrey of The Who who walked in with two ladies.

Place must be popular with the rock star set. Maybe next time I'll see Bono...

Did they ask for your pic or autograph?

quickbeam

Wibbs wrote: »

On that score; in Rome there is a hill called Monte Testaccio that's today 120 feet/35m tall and covers a few acres. It's made up almost entirely of broken pottery from discarded amphora that were used to carry olive oil.

A Roman bottle bank. I love it!

SimonTemplar

Youtube has a unque ID for each of its videos, which you can see at the end of the URL, such as:

https://www.youtube.com/watch?v=dQw4w9WgXcQ

This is an 11 character Base64 value.

Firstly, I'll explain what Base64 means in case you don't know it already. People generally count using Base10. That means each character in a number has 10 possible values, from 0 to 9. So the maximum value a 2 character number can hold is 99, the maximum a 3 character number can hold is 999 and so on.

So sticking with Youtube's 11 character length for its ID, if it just used a bog standard Base10 number, the maximum quantity of videos that ID system could handle is 99,999,999,999. Still a huge number. I think Youtube currently has somewhere between 7 to 8 billion videos so the fact that a Base10 ID could handle over 99 Billion seems high enough.

But Youtube actually uses Base64. This means each character in the ID has 64 possible values. These are all the numbers from 0 - 9, all 26 uppercase letters, all 26 lowercase letters, and then two symbols. Youtube uses a hyphen and underscore.

So using this system, you can count up to 64 items using a single character.
Using just two characters, you can count up to 4,096 items (64 x 64).
Using just three characters, you can count up to 262,144 items (64 x 64 x 64).

So you can see that the Base64 allows you to cram a large number into a smaller quantity of characters than normal Base10. You can also see each time we add a character to the Base64 number, there is a significant jump in the maximum value it can hold.

So, using Youtube's 11 character length for its ID, what quantity of videos can a Base64 ID system handle. Well, that 64 to the power of 11 which is,

73,786,976,294,838,206,464

or 73.7 quintillion

That means that everyone currently on earth could upload a video every minute for well over 18,000 years and Youtube still wouldn't run out of IDs.

So when a user uploads a video, Youtube just generates a random 11 character Base64 number, checks to make sure it isn't already being used, and then assigns that to the video.

Also, as I said, there is currently about 7 - 8 billion videos on Youtube. With 73.7 quintillion possible IDs, if you type in a random 11 character Base64 number, you have a one in 10 billion chance of actually typing a number that is currently being used by a video. The odds of winning the euromillions jackpot is just one in 139,838,160 by comparison.

Two things to note:

Youtube probably maintains a list of character combinations that it won't allow in its IDs so to avoid any rude or vulgar phrases, but those disallows IDs are likely to be a tiny portion of the overall figure of 73.7 Quintilian so as to not make any real difference.

You might wonder why Youtube doesn't just allow a 20 character ID and count sequentially using a normal Base10 number. This presents loads of challenges for a site like Youtube. They'd have to sync this number across all their upload servers which would be a major issue as 300 hours of video are uploaded to YouTube every minute!

Nuno

Very interesting video from Tom Scott on the same topic. This guy has an amazing memory. 5min video, no cuts, first take.
Will YouTube Ever Run Out Of Video IDs?

its_steve116

Indian classical pianist Utsav Lal was in the original line up of Irish band Little Green Cars.

lan

SimonTemplar wrote: »

But Youtube actually uses Base64. This means each character in the ID has 64 possible values. These are all the numbers from 0 - 9, all 26 uppercase letters, all 26 lowercase letters, and then two symbols. Youtube uses a hyphen and underscore.

So using this system, you can count up to 64 items using a single character.
Using just two characters, you can count up to 4,096 items (64 x 64).
Using just three characters, you can count up to 262,144 items (64 x 64 x 64).

Another common use for Base64 is email attachments. To explain why, I need to give a little background.

All data on modern computers is stored in bytes. A byte is made up of 8 bits, which are each just a 1 or a 0. A byte can store any number from 0 to 255 (that’s 256 different values, or 2 to the power of 8).

Everything is stored as numbers internally. To store text then, there needs to be a way to convert between numbers and characters. The most common standard for this is called ASCII. In ASCII, every character takes up one byte, the letter “A” is defined to be 65, “B” is 66, and so on. ASCII also defines the lowercase letters, numerals and some symbols. It only defined the first 127 numbers though, and the first 32 are unprintable (non displayable) “control” characters, like Carraige Return, Tab and NULL.

Originally when email was first invented, it only supported ASCII, and the message body was mostly restricted to just the printable characters. This meant that you couldn’t embed raw binary files, e.g. images or programs, as they could contain bytes outside that 32 - 127 range. To get around that limitation, attached binary files first have to be encoded in Base64, so they’re still within the printable ASCII range (all modern mail programs do this automatically). Storing raw byte data in Base64 is somewhat inefficient though, as each each Base64 digit can only store 6 bits, not 8. That means for every 3 bytes (or 24 bits) you need 4 Base64 encoded bytes.

Have you ever noticed that your email attachments are larger than the files themselves? That’s why, it takes 33% more space to encode a binary file in Base64. If your email provider has a limit of 10 MB, for example, you actually won’t be able to send a file much over 7 MB.

Liam28

Candie wrote: »

Even more interestingly, unexploded WW2 bombs are still being found all over Germany, weighing in at over 20,000 tons a year. Which everyone else might know, but I didn't!

Yup. I, and hundreds of Irish football fans, experienced this in Dusseldorf airport in 2014.
https://www.boards.ie/vbulletin/showthread.php?p=97600159

valoren

I bet you didn't know that there is a public golf course that is so tough that a warning sign is required.

The PGA Championship major is currently underway at the Black course (one of five courses) at Bethpage State Park in New York. It has this ominously foreboding sign on the first tee.

Liam28

Carton House in Maynooth, Montgomery course, has this sign on the first tee:

https://pbs.twimg.com/media/BNne_E5CQAAESV2.jpg:large

RiderOnTheStorm

Just finished watching Upstart Crow. Very funny series about Will Shakespeare. Several laugh out loud moments. But the last 5 mins of last episode broke my heart.....

So, did you know, there are no direct heirs of Shakespeare. His 2 daughters (Judith and Susanna) did get married. Susanna child Elizabeth did marry, but didn't have any children. Judith had 3 children, all boys, who remained unmarried and without progeny. Shakespeare sister, (not the band!) Joan, is the only member of the family whose known descendants continue down to the present day.

Shakespeare son, Hamnet, dies age 11. Cause of death....plague.

"Grief fills the room up of my absent child,
Lies in his bed, walks up and down with me,
Puts on his pretty looks, repeats his words,
Remembers me of all his gracious parts,
Stuffs out his vacant garments with his form;
Then have I reason to be fond of grief?"
King John, A3/S4/L95

Slippin Jimmy

JupiterKid wrote: »

Leaving Dromoland Castle this evening after a bite to eat, my OH and I passed Pete Townshend and Roger Daltrey of The Who who walked in with two ladies.

Place must be popular with the rock star set. Maybe next time I'll see Bono...

Funny that they were in NYC that night.

https://www.setlist.fm/setlist/the-who/2019/madison-square-garden-new-york-ny-6390d253.html

Buford T. Justice XIX

Just in time for the anniversary of Shackleton, Worsely and Creans arrival to safety after their odyssey.
https://twitter.com/SouthPoleTom/status/1130382218919075841?s=19

dxhound2005

Someone on TV tonight said that China has manufactured more steel in the last two years than Britain has in all of history. It may or may not be true.

partyguinness

dxhound2005 wrote: »

Someone on TV tonight said that China has manufactured more steel in the last two years than Britain has in all of history. It may or may not be true.

There is something similar about concrete. Apparently China used more concrete between 2011 and 2013 than the US did during the entire 20th century which is mind boggling...

4068ac1elhodqr

dxhound2005 wrote: »

Someone on TV tonight said that China has manufactured more steel in the last two years than Britain has in all of history. It may or may not be true.

Very likely.



A total of 88 buildings measuring 200^ meters (656 feet) or above were completed in cities across China for 2018.

^ Ire's tallest building the Belfast Obel Tower is 88m.

The figure sets a new benchmark for annual skyscraper construction in a single country, and is almost seven times higher than the 13 completions recorded in the US, which ranked a distant second.

ohnonotgmail

Something I did not know until today (but i'm sure fourier did). The man who proved Einstein was right

https://www.bbc.com/news/science-environment-48369980

mzungu

Ever wonder why the shower curtain moves towards the water?

Known in physics as the Shower-Curtain Effect, one theory has suggested that the hot shower causes the air temperature in the shower to rise, thus reducing it's density. Hence the pressure on the shower side of the curtain will be lower than the outside at the same height causing the curtain ti move towards the lower pressure side. Only problem there is that the same thing happens with cold water.

However, using a computer simulation, it was observed that the spray drove a vortex which has a centre similar to a cyclone. This centre is a low pressure area. It is thought that this is what drags the shower curtain towards the water. This is a weak force and explains why heavy shower curtains to not experience the drag, only the lighter ones. Likewise, showers with poor water pressure or poorly atomising shower heads will not have much of an effect.

Capt'n Midnight

mzungu wrote: »

Ever wonder why the shower curtain moves towards the water?

Always assumed it was Bernoulli.

ILoveYourVibes

Horses have the remnants of what people think might be an extra toe their ancestors had. Some people think its a scent gland. Some peeps say they protect some ligaments.

They are called ergots and they are under the fetlocks. They also have chestnuts which are made of the same callousy tissues above the knee and below the hock.

On some horse breeds they don't grow much. But on draft horses they grow much faster. If they get really long they can snag on stuff and bleed. So its best to tame em. You break them off or keep them trim. Use oil so they don't bleed.

A farrier can do it. But doing it yourself is the most satisfying thing ever. Use some oil.


I SO want to pick these off. I am weird.
WAY OVERGROWN Chestnuts




This is what they should look like



Ergots due for a trim.


Some breeds don't have much ergots or chestnuts on the back. Most have four though. Generally cold bloods grow them faster.

The central nervous system is made up of the brain and spinal cord, and the peripheral nervous system covers all the branches outward and around your body, all the nerves from the tip of your fingers to the top of your toes. This is further subdivided into two categories, the autonomic and the somatic nervous system. The somatic system regulates your voluntary movements and the autonomic the involuntary, knee jerk reactions you have no conscious say over.

Nerve fibres are communication lines that transmit signals between the receptors and nerve cells, and the timing of signals between them can vary. The touch sensitive neurons signal that you've bashed your elbow on the corner of the table ten times faster than the pain fibres tell your brain that you're in mortal agony.

Which is why you can bang your thumb with a hammer and know you've done it for a moment before you feel the pain, or why you bash your toe on the edge of a step and the pain hits a little later. Or why small children only realise the injection has taken place a moment after the needle has been withdrawn and it's all over.

Alcohol further complicates the lines of communication between receptors and brain, which anyone who's hurt themselves while drunk may know. You might look down to see someone has trodden on your toe, and only begun to feel it when you realize it should be hurting!

its_steve116

Dr Seuss invented the word "nerd".

Esel

A 'nerd' was a term for a plastic pocket protector back in the day.

Candie

Candie wrote: »

The central nervous system is made up of the brain and spinal cord, and the peripheral nervous system covers all the branches outward and around your body, all the nerves from the tip of your fingers to the top of your toes. This is further subdivided into two categories, the autonomic and the somatic nervous system. The autonomic system regulates your voluntary movements and the somatic the involuntary, knee jerk reactions you have no conscious say over.

Excellent sumation of our differing categories of nervous system Candie;
just want to point out that it's the somatic system that is voluntary and the autonomic which is unconscious

Batrachotox

Batrachotox wrote: »

Excellent sumation of our differing categories of nervous system Candie;
just want to point out that it's the somatic system that is voluntary and the autonomic which is unconscious

Typing (and thinking) while tired is a bad idea.

Also known as the "Feynman point", at the 762nd digit of Pi there are six 9s in a row

Squall Leonhart

They're up to 2.7 trillion digits after the decimal point now, with no patterns emerging yet .

That's 2,700,000,000,000... But only 39 points are required to calculate the circumference of the known universe to within the width of a hydrogen atom.

So I don't really know why it matters how far it goes before it becomes patternic (made that word up )

New Home

Because nobody likes a pi(e) with a piece missing, that's why.

quickbeam

Anyone got any info on how they actually calculate pi to that many decimal points?

Chancer3001

Anyone know why they care so much ?

quickbeam

quickbeam wrote: »

Anyone got any info on how they actually calculate pi to that many decimal points?

They divide 22 x 7 and keep going.

quickbeam

Deleted User wrote: »

They divide 22 x 7 and keep going.

I know enough to know that that is not true. Pi is irrational. 22/7 is a rational number.


Also 22/7 = 3.14285...
Pi = 3.14159...



It doesn't take long for the difference to appear.



I know in school we used 22/7 as a good approximation. But I was wondering how they actually work out the 2.7 trillion numbers of it. I know there's a Wiki article but I'm not smart enough to understand it and was wondering if there was a simplified explanation.

Capt'n Midnight

quickbeam wrote: »

I know enough to know that that is not true. Pi is irrational. 22/7 is a rational number.
...

I know in school we used 22/7 as a good approximation.

22 over 7 is NOT a good approximation.

It's nearly five thousand times further from Pi than dividing 113 into 355.



As for calculating Pi there are two main ways

- one is to use a shape like a hexagon or dodecahedron inside the circle and another outside it. Then from the centre you divide them into triangles.

The triangle on the inside is an isosceles triangle, the long sides are the radius of the circle and the short side is slightly shorter than the curved part of the circle.

The triangle on the outside is continuation of the triangle above into a right angle triangle. Same angle at the centre, same base , except the top side is now very slightly longer and the small side is slightly longer than the curved part of the circle.

So you now have two approximations to Pi , one slightly higher and one slightly lower and the answer must be somewhere in between.




- two you find an equation that Pi pops up in
some work better than others http://mathworld.wolfram.com/PiFormulas.html

This is one of the simplest and worst


Simplest because you add and subtract alternative reciprocals of every odd number.
Worst because to get to 355/113 accuracy you have to through millions of steps.
https://en.wikipedia.org/wiki/Leibniz_formula_for_%CF%80

Capt'n Midnight

Chancer3001 wrote: »

Anyone know why they care so much ?

Like searching for primes it's a traditional way to test or burn in a new super computer. Also bragging rights.

quickbeam

Capt'n Midnight wrote: »

22 over 7 is NOT a good approximation.

Good enough approximation for second level education then??


I don't really get your explanation, but thanks for trying. It does seem like a somewhat inaccurate way of calculating it ("two approximations to Pi ... and the answer must be somewhere in between"), so I'm wondering how scientists / mathematicians have come to an agreed number. Or an agreed 2.7 trillion numbers?

KevRossi

There are no Aldi's in Northern Ireland.

Mollyb60

KevRossi wrote: »

There are no Aldi's in Northern Ireland.

A constant source of consternation for many. At least we have Lidl though.

Capt'n Midnight

mikhail

Capt'n Midnight wrote: »

https://blog.xkcd.com/2008/09/09/the-goddamn-airplane-on-the-goddamn-treadmill/comment-page-15/

Fourier

quickbeam wrote: »

Good enough approximation for second level education then??


I don't really get your explanation, but thanks for trying. It does seem like a somewhat inaccurate way of calculating it ("two approximations to Pi ... and the answer must be somewhere in between"), so I'm wondering how scientists / mathematicians have come to an agreed number. Or an agreed 2.7 trillion numbers?

There are simply hundreds of different formulas for pi that take the form of adding together a never ending sequence of numbers.

One case is 1 - 1/3 + 1/5 -.... which is adding then subtracting 1 divided by each odd number. This is the one Capt'n Midnight mentioned, but there are several others. Some add to pi faster than others do.

The multiple trillion decimal place calculations are found using the sequence that adds up to pi the quickest. However the formula for it is a good deal more complicated than the 1 - 1/3 + 1/5... one.

quickbeam

Fourier wrote: »

One case is 1 - 1/3 + 1/5 -....

Sorry for being dim, but:


1 - 1/3 + 1/5 = 0.86666....
I keep going (I'm using an Excel formula) to 1/1999 and it's giving me 0.785148.

It's been fairly consistently around the 0.785 mark since 1/1253.



So, where is 3.14... come from?


Edit: never mind, I see CM's explanation that above is pi/4, so multiplying by 4 gives 3.140593.

Grand. Thanks.

I won't get into *why* that's the case as I think it's too much for me.

Squall Leonhart

quickbeam wrote: »

Grand. Thanks.

I won't get into *why* that's the case as I think it's too much for me.

I had to smile at this. Grand. Thanks. I know when something starts getting beyond me and I have the same reaction

mikhail

quickbeam wrote: »

I won't get into *why* that's the case as I think it's too much for me.

Do you remember the Taylor series from school? It's a way of writing a function as a sum based on its derivatives. The series above comes from the Taylor series of arctan(x) evaluated at x = 1.

There are various proofs, and they're just about accessible to someone with LC maths; see, e.g., https://en.wikipedia.org/wiki/Leibniz_formula_for_%CF%80

Fourier

quickbeam wrote: »

I won't get into *why* that's the case as I think it's too much for me.

Basically every function can be written as a combination of simple functions with an increasing number of bumps in them. You can see this process in action here:

As more of the simple functions are added they get closer to the main function shown in blue.

In these series for pi what's going on is that the value of the main function at some point is pi and the 1, -1/3, 1/5,... are the values of the simple functions at that point.

A simpler way to imagine it is basically music. The true function is an actual piece of music let's say. The simple functions are each individual note. They have to combine to give the actual piece of music. So you pick a part of the song where the music is Pi decibels loud and you know how loud each note is must add up to Pi.

The different ways of getting Pi are just different song choices and for some the notes add up quicker because the song is dominated by those notes.