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

seagull · 27-03-2019 6:04pm

Is it still a triangle if it's not on a flat surface?

ohnonotgmail · 27-03-2019 6:13pm

seagull wrote: »

Is it still a triangle if it's not on a flat surface?

it is still a triangle but the properties of a triangle that you are familair with from school dont apply. those properties, like the angles adding up to 180 and the Pythagorean theorem, only apply to the euclidean plane i.e. a flat surface.

Fourier · 27-03-2019 6:30pm

So here you can see both a square and a triangle on a sphere:

You can see on the square that two of the sides overshoot the point of closure and continue on past where they meet. Triangles have angles that sum to over 180 and also circles will have circumferences greater than pi times their diameter. This is called positive curvature.

On other shapes, like a horse saddle, two lines will undershoot the point of closure and fail to seal off the area, triangles will have angles that add to less than 180 and circles will have circumferences less than pi times their diameter. This is called negative curvature.

Another way of measuring it is how two lines move away from each other as they extend forward. Note how for positive curvature they flow toward each other. I'll mention this again below.

Of course spheres and saddles are special cases where they're negatively or positively curved everywhere. In other shapes it varies.

Like a kettle:

Or a wine glass:

Light blue is very negative curvature, Yellow is very positive curvature. If you draw a little square near a yellow point it will overshoot closing off. Or going back to my third picture, little lines drawn near it will flow together.

Now that's enough for 2D surfaces.

For 3D surfaces you can't use how a square closes off to check curvature, you need a cube. Instead of checking the angles of triangles, you need to check the angles of pyramids. And instead of circles, you need spheres.

A human can't imagine a curved 3D space, but mathematically it's basically as easy to handle as the 2D case.

And this is in fact leads to what Einstein's Field Equation says:

The left hand side measures how much cubes close off and the right hand side measures the density of mass.

What it's basically saying is that cubes will overshoot their closure more the more dense the matter is inside them. However using the way of thinking of curvature given in the third picture it means lines will flow together near points with high mass, i.e. things will move toward high mass => gravity.

27-03-2019 6:42pm

Owl's eyes are not spherical like ours but are actually tubular.
As a result of this they cannot change the direction of their eyeballs (or should that be eyetubes?), hence the necessity that they have such an extensive range of motion in their head and neck.

Capt'n Midnight · 27-03-2019 7:40pm

Fourier wrote: »

It's actually because the Earth gets fatter toward the equator that walking 100 miles in each direction doesn't have you end up back where you started.

I'll put up a bit more of an explanation later today.

It's hotter at the equator , so things expand ?

27-03-2019 11:55pm

The number of people to graduate from university/college in this country in 1952 was around 1,400, while in 2017 it was around 70,000. That is a 50 fold increase over a time period when the population as a whole didn't even double (increased by 60%).

In the late 60s the figure was about 3,500, so even since then it has increased 20-fold (population was then similar to the early 50s).

Edit: I just remembered that the numbers of women graduating in the 50s and 60s would have been very low and that the high numbers of today reflect their equal (probably higher?) participation in third level, but even taking that into account the numbers are interesting I think.

Also, source is page 3 of this ESRI paper from the late 60s: https://www.esri.ie/system/files/media/file-uploads/2012-09/GRS43.pdf

Another interesting note: "Irish industry at the present time (November 1968) only recruits about 100 graduates a year." :O. Different times!

Sephiroth_dude · 28-03-2019 8:30am

Sections of the Autobahn in Germany have no speed limit.

28-03-2019 2:28pm

There is a big building just off the M1 at Donabate, you can see one elevation of it as you're driving into the village, it even has its own wind turbine for power generation

This is the Tesco distribution centre for Ireland. All goods are shipped to Dublin port, brought there and then loaded up for distribution to the 150-odd Tescos around the country, including all the NI stores.

https://www.google.ie/maps/@53.4781389,-6.199248,3a,24.5y,39.42h,90.1t/data=!3m6!1e1!3m4!1sEq3Rwv6uO5nio6LnaeBTPg!2e0!7i13312!8i6656

It looks big, even from that point which is about 1.5km away. And it IS big.

Huge, in fact.

It has a footprint of over 80,000 sq. metres, which is impressive on it's own. But the fact that it is essentially one big rectangular cube means it has a volume that is even more impressive: over 1.5 million cubic metres. To put that in context, it is the 10th biggest building, by volume, in the world. In. The. World.

It was number 9 until the Finnish entry at number 8 was completed last year.

Edit: forgot the Wikipedia link

https://en.wikipedia.org/wiki/List_of_largest_buildings

Quazzie · 28-03-2019 2:51pm

Sephiroth_dude wrote: »

Sections of the Autobahn in Germany have no speed limit.

I know as I was just driving 250km/h on it two weeks ago :P

b318isp · 28-03-2019 3:09pm

Capt'n Midnight wrote: »

It's hotter at the equator , so things expand ?

At the equator, the effective gravitational acceleration is 9.7805 m/s2. This means that the true gravitational acceleration at the equator must be 9.8144 m/s2 (9.7805 + 0.0339 = 9.8144).

At the poles, the gravitational acceleration is 9.8322 m/s2. The difference of 0.0178 m/s2 between the gravitational acceleration at the poles and the true gravitational acceleration at the equator is because objects located on the equator are about 21 kilometers further away from the center of mass of the Earth than at the poles, which corresponds to a smaller gravitational acceleration.

https://en.wikipedia.org/wiki/Equatorial_bulge

Sephiroth_dude · 28-03-2019 3:27pm

Quazzie wrote: »

I know as I was just driving 250km/h on it two weeks ago :P

:eek::eek:

Esel · 28-03-2019 7:28pm

The mountain whose summit is furthest from the centre of the earth is Chimborazo in Ecuador.

https://en.m.wikipedia.org/wiki/Chimborazo

Skylinehead · 28-03-2019 7:48pm

Esel wrote: »

The mountain whose summit is furthest from the centre of the earth is Chimborazo in Mexico.

https://en.m.wikipedia.org/wiki/Chimborazo

Ecuador is not Mexico :pac:

The main reason for this is that the Earth bulges at the equator, giving it an extra 20km or so of distance to the centre compared to the poles.

Esel · 28-03-2019 7:53pm

Nixonbot wrote: »

Ecuador is not Mexico :pac:

The main reason for this is that the Earth bulges at the equator, giving it an extra 20km or so of distance to the centre compared to the poles.

It is now. I edited the Wiki page to make it so.

Everyone on this thread knows about the Earth's spare tyre already.

lapua20grain · 28-03-2019 8:23pm

Deleted User wrote: »

There is a big building just off the M1 at Donabate, you can see one elevation of it as you're driving into the village, it even has its own wind turbine for power generation

This is the Tesco distribution centre for Ireland. All goods are shipped to Dublin port, brought there and then loaded up for distribution to the 150-odd Tescos around the country, including all the NI stores.

https://www.google.ie/maps/@53.4781389,-6.199248,3a,24.5y,39.42h,90.1t/data=!3m6!1e1!3m4!1sEq3Rwv6uO5nio6LnaeBTPg!2e0!7i13312!8i6656

It looks big, even from that point which is about 1.5km away. And it IS big.

Huge, in fact.

It has a footprint of over 80,000 sq. metres, which is impressive on it's own. But the fact that it is essentially one big rectangular cube means it has a volume that is even more impressive: over 1.5 million cubic metres. To put that in context, it is the 10th biggest building, by volume, in the world. In. The. World.

It was number 9 until the Finnish entry at number 8 was completed last year.

Edit: forgot the Wikipedia link

https://en.wikipedia.org/wiki/List_of_largest_buildings

There are 700,000 pallets spaces with on average of 1.8million cases of stock picked and dispatched from there with a further approx 8k roll cages of slow moving stock trunked to there from other Tesco depots in the UK which is then distributed to ROI stores. The majority of stock is sourced in Ireland and not through Dublin port as you have stated, I know this as I worked in their supply chain and distribution.

28-03-2019 8:27pm

Deleted User wrote: »

There is a big building just off the M1 at Donabate, you can see one elevation of it as you're driving into the village, it even has its own wind turbine for power generation

This is the Tesco distribution centre for Ireland. All goods are shipped to Dublin port, brought there and then loaded up for distribution to the 150-odd Tescos around the country, including all the NI stores.

https://www.google.ie/maps/@53.4781389,-6.199248,3a,24.5y,39.42h,90.1t/data=!3m6!1e1!3m4!1sEq3Rwv6uO5nio6LnaeBTPg!2e0!7i13312!8i6656

It looks big, even from that point which is about 1.5km away. And it IS big.

Huge, in fact.

It has a footprint of over 80,000 sq. metres, which is impressive on it's own. But the fact that it is essentially one big rectangular cube means it has a volume that is even more impressive: over 1.5 million cubic metres. To put that in context, it is the 10th biggest building, by volume, in the world. In. The. World.

It was number 9 until the Finnish entry at number 8 was completed last year.

Edit: forgot the Wikipedia link

https://en.wikipedia.org/wiki/List_of_largest_buildings

Now I know where to head when the zombie apocalypse hits.

Sleepy · 29-03-2019 10:43am

I pass the Tesco Distribution Centre every day. Our Zombie apocalypse plan involves raiding it before heading out to Lambay

Esel · 29-03-2019 10:55am

Sleepy wrote: »

I pass the Tesco Distribution Centre every day. Our Zombie apocalypse plan involves raiding it before heading out to Lambay

You can eat the wallabies there too.

Capt'n Midnight · 29-03-2019 9:11pm

https://xkcd.com/2129/

mzungu · 29-03-2019 9:37pm

The Eiffel Tower was originally supposed to be in Barcelona. But thinking the thing would end up looking like an eyesore, the city rejected Gustave Eiffel's plans, and he was forced to repitch the project elsewhere. Luckily, Eiffel found a home for his idea in Paris. The rest is history.

Capt'n Midnight · 29-03-2019 10:04pm

The Eiffel Tower was only supposed to be temporary.

Capt'n Midnight · 29-03-2019 10:18pm

EVERYBODY expected the Spanish Inquisition - they were legally obliged to give 30 days notice

4068ac1elhodqr · 29-03-2019 10:26pm

The o2 Dome features on the previous page's link (along with Tesco Ire's DC) as one of the 10 largest buildings in the world by volume.

But the o2 may face competition from a new dome in East Ldn: The MSG Sphere.
If it gets the go-ahead, will be the uk's largest indoor concert venue with room for 21,500 (17.5 seated).

Other features:

The largest and highest resolution LED screen in the world. The building would be wrapped in triangular LED panels
A diameter of 120m and a height of 90m, Haptic flooring system conveying bass through the floor so that the audience can ‘feel’ the experience
An adaptive acoustics system to deliver ‘crystal-clear audio to every guest, no matter the size or type of event’
Wireless connectivity delivering 25 megabits per second for every guest, ‘enabling a broader range of content, greater interaction among guests, and more immersive entertainment experiences’

Kat1170 · 30-03-2019 1:58am

Sephiroth_dude wrote:

Sections of the Autobahn in Germany have no speed limit.

They do in fact have a speed limit albeit a minimum one not the more common maximum one.

Realt Dearg Sec · 30-03-2019 2:31am

Capt'n Midnight wrote: »

The Eiffel Tower was only supposed to be temporary.

And it was despised by Parisians. Guy de Maupassant would eat there every day because it had the only view of the city where he couldn't see it.

branie2 · 30-03-2019 8:49am

The recently deceased actor, Shane Rimmer, appeared in Coronation Street

branie2 · 30-03-2019 8:59am

Capt'n Midnight wrote: »

EVERYBODY expected the Spanish Inquisition - they were legally obliged to give 30 days notice

The number of people killed by the Inquisition was actually lower than believed.

Capt'n Midnight · 30-03-2019 12:28pm

branie2 wrote: »

The number of people killed by the Inquisition was actually lower than believed.

People given a choice between the civil authorities and the inquisition usually took the latter, because they had rules.

Also most of the torture was psychological. Rather than set to with red hot pincers, they'd show the client all the tools and explain in detail how each was used. Then a night in the cells to concentrate the mind. Most people didn't go on to actual torture. But if they did there were rules about what could be done and for how long.

Also a lot of it was political early on after the re conquest of Spain. Once it settled down a lot of it was people denouncing their enemies for profit.

The reason why the inquisition stands out is because the invention of printing meant it was widely denounced in Northern Europe where the Protestant witch hunts were killing more.

Realt Dearg Sec · 30-03-2019 2:40pm

Protestants! Up to their old tricks again!

Capt'n Midnight · 30-03-2019 4:30pm

The asteroid that wiped out the dinos hit 65.76 million years ago

branie2 · 30-03-2019 5:18pm

The words "Beam me up, Scotty" were actually never said in Star Trek

Professor Moriarty · 30-03-2019 5:33pm

The words "Play it again, Sam" weren't said in Casablanca. The line is actually "Play it once, Sam".

Esel · 30-03-2019 5:36pm

Capt'n Midnight wrote: »

The asteroid that wiped out the dinos hit 65.76 million years ago

This might be of interest.

https://boards.straightdope.com/sdmb/showthread.php?t=873236

Fourier · 30-03-2019 7:55pm

Esel wrote: »

This might be of interest.

https://boards.straightdope.com/sdmb/showthread.php?t=873236

Wow! Can't wait to hear more about this. Actual victims of the impact.

StupidLikeAFox · 31-03-2019 12:46am

Capt'n Midnight wrote: »

The asteroid that wiped out the dinos hit 65.76 million years ago

65.76 million years ago today? I must light a candle for them

KathleenGrant · 31-03-2019 1:00am

StupidLikeAFox wrote: »

65.76 million years ago today? I must light a candle for them

:D:D:D

Ipso · 31-03-2019 1:12am

Capt'n Midnight wrote: »

The asteroid that wiped out the dinos hit 65.76 million years ago

False flag.

31-03-2019 9:40am

Marbles are not made of marble, they're made of glass.

Capt'n Midnight · 31-03-2019 10:45am

StupidLikeAFox wrote: »

65.76 million years ago today? I must light a candle for them

We will have a better idea when there's more evidence. Plant growth rings and other seasonal changes should tell us what time of year it happened.

BTW the Ice age ended on July 19th 11,722 years ago, probably about three-ish in the afternoon since that's the warmest time of the day.

They weren't using Daylight Savings Time back then so it's only an approximation.

joujoujou · 31-03-2019 12:27pm

The WitchKing of Angmar wrote: »

Marbles are not made of marble, they're made of glass.

Some are made of rubber, especially on a race track.

ytpe2r5bxkn0c1 · 31-03-2019 1:05pm

The WitchKing of Angmar wrote: »

Marbles are not made of marble, they're made of glass.

They were originally made from polished marble though. Modern marbles are glass but began as marble, other stones, and clay.

peasant · 31-03-2019 1:57pm

Deleted User wrote: »

It looks big, even from that point which is about 1.5km away. And it IS big.

Huge, in fact.

bloody heck...it is huge :eek:

for reference...bottom left is terminal 2 of Dublin airport...top right is the distribution centre

Gloomtastic! · 31-03-2019 5:57pm

Anyone here called Fionn or called their son Fionn? Avoid going to France or else change names. It translates to anus! :rolleyes:

Capt'n Midnight · 31-03-2019 6:02pm

Gloomtastic! wrote: »

Anyone here called Fionn or called their son Fionn? Avoid going to France or else change names. It translates to anus! :rolleyes:

Finn McCool would be Bottom McBottom :eek:

Signore Fancy Pants · 31-03-2019 6:50pm

David Jason has an 18 year old daughter.

He was 61 when she was born...dirty old git!

New Home · 31-03-2019 7:15pm

Dale Doback wrote: »

David Jason has an 18 year old daughter.

He was 61 when she was born...dirty old git!

And Rowan Atkinson, now aged 64, has a 2-year-old child.

Also, in March 2001, while he was on a holiday trip to Kenya, the pilot of his private plane fainted. Atkinson managed to maintain the plane in the air until the pilot recovered and was able to land the plane at Nairobi's Wilson Airport.

Ineedaname · 31-03-2019 7:37pm

Dale Doback wrote: »

David Jason has an 18 year old daughter.

He was 61 when she was born...dirty old git!

Mick Jagger has a daughter younger than his great-grandchild.

branie2 · 31-03-2019 9:48pm

Mel Blanc, the voice of Bugs Bunny, was allergic to carrots

johndaman66 · 01-04-2019 12:12am

New Home wrote: »

And Rowan Atkinson, now aged 67, has a 2-year-old child.

I feel I have to correct you on that one, he's 64

764dak · 01-04-2019 12:27am

You can use emojis on a Windows 8 or 10 PC by pressing Win+. or Win+; ��.

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

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