Today I Learned

[DaveC426913]

Today I learned that the Earth was (ever) tidally locked to one of our (Indonesian) satellite?

You jest.

 

[mfb]

What's special about that random GEO satellite? There are ~500 satellites in geostationary orbit. Some have a mass of about 7 tonnes.

 

[berkeman]

https://en.wikipedia.org/wiki/Garuda_1

TIL from this previous TIL link about an old geostationary satellite that one goal for satellites at the end of their operational life is to either de-orbit them (which I knew about), or move them to "Graveyard Orbits":

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

Overview

A graveyard orbit is used when the change in velocity required to perform a de-orbit maneuver is too large. De-orbiting a geostationary satellite requires a delta-v of about 1,500 metres per second (4,900 ft/s), whereas re-orbiting it to a graveyard orbit only requires about 11 metres per second (36 ft/s).[1]

For satellites in geostationary orbit and geosynchronous orbits, the graveyard orbit is a few hundred kilometers beyond the operational orbit. The transfer to a graveyard orbit beyond geostationary orbit requires the same amount of fuel as a satellite needs for about three months of stationkeeping. It also requires a reliable attitude control during the transfer maneuver. While most satellite operators plan to perform such a maneuver at the end of their satellites' operational lives, through 2005 only about one-third succeeded.[2] As of 2011, most[clarification needed] recently decommissioned geosynchronous spacecraft were said to have been moved to a graveyard orbit.[3]

 

[Borg]

TIL about Acapella Science.

 

[BillTre]

TIL about high and low temperature hot spots in the US over the last 20 years (from NY Times):

 

[rsk]

TIL that Skype is still a thing

I also learned this recently. It's a very long time since I used my Skype account and I can't remember the password.

Sadly, I also learned that some time back when I updated the email address in my Skype account because the old one was expiring, it didn't actually update the recovery address. Yes, I learned that Microsoft will allow you to change your email address, but will continue sending password recovery information to the old address.

I also learned that Microsoft Support is pretty much useless in such cases because they just keep suggesting things I could only do once logged in.

 

[mfb]

I had similar experiences with Google. Had an old Youtube account that I didn't use for a while. Tried to log in again - I knew the password, but Google decided that it doesn't recognize my device and needs extra verification it's me. I didn't give Youtube (back when the accounts were separate) my phone number or any RL information Google would have accepted, so the account is dead.

 

[Ibix]

I didn't give Youtube (back when the accounts were separate) my phone number or any RL information Google would have accepted, so the account is dead.

Indeed. And to add insult to injury, every time I try to log in it sends me an email telling me someone tried to log into my account and asking me to click on a link to confirm that I'm me - at which point it asks for my password and round we go again.

 

[rsk]

It's SO frustrating.

 

[BillTre]

TIL that airlines want 5G technology delayed near airports, as they are afraid that it will interfere with some of their technology.

The representatives of 10 carriers asked the administration in a letter obtained by CNN to further delay the rollout near airports where Federal Aviation Administration flight restrictions take effect once the technology kicks in. The aviation world is concerned 5G signals will interfere with aviation technology including the radar altimeter onboard planes.

"The ripple effects across both passenger and cargo operations, our workforce and the broader economy are simply incalculable," the executives wrote. "To be blunt, the nation's commerce will grind to a halt."

 

[fresh_42]

TIL that airlines want 5G technology delayed near airports, as they are afraid that it will interfere with some of their technology.

https://www.physicsforums.com/threa...-delay-in-u-s-5g-wireless-deployment.1010462/

See especially @berkeman's answer in post #3.

 

[Ibix]

Today I learned that trisection of an arbitrary angle using only a ruler and unmarked straightedge was proved impossible in 1837. In 1980, it was shown to be possible using origami (essentially because folding pieces of paper allows you to add marks to your straightedge). Off the back of that I discovered the Miura map fold, a fold of a piece of paper that allows you to collapse it into a small square and expand it again just by pushing or pulling on opposite corners. It's been used in space programs to store solar panels in a compact form that's mechanically simple to open.

 

[rsk]

TIL that airlines want 5G technology delayed near airports, as they are afraid that it will interfere with some of their technology.

I was a bit alarmed when I heard this as I have to fly long haul next week and this, together with the dust on the fan blades episode, made me a bit nervous. Fortunately I'm not going through US airspace.

 

[Klystron]

TIL not for the first time that I can visualize a problem and possible solutions but have difficulty expressing the answers in English, due to age and injuries.
https://www.physicsforums.com/threads/lock-in-amplifier-with-pulsed-sinewave.1011450/

Specifically, I know or knew methods to measure the requested signal lock but 1) my equipment knowledge is years out of date and 2) exact details are sketchy such as coupler attenuation. I would try using the reference pulse to synchronize the PRF (pulse repetition frequency) and/or alter the carrier pulse width to optimize lock but doubt these generalities would help a working engineer.

 

[DaveE]

TIL not for the first time that I can visualize a problem and possible solutions but have difficulty expressing the answers in English, due to age and injuries.
https://www.physicsforums.com/threads/lock-in-amplifier-with-pulsed-sinewave.1011450/

Specifically, I know or knew methods to measure the requested signal lock but 1) my equipment knowledge is years out of date and 2) exact details are sketchy such as coupler attenuation. I would try using the reference pulse to synchronize the PRF (pulse repetition frequency) and/or alter the carrier pulse width to optimize lock but doubt these generalities would help a working engineer.

Yes, me too. I was sooo much smarter 30 years ago. I knew a bunch of stuff I never used much, or ever, which has now drifted away.

But, a couple of related points.

1) This is the sort of problem that can have several solutions from simple (buy the right instrument) to complex (PLLs to filter, demodulate and sample etc.). Which are really based on how much you care, how hard is the problem, and how much time and money you have. This causes a bit of confusion to people that understand the options but not the all of the constraints.

Which leads us to:

2) Working engineers are working. They will spend much more time and effort thinking about their specific problems than we will. When I was actually paid for this sort of thing I probably would have spent at least a day thinking about the solution, sometimes much more. OTOH, we won't. We toss out ideas based on our previous experience, learned by actually solving these things. If you cared more because this was your problem, not someone else's, you would sort all of that out.

 

[Klystron]

Yes, me too. I was sooo much smarter 30 years ago. I knew a bunch of stuff I never used much, or ever, which has now drifted away.

But, a couple of related points.

1) This is the sort of problem that can have several solutions from simple (buy the right instrument) to complex (PLLs to filter, demodulate and sample etc.). Which are really based on how much you care, how hard is the problem, and how much time and money you have. This causes a bit of confusion to people that understand the options but not the all of the constraints.

Which leads us to:

2) Working engineers are working. They will spend much more time and effort thinking about their specific problems than we will. When I was actually paid for this sort of thing I probably would have spent at least a day thinking about the solution, sometimes much more. OTOH, we won't. We toss out ideas based on our previous experience, learned by actually solving these things. If you cared more because this was your problem, not someone else's, you would sort all of that out.

Thanks for the corroboration. Forty to fifty years since my hands-on RF lab work. Your second point contains the corollary that inputs from another engineer not invested in the outcome can help clarify one's thinking; true for many professions such as medical diagnostics.

Good point about cost as an aspect of problem solving. Scale also limits solution sets. For example, I would design a full-scale data center with an ATS (automatic transfer switch) between municipal power and emergency generators, while a DIY homeowner might rely on manual switching.

 

[Borg]

TIL an interesting bit of information. I was reading an article from this month's Scientific American about When Animals Started Making Noise. Near the end, the discussion went into how humans were unique in the animal kingdom for their ability to teach each other language. The sign language statement from the chimp at the end of the paragraph left me floored.

It is not just the possession of language that is so powerful: humans are unique in their abilities to teach, learn and record language. Although researchers have successfully taught some other primates to use sign language, none of these educated apes has ever taught this language to others of its species, even when given the opportunity. In one case, a chimpanzee at the Duke University primate facility who had been taught sign language was reunited with his troupe. He tried to use his new skill set to communicate with his fellow chimps. After a week of attempts, his keepers found him in a corner of the paddock, where he had isolated himself. When they asked him in sign language why he was not with the other chimps, he signed back, “Because they are insects.”

 

[Hornbein]

TIL an interesting bit of information. I was reading an article from this month's Scientific American about When Animals Started Making Noise. Near the end, the discussion went into how humans were unique in the animal kingdom for their ability to teach each other language. The sign language statement from the chimp at the end of the paragraph left me floored.

Aha. I bet if you taught a group of apes to sign, they would be able to teach others who wish to join the group.

 

[Borg]

Aha. I bet if you taught a group of apes to sign, they would be able to teach others who wish to join the group.

I don't know. Using a tool isn't the same thing as creating it.

 

[berkeman]

Aha. I bet if you taught a group of apes to sign, they would be able to teach others who wish to join the group.

Ool? Bobo!

https://haphazardstuff.com/caveman-1981-movie-review/

 

[Melbourne Guy]

TIL that the best way to paint a wood paling fence is before you nail all the palings up

I also learned that colour selection is impossible! Tiny swatches, terrible store lighting, expensive sample pots, and marketing names that have nothing to do with reality. It's a choice nightmare

 

[Ibix]

I also learned that colour selection is impossible! Tiny swatches, terrible store lighting, expensive sample pots, and marketing names that have nothing to do with reality. It's a choice nightmare

When we moved into our house, the downstairs bathroom was painted an off-white, but a nasty one that looked sort of dilute nicotine yellow. We decided a light colour was good but the yellow was ugly, so we went out and bought three sample pots in blue, green and brown tinted off-whites. I painted three patches, left them to dry, and found that there were only two patches because our nice brown tinted off-white turned out to be identical to the nasty nicotine yellow tinted one. Fortunately the blue tinted one was nice.

 

[Borg]

Sample paints are on the agenda for me today. We're getting ready to paint the kitchen a new color.

 

[Jonathan Scott]

Sample paints are on the agenda for me today. We're getting ready to paint the kitchen a new color.

When my daughter was a toddler, she managed to paint a large part of the "play room" in raspberry spots - I think it was by sneezing into her drinking cup. You won't find that scheme in sample paints!

 

[Rive]

TIL about the absolute 'destined to lose' situation: colds lasts 4-5 days, but if you use a nasal spray that long, what you are up to is a rebound congestion.
Does not feels good.

 

[DrGreg]

Yesterday I learned that Roger Penrose once sued a toilet paper manufacturer for using his Penrose tiling without permission.

A Penrose tiling is infinite but non-periodic (never repeats itself), so, when embossed on a roll of paper, would reduce the chances of adjacent sheets sticking together.

Ref: Toilet Paper Plagiarism

 

[Klystron]

When we moved into our house, the downstairs bathroom was painted an off-white, but a nasty one that looked sort of dilute nicotine yellow. We decided a light colour was good but the yellow was ugly, so we went out and bought three sample pots in blue, green and brown tinted off-whites. I painted three patches, left them to dry, and found that there were only two patches because our nice brown tinted off-white turned out to be identical to the nasty nicotine yellow tinted one. Fortunately the blue tinted one was nice.

The contractor who helped me fix up my current abode found a solution to this color problem.

Pure white walls appear stark, excessively bright, and easily show dirt and stains.
Adding yellow can result in an aged, literally 'yellowed', appearance unpleasant to many people.

The contractor added red to a flat white base achieving a mellow rose tint pleasing to the eye that hides or deemphasizes basic stains. I forget the name of the red pigment, but the resultant tint remains popular in American southwest and Mexican interiors. The rose color matches light or 'oak' wooden floors and wooden furniture. We painted ceiling, doors and mouldings in white semi-gloss that compliment the rose walls.

The blue solution also works well, particularly in bedrooms and bathrooms, also matching wood wainscoting and floors.

 

[Ibix]

The contractor added red to a flat white base achieving a mellow rose tint pleasing to the eye that hides or deemphasizes basic stains. I forget the name of the red pigment, but the resultant tint remains popular in American southwest and Mexican interiors. The rose color matches light or 'oak' wooden floors and wooden furniture.

Magnolia? That's the standard "neutral" colour that everyone here paints their house when they're trying to sell it. A lot of the walls here are magnolia because the previous owners did that (it belonged to their mother and I think the original colour scheme reflected a unique taste, shall we say) and I've no particular urge to repaint them. The bathroom was a slightly different colour, though, and rather ugly.

 

[Klystron]

Magnolia? That's the standard "neutral" colour that everyone here paints their house when they're trying to sell it. A lot of the walls here are magnolia because the previous owners did that (it belonged to their mother and I think the original colour scheme reflected a unique taste, shall we say) and I've no particular urge to repaint them. The bathroom was a slightly different colour, though, and rather ugly.

Hmm... Magnolia appears to be a cream color. The white paint can is labelled 'eggshell'. The red additive can has a list of numbers without a descriptive label. The painter mixed the colors at the paint store then brought the 'rose' tint in the original 'eggshell' gallon cans. I will ask the painter what they call the result.

 

[Keith_McClary]

paint a large part of the "play room" in raspberry spots - I think it was by sneezing into her drinking cup

A baby experimentalist.

 

[Keith_McClary]

the standard "neutral" colour

How about a nice warm colour?:

 

[Buzz Bloom]

That color approximately is the current color of the sky where I am. The local temperature is 25 degrees F.

 

[berkeman]

TIL that NFL "Long Snappers" have developed the amazing skill to be able to snap field goals so that the laces of the football consistently face forward toward the goal posts when the holder catches the snap and puts the football straight down on end (so that the holder does not need to rotate the football and the kicker never sees the laces) -- "Laces Out!.

I was listening to a local sports talk radio station on my way home from work today (yes, it's Saturday), and they were interviewing a retired veteran football player whose specialty was "Long Snapper". That's the player who hikes the ball for field goals and punts. I was amazed when he said that he was one of the first long snappers who developed the skill to always snap the football so that the holder who catches the snap and puts it down for the kicker does not need to rotate the ball at all before the kick.

Apparently when he first got to the professional level, his first kicker asked him "Can you snap it so the laces are always out?" He thought he might be able to do it, and with practice he perfected the art of maintaining just 3-3.5 rotations of the football (depending on a right- or left- footed kicker) from his snap to the catch by the field goal holder.

What amazing skill, and I had no idea. I do remember that years ago it was common to see the holder routinely rotate the football as part of the field goal, and I hardly ever see that happening anymore. So apparently it has caught on as a required skill for long snappers in the NFL. I don't think I could be that consistent in my overhand throws!

Here's a blog entry describing the skill:

https://longsnapper.com/laces-out/

 

[strangerep]

TIL that the best way to paint a wood paling fence is before you nail all the palings up

I also learned that colour selection is impossible! Tiny swatches, terrible store lighting, expensive sample pots, and marketing names that have nothing to do with reality. It's a choice nightmare

You can (effectively) get 3-in-1 from a single sample pot by going half-tint and quarter-tint (diluting with white). Don't skimp on sample pots. They're not expensive compared to the psychological cost of living with something you don't like.

Start by making medium sized samples, say 300mm square(ish). When you think you're getting close to right hue+shade, make some very large samples, 900x600 or bigger, e.g., on sheets of cardboard of whatever. If it's still not quite right, go get some more sample pots and repeat.

For the samples, if your starting board is not already white, then use a double white undercoat first, then 2-3 topcoats, to be sure you're getting a correct impression.

 

[Melbourne Guy]

You can (effectively) get 3-in-1 from a single sample pot by going half-tint and quarter-tint (diluting with white). Don't skimp on sample pots. They're not expensive compared to the psychological cost of living with something you don't like...

@strangerep, I can see now that I approached the entire fence painting project with ZERO effective planning and it's coming back to bite me. Fortunately, Melbourne's summer is finally biting this week, so I've a natural reason to regroup because it's too hot to paint much. But we've a single coat on most of the palings already, so am committed to at least completing a first coat on the rest, then the colour matching can commence in earnest. And in this case, colour is important because the fence is 13 meters long along the driveway and highly visible, so your advice is spot on

 

[ergospherical]

 

[strangerep]

[...] colour is important because the fence is 13 meters long along the driveway and highly visible, so your advice is spot on

For exterior timber like fences (and also deck supports if visible) I reckon it's hard to go wrong with "forest green" from the colourbond range. It's a very dark grey but with a green hint, so it blends well with any surrounding vegetation. Dark colours also have a de-emphasizing visual effect -- which is probably what one wants since paling fences are not exactly the most attractive things.

Btw, that colour is also called "zeus" in the dulux range.

 

[DaveC426913]

For exterior timber like fences (and also deck supports if visible) I reckon it's hard to go wrong with "forest green" from the colourbond range. It's a very dark grey but with a green hint, so it blends well with any surrounding vegetation. Dark colours also have a de-emphasizing visual effect -- which is probably what one wants since paling fences are not exactly the most attractive things.

Btw, that colour is also called "zeus" in the dulux range.

Disney invented "Go Away Green".

https://www.housebeautiful.com/room-decorating/colors/a3915/disney-go-away-green/

 

[ergospherical]

Crabs can get scammed too.

 

[OmCheeto]

"most skilled typists don't know where the letters are located on the standard keyboard". [ref]

I found this out this morning after playing Wordle, and was curious why my fingers typed out a word that was phonetically correct, but spelled with the wrong letter, but was spelled correctly.

 

[jack action]

TIL:

Bluetooth technology​

The Bluetooth wireless specification design was named after the king in 1997, based on an analogy that the technology would unite devices the way Harald Bluetooth united the tribes of Denmark into a single kingdom. The Bluetooth logo

consists of a Younger Futhark bind rune for his initials, H (ᚼ) and B (ᛒ).

 

[jtbell]

Today I learned that professional pillow fighting is a thing.

 

[jack action]

TIL that the 21^st century began on January 1^st, 2001.

Like a stupid programmer, I instinctively thought It began on January 1^st, 2000.

I never realized the year zero doesn't exist.

 

[BWV]

You can modulate from C major to B# major, but would not recommend trying this at home

 

[Keith_McClary]

I never realized the year zero doesn't exist.

I tried telling people that in 2000, but soon gave up. Is there an official definition of 21^st century anywhere?
Wikipedia says there are two viewpoints :

 

[jack action]

I tried telling people that in 2000, but soon gave up. Is there an official definition of 21^st century anywhere?
Wikipedia says there are two viewpoints :
View attachment 296521

There's a lot more info on the page Year Zero.

Not having a year zero might create a problem mathematically when doing calculations across BC and AD, but really what does "Year 0" mean? Zero is supposed the be a single transition point, not an elapsed time.

Even if we want to use a Year Zero, it would be more logical mathematically to use a 0 BC and a 0 AD. This way the date would represent "the number of years since" and the month and day would be the decimal part. But that would be confusing to everyone now as we would have to subtract 1 year from the years on the Gregorian calendar.

 

[strangerep]

You can modulate from C major to B# major, [...]

It's been a long time since I formally learned music, but I thought that B# is the same thing as C (at least, on a normal piano keyboard)?

 

[BWV]

It's been a long time since I formally learned music, but I thought that B# is the same thing as C (at least, on a normal piano keyboard)?

Yes, C and B# are the same note on a piano, but theoretically not the same. In the key of C#, for example, B# is the correct notation for that pitch. But the key of B# is silly, even though the modulation I posted came from a book by Max Reger, who was a great turn-of-the century composer

 

[Jodo]

Today I learned that "chasing the dragon" is slang for smoking heroin.

It refers to chasing the initial high off of many drugs. Unfortunately that initial high "feel" is no longer obtainable. One can certainly spiral into addiction chasing it.

 

[jack action]

TIL:

1936 - the term “volkswagen” was used on entry level cars from different companies before it became the Volkswagen we know from the KdF car.