Questions you've always wanted answered

[Elliott Mellor]

I still think it's a stretch for anyone who doesn't play tennis fairly competently, but I admire your optimism.

If a non player was taken off the street and went on a grass court and was offered the wager then I would say said person is most likely to lose but if Jono or Gevin was asked and they could choose a clay court and could spend a few days practising with a machine beforehand then my money is on either of them

That's making it a different problem though. You might as well add that they can have an extendable racket as well. Obviously it's possible to improve your chances by changing the variables but my point stands that, with no preparation, the average person wouldn't succeed.

[Marc Meakin]

I think if I was allowed to play at Roland Garros, even at 60 I would be reasonably confident I could get 1 ball over the net.
For context I did play tennis most summers in my 20s in the park and I do still have good hand/eye co-ordination
Plus fatigue would set in for the pro during those hundred serves if he cannot have a break every 10 serves
However I couldn't face a cricket ball from a fast bowler.
Those balls hurt.

[Adam Gillard]

I still think I could do it as well, and the optimism / belief would help with that. If you're going into it thinking you have no chance then you will be more likely to fail.

[Jon O'Neill]

I still think it's a stretch for anyone who doesn't play tennis fairly competently, but I admire your optimism.

If a non player was taken off the street and went on a grass court and was offered the wager then I would say said person is most likely to lose but if Jono or Gevin was asked and they could choose a clay court and could spend a few days practising with a machine beforehand then my money is on either of them

That's making it a different problem though. You might as well add that they can have an extendable racket as well. Obviously it's possible to improve your chances by changing the variables but my point stands that, with no preparation, the average person wouldn't succeed.

I think it's fair to take the original statement in the most advantageous way. So I would get the slowest or worst first-serving ATP pro in the most favourable conditions within the laws of tennis, which I don't think an extendable racquet would be.

However, I am not sure I'd prefer clay over grass. Obviously the ball will come slower but with much more spin and variety of angles. You might get your racquet on more but I feel like that variety is going to reduce your chances. I might be inclined to go with a hard court as I understand they are a bit slower but not as bouncy as clay.

[Elliott Mellor]

If a non player was taken off the street and went on a grass court and was offered the wager then I would say said person is most likely to lose but if Jono or Gevin was asked and they could choose a clay court and could spend a few days practising with a machine beforehand then my money is on either of them

That's making it a different problem though. You might as well add that they can have an extendable racket as well. Obviously it's possible to improve your chances by changing the variables but my point stands that, with no preparation, the average person wouldn't succeed.

I think it's fair to take the original statement in the most advantageous way. So I would get the slowest or worst first-serving ATP pro in the most favourable conditions within the laws of tennis, which I don't think an extendable racquet would be.

However, I am not sure I'd prefer clay over grass. Obviously the ball will come slower but with much more spin and variety of angles. You might get your racquet on more but I feel like that variety is going to reduce your chances. I might be inclined to go with a hard court as I understand they are a bit slower but not as bouncy as clay.

Sure, if you want. However, I think that mitigates some of the intended nature of the challenge. Anyone who's within the top 50 or has a particularly thunderous serve, I think it's fair to say that you've got pretty much no chance. If you're allowing, say, #1000 to count as professional and also to play under the most favourable conditions from a receiver's point of view, then at that point I'd say it's fair to back yourself.

[Gavin Chipper]

Why they don't use automatic hawkeye at Wimbledon when they clearly have the technology for it, and wrong calls are potentially influencing the outcomes of matches. It seems so daft when a ball is called out, and then commentary says "actually, hawkeye says that was in. He should have challenged that". They don't have a "challenge" system in football for if the ball has gone over the goal-line - as soon as they got the technology at a level where they could eliminate the human error, they implemented it. Wimbledon has had the technology for a good while, but still insists on using a system whereby players are expected to use a limited number of challenges to counter subjective calls.

Way ahead of you.

Edit - They also used to have a thing that beeped when a serve went out (maybe just if it went long?) and that must have been going decades ago. Weird they haven't got a proper all-encompassing system by now.

[Sam Cappleman-Lynes]

Edit - They also used to have a thing that beeped when a serve went out (maybe just if it went long?) and that must have been going decades ago.

Maybe we're not thinking of the same thing, but the beep I can recall was triggered by the ball hitting the net cord.

[Jon O'Neill]

Edit - They also used to have a thing that beeped when a serve went out (maybe just if it went long?) and that must have been going decades ago.

Maybe we're not thinking of the same thing, but the beep I can recall was triggered by the ball hitting the net cord.

There were 2 with different beeps.
Watch the first 2 games and you'll hear both: https://youtu.be/-9s3MKnHKYY

I think it might have just been on hard courts though.

[Gavin Chipper]

Edit - They also used to have a thing that beeped when a serve went out (maybe just if it went long?) and that must have been going decades ago.

Maybe we're not thinking of the same thing, but the beep I can recall was triggered by the ball hitting the net cord.

There were 2 with different beeps.
Watch the first 2 games and you'll hear both: https://youtu.be/-9s3MKnHKYY

I think it might have just been on hard courts though.

Wimbledon as well. The second point in this match.

[Jon O'Neill]

How did it work?

[Gavin Chipper]

How did it work?

Dunno.

[David Williams]

Why they don't use automatic hawkeye at Wimbledon when they clearly have the technology for it, and wrong calls are potentially influencing the outcomes of matches. It seems so daft when a ball is called out, and then commentary says "actually, hawkeye says that was in. He should have challenged that". They don't have a "challenge" system in football for if the ball has gone over the goal-line - as soon as they got the technology at a level where they could eliminate the human error, they implemented it. Wimbledon has had the technology for a good while, but still insists on using a system whereby players are expected to use a limited number of challenges to counter subjective calls.

Has this been answered? I only have a passing interest in tennis, but I thought other tournaments already did this and it was going to be universal from 2025.

[Elliott Mellor]

I make it three wrong calls in the Wimbledon final so far (and it's not even the end of the second set), and two of them were more in than out. It's really time they addressed this issue, because fine margins count at this level and one error can make all the difference.

I'm pretty sure that the calling never even used to be this bad, though maybe I'm looking at the past through rose-tinted spectacles.

Also about time they addressed the 25 seconds between points rule - either implement it consistently or don't have it at all. Average time between points for both players is above 25 in this final (though Djokovic is considerably more over).

[Gavin Chipper]

Is this the tennis thread now?

Why don't they have the ball a colour that better contrasts the court? A greenish yellow ball on a green court doesn't come across on television very well. Maybe bright orange. Or blue grass.

[Gavin Chipper]

How did it work?

Dunno.

Someone just reminded me it was called Cyclops.

[Jon O'Neill]

How did it work?

Dunno.

Someone just reminded me it was called Cyclops.

Nice!

[Marc Meakin]

I remember Cyclops, I used to wonder why the beep didn't sound during a rally of the ball went out.
I assumed the umpire had to deactivate it after the serve.
It was efficient but noisy

[David Williams]

While we're at it, can anyone explain how Hawk-Eye determines the size of the impact on the ground?

A perfect solid sphere resting on a perfect flat surface would have an infinitesimally small area of contact. I don't imagine that the dent in the surface caused by the weight of the ball, nor the compression of the ball under its own weight amount to much. The imperfections of the surfaces of both will have an effect, but the biggest element has to be how much account you take of the grass and the nap on the ball. Does a single blade touching a single hair count? Is the area less on clay?

Then you have to take account of the speed and trajectory of the ball. A drop shot that clips the net and falls just over will be very little different to a resting ball. A high lob will make a larger contact as the ball must compress enough to transfer energy for it to bounce high into the air, but the area will still be essentially circular. Whereas a fast first serve will not compress as much, but will cover an elliptical area.

It's always seemed to me that the areas shown by Hawk-Eye look too large, almost the width of the ball, as in football's 'all of the ball over all of the line', so a ball can still be in even if it doesn't actually touch the line, merely had some part of the line under it when it bounced.

[Gavin Chipper]

There was some discussion of Hawk-Eye and its accuracy here.

Also, just looking at the Wikipedia article. The advertised average error is apparently 3.6mm. I'd say that's not exactly negligible, and you have to take into account that any advertised accuracy is likely to be exaggerated in favour of the manufacturer. Without an independent measure it's pretty meaningless. And as I said in that 2011 post:

I always think it's a bit funny that someone challenges a call, and they decide to "see what really happened" and actually just watch some computer game of the action.

[Jon O'Neill]

It's always seemed to me that the areas shown by Hawk-Eye look too large, almost the width of the ball, as in football's 'all of the ball over all of the line', so a ball can still be in even if it doesn't actually touch the line, merely had some part of the line under it when it bounced.

I don't have the answers you need (and would like to know more) but I always find it counter-intuitive the degree to which balls deform when they bounce, which I think is what HawkEye will be depicting. Example: https://www.youtube.com/watch?v=1yT0hxplVBg

[Gavin Chipper]

Good video. In the discussion I linked to, Michael Wallace linked to some pictures showing quite a big amount of deformation but the link doesn't work any more.

[Andres Sanchez]

How the fuck are the bags under your eyes made? And can you have bags under your bags?

[Mark Deeks]

Why, when your voice gets louder, does it also go higher?

[Fiona T]

Did everyone read that in an increasingly high pitched head-voice?

[Matt Morrison]

I always find it counter-intuitive the degree to which balls deform when they bounce, which I think is what HawkEye will be depicting. Example: https://www.youtube.com/watch?v=1yT0hxplVBg

This one is good: https://www.youtube.com/watch?v=FC8Tpi3U0H0 - I wanted, but failed after fairly minimal effort, to find an equivalent video for a tennis ball travelling at an angle to the surface more closely equivalent to the kind of shot HawkEye is having to deal with. Let me know if you find one.

[Ian Volante]

Why, when your voice gets louder, does it also go higher?

Mine doesn't generally as far as I'm aware, but maybe that's with some self-taught projection practice in the context of pub quiz presenting. I suppose if you shout, it's maybe easier on the larynx to go to a higher register to deal with the extra energy, possibly also easier to hear.

[Mark Deeks]

I dunno man. The flute's a sneaky-cool instrument and all, but I can't remember us beatifying a flautist before. She seems to have transcended society with it.

My take on her is like Keanu Reeves, who is so personable and an all round Nice guy and you can forgive his crap serious acting.
Lizzo is also very personable and an all around nice gal.

..

[Marc Meakin]

I dunno man. The flute's a sneaky-cool instrument and all, but I can't remember us beatifying a flautist before. She seems to have transcended society with it.

My take on her is like Keanu Reeves, who is so personable and an all round Nice guy and you can forgive his crap serious acting.
Lizzo is also very personable and an all around nice gal.

..

I'm gonna cross my fingers and hope this is another Kevin Spacey type scenario.

She has denied the allegations btw
https://www.theguardian.com/music/2023/ ... er-dancers

[Mark James]

I'm gonna cross my fingers and hope this is another Kevin Spacey type scenario.

What, that she's guilty but will get away with it anyway?

[Marc Meakin]

I'm gonna cross my fingers and hope this is another Kevin Spacey type scenario.

What, that she's guilty but will get away with it anyway?

Innocent until proven Irish or otherwise

[Mark James]

Have they ever tried introducing polar bears to the antarctic?

[Marc Meakin]

Have they ever tried introducing polar bears to the antarctic?

You'd probably have to introduce more seals at the same time if you didn't want them to die out

[Mark James]

Have they ever tried introducing polar bears to the antarctic?

You'd probably have to introduce more seals at the same time if you didn't want them to die out

Apparently there's more than enough. It would be a tremendously bad idea because of how it would fuck up the ecosystem but I was wondering if anyone ever tried it and that's how we know it's a bad idea or did people know it would be a bad idea and never tried it. Surely someone must have put one there at least just to see how it got on.

[Fiona T]

https://www.newscientist.com/lastword/m ... e-species/

https://www.forbes.com/sites/alleneliza ... ould-they/

TL;DR - fix climate change instead

[Mark Deeks]

When I was young, we would load up the dogs in the car and make the drive to my Granny's house a few times a year. It was about 100 miles/2 hours each way. Every single time, without fail, our dog Sam - who had been sitting in the back with his head down the whole way, not looking out the window or anything - would start barking with excitement whenever we got to the shirt right hand junction two miles before getting to her house. Every single time, the same place. Somehow, he always knew when we were nearly there. Did my dog have built-in GPS?

[Marc Meakin]

I know dogs have a great sense of smell but I can't see how that helps unless you had the window open

[Mark Deeks]

It's possible. If they can smell cancer from outside the body then they can definitely smell certain countrysidey smells through a Volvo window. If it isn't that, though, then I've no idea. It can't have been time because no two trips ever took the same amount, and he definitely wasn't looking out the window every time because he was in the back with us, we would have seen. It was just a thing he did at that same turning, honestly dozens of times.

[Gavin Chipper]

Could he have recognised where he was from his peripheral vision, or the corner sequences?

[Marc Meakin]

The difference between Ghosting and Grey Rock

[Mark Deeks]

What actually is/happens in a black hole? How can there just be nothing?

[Ben Wilson]

What actually is/happens in a black hole? How can there just be nothing?

The latest episode of the Sky at Night (broadcast this Monday) was literally about black holes and is a recommended watch. but in short: there isn't 'nothing' in there, a black hole in the conventional sense is an area surrounding a point of infinite density where the gravity is so huge that light can't escape. In short: lots of stuff goes on in there, we just can't see it because physics.

[Ian Volante]

What actually is/happens in a black hole? How can there just be nothing?

A lot of this was beyond my undergrad, but it is theorised that black holes, via Hawking radiation, re-emit the information that they swallowed in the past place, and eventually evaporate. Due to quantum.

[Mark Deeks]

How can there be a shitload of gravity if there's not, like, a giant lump in the middle that actually causes it?

[Gavin Chipper]

There is a giant lump. Well a very dense lump. It might not be that big but it's massive.

[Mark Deeks]

I don't think I understand the difference between big and massive in this context!

[Gavin Chipper]

I don't think I understand the difference between big and massive in this context!

Big as in taking up lots of space. Massive as in lots of mass. Something really dense can be massive but not big.

[Ben Wilson]

I don't think I understand the difference between big and massive in this context!

Zero volume, very large weight*, infinite density. The volume of the 'hole' part of the black hole depends entirely on how 'heavy' the centre of it is.

*mass is a more technically correct term here but I'm using weight for simplicity

[Mark Deeks]

Something really dense can be massive but not big.

Half a mind to report you for this personal attack.

[Mark Deeks]

I'll be honest, I still don't really get it. It's like when they say that molecules (or atoms or whichever it is) are made up of electrons or whatever orbiting nucleuses through magnetism, meaning they are mostly just loads of empty space. How can everything be made up of mostly empty space! And why don't the protons or whatever just go off into another nucleus's magnetic sphere?

I never really understood science, as can be seen from the above.

[Mark Deeks]

Also, in addition to all apparently being made of empty space with the occasional magnetic lump in it, how can basically everything - from the shorts I am wearing right now to the pencil on the table over there to the table itself to the bit of wood that just hit the window - all be made of carbon?

[Marc Meakin]

Also, in addition to all apparently being made of empty space with the occasional magnetic lump in it, how can basically everything - from the shorts I am wearing right now to the pencil on the table over there to the table itself to the bit of wood that just hit the window - all be made of carbon?

Carbon forms readily with other atoms.
That's how I remember my chemistry teacher describe it

[Ian Volante]

I'll be honest, I still don't really get it. It's like when they say that molecules (or atoms or whichever it is) are made up of electrons or whatever orbiting nucleuses through magnetism, meaning they are mostly just loads of empty space. How can everything be made up of mostly empty space! And why don't the protons or whatever just go off into another nucleus's magnetic sphere?

I never really understood science, as can be seen from the above.

Nothing is touching. Slapping your hand on a table is simply a demonstration of the repulsion of a large number of atoms not wanting to be any closer to each other because their nuclei share the same charge.

Atoms are tiny, and electromagnetic forces extend way beyond the nuclei which contain the protons and therefore the positive force. Different materials pack differently due to the number of particles in the atoms/molecules, how they are arranged within materials affects their macroscopic properties. The most obvious example here is that graphite and diamond are made from the same stuff in different arrangements.

The reason protons don't go off is because they are close enough to each other that the strong nuclear force holds them together - overcoming the electromagnetic repulsion exhibited by the positive charge they hold. This is one reason why nuclear fusion is difficult. The energy required to force two nuclei close enough to each other to overcome that electro repulsion and to access the strong force range is quite a lot.

[Gavin Chipper]

If certain insects that find their way into your kitchen are prone to instant drowning as soon as they come into contact with a drop of water, why don't whole species go extinct when it rains?

[Ian Volante]

Also, in addition to all apparently being made of empty space with the occasional magnetic lump in it, how can basically everything - from the shorts I am wearing right now to the pencil on the table over there to the table itself to the bit of wood that just hit the window - all be made of carbon?

Carbon forms readily with other atoms.
That's how I remember my chemistry teacher describe it

Carbon is an atom which forms molecules with a wide range of other substances; the energy required for those reactions to occur, for example for a tree to take in carbon dioxide from the atmosphere and to convert it into lignin, the hard molecule which gives wood much of its stability, is low enough that this can be achieved naturally without, say, the external provision of energy in the form of hot gas from a Bunsen burner.

Silicon, being in the same group as carbon, could in theory exhibit a lot of the same chemical properties in nature as carbon, but because it takes a lot more energy to separate it from molecules which it's often found in (e.g. silicon dioxide, which is often a large proportion of sand), then it just doesn't become part of natural chemical processes in the same way as carbon, and we therefore don't see silicon-based life as far as we know.

Macroscopic properties of materials depend on on the molecules that they are made of, and how those molecules are bound together. Carbon's versatility again means that it naturally appears in many molecules that are all sorts of shapes and sizes, and many of them exhibit useful properties that we take advantage of. There's nothing stopping us making trousers out of thread made of non-carbon materials, but it's generally more difficult to do so, so why would we?

Human history in many ways has been driven by the amount of energy available to it. We could only work with stone originally, but then eventually worked with fire in a way that allowed some metals to be smelted, the ones with a lower boiling point first like copper and tin, hence the bronze age. Then we managed to smelt iron, which was more difficult to work, but also stronger and more durable. Later still, we've accessed aluminium (lighter and stronger than iron), etc etc. Further energy leads to computing, to AI, to quantum computing, and we might eventually get on to nuclear fusion, Dyson spheres, many other things.

Bit of a tangent there, but there are so many questions for every statement, it's tough to stick to one point.

[Ian Volante]

If certain insects that find their way into your kitchen are prone to instant drowning as soon as they come into contact with a drop of water, why don't whole species go extinct when it rains?

They hide in dry places, and raindrops push them out of the way as they fall.

[Fiona T]

I'll be honest, I still don't really get it. It's like when they say that molecules (or atoms or whichever it is) are made up of electrons or whatever orbiting nucleuses through magnetism, meaning they are mostly just loads of empty space. How can everything be made up of mostly empty space! And why don't the protons or whatever just go off into another nucleus's magnetic sphere?

I never really understood science, as can be seen from the above.

Nothing is touching. Slapping your hand on a table is simply a demonstration of the repulsion of a large number of atoms not wanting to be any closer to each other because their nuclei share the same charge.

Atoms are tiny, and electromagnetic forces extend way beyond the nuclei which contain the protons and therefore the positive force. Different materials pack differently due to the number of particles in the atoms/molecules, how they are arranged within materials affects their macroscopic properties. The most obvious example here is that graphite and diamond are made from the same stuff in different arrangements.

The reason protons don't go off is because they are close enough to each other that the strong nuclear force holds them together - overcoming the electromagnetic repulsion exhibited by the positive charge they hold. This is one reason why nuclear fusion is difficult. The energy required to force two nuclei close enough to each other to overcome that electro repulsion and to access the strong force range is quite a lot.

I remember our physics teacher (who always had chalkdust round his groin area) getting a class of 3rd year girls to stand in a line and jump up and down to demonstrate why things expand when heated.... (this was the olden days when schools had 3rd years and blackboards with chalk...)

[Ian Volante]

I'll be honest, I still don't really get it. It's like when they say that molecules (or atoms or whichever it is) are made up of electrons or whatever orbiting nucleuses through magnetism, meaning they are mostly just loads of empty space. How can everything be made up of mostly empty space! And why don't the protons or whatever just go off into another nucleus's magnetic sphere?

I never really understood science, as can be seen from the above.

Nothing is touching. Slapping your hand on a table is simply a demonstration of the repulsion of a large number of atoms not wanting to be any closer to each other because their nuclei share the same charge.

Atoms are tiny, and electromagnetic forces extend way beyond the nuclei which contain the protons and therefore the positive force. Different materials pack differently due to the number of particles in the atoms/molecules, how they are arranged within materials affects their macroscopic properties. The most obvious example here is that graphite and diamond are made from the same stuff in different arrangements.

The reason protons don't go off is because they are close enough to each other that the strong nuclear force holds them together - overcoming the electromagnetic repulsion exhibited by the positive charge they hold. This is one reason why nuclear fusion is difficult. The energy required to force two nuclei close enough to each other to overcome that electro repulsion and to access the strong force range is quite a lot.

I remember our physics teacher (who always had chalkdust round his groin area) getting a class of 3rd year girls to stand in a line and jump up and down to demonstrate why things expand when heated.... (this was the olden days when schools had 3rd years and blackboards with chalk...)

I hate to ask, but what was theoretically expanding?

[Fiona T]

Nothing is touching. Slapping your hand on a table is simply a demonstration of the repulsion of a large number of atoms not wanting to be any closer to each other because their nuclei share the same charge.

Atoms are tiny, and electromagnetic forces extend way beyond the nuclei which contain the protons and therefore the positive force. Different materials pack differently due to the number of particles in the atoms/molecules, how they are arranged within materials affects their macroscopic properties. The most obvious example here is that graphite and diamond are made from the same stuff in different arrangements.

The reason protons don't go off is because they are close enough to each other that the strong nuclear force holds them together - overcoming the electromagnetic repulsion exhibited by the positive charge they hold. This is one reason why nuclear fusion is difficult. The energy required to force two nuclei close enough to each other to overcome that electro repulsion and to access the strong force range is quite a lot.

I remember our physics teacher (who always had chalkdust round his groin area) getting a class of 3rd year girls to stand in a line and jump up and down to demonstrate why things expand when heated.... (this was the olden days when schools had 3rd years and blackboards with chalk...)

I hate to ask, but what was theoretically expanding?

Metal perhaps. Hopefully not wood...

[Marc Meakin]

Why does my chilly bottle keep things cool for up to 24 hrs but can only keep hot drinks hot for 12 hours?
I'm guessing it's the same with conventional Thermos too as a ratio rather than the exact length of time

[Gavin Chipper]

Why does my chilly bottle keep things cool for up to 24 hrs but can only keep hot drinks hot for 12 hours?
I'm guessing it's the same with conventional Thermos too as a ratio rather than the exact length of time

Probably a temperature difference thing. Cool things are closer to room temperature than a hot drink. The bigger the difference the quicker it will lose (or gain) heat.