Speaker 1: Now instead of doctor carb this warning answering your questions,
Speaker 1: it's Biancher. No, Grady, do I call you doctor Biancher?
Speaker 2: Ah kay if you like. It's not technically my title,
Speaker 2: but I'm happy to take it.
Speaker 1: What about brainy bi anchor?
Speaker 2: Yes, good at improvising. Bianca might work you go.
Speaker 1: Let's get to some of these questions, and I love them.
Speaker 1: This one from Paul. When you're standing on the shoreline,
Speaker 1: how far away is the horizon with the curvature of
Speaker 1: the Earth.
Speaker 3: So the answer to this is both simple and complicated.
Speaker 3: So it's simple because it's actually relatively easy to work
Speaker 3: this out. Essentially just a mathematical formula. It uses Pythagris's
Speaker 3: theorem and essentially it takes into account your height and
Speaker 3: the diameter of the Earth, but the actual mass of
Speaker 3: that is in terms of and I say this because
Speaker 3: I am not a mathematically inclined.
Speaker 2: Person, but I'll try and talk you through it.
Speaker 3: So essentially, if you imagine that you've got a triangle
Speaker 3: where one side of the triangle is a distance from
Speaker 3: let's say you're eyes right down to the center of
Speaker 3: the Earth. The other side of the triangle is the
Speaker 3: distance from the horizon all the way to the center
Speaker 3: of the Earth. And then the third side of the
Speaker 3: triangle is the line from your eyes to that point
Speaker 3: on the horizon. So you're creating a kind of a
Speaker 3: triangle that you can then measure. Now, if you use
Speaker 3: Pythagris's theorem, you can actually then work out because you
Speaker 3: know how long. We know what the diameter of the
Speaker 3: Earth is, and we know what our own height is,
Speaker 3: so we can work out the length of two sides
Speaker 3: of the triangle. And then you can use Pythagrisi's theorem,
Speaker 3: which I'm not going to do live on air because
Speaker 3: I'm not a mathematically inclined person, but you can then
Speaker 3: relatively easily use that to work out how long the
Speaker 3: line is then from your eyes to the horizon. Or
Speaker 3: you can cheat, and there is actually a website online
Speaker 3: where you can enter your height or the height the
Speaker 3: altitude that you're at, and then it will tell you
Speaker 3: how far it is to the horizon. So in my case,
Speaker 3: I'm about one point five meters home. I think it
Speaker 3: might be one point six, I'm not sure. So if
Speaker 3: I was standing at sea level, like on a beach,
Speaker 3: and I was looking over to the horizon, it would
Speaker 3: be about four point three seven kilometers away. If you're
Speaker 3: a bit taller, obviously it's a little bit further. And
Speaker 3: then if you're in an aeroplane, so let's say you're
Speaker 3: flying in ten kilometers above the Earth's surface, you will
Speaker 3: be able to see three hundred and fifty seven kilometers
Speaker 3: to the horizon, and obviously the further up you go,
Speaker 3: the further out you can see.
Speaker 1: Okay, I just want to pick up on one thing though,
Speaker 1: Paul said, curvature of the Earth, obviously not realizing that
Speaker 1: the Earth is in fact flat.
Speaker 3: Well, that would make the calculations a lot simpler if.
Speaker 1: That throws everything easily into the bucket. Here's a question
Speaker 1: from Sue. What's the smallest possible unit of time?
Speaker 3: This is a great question because you know, we initially
Speaker 3: might think, oh, it's like a microsecond or a pico second,
Speaker 3: or some kind of weird thing that you could measure
Speaker 3: on the stopwatch. But actually we're getting down into the
Speaker 3: realm of the quantum with this, because the smallest unit
Speaker 3: of time that can, in theory be measured is actually
Speaker 3: called the plank time. Brilliant and weird stuff happens at
Speaker 3: plank time, So it's the plank time, so it's p
Speaker 3: L A N c K. So this is names after
Speaker 3: Max Plank, who was a German theoretical physicist, and.
Speaker 2: He actually discovered.
Speaker 3: Energy quanta, the kind of packet parcels of energy in
Speaker 3: the earlier nineteen hundreds, won him the Nobel Prize in
Speaker 3: Physics in nineteen eighteen. So plank time is defined as
Speaker 3: the amount of time it takes a photon of light,
Speaker 3: so a particle of light which is traveling at the
Speaker 3: speed of light as they do, it's a time it
Speaker 3: takes to cross the distance of one plank length.
Speaker 2: So what is a plank length.
Speaker 3: Plank length is one point six times ten to the
Speaker 3: minus thirty five meters, So I kind of even give
Speaker 3: you a comparison of how many plank lengths there are
Speaker 3: in a you know, with the human hair, it's so
Speaker 3: infinitesimly tiny. And so the amount of time that it
Speaker 3: takes for light to cross a plank length is five
Speaker 3: point thirty nine times ten to the minus forty four seconds.
Speaker 2: And some really weird.
Speaker 3: Stuff happens in the kind of plank length and plank time.
Speaker 3: So this is essentially where gravity, what we understand as
Speaker 3: the behavior of gravity doesn't kind of work. And it's like,
Speaker 3: this is where I don't know if you've ever heard.
Speaker 2: It's idea of a theory of everything, and.
Speaker 3: It's this kind of quest in theoretical physics to try
Speaker 3: and combine general relativity, which is, you know, things that
Speaker 3: are affected by gravity, with quantum mechanics, which is things
Speaker 3: that are essentially below you know, at this level. And
Speaker 3: there's always this quest to try and unite those two
Speaker 3: things so that it all makes sense one great, big,
Speaker 3: beautiful theory, and so far physicists haven't quite managed to
Speaker 3: do it. So, yeah, plank time and plank length is
Speaker 3: the smallest measurable distance and unit of time.
Speaker 1: You're so clever. And you know what, because I'm the
Speaker 1: most annoying person anybody would ever meet. Just ask the listeners.
Speaker 1: They'll tell you that I'm going to actually respond to
Speaker 1: people when they say I'll be there in a sec
Speaker 1: I'll go, yep. And what's that name plank time?
Speaker 2: You know, one day you'll do that.
Speaker 3: And if it's a theoretical physicist, they're going to give
Speaker 3: you money.
Speaker 1: Yeah, then I really look like an idiot. What more
Speaker 1: from Steve? Steve says, what color is the surface of
Speaker 1: a mirror.
Speaker 2: Well, this was an interesting one.
Speaker 3: So I guess when we're talking about the actual surface
Speaker 3: of a mirror, there's kind of two bits there. So
Speaker 3: there's the surface, which is the glass that forms I
Speaker 3: guess what you think of as the front part of
Speaker 3: a mirror. But then the back part of the mirror
Speaker 3: is the silvery reflective layer. So if we say the
Speaker 3: silvery reflective layer, well, I guess it's a sort of
Speaker 3: a silvery color in and of itself, but then it's
Speaker 3: also reflecting whatever is in front of it.
Speaker 2: So what we see is that.
Speaker 3: Color is going to be whatever it is that we're
Speaker 3: seeing reflected. But the glass is an interesting one because
Speaker 3: we think of glass as being clear, and for the
Speaker 3: most part, what we see out of you know, a
Speaker 3: typical glass window like the one I'm looking out now,
Speaker 3: it's clear.
Speaker 2: We don't really see any tint in it.
Speaker 3: But real glass does actually have a slight greenish tint,
Speaker 3: and that's because there's a small amount of iron oxide
Speaker 3: that's in the sand that's used to make what we
Speaker 3: think of as normal glass. So the short answer would
Speaker 3: be the surface of that mirror would.
Speaker 2: Be a very, very very faint greenish tint.
Speaker 3: So if you think about a really thick pane of glass,
Speaker 3: if you're able, if you look at it side on.
Speaker 2: Sometimes if you see like a glass piece of glass.
Speaker 3: Looking like a shower cubicle, you can look at it
Speaker 3: side on and you can see it's a little bit greenish.
Speaker 3: So that's the sort of color if you're going to
Speaker 3: be really technical, looks clear, but in fact there's a
Speaker 3: bit of green in it.
Speaker 1: I'm so glad we're able to talk about this morning.
Speaker 1: And when I go in to get some paint to
Speaker 1: paint the bathroom, that's what I'm going to ask for.
Speaker 1: I want ten to mirror green.
Speaker 2: Yeah, it'd be very tricky to find that one. I
Speaker 2: think it's a very faint color.
Speaker 1: So tell us this, Why is dog walking so dangerous?
Speaker 3: Well, so I'm a dog person, so I need to
Speaker 3: counter this by saying, first of all, dog walking is
Speaker 3: very good for your health. It gets you out, and
Speaker 3: it's a lot of physical activity, and that we should
Speaker 3: all be doing this. So let's just put that kind
Speaker 3: of qualifying out first. But there is also some risk
Speaker 3: involving involved in dog walking, and this is actually some
Speaker 3: research that came out of the UK and they found
Speaker 3: that the annual cost of injuries from dog walking is
Speaker 3: estimated to be about fifty million dollars in.
Speaker 2: Australian wow each year.
Speaker 3: Yeah, so and look, there's no reason to think that
Speaker 3: the UK would be particularly different to Australia. And what
Speaker 3: they're looking specifically at, or what seems to be the
Speaker 3: most common form of injuries injuries to wrists and hands
Speaker 3: and fingers. So I don't know if you're a dog
Speaker 3: on a field, but I had dogs dog. You know,
Speaker 3: they could be pretty enthusiastic. It depends on how well
Speaker 3: they're trained. But if you've got a big, heavy set
Speaker 3: labrador that really likes just sniffing and dragging you off
Speaker 3: into every direction, that can actually put a lot of
Speaker 3: strain on wrists and fingers and arms and elbows. And
Speaker 3: so when they were looking at these studies, they found
Speaker 3: that about one in I mean, it's twenty two percent
Speaker 3: of the injuries were soft tissue injuries, so.
Speaker 2: People were getting sprains of their wrist.
Speaker 3: But also it goes even to something like kind of
Speaker 3: tendon itis, like almost like a form of tennis elbow
Speaker 3: because you're constantly especially if you're walking a dog, you know,
Speaker 3: for an hour or half an hour every day, they
Speaker 3: can actually build up a lot of strain of muscles
Speaker 3: and tends that perhaps otherwise aren't used in that fashion.
Speaker 3: But then another risk was actually also fractures. You know,
Speaker 3: if you think you're kind of walking along and maybe
Speaker 3: you've got the lead looped around your wrist, and then
Speaker 3: suddenly your dog kind of jerks off in an unexpected direction,
Speaker 3: that can actually be enough force to cause a fracture
Speaker 3: of I mean, there's lots of delicate bones in our
Speaker 3: hands and wrists, and I mean what was interesting with
Speaker 3: this was that when they were looking at the injuries,
Speaker 3: about three quarters of them were in women.
Speaker 2: Maybe that's because women might be more.
Speaker 3: Likely to walk the dog, who knows, But particularly in
Speaker 3: older women, this was a problem. And that's a little
Speaker 3: bit of a clue to what might be going on
Speaker 3: here for some of these injuries. Because older women, particularly
Speaker 3: if the postmenopausal, they might have lower bone density, Their
Speaker 3: bones are a little bit more kind of fragile and brittle,
Speaker 3: maybe they've got osteoporosis, and it makes them much more
Speaker 3: vulnerable to breaking a bone from something, you know, like
Speaker 3: a you know, the lead being kind of jerked off
Speaker 3: to one side. Might be fine if you're a healthy
Speaker 3: eighteen year old, but when you're sixty, that can actually
Speaker 3: be quite a serious break. And I mean the other
Speaker 3: thing as well is also sometimes people get pulled over
Speaker 3: by their dog if the.
Speaker 2: Dog's a particular spotted a cat or something.
Speaker 3: Yes, and people were tripping over the leash sometimes, you know,
Speaker 3: if a dog kind of runs around you, or if
Speaker 3: you're walking two dogs at the same time, trip over
Speaker 3: the dog sometimes.
Speaker 2: So there were all sorts of injuries, but predominantly they're.
Speaker 3: Really about sort of hands and wrists and fingered injuries.
Speaker 2: So it's you know, it's one of those things to.
Speaker 3: Just be aware of that, particularly as you get older
Speaker 3: and you might be a little bit less dady on
Speaker 3: your feet as well, that walking the dog, you kind
Speaker 3: of got to take extra care just to look at how.
Speaker 2: You're holding the lead and also how well you trained
Speaker 2: your dog. Is fantastic.
Speaker 1: I'm going to take some calls on this one three,
Speaker 1: one eight seven three. Tell me about how you injured
Speaker 1: yourself walking your dog. This is brilliant in the history
Speaker 1: of radio topics. Tell me about your dog walking injury.
Speaker 1: One three, one seven to three On that let's talk
Speaker 1: about killer whales off the coast of North America spotted
Speaker 1: making tools, what hammers, chisels, that kind of.
Speaker 2: You know, we always think of tools as being I mean,
Speaker 2: like tool use is not uncommon amongst animals.
Speaker 3: I mean, there's so much evidence of crows using them,
Speaker 3: and obviously we know a lot about chimpanzees using tools,
Speaker 3: but this is one of the first times that tool
Speaker 3: use has actually been reported in marine mammals. And what
Speaker 3: I love about this is because they were using it
Speaker 3: for grooming. So it was this group of killer whales
Speaker 3: living kind of the Pacific, just off British Columbia and Washington,
Speaker 3: and they found they spotted them picking or kind of
Speaker 3: breaking the ends off bull kelp. So they're really big, long,
Speaker 3: thick rubbery strands of bull kelp.
Speaker 2: And then they would press these pieces.
Speaker 3: Of kelp against a partner, you know, a partner and
Speaker 3: other whale and then basically roll along, so roll the
Speaker 3: kelp between their bodies back and forward for long periods
Speaker 3: of time. And they were trying to understand why they
Speaker 3: were doing this, and so they were kind of looking
Speaker 3: for what might explain it. The first thing they saw
Speaker 3: was that the whales were more likely to groom other
Speaker 3: whales that were closely related or of a similar age,
Speaker 3: So that suggests there's a social dimension to this. This
Speaker 3: is you know that there's I guess a social purpose
Speaker 3: to it. But then the other interesting thing was they
Speaker 3: found that it seemed to be more common with whales
Speaker 3: that had more kind of.
Speaker 2: Molting skin or dead skin on.
Speaker 3: Their backs and on their sides, So that points to
Speaker 3: there being an actual function of this. It's not just
Speaker 3: kind of, you know, giving someone a little bit of
Speaker 3: a backscratch because it feels good. This is actually there's
Speaker 3: a kind of a beauty though, basically giving each other
Speaker 3: a seaweed wrap, you know, taking rid of that, getting
Speaker 3: rid of that dead skin, having a good scratch, making friends.
Speaker 2: But it's the first time it's been seen in marine mammals.
Speaker 1: That's so interesting. Thank you so so much. I feel
Speaker 1: so much smarter. I especially want to get back to
Speaker 1: you next week with the results of dog walking injuries.
Speaker 1: Can you join us again next week?
Speaker 2: Indeed,