Sherlock & Co. - Introducing The Rest Is Science

Episode Date: December 4, 2025

Forget what you think you know about reality. The Rest Is Science is a mind-bending new show from Goalhanger that tears down familiar ideas… time, randomness, beauty, it will reveal just how bizarre the world truly is. Join Professor Hannah Fry and science creator Michael Stevens (aka Vsauce) twice a week to explore big, small and surprising questions as they deep dive into theories, concepts, objects and thoughts and take us on a journey into the unexpected. If you love digging into details that usually get skipped over, this is the show that proves reality is stranger than fiction. ⁠Click here to subscribe to The Rest Is Science⁠. Learn more about your ad choices. Visit podcastchoices.com/adchoices

Hello Sherlock listeners. I'm Michael Stevens. And I'm Professor Hannah Frye. Well, thank you, John and Sherlock, for letting us take over the channel. We are here to tell you about our new show for Goldhanger. The rest is science. Every week, we take a fresh look at the familiar. We're going to be exploring the forces, the theories and the phenomena that shape how we live in, think about and see the world. We're going to pull apart what we take for granted to reveal the unexpected point. patterns and hidden logic just beneath the surface. Because that's what moves science forward, not the polishing of answers, but the sharpening

of questions. It's curiosity that sparks those, hey, wait, how does that actually work kind of a moment that changes the way we see the world? So, okay, here is a little glimpse of what is to come from our podcast, and if it sparks something unexplainable for you, then you can join us every Tuesday and Thursday for new episodes of the rest of science, and we'll figure it out together. How would you describe gravity to an alien from another universe that had never experienced gravity? The simplest way to think of it is that in our universe, objects are attracted to each other.

And if you, without any interfering from outside, if you just have two objects near each other, they will come together. That's it. I mean, that's it, really. And at this point, the alien goes, what? That is so odd. Right. And what do you mean by an object? Anything with mass. Anything with mass.

Because I think that we sort of imagine gravity as though it's like the Earth is pulling us down. But the thing is, is that we're also pulling the Earth up, right? And if you get much small objects than planets and you put them in space, they're pulling each other and we'll come together. That's right. Yeah, I once calculated the two baseballs placed in intergalactic space. A meter apart would very slowly collapse in towards each other. until they touched it would take three days for that to happen but it would be because of their

gravitational attraction to each other we are gravitationally attracted to each other right now it cannot overcome the air it would have to push out of the way the friction between our butts and the seats but yet we are attracted in fact when you're born right you've got some some zodiac constellation that's like i don't know it's how does how does astrology work Something, something, something, Pisces. Right. Okay, so, okay, you're a Pisces if you're born in a particular time of the year. But yet the gravitational influence of Pisces on you is less than the gravitational influence of the doctor who delivered you on you.

Because otherwise, birth ain't working. That's why, yeah, people are like, oh, so you're an Aquarius. And I'm like, no, I'm a schnick cookie. Because Dr. Schnit Cookie was there influencing me. To catch you. At a physical level. Yeah, not just the catching. not just the physical touch, but the gravitational attraction to his mass.

Right. We've been talking a lot about very, like, fundamental things in this really abstract way to just explain that things fall down. Because here on Earth, they're attracted to the Earth. And you were talking about how it's not just the Earth pulling things in. Things pull the Earth as well, but the Earth is so much bigger than everything else we work with that equal attraction they have affects other stuff. like a pen, a lot more than it does the earth.

But I once calculated that if you dropped a pen from six feet up, it actually pulls the earth up towards it, nine trillionsth the width of a proton. Oh! Which is, by my calculation, small. It's very small. So the pen falls the remainder of that distance, which is still pretty much six feet.

But they are coming to meet each other. But they're coming to meet each other somewhere in between. Yeah. It just happens to be a much longer trip for the pen. And there you've got both of those senses of mass happening together, the gravitational attraction, but then also that force moves each object with very different accelerations.

I mean, that pen, though, is particularly light. If you take an object that is heavier, denser. I mean, heavier actually, there's sort of an implication of gravity in that statement itself, right? But if you take something that has more matter, the amount that the earth would move would change too. That's right. That's right. And so when people say a feather and a hammer

dropped in a vacuum, so there's no air to move out of the way, they will fall at the same rate. They'll hit the ground at the same time. I'll tell you what, why don't we just clear up the question of what is gravity according to what different people thought at different times? Yeah.

Because everything you're describing so far is essentially like a Newtonian view of gravity. So Newton has this idea. did that actually gravity is all about objects accelerating towards each other, right? You know, like forces mass time's acceleration was one of his, was one of his laws. And he was saying that we are accelerating towards the earth, which is the reason why when you chuck an apple, or any object, your baseball, if you like, when you chuck it, it accelerates towards the earth and follows this curved path.

And everyone for, you know, many hundreds of years was like, that guy Newton, he's, he's got it made. He's done it for us. That's perfect. but there were still some lingering questions, some little things that didn't quite make sense. So, for instance, how is this force sort of acting? Like, let's say you took the sun and you had like a magic wand that made the sun disappear instantaneously.

It would take eight, nine minutes for the light to hit us. But according to Newton's version of gravity, we would immediately stop accelerating towards the sun, which means that the earth should immediately spin off. into the blackness of space. But that sort of doesn't really make any sense, right? Because isn't it that nothing can travel faster than the speed of light? So how can it be that we would feel

the loss of the gravitational pull of the sun before the light switched out? Right. Yeah. And so we know for a fact today that gravity travels how fast? Speed of light. Speed of light.

No faster. It's the universal speed limit. Yeah. Certainly it's not instantaneous. Absolutely. Which means that if the sun suddenly vanished, we wouldn't know about it at all. But was that a problem for Newton? Newton, no.

But as the time went on, people were like, there's something a bit fishy going on. It's something a bit weird. I'm not sure I like this. The other one that was a bit weird that people just couldn't quite work out is Mercury's orbit. The thing about Mercury, closest planet to the Sun, it has this elliptical orbit. But that elliptical orbit is itself spinning around. It's affected by the other planets. So it doesn't trace out the same ellipse

Every single time it orbits the sun That ellipse is moving around a lot It's called the perihilion of Mercury's orbit Which sort of makes sense, right? Hillian meaning sun And everyone was cool with that Everyone was absolutely fine with that That they knew that the orbit was going to change

Because of where different planets were But when they ran the calculations According to Newton's version of gravity That it's essentially just objects accelerating towards each other Something was off, right? It was like the number of arc seconds of Mercury's orbit just didn't totally make sense. And for a long time, you know, the telescopes weren't that accurate. People were like, maybe we've just made a miscalculation.

It's sort of a bit, I don't know. And this was for a long time. Long times. Hundreds of years. Hundreds of years. And then when Einstein came along and he was like, I think there's something else going on here. Einstein has this great intuition that it's not just that objects are magically accelerating towards each other, but that space time itself has this curvature to it.

So the sun, for instance, this giant gravitational force is literally bending and warping space time between us and it. And so if you got a magical wand and you made the sun disappear immediately, there would be this ripple that was sent out from the absence of that sun. Imagine taking a bowling ball on a rubber sheet and then removing it. That rubber sheet is going to kind of bounce up and down and ripple as you remove the weight. And that that ripple would would reach us at the speed of light. He had this great intuition, worked out all the calculations for it, and one of the very first things that he turned his equations to

was the prohillion of Mercury's orbit, to see if his new theory came up with a more accurate prediction than Newton's, and he absolutely nailed it. Nailed it. Level of precision. I mean, he said that he was happy for days after he looked those calculations, was like, I've absolutely got it.

I found the missing piece to the puzzle. So two things. First, that leap from there's a force acting on things. Maybe it's mediated by some particle or whatever to leap from there to actually maybe gravity is just a change in the shape of space time is really gigantic. Gigantic. Because space time is such a bizarrely abstract thing. It's the canvas that we are.

on. If we were two-dimensional, this would be easier. We could say, you know, a two-dimensional creature could be painted onto this curtain. And if I crumple the curtain up, they're still stuck on it and they're going over all of these crinkles, but they don't even know it. I can bring them together and push them apart. If it gets crumpled up or curved, you're just going to follow along that curve. You cannot leave it. And so, yeah, Einstein is like, but what if it's the shape of the canvas that we are on? Exactly. Even the shape of time and how quickly time runs for you. If we allow that to change, then Mercury's orbit makes sense. Exactly right. They're crumpling the curtain. That's a really nice way to do it. Yeah. I think you need analogies because

we're just talking about things that are so outside of our normal day-to-day activities. Totally. We understand forces. We understand pushes and poles. But to say that space and time themselves push and pull, it's kind of more like you're just in them. But here's the thing, right, the implications of this idea that space time is like a crumpled curtain. It means that across the surface of the earth, even, the gravitational effects are slightly different. So I did some calculations. Boulder in Colorado, right, which of course is like a very high altitude compared to Greenwich in London, where I am, the gravitational effect in Boulder is 9.796 meters per second.

And what is it in Greenwich? 9.812. Wow. I've got higher gravitational effect than you. Yeah. So you are more attracted to the center of Earth than I am in Boulder. Yep. Because I'm further away.

Yep. And the inverse square law says that. Further away. That gravitational effect is, yeah, diminishes. Except that what that means, given Einstein's version of gravity, is that the way that time changes in Boulder is different to the way that time changes in Greenwich. because what gravity is doing is it's bending and warping space time. So what this means is that time travels slower in Greenwich than it does in Boulder, and the difference is about 5.6 microseconds a year.

So what I will say is that you are aging faster than me. Thank you.