Brian Clegg
speaker
45 appearances
1 recordings
1 series
first heard Mar 2025
last heard Mar 2025
Brian Clegg’s voice in public audio — every appearance, attributed to the second.
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Appearances
There just is no good scientific evidence. When you treat it scientifically, which means you have to separate off all the different influences, put people in a controlled situation so that you can actually separate off what is causing something, there is no good evidence that consumption of sugar actually makes them hyper.
That's quite a nice little example of the it's a bit more complicated than that. The Big Bang theory is a theory of how the universe works. grew from practically nothing all the way up to what we have today. And we think that has taken about 13.8 billion years for it to go from a very tiny, pretty practically nothing up to what we have now.
And the Big Bang Theory is very successful at explaining that. But we tend to kind of associate it with literally the beginning of everything. And that's the one thing the Big Bang theory doesn't do for us. It doesn't actually explain why or how the universe came into being initially. That very first start, it has to already have, if you like, the laws of physics have to be there already.
It doesn't explain where they come from. And the actual initial start of the whole thing requires, if you like it, to be there already for it to then start expanding. So it's not quite made it. And the other thing about it is we have a problem just seeing back that far. Now, the universe is really quite generous to us because light takes a long time to get to us from very distant places.
So the further out you look in the universe, the further back you see in time. And we can see back until maybe 300, 400,000 years after the beginning. But beyond that, we can't see because the universe wasn't transparent before then. Light couldn't get through it. So what that does mean is that those first years, we struggled a little bit to be sure exactly what happened then.
And certainly the Big Bang doesn't give us any insights of the initial beginning. So it's just a slight tweak, if you like. It's a great theory. It explains a lot. It gives us a timescale for the universe. But what it doesn't do is say how the universe came into being.
Blood is red because of haemoglobin. So there's substance in the stuff that carries the oxygen around the body. And that haemoglobin does contain iron. And so it's quite easy to get a little bit confused and think, OK, well, iron usually makes things reddish. So rust is iron oxide. It's an iron compound. Mars looks red because there's a lot of iron in the surface.
So we tend to associate iron and redness. But it happens, the reason hemoglobin is red is actually due to the shape of the molecule, the way it interacts with light. It's nothing to do with the fact the iron's in there. So that's one aspect of it. It's not actually caused by the iron. And the other thing is the blue blood thing is not about the color of the blood itself.
It's about the way that light interacts with your veins. It's quite separate from the colour of the blood in them. Colour is quite interesting. Sometimes it's caused by a pigment. So sometimes it's caused by the colour of stuff, but sometimes it's structural. So actually the shape of something can change the appearance or the way light interacts with molecules.
If you look up at the sky, the sky is blue, but there's no blue colour. pigment in the sky. There's nothing up there that is blue. It's literally the way the light is interacting with the molecules of air. And similarly, when you see the blue veins in your arm, it's not that the blood in them is blue. It's the way the light interacts with the material that makes up the veins.
The reality is that bumblebees don't fly the way you might think. So if you think of a bird flapping its wings, it's fairly obvious what's happening. It's flapping its wings up and down. That pushes the air down, effectively pushes the bird up as it pushes the air down.
bumblebees wings move in a much more complicated way they basically almost act a bit like a helicopter in that they have a kind of curved motion and the result of that is they actually generate more lift than you expect from those little wings
The other thing about bumblebees actually is they look chunky, you know, compared with an ordinary insect, they look pretty fat, but actually it's still very light. So it isn't as dramatic looking, as dramatic as it actually looks to be. And the fact is there's no problem at all with bumblebee wings supporting bumblebees. In some ways, a more interesting example is kangaroos.
Of course, it is genuinely true that kangaroos use more energy or appear to use more energy when they bounce along than they consume. They seem to be able to actually give out more energy in their bounces than they've consumed in their food. And the reason for that is it's a bit like the way a rubber ball works. You know, if you drop a rubber ball on the floor, it bounces.
When I was young, they had these things called super balls, super balls that bounced really high. I don't know if you ever had one of those. And kangaroos are a bit like that. So when they hit the ground, it's not a case of all the energy they're putting into their muscles is wasted.
It's actually more like storing up energy in a rubber band as they hit the ground and then it bounces off and they use up that extra energy they've stored away. So they can do what seem to be amazing things, even though in practice they're not breaking the laws of physics.
It's another of those little, it's a little bit more complicated. We're oversimplifying when we say the speed of light is the limit. The real thing is the speed of light in a vacuum is the limit. So the fastest anything can go is the speed that light goes through empty space. but light can also go through other stuff. It can go through water, it can go through glass.
And when it does, it slows down. So light goes considerably slower through water or through glass or another solid transparent substance. And when it does that, it's closed down sufficiently that physical objects can move faster than the speed the light's going. And there's something called Cherenkov radiation that happens in nuclear reactors.
Have you ever seen a video of one of the old nuclear reactors that had water surrounding the nuclear pile? it glows blue. And the reason it's glowing blue is that little particles that are coming off out of the nuclear reactor are actually going faster through the water than the speed of light through the water.
And that produces a kind of optical equivalent of a sonic boom, which produces this blue glow. So yes, it's true. The speed of light in a vacuum is the absolute limit. But if we just say the speed of light is as fast as you can go, it's not true if you're not in a vacuum.
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