In Our Time - William and Caroline Herschel

Episode Date: November 11, 2021

Melvyn Bragg and guests discuss William Herschel (1738 – 1822) and his sister Caroline Herschel (1750 – 1848) who were born in Hanover and made their reputation in Britain. William was one of the most eminent astronomers in British history. Although he started life as a musician, as a young man he became interested in studying the night sky. With an extraordinary talent, he constructed telescopes that were able to see further and more clearly than any others at the time. He is most celebrated today for discovering the planet Uranus and detecting what came to be known as infrared radiation. Caroline also became a distinguished astronomer, discovering several comets and collaborating with her brother.WithMonica Grady Professor of Planetary and Space Sciences at the Open UniversityCarolin Crawford Institute of Astronomy, Cambridge and an Emeritus Fellow of Emmanuel College, University of CambridgeAndJim Bennett Keeper Emeritus at the Science Museum in London.Studio producer: John Goudie

BBC Sounds, music, radio, podcasts. Thanks for downloading this episode of In Our Time. There's a reading list to go with it on our website, and you can get news about our programs if you follow us on Twitter at BBC In Our Time. I hope you enjoy the programmes. Hello, William Herschel, 1738 to 1822, is one of the most eminent astronomers in British history. Although he started life as a musician,

as a young man, he became interested in studying the night sky. As a result of his extraordinary talent, he constructed telescopes that were able to see further and more clearly than any others around at that time. He's most celebrated today for discovering the planet Uranus and detecting what came to be known as infrared radiation. His sister Caroline Herschel, 1750 to 1848, also became a distinguished astronomer, as well as providing vital assistance to her brother, she discovered several comets and carried out highly important work on stars. With me to discuss William and Caroline Herschel are Monica Grady, Professor of Planetary and Space Sciences at the Open University, Carolyn Crawford from the Institute of Astronomy, Cambridge,

and an Emeritus Fellow of Emmanuel College University of Cambridge, and Jim Bennett, Keeper Emeritus at the Science Museum in London. Jim Bennett, William and Caroline were born in Hanover. How did they come to be living in England? Yes, well, they were indeed born in Hanover, and that was important because it was, William's father was a musician, a bandsman in the band of the Hanoverian Guards. This wasn't a particularly auspicious beginning in life.

They had certainly very limited means, but at least it meant in this large family that Herschel was able to go to school. He went to the Garrison School, in fact, of the guards, and he stayed there until he was 14. At 14, however, he followed his father into the band, having learned musicianship mostly at home, we think. And it was that that brought him to England in the first place. His older brother, by the way, his oldest brother was also in the band.

So it was a bit of a family tradition. But in 1756, George II, King of England, but also elector of Hanover, in the very beginning of the Seven Years' War, I thought it might be a good idea to have his Hanoverian guards over in England with him, and he summoned them, and the band Julie, went along with the rest of the company. This didn't last very long this trip to England. They were back in Germany the following year, but it was enough for William to make a start in English life and to learn a bit of English. But the following year, they were indeed. They did need to go back to Germany,

and they saw action in the Battle of Hastenbeck, again. the French, they were defeated by the French at Hastenbeck. The bandsmen weren't expected to fight, but they certainly saw the aftermath and the devastation. It was a very fierce battle, and there was a lot of devastation, and William's father, Isaac, thought it might be a good idea if William sort of slipped away back to England and suggested that he did that. So William does indeed come back to England, but in less than auspicious circumstances, I mean, he's a war refugee in part, but in part he's also an army deserter at this stage. And that has to be regularized later on when he's given a discharge. But what he's got is his great skill as a musician of several

instruments and he's starting to be a composer and he goes to different provincial towns in England, is in Leeds, Derby, and he ends up in Bath. So, Did he seem to be set on a musical career at that early stage? In his early 30s then. He gets his big break with a bath appointment where he's appointed as organists to the octagon chapel, the new octagon chapel, not quite finished, not even quite with this organ installed when Herschel's first appointed. But this is a great step up for him because, of course,

Bath is a fashionable resort. There's a big demand for music and musical services. The octagon chapel is an interesting. place because it's both a place of worship and a venue for musical entertainment. He's very resourceful and hardworking and committed. He's doing a lot of teaching. He has perhaps eight lessons a day at times. But in spite of this very busy schedule, he somehow finds time for a new passion, which is science and particularly astronomy. I think we should take with us in this program, an image of Herschel as a great natural enthusiast.

His sister, his younger sister, Carolyn, of course, who knew him very well, wrote that he had what she called an uncommon precipitancy, which accompanied all his actions. And if you add to that an obsessive streak, then I think you've got Herschel. Thank you. Caroline, what was this state of astronomy in the mid-18th century when Herschel was a young man? Well, professional astronomers across Europe had two primary concerns. The first one was just creating the most accurate star maps they could.

So that's positional astronomy, where you're very accurately measuring the angular separation of stars and charting them. And that was driven by this sort of practical requirement to improve navigation for long sea voyages. And that obviously required the best star charts you could get. And there was also an interest in plotting the motions of objects. in the solar system, not just the planets, but also discovering and following up comets as they travel through the solar system. And all of this is testing our understanding of how the solar system works and Newton's laws of gravitation on the grand scale. What's your view and why he suddenly took to astronomy, went from the oboe to astronomy?

It's clear that when he was back in Hanover, his father didn't just pass on to his sons the interests and abilities in music, but he had a keen interest in scientific knowledge and maths and philosophy and languages, which he also passed on to the boys. And so by the time William is more established in Bath, music isn't occupying all his time, and he's able to develop these interests that were instilled by his father, Isaac, in maths and languages. And he starts off with, well, some of the books he starts off reading. One of them is by the Cambridge Professor Robert Smith, and it's about the harmonics of musical sounds.

And William really enjoyed this book. And so by the early 1770s, he gets hold of Robert Smith's two-volume treaties and optics. That's really when he gets plugged into the mechanics of astronomy, because in these books, there's the how to design and build a telescope. So at this point, he buys a small telescope. he buys a quadrant and by the mid 1770s he's beginning to make his own observations and he's also buying a new lens with the intention of making a telescope but the thing that is really interesting

about this point is that william is coming to astronomy not as part of the scientific establishment he's self-taught from his own reading it from these books and this in some sense allows him to develop his own interests and ambitions. And this is relevant later on about how he can see things and discover things because he's not just interested in observing planets and emotions of the planets. He's actually got a curiosity about the nature of the heavens beyond the solar system, the nature of the stars, how they relate to another, what their distances are, their distribution. And all of this is driven just by his own self-teaching, his reading and astronomy. And happy to be doing the two things.

He hasn't at that early stage decided to dump music and concentrate on astronomy. Not yet. That will come later. He will get more obsessed with building telescopes, making mirrors, and carrying out the observations. And there does come a point, sort of early 1780s, where his music will begin to suffer. But we haven't quite reached that point yet. No. Monica, Monica Grady, one of the first things that Herschel looked at, was the nebulae. Why I was interested in the nebulae, what are they, and how did he get to look at them?

Well, the nebulae that William Herschel was looking at are things that we wouldn't really call nebulae these days. Nebulae, vague, nebulous, cloudy, just fuzzy objects. So when William Herschel was looking at some of these things, objects that we now know as galaxies, he just called nebulae, because he thought they were clouds of dust, clouds of stars, and not fully understanding because the telescopes at the time weren't sufficiently good to actually distinguish individual stars and to see that they were galaxies. Now, these days, when we talk about nebulae,

we're talking about something very specific. We're talking about clouds of gas and dust were in new stars form. So the telescope that Herschel had, he was dissatisfied with because he wasn't able to see what he wanted to see. And so he started making his own mirrors. He started using a reflecting telescope of the sort, first developed by Newton, which had mirrors in rather than lenses. Can we go back to these, Nebula, Nebula, Monica.

What did he do to bring them into view, to accurate view? Well, he made his own mirrors. and polished the mirrors. So one of the... Why did nobody do not before? Well, they had, but they hadn't really... A lot of the people who were studying the stars had... They were using lenses, refractive telescopes,

which were, unfortunately, they suffered from aberrations at the edges of the lenses, and so you couldn't get well-focused images. Newton introduced the reflecting telescope using mirrors, and he had two mirrors in his telescopes, which required both to be of very, very specific curvatures. So the path of the light was reflected from one mirror onto the other. Herschel changed that by actually just having the single mirror and viewing an object more directly. He made bigger and bigger mirrors that he polished himself, huge amount of work.

Jim, Jim, but can we develop that? and can develop the difference between his telescopes compared with those of other people at the time? Well, certainly, but it's interesting, Melvin, that you said that why hadn't anyone done that before? I mean, interestingly, Newton had done exactly that. That's to say Newton was making his own mirrors. So there was a good precedent, I mean, a very positive precedent that people could do what Newton did. And you might not be able to understand all the subtle mass of the Principia, but you could follow Newton in this area, in the area of optics,

and that's part of the attraction that you were finding a bit puzzling, as well as the fact that this was simply a fashionable thing to do, and was made easy. One of the books that Herschel studied astronomy and is Ferguson's astronomy explained on Sir Isaac Newton's principles for those who haven't studied mathematics. So this work is geared towards, is aimed at people who aren't professionals. The scope of their work will be different. It won't be making measurements with small refractors.

It'll be looking at, it'll be stargazing rather than star measuring, if you like. They need these reflecting telescopes, which, if they have the patients and don't have the money, they can make themselves. And the point is that they can make larger receptors, if you like. They can make larger mirrors to catch more light, to see these objects more distinctly. all of that's very exciting for the amateur and the reflecting telescope is just what is needed for that kind of work.

And Herschel, if I can take that it as a little bit further. Herschel, however, with his natural enthusiasm for things, which always takes over, he takes it further than everybody else. By 1776, he has three large working telescopes of the kind that he couldn't really have bought from anyone. Why? Because there hadn't been, nobody had been, nobody would mind them. It wouldn't have been a commercial proposition

for a maker to have spent all these hours and hours and hours polishing and polishing obsessively, which Herschel was very good at. And there's these famous stories of Herschel not wanting to stop the polishing. These were metal mirrors, remember, of an alloy of copper and tin. And Pyrill Caryl was having to feed him by hand because he couldn't lift his hands from off the, mirror, which was being moved on top of the polisher, because he'd forget where he was,

he'd lose the feel of it. And he simply had to continue for ours. No maker is going to be able to do that, not because they couldn't do it. Maybe they couldn't do it, but they couldn't charge an appropriate fee for doing it because no one would pay. And the interesting thing about this is that Herschel ended up by this period when he had these three telescopes going up to one of 20 foot in length, We tend to talk about focal lengths and telescopes in the 18th century. We now talk more about diameter or aperture. But by the time he had these three telescopes, he had the best telescopes of their kind in the world. That sounds like an exaggeration.

It is not. But Herschel didn't know that. He couldn't understand why people didn't see what he saw. So did this, Carly, did this get in the way of his views being transmitted? He said, I've seen that and everybody looked, the others looked through their telescopes and they couldn't see it. And they would say, well, what and how do I get there? He would give positions and it was hard for other professional astronomers to confirm his findings because their telescopes weren't so good to show the differences that he could see.

Their telescopes could not resolve stars that he marked down his double. And so it was very difficult for other people to believe that an amateur telescope maker could make such good telescopes that would enable him to make discoveries. So there was some hesitation at crucial points in his career about accepting some of his results because this understanding that his telescopes really were as good as he claimed they were. And eventually the rest of the professional astronomy world

caught up with his brilliance. There is a very nice example of that. Polaris, he found, the pole star is double. No one had, the pole star is perhaps one of the best known stars in the sky. No one had noticed it was double until Herschel did. Thank you. Do you want to take that up, Monica? One of the things that Herschel was looking at was individual stars and trying to see if they were double stars.

Can you explain exactly what a double star is? We've got two sets of things that are sometimes called double stars. stars. We've got double stars and we've got binary stars and they are slightly different. But at the time when Herschel was observing them, there wasn't an understanding of that difference, but he did a lot to show it. So a double star, as you might imagine, is where you have two stars that may appear to be close together, but they are actually far apart and it's just the way they appear on the sky that makes them seem to be close to each other. And they may have no interaction between the two stars. They just, from the viewing angle, they seem to be close.

And what Herschel was trying to look at was to see that if you observed a double star at different times, then their relative positions would change. You know, this is the same as if you look at two fingers with one eye closed and then you close your right. eye and open your left eye, the fingers seem to have moved. And that's called parallax. And so he was looking to see if the parallax of the two objects changed so he could get an idea of the distance between them, which again, as Caroline said earlier, was very important for understanding navigation. What he actually found, though, was that some of the double stars were not obeying what could be explained by parallax. They seem to have slightly different positions. And he discovered binary stars.

Now, this is where you have two objects, which are relatively close to each other, so that they interact gravitationally. Almost in the same way as a planet goes around the sun, where gravitationally bound to the sun, you get systems where you have two stars, or you can have more than two stars, but mainly binary star systems, where the two systems are gravitationally bound, and they orbit each other and they orbit a common center of mass. Probably Kobe said that the first big impact he had was when he discovered Uranus, Jim.

Jim Bennett, can you tell us how he discovered it and how significant that was? Yes, we can begin, I think, with the significance. I mean, it was because that's so utterly extraordinary. I mean, you know, throughout the period of written astronomy, me. We'd known the planet. The Babylonians had the same planets as they knew in the late 18th century. And here was this musician, nobody really knew, observing in his garden with homemade telescopes. He discovered another one. I mean, the thing was utterly amazing, an extraordinary revelation to the astronomical world.

And this is down to the fact that he's got better telescopes than before. That's right. That's right. Because the interesting thing is that people had seen Uranus before. I mean, the first astronomer royal, John Flamsteed, had seen Uranus with his relatively small aperture refracting telescopes, as used as telescopic sights, but he thought it was a star. It looked like a star in his telescope. So he noted down its position, and then he comes back years later to look at it again, take his position again, and it's gone. Okay, of course it's gone because it's a planet in orbit around the sun and has moved off somewhere else in the zodiac.

In order to discover Uranus, you have to see immediately that it's not a normal star. And that's what Herschel did. How did you do then? He was conducting a survey looking for these double stars that Monica has been talking about. And he was surveying the whole sky. And he noticed this, he thought it might be a comet or a nebulous star or something like that. But he wasn't able with his telescopes to work out how it was moving. But he came back and looked at it, not four years.

later, but four nights later, and it had moved. Therefore, it was in the solar system, so probably a comet. But when other astronomers who had measuring instruments worked out its orbit, well, it did have an orbit. And not only was this a new planet that no one had ever seen before, but was way out into space. I mean, it was far further away than Saturn. Herschel also doubled the size of the known solar system. And it's interesting, you were saying, how did this happen? It, Herschel was often congratulated by people, well-meaning souls who said, you know, what a lucky chance. And he all was bristled a little and said, no, it wasn't chance at all. I was looking at the heavens systematically with my telescope. If I hadn't discovered it that night, I would have discovered it the next good night. And he had a point because in order to discover it, you have to see immediately that it's not a star. What impact did this have, Carolyn? He's discovered this planet had been there before.

Did he get it published? Was there a great acclaim from the astronomical world? Did he, at last enter the astronomical establishment? What happened? Well, almost instant fame. Once his observations had been confirmed and the path had been plotted, as Jim says, found it was way out beyond Saturn.

First planet to be discovered in human history. And suddenly, William Herschel and the quality of his telescope start to be taken seriously all across, Europe. In England, he's invited to address the Royal Society about his findings. He receives the Copley Medal, high award for this discovery. He becomes a fellow of the Royal Society later that year. And he is being championed by people no less than the Astronomer Royal, Neville Masculine, by Banks. And they're also looking at a way that he can relinquish being a musician because he's still earning his living from his music. And they start making, they start petitioning the

king and the advisors trying to find a role for Herschel so that he can relinquish the music altogether and start observing full time. And there is a slightly ill-advised attempt to name Uranus, Georgium Sidus, after the king, to try and sort of curry favour before it is, Europe-wide decided it's going to be called Uranus. But this pushing of Herschel becomes successful, and he becomes a sort of court astronomer to George III. And his role there is, if you like, one must to provide stargazing is entertainment to the king and royal guests. Can I bring his sister, Caroline, into the equation. They had two brothers, Jacob and Alexander, I believe by this time they were both over in England with him, helping him or do.

other jobs that fed into what he was doing, then she came over. At this time, Jacob would have gone back to Hanover and Alexander and William were in Bath. Now, Caroline is their little sister. She was born in 1750, so she was 12 years younger than Herschel, and she's not having a great time of it in Hanover. Whereas their father had taught the boys all about music and languages and philosophy, Their mother, Anna, had been left to the education of the two girls and Caroline's sister left when she was five. And Anna saw that her daughter should be employed as more or less domestic help in the home.

She didn't see her as being a great marriageable prospect and she wanted somebody to basically run the household with her. So Caroline, despite being incredibly intelligent, was given no, only rudimentary reading and writing skills. She didn't learn languages or any skills that could allow her to go and independently earn means as a governess or a teacher. So she's incredibly unhappy. She doesn't get on with Jacob, the oldest brother, when he's returned back to Hanover. And at this point, so we're now talking about 1772, William and Alexander back in Bath, contrive a way to almost like rescue Caroline. and they return back to Hanover and pull her away from her mother

on the basis that they were going to take her back to Bath and train her to be a professional singer. Can you take up the story from there, Monica? She pretty soon slotted into the scientific team. She did recitals. She didn't like singing in public. She didn't like singing for anyone other really than her brothers. But she got more and more sucked into.

listing his findings and his discoveries, and she didn't like it at first. She was a bit miffed because she wanted to actually do more singing. But she got hooked. She started looking at the night sky herself, mainly because William couldn't do it all himself. And she was using some of the catalogs of the time, the Messier catalog and Flamsteed's catalogue. and she found that there were things there in the sky that they hadn't seen. She didn't like the way some of the records in Flamstice Catalogue were organised, so she reorganised them.

And she started making her own observations. And then William found out that she was finding these unusual things. And he said, well, hang on a minute, I want to look at them. And so she was then again relegated to being a record keeper. And she more or less had to do what she was told. You know, she enjoyed being in Bath, but when they moved to Windsor Castle, when William was given a post, she had to move as well, and she wasn't very happy. But again, she was keeping the records for William. And she started using the telescope independently, and that's when she started finding comets.

And was that a difficult thing to do at the time? She found seven, didn't she? I think it was eight comets. She found five very quickly. She had a very superior telescope. She had time. And of course, the night sky, even in Windsor Castle at the time and Datchett at the time, were dark. So she would be able to keep track of these objects, which move relatively fast compared to the stars.

So she could make these observations really well. And because she was such a meticulous record keeper, and because by this time she knew the night sky really well, She was able to see these changes in the night sky and see that they were actually comets because of the way she could then see how they were moving. The phrase, meticulous record keeper, Jim, Jim Bennett, how important was that? Yes, we normally think about Carolyn's work on Flamsteen's catalogue in this context

because the great star catalogue that Flamsteed produced was published in 1725 was the great achievement of Greenwich Observatory and indeed one could say of British astronomy. But they were beginning, the Herschels were beginning to find mistakes in it and problems with it. And one sort of problem that there was was that there are the observations, the original observations that are taken of the stars,

and then they are distilled into a catalogue with all the positions, the stars identified, and their positions rationalised. And they were noticing that not all the observations got picked up and included in the final volume, which was the great catalogue. William suggested, perhaps I should put suggested in inverted commas, prevailed upon Carolyn to produce an index so that she would find, they would be able to check back

from the observations to the catalogue and vice versa to make sure that there weren't any mistakes and to make sure that all the stars that were available in the observations had been cataloged. And she did this. It took quite a long time. It's a tremendously challenging work in terms of concentration and care. And she actually added about 500, well, more than just over 500 stars, two flam seeds, 3,000 stars are an extraordinary achievement, so extraordinarily that it was published. And this is what was important for Carolyn's standing. It was published by the Royal Society as an independent volume, a terrific recognition for Carolyn. She also went on, though, to do a second edition after William had died to help her nephew, William's son, John.

And it was called the New General Catalogue, which is abbreviated as NGC. And there are many, many stellar objects which still are known by their NGC catalogue number. So that's, you know, going straight back to Caroline. And her work is remembered today with the naming of those obfews. which is a phenomenal achievement for a woman of her day. What assistance did Caroline give to or provide for William? You have to think of the mechanics of this large 20-foot telescope and also a larger telescope that Herschel built later.

She was his assistant. Now Herschel is up a ladder at night peering down the other end of this 20-foot-long tube. he can't make the, he can't record his observations himself, you know, he's in a practical position, using a candle would destroy his night vision. So he's calling down and recording his results to Caroline, who has to sit there and write them down. Sometimes in freezing temperatures, you know, she recorded in her diary one day in 1783 that her ink had frozen. It was so cold. And so she would keep a record of his observations, what parts of skies they'd search, and she'd write up all his notes the next day.

But one thing she did that was revolutionary is that she reordered Flamstey stars in a much more logical order so that other observers could use them. He had gathered stars together by constellation. She ordered them in terms of angular distance from the North Pole and from the west to east across the sky.

So in a much more systematic way and there was a lot of work in terms of working out the angular separation of the nebulae from nearby stars to actual these coordinate systems in the sky. Monica, what did William Herschel discover? How did he discover infrared? And how significant was that?

Well, his discovery of infrared radiation was amazing. He was looking at filters, coloured filters that he would use in his telescope and he noticed that actually his hand when he was looking at some of the filters, the red one would get a bit warm. And he actually put a thermometer under these to actually see, was this true? You know, was he actually seeing something different? And yes, it was. He found that there was a part of the spectrum with a wavelength longer than red. So if you think about

the visible spectrum, we have blue light, which is very short wavelengths, and below that, and below that you have ultraviolet. And then as the wavelength of the radiation gets longer and longer and longer, the colour changes until you're at the red end. And then above that you have infrared with longer wavelengths. And what he found was that the temperature of something that was coming from the sun that was just higher than the red end of the spectrum, he found that it was hotter. And so he called this sort of invisible starlight, invisible light. And he'd found the thermal emission Now, this was incredibly significant, and we use this when we're looking at night vision goggles and things like that. What you're looking at is the emitted radiation.

You're looking at reflected radiation in the infrared. It's telling you more about the objects. It's telling you about the heat that's coming from the objects. It's telling you about how the atoms in a molecule, how they react with each other. Jim, Jim Bennett, William Herschel was interested in my morning. what he called the construction of the heavens. What did he mean by that? What he meant was, how are the stars arranged in space?

How big is the Milky Way? What's its shape? It's clearly what he called a stratum of stars. There are stars arranged and it branches in different ways. Where you look, you see more density, a greater density of stars. Sometimes when you're looking out of the stratum, you see fewer stars. And he'd map that. into a system.

But then he thought, well, are there other systems, are there other strata of stars, what we would call galaxies, that are independent of the Milky Way? And he was interested very much in that. And he thought in the end that the Orion Nebula, for example, might be another stratum, an independent stratum. And he was wondering about what the nebulae were.

I mean, are they different clusters of stars are too far away for the telescope to resolve, or are they indeed nearby gaseous, luminous matter? So all of these questions relate to the large-scale cosmology, the big structure of what he called the heavens, what we would call the universe. And that, strange, as it may seem, was not what astronomy was supposed to be about.

Kallin introduced us at the start to the idea of making measurements and the importance of position and navigation applications and so on. That was professional astronomy done in observatories. What Herschel was doing seemed utterly bizarre. And even more remarkably, he realized that the light that was coming from very distant systems or very distant stars had taken a long time to reach him.

He realized that in looking further into space, he was looking further into the past. Again, something we take for granted now, that there's an evolutionary dimension, There's a time dimension to our study of the universe. And it was Herschel who introduced that into astronomy. He said that the light that I'm seeing now may have taken two million years to reach me. Now, we deal in much bigger numbers now. But nonetheless, that was an amazing thing to claim to make in the 18th century. Such that, going back again to could he be believed,

Some people thought he was really a bit unstable. You know, he was fit for Bedlam was what was said. A few people said that. But nonetheless, he introduced these really big questions, and he couldn't be dismissed as a crank because he had this great sort of legitimizing discovery of Uranus. No one else could match that. Carlin, what would you say that Caroline Herschel's legacy is?

She was the first woman to discover a comet And as Monica said, she went on to discover eight comets. And this is at a time when just discovering a comet was a big deal in its own right. So she became fated as an astronomer across Europe and celebrated. So she didn't just discover New Nebulae and eight comets and all this meticulous cataloguing. But she became the first woman to earn a salary as an astronomy. because William had petitioned to the King as part of the funding for this 40-foot telescope he wanted to build that Caroline could have a lifelong pension of 50 pounds per annum as his assistant.

So this is unheard of at the time for a woman to earn a salary as an astronomer and be sort of financially independent on the basis of her own discoveries. And for her work on the catalogs, she owned the gold medal of the Royal Astronomical Society and became one of the first female fellows of the Royal Astronomical Society and the Royal Irish Academy as well. So she had professional recognition for her efforts. And it was almost... Sorry, and I was going to carry on from that and say,

it wasn't until 150 years later, or even, you know, close to 200 years later, that another woman got a gold medal of the Royal Astronomical Society. You know, so it was her achievements were just absolutely. Absolutely. Amazing. In 2009, the European Space Agency named its Space Observatory after Herschel. Would it obviously choose his name or was there any discussion about it? Well, one of the things that the Herschel Observatory was going to do is it was going to observe the, well, the solar system, the galaxy, the universe in infrared and a longer wavelength in infrared.

So it made a lot of sense for it actually to be named after Herschel because he was the first person who realized that there was something beyond red. And it worked for four, nearly five years, almost two years longer than it was supposed to work. It could only work when it was cooled and its coolant ran out, as was known. and it produced an enormous number of scientific discoveries from Kuiper belt objects at the edge of our own solar system to looking at the Milky Way to looking at the structure of the wider universe. And so it's been hugely, it's given us a huge amount of information and it's been very important in actually helping us understand the universe at longer wavelengths.

Finally, Jim, is there any overall way to tell listeners what the contribution of William Herschel was? Yes. Think about Herschel's program. It consists of the construction of the heavens, the large-scale cosmology, the evolution of the universe over time, cosmogism. And all of this fed by observations from giant reflectors, I mean, that sounds like what astronomers do today, doesn't it? Or at least at a basic level, it sounds very much like what they do. But it was seen very strange in the 18th century. Herschel was a disruptor, I would say. He came with a different program from the professional astronomers. And as I said, as I said, before the discovery of Uranus made it possible for him not to be dismissed as a crank, but he brought in this new program, which was very radically different from what professional astronomers were supposed to do. Now, I'm not saying that this took over astronomy quickly.

Of course it didn't. It took time. But Herschel began that turn towards what we think astronomy is now. And there were successors who liked what he did and continued with it, particularly, continuing very large telescopes. And that idea of the heroic aspect of astronomy, you know, big, big instruments and even now, of course, space instruments and so on, I think an awful lot of that register starts with William Herschel and his natural enthusiasm, his kind of innocent commitment to,

pursuing his observational astronomy and his radically different account of what astronomers should be doing. All of that had an effect. William Herschel is remembered not just for the telescopes that he made for himself and for others and for the space mission, but there's also a William Herschel telescope on La Palma in the Canary Isles as part of the observatory there. It was named after William Herschel because it was opened and started taking its first measurements about 200 years to the day from his first observations of Uranus. And so it's named in his honour. It uses a mirror. It is looking at visible light and also short the near infrared and has made very many discoveries and is what we would call, I think, a workhorse instrument for astronomers all around the world,

but certainly for many UK astronomers, a very, very significant telescope for us. Well, thank you very much. Thanks, Jim Bennett, Carolyn Crawford and Monica Grady and our studio engineer, Jackie Marjoram. Next week, the British decadent movement of the 1890s, celebrating or examining Dandism and excess with Aubrey Beardsley, and Oscar Wilde and others. Thank you for listening. And the In Our Time podcast gets some extra time now

with a few minutes of bonus material from Melvin and his guests. The easiest way for me to kick off is to say, what did you feel that you would like to have said that you didn't feel you had time to say? One thing that we didn't discuss is, I mean, obviously we've talked about the grand scheme of Williams' interests in the cosmos beyond the solar system it's worth noting that he did actually contribute quite a lot to studies of the planets.

So he discovered the sixth and seventh moons of Saturn and he estimated the rate that Saturn takes to rotate around its access and he was only about half an hour out, the currently accepted daytime on Saturn. And he also could see that Saturn was slightly flattened and therefore speculated it had a very thick atmosphere correctly. He discovered two moons of Uranus, so not just the planet, but also two moons. And he was also intrigued by Mars.

He showed that Mars rotated around an axis inclined 25 degrees from the vertical. So that's an angle that's very similar to Earth. And that therefore it would have comparable seasons to seasons on Earth. I mean, obviously lasting twice as long because the Martian year is twice as long. and he even looked at the white patches, which we now know to be the polar caps around the north and south poles of Mars, and could show how they would change, they would grow and shrink. And he's speculating that they are melting and freezing

and that there is an atmosphere on Mars and even some speculation about what life would be like for the inhabitants on Mars. So again, probably much more chiming with some of the interests in the day. but nonetheless a major contribution. What I was thinking we might have mentioned is perhaps not quite so positive as all the things we've been saying so far. And I thought it might be interesting

to think about the asteroids. And the reason why that's relevant to Herschel is that Herschel coined the word asteroid. He introduced it. And it's not a very good word because an asteroid would be a little star, and these aren't little stars, they're little planets. And other astronomers at the time thought this wasn't a very good idea,

and that it would be better if they were called planetoids, because they were just beginning to discover these asteroids that lie between Mars and Jupiter. And Herschel didn't like that. And it's thought that perhaps the reason was that he wanted to continue to be the only person who discovered a planet. And if there were all these people discovering planetoids, that rather took the shine off being so quite unique, you know,

since the Babylonians and all that stuff. So, well, we don't quite know. Not really. It's just hard to see. It's so obvious that these aren't asteroids and they are planetoids that, you know, any kind of rational choice, they would have been planetoids. But no, we call them asteroids. That's due to William Herschel.

I don't know if our astronomers think I'm being unfair. To be honest, since I've always called them asteroids, I've never really worried about them being asteroids and not planetoids. Because planetoids, to me, sounds like something, you know, you need to get an ointment for. He also looked at our own star, as well as stars. beyond the solar system. I mean, he looked at sunspots and he followed solar activity that way. You know, so he was one of our first solar observers. And that's why he was looking at filters

when he discovered the infrared radiation because he needed to know what filters he needed to actually be able to observe the sun safely. And so he had again records of sunspot activity and the 11-year apparent 11-year sun's spot cycle. One thing I wonder if we've left the listeners with a proper sense of, and I propose the accumulation of what we were talking about, we'll do it. But just the relentless, you know, night after night, what he calls sweeping the heavens for nebulae. And we didn't explain what sweeping was with his telescope,

with Carolyn at the window of the upper floor and so on. in the house. And that night after night, relentless, systematic sweeping, as he called it, which was a movement of the telescope, which made sure that he covered the whole sky. And just the sheer, the sheer volume of achievement there, because he discovered two and a half thousand nebulae. And when he started, they had the Messiae catalog of nebulae, which has about a hundred objects in it. And Herschel ended up with, and Herschel and Carlin. and one would have to say there definitely increased that by an extraordinary factor. The other thing that we didn't mention was his last great telescope, which occupied.

Yeah, I was thinking that. Yeah, a lot of his time when he's now the court astronomer, and he petitions the king for money to build what would be the largest telescope in the world. Now, he'd played with the idea of making large mirrors in Bath, you know, one sort of three feet across with not much success. His ambition was to create a four-foot-wide mirror. Now, that would require the focal length, so in other words, the length of tube that you house a mirror in

before the light collected by the mirror comes to focus. That's going to be a sort of 40-foot-long tube, five inches in diameter made of iron. And even crafting a mirror that size of specular, was incredibly difficult. He made one that was too thin, would then easily deform and not keep that precise parabolic shape he needed.

Second one cracked, and it was only the third mirror that he ended up using, but that weighed half a ton. So you've then got to build this enormous scaffold that will support this heavy mirror within this 40-foot iron tube and make it maneuverable so you can see all around the sky.

So you've got to be able to rotate in azimuth, from east to west across the sky and in altitude up and down. And you've got two huts within the scaffolds. You've got Caroline recording observations. You have an assist that needs to move the telescopes and some pulleys. This was an enormous structure. I mean, what we call first light. First observation was with 1787.

And William was expecting that this would lead to even greater discoveries, but he never really realized that potentially. It didn't live up to expectations. And part of this, maybe he was a bit ahead of his time, but if you have a larger telescope, you see a smaller patch of sky through it, and that meant he couldn't systematically sweep the sky. It would just take too long.

The mirrors would tarnish. He'd need to remove them and repolish them. The whole structure was unwieldy. So in fact, most of his observations were made with, the 20-foot-long telescope and this 40-foot-long kind of languished it wasn't used after 1813. But it's worth saying that it showed the promise that it was possible to make these large reflecting telescopes in the future. And it was for a while, you know, a local landmark, you know, tourists would come to see this. And it was even marked on the 1830 Ordin Survey map as a local landmark.

So it was probably ahead of his time, too much ambition. but it was still a major achievement to have built something of this size. Thank you all very much indeed. I hope you enjoyed it. In our time with Melvin Bragg is produced by Simon Tillotson. If I think I've made a mistake, I'll just sort of pause and try and read it again so you can get your scissors in. Paul McCartney, as you've never heard him before. Are you ready? Revealing the stories behind his life and music.

We hear about superstardom. When the show heard, 73 million people watched us. Drugs. What we had to get into our lives, it seems, was marijuana. Falling out with John and Yoko. The thing is, so much of what they held to be truth was crap. He's grief after Lenin's death. I was just sitting there in this little bare room thinking of John

and realizing I'd lost him. And his sense of wonder. Sometimes I pinch myself and think, were we there? To hear all 10 episodes from BBC Radio 4, just search for Paul McCartney inside the songs on BBC Sounds. Thanks.