Posts Tagged ‘Herschel’

Deep Space; Deep Time

William Herschel seems to have been the first person to recognize – the first to state explicitly – that deep space implies deep time. While others mapped the skies as if they were a sparkling dome above the Earth, or, at most, above the solar system, he thought (in 1780) in terms of space stretching out to unimaginable depths – depths that must, based on the estimated speed of light, imply at least 2 million years of time for light to reach us. It was an amazing insight. In that span of time, Herschel believed that stars had been born and died, and that the light now reaching us must often come, like ghosts, from stars that no longer exist.

Herschel believed this because he perceived that the stars were set in deep space, that they had relative motions. He believed that many of the differences in stars and in starry clusters were differences in the same types of objects seen at different points in a cycle of change, a cycle as definite as the growth of a tree or a child.

This idea of changing stars and an evolving universe was new in the 18th century, but was readily taken up by an intellectual world that was eager to ask unexpected questions and, willing to push against against the notion of a world just 6,000 years old. Nicholas Steno (St. Niels Stenson) and James Hutton had in various ways shown that certain geological forms must be the record of ancient times; now Herschel was taking astronomy into the realm of a very much deeper time.

Today, it is understood that the universe is several billion years old, and that lives of stars – their cycles from first ignition to final cooling — vary considerably. The largest stars are the shortest-lived, perhaps a few million years, while the smallest may be as old as the universe, 13 billion years with as long again to continue. Most stars take so long to burn out that what we see in the sky comes from stars which are still out there; furthermore, we know what is most likely to blow up in the near future – or to have blown up already.

But Herschel was quite right that the presence of light from deep space implies its travel through vast reaches of time. It was a fundamental insight. And the speed of light had been calculated by Huygens as the unimaginable rate of twelve million miles per minute, a very good value, within 10% of the value we presently use. In many ways, Herschel would have been very much at home in today’s world of astronomy.

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Once Joseph Banks was head of the Royal Society, he was the natural contact for anyone who found a promising new scientist. One late night in Bath, when a certain Mr. Watson found William Herschel, the orchestra conductor, standing in a cobbled backstreet looking through his homemade telescope at the most extraordinary view of the Moon ever seen on earth, the news was promptly sent to London. when he discovered Uranus, his reputation was secure.

William and Caroline Herschel, a brother-sister team of astronomers, came to know the skies with a detail that few have matched in all of history. They were born in Hanover and moved to England as musicians, first the brother and, much later, his unhappy little sister. She was, indeed, very little, just over 5’ tall, her face scarred by smallpox, her growth stunted by typhus, and her mother certain she could never be anything but a housemaid. When her adored elder brother brought her to England and arranged for voice lessons, however, she developed a lovely voice; it might have been her living had she not turned to the discovery of comets instead.

At that time, England was governed by King George III, also from Hanover. Over the next ten years, he would provide £4,000 for the construction of the largest and most ambitious telescope of the time. Some considered it one of the 7 wonders of the world, and it became a kind of tourist attraction, visited not only by any astronomer who went to England, but also by Keats, Shelley, Byron, Coleridge, and many other men of letters.

Unfortunately, it was so large that the arrangements to make it maneuverable were barely sufficient and the effects of weather on its mirror were even more troublesome than anticipated. Still, it gave William Herschel a spectacular view of the skies and led to various new discoveries both inside and outside the solar system.

Meantime, Caroline kept busy with a smaller telescope, discovering one comet after another and making a name for herself.

Using a telescope

As anyone who has used binoculars knows, only a tiny fraction of the vastness of the sky is visible through an eyepiece. You go out and see the Dipper, and lift the binoculars to examine it more closely. Pouf! All you see is a few non-descript stars; you have no idea whether they are Dipper stars or just some random collection from nearby. You move the binoculars around to see if you can figure anything out, and the view only becomes more confusing. Someone must explain to you that the way to find a star in the binoculars is to fix on it very steadily and, without moving eyes or head, sweep the binoculars up to your eyes. Ahhh! The second star in the handle, the double star, swims into view. It is beautiful and definite.

With a telescope, however, these problems are multiplied. A stronger magnification yields a better vision of — alas! – an even smaller portion of the sky. A vastly larger telescope will again give a larger portion of the sky, but you can’t just be sweeping it around; it’s too heavy. You need to know what you are looking at. And the Herschels did. They could look at any two-degree segment of the sky – about twice the width of the Moon – and immediately know where they were and the names of all the stars within view. This detailed knowledge of the sky was what enabled them to identify anything unusual. William Herschel had discovered Uranus in the telescope in Bath; it was months before others could verify his discovery, even when he told them exactly where to look.

Other life?

No sooner had Herschel found his excellent view of the Moon, than he became convinced that it had vegetation and must certainly be inhabited. Indeed, he thought all the planets likely to be inhabited, and perhaps all the stars likely to have still more inhabited planets. What a thought! And it was not so badly received as it might have been a hundred years earlier.

William Herschel, after all, was born in 1738, a contemporary of Benjamin Franklin, (whom he met), a man whose best work was contemporary with the American and French Revolutions. Thus he belonged to the time of intellectual ferment known as the Enlightenment in which reason was elevated at the deliberate expense of faith. His speculations on the likely abundance of life throughout the universe led to immediate speculations about the status of intelligent life beyond Earth: Would it not be fallen? Would it be without redemption? Would Jesus have come to each planet as a member of its intelligent but fallen life? Or did the reality of many worlds show the folly of thinking we are so special that God would come to us?

These speculations were very lively, and they became part of the worldview that eroded the faith of Europe. It is interesting to look at a larger sweep of history and see them in context.

A brief history of cosmology

Before Galileo, whose first telescopic observations took place in 1609, it was thought that the heavens were composed according to a different physics from earth, one based on beautiful spheres of quintessence, wherein only the angels lived. Over the 17th century, however, people gradually got used to the idea that all the stars and planets were governed by the same laws of gravity as our apples and spoons, and when Newton spelled out the math, people were ready to fall into line. The new physics put the Earth into an insignificant position within the Solar system, however, and for some people, this lack of privilege was a problem of faith.

Why? Why should the size or position of our household affect our theology about an infinite God? It was not a problem for everyone.

With Herschel, two hundred years after Galileo, people had become thoroughly used to the idea that the physics was the same throughout the universe, and they were quite ready to think the biology might be the same as well. Again, the question of human importance was raised as the consideration of extra-terrestrial intelligent life suggested new levels of insignificance for mankind. Could God have significant relationships with the inhabitants of so many planets? Surely not! Reason should show us the folly of thinking ourselves significant.

What? Again: surely it is childish to think that God cannot care for us just supposing there are other centers of civilization!

A hundred years later, (three hundred years after Galileo), as the 20th century developed, it was fairly clear that there was no life on other planets within the solar system, but Carl Sagan famously asserted that there must be at least 10,000 inhabited planets in each galaxy, and the number of galaxies was rapidly becoming recognized as vast beyond imagination. There are probably a billion. This — why? — seemed new reason to doubt that God, Who is infinite, could keep track of mere humans or care about them.

Now we are a hundred years later again, four hundred years after Galileo, in the first years of the 21st century. We are used to the idea that the Earth is not in the center of the Solar system; the Solar system is not the center of the Milky Way; and the Milky Way is not the center of the Universe. On the other hand, we have come to recognize that there are no other intelligent inhabitants anywhere in our sector of the Milky Way and that the requirements for intelligent life are such that it cannot be common, and indeed we may be entirely alone in the Universe. An amazing thought, perhaps disquieting, perhaps humbling…  But has this led back to a certainty, even to a suggestion, of God’s providence? No. Rather, in the eyes of the present cosmic fad, it makes us the sheerest of vulnerable accidents, and the cultural despair is final.

So there’s your lesson on the philosophical childishness of those educated only to math and physics without even a dose of logic, let alone serious theology. Real education is education of the whole man, for the whole man always has a cosmology, and if it’s not educated beyond kindergarten, it will not match his other best achievements.

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