Moonflight Dream
from Gerhard Holtkamp, 26. July 2009, 02:21
Long before the first human footprints on Mare Tranquilitatis 40 years ago man had travelled to the Moon. Not physically of course - this had to await the space age - but in our mind we are free to follow our phantasy ...
One of the best known science fiction journeys to the Moon was written by 19th century French writer Jules Verne.
In "From the Earth to the Moon" three men launch in a capsule from Florida, fly around the Moon and return to Earth with a splashdown in the Pacific Ocean - exactly what happened a century later with Apollo.
Lacking something like the big Saturn V rocket Jules Verne proposed a huge gun to shoot the capsule into space. As usually happens with science fiction there are a number of flaws in this story. For instance the forces during launch with such a gun would have squashed any would-be Astronaut.
When Jules Verne wrote this novel a flight to the Moon would have been considered very unlikely but not totally impossible pending major advances in science and technology. Some of the later spaceflight pioneers like Konstantine Tsiolkovsky and Hermann Oberth were inspired by this book and hit upon rocket propulsion instead of a gun to make flights into space a reality. This is an example how science fiction sometimes turns into fact.
In the 16th and 17th century the idea of man leaving Earth would have deemed absolutely impossible. In fact even thinking about this might have been seen as heretic and could cause problems with the authorities. Yet 400 years ago a manuscript was written about a journey to the Moon.
"Somnium" (The Dream) by famous astronomer / mathematician Johannes Kepler is sometimes labelled as the first science fiction novel. In its time it was usually seen as a satire. But it really is a clever scientific paper dressed up in a story.
The whole thing started in 1593 while Kepler was still a student at Tübingen University. All but one of his teachers were hostile to Copernican astronomy which stated that the Earth would move around the Sun rather than remaining fixed in the center of the world. A major argument put forward by anti-Copernicans was that nobody could feel the swift movement of the Earth around the Sun.
There was one thing, however, that everybody agreed on: The Moon is orbiting the Earth. As seeing something from a different angle often helps to gain new insights into a problem Kepler hit on the idea to write a dissertation about how the world would look like to an observer stationed on the Moon. Such an observer would not feel any motion of the Moon even though we know that the Moon is moving. This in turn should make it clear that terrestial observers don't have to feel any movements of the Earth.
The professor in charge of academic exercises was too stubborn to see the beauty of this argument and didn't allow the thesis to go ahead. Kepler put it in a drawer for the time being.
It was in 1609 that Kepler remembered his piece on lunar astronomy. Holding a prestigius job by now as Imperial Mathematian in Prague his most important work, the "Astonomia Nova", had just been published. Directly talking about an astronomer on the Moon might have seen by the Church as interfering with their authority so Kepler felt it prudent to dress it up as a dream.
Latin being the lingua franca at the time Kepler called his manuscript "Somnium" (The Dream). The story goes like this: Kepler falls asleep and starts dreaming how a famous Bohemian fairy brings him a book to read about an astronomer in Iceland. The mother of this astronomer is proficient in witchcraft and one day summons a (benevolent) dark spirit to tell her astronomer son about the remarkable jouney to a distant land these spirits sometimes perform. (See how Kepler puts up various firewalls between himself and the actual story to keep dangerous critics off his back?)
The distant land is called Lavania (which Kepler derived from Levana, the Hebrew word for Moon). How do spirits which dwell in the dark manage to travel between the Earth and the Moon? For Kepler no problem: Occasionally something dark from the Earth touches the Moon - its shadow during a total eclipse of the Moon. Likewise the Moon's shadow touches the Earth during a total eclipse of the Sun.
Having been to the Moon often enough thanks to the shadows of eclipses our dark spirit now tells about how the sky looks like from there. What follows is essentially the original manuscript Kepler drew up as a student.
Like on Earth the sky seems to turn around the Moon but it takes one month rather than one day and the position of the celestial poles are different for the Moon because its axis is inclined differently. Over the course of a year the Sun will move through the signs of the zodiac just like it does on Earth.
But there is something strange in the sky over Lavania which divides the land into two hemispheres called Privolva and Subvolva. While Subvolva always enjoys its Volva Privolva is deprived forever of this sight. By now you may have guessed that Volva has nothing to do with a popular Swedish car but is actually our Earth. For observers on the Moon the Earth seems to remain (almost) fixed in the sky but it revolves around its axis.
Kepler realizes that there is a difference between the two hemispheres not just with regard to seeing the Earth but also with the Sun. The Sun shines for a longer time (but appears slightly smaller) over the hemisphere facing the Earth than on the far side of the Moon. This is because during daylight hours on the Earth-facing side the Moon is further away from the Sun and moving with higher speed than during nighttime (which corresponds to daytime on the far side).
There are a few remarks about imaginary life in Lavania before Kepler wakes up from his dream and the story finishes.
As careful as Kepler may have been this Dream nearly cost the life of his mother. A few copies of the manuscript began circulating and fell into the wrong hands. Kepler's mother collected medicinal herbs and may have known a few things about the sky. In our modern world she might have been a pharmacist and amateur astronomer but 400 years ago those traits could bring you before the inquisition.
Kepler's reference to an astronomer was seen as autobiographical and an admission that his mother was indeed a witch. It took Kepler about a year to get his mother aquitted. This episode suggested that the manuscript wasn't ready for publication yet but needed some explanatory notes.
These notes were written between the years 1620 and 1630 (the year of Kepler's death). They are about three times longer than the actual story and contain a lot of scientific knowledge Kepler had gained toward the end of his life. It is interesting to see just how close he came to our modern concept of gravity and inertia.
In addition to the explanatory notes there is also a geographic appendix (with more notes attached) which incorporates details of telescopic observations (the telescope had been invented in the meantime). Kepler muses about how the circular structures visible (which we now know are craters) are being constructed by moon dwellers. (We always seem to connect regular geometric features with intelligent work rather than with nature. Think about the Martians constructing canals on Mars or when the first radio signals from Pulsars were received the first thought was about Extra-Terrestials!)
The book was finally published posthumously in 1634. An English language copy of "Somnium" translated by Edward Rosen with a lot of additional commentary is available by Dover Publications, ISBN 0-486-43282-3.
One of the best known science fiction journeys to the Moon was written by 19th century French writer Jules Verne.
In "From the Earth to the Moon" three men launch in a capsule from Florida, fly around the Moon and return to Earth with a splashdown in the Pacific Ocean - exactly what happened a century later with Apollo. Lacking something like the big Saturn V rocket Jules Verne proposed a huge gun to shoot the capsule into space. As usually happens with science fiction there are a number of flaws in this story. For instance the forces during launch with such a gun would have squashed any would-be Astronaut.
When Jules Verne wrote this novel a flight to the Moon would have been considered very unlikely but not totally impossible pending major advances in science and technology. Some of the later spaceflight pioneers like Konstantine Tsiolkovsky and Hermann Oberth were inspired by this book and hit upon rocket propulsion instead of a gun to make flights into space a reality. This is an example how science fiction sometimes turns into fact.
In the 16th and 17th century the idea of man leaving Earth would have deemed absolutely impossible. In fact even thinking about this might have been seen as heretic and could cause problems with the authorities. Yet 400 years ago a manuscript was written about a journey to the Moon.
"Somnium" (The Dream) by famous astronomer / mathematician Johannes Kepler is sometimes labelled as the first science fiction novel. In its time it was usually seen as a satire. But it really is a clever scientific paper dressed up in a story.
The whole thing started in 1593 while Kepler was still a student at Tübingen University. All but one of his teachers were hostile to Copernican astronomy which stated that the Earth would move around the Sun rather than remaining fixed in the center of the world. A major argument put forward by anti-Copernicans was that nobody could feel the swift movement of the Earth around the Sun.There was one thing, however, that everybody agreed on: The Moon is orbiting the Earth. As seeing something from a different angle often helps to gain new insights into a problem Kepler hit on the idea to write a dissertation about how the world would look like to an observer stationed on the Moon. Such an observer would not feel any motion of the Moon even though we know that the Moon is moving. This in turn should make it clear that terrestial observers don't have to feel any movements of the Earth.
The professor in charge of academic exercises was too stubborn to see the beauty of this argument and didn't allow the thesis to go ahead. Kepler put it in a drawer for the time being.
It was in 1609 that Kepler remembered his piece on lunar astronomy. Holding a prestigius job by now as Imperial Mathematian in Prague his most important work, the "Astonomia Nova", had just been published. Directly talking about an astronomer on the Moon might have seen by the Church as interfering with their authority so Kepler felt it prudent to dress it up as a dream.
Latin being the lingua franca at the time Kepler called his manuscript "Somnium" (The Dream). The story goes like this: Kepler falls asleep and starts dreaming how a famous Bohemian fairy brings him a book to read about an astronomer in Iceland. The mother of this astronomer is proficient in witchcraft and one day summons a (benevolent) dark spirit to tell her astronomer son about the remarkable jouney to a distant land these spirits sometimes perform. (See how Kepler puts up various firewalls between himself and the actual story to keep dangerous critics off his back?)
The distant land is called Lavania (which Kepler derived from Levana, the Hebrew word for Moon). How do spirits which dwell in the dark manage to travel between the Earth and the Moon? For Kepler no problem: Occasionally something dark from the Earth touches the Moon - its shadow during a total eclipse of the Moon. Likewise the Moon's shadow touches the Earth during a total eclipse of the Sun.
Having been to the Moon often enough thanks to the shadows of eclipses our dark spirit now tells about how the sky looks like from there. What follows is essentially the original manuscript Kepler drew up as a student.
Like on Earth the sky seems to turn around the Moon but it takes one month rather than one day and the position of the celestial poles are different for the Moon because its axis is inclined differently. Over the course of a year the Sun will move through the signs of the zodiac just like it does on Earth.
But there is something strange in the sky over Lavania which divides the land into two hemispheres called Privolva and Subvolva. While Subvolva always enjoys its Volva Privolva is deprived forever of this sight. By now you may have guessed that Volva has nothing to do with a popular Swedish car but is actually our Earth. For observers on the Moon the Earth seems to remain (almost) fixed in the sky but it revolves around its axis.
Kepler realizes that there is a difference between the two hemispheres not just with regard to seeing the Earth but also with the Sun. The Sun shines for a longer time (but appears slightly smaller) over the hemisphere facing the Earth than on the far side of the Moon. This is because during daylight hours on the Earth-facing side the Moon is further away from the Sun and moving with higher speed than during nighttime (which corresponds to daytime on the far side).
There are a few remarks about imaginary life in Lavania before Kepler wakes up from his dream and the story finishes.
As careful as Kepler may have been this Dream nearly cost the life of his mother. A few copies of the manuscript began circulating and fell into the wrong hands. Kepler's mother collected medicinal herbs and may have known a few things about the sky. In our modern world she might have been a pharmacist and amateur astronomer but 400 years ago those traits could bring you before the inquisition.
Kepler's reference to an astronomer was seen as autobiographical and an admission that his mother was indeed a witch. It took Kepler about a year to get his mother aquitted. This episode suggested that the manuscript wasn't ready for publication yet but needed some explanatory notes.
These notes were written between the years 1620 and 1630 (the year of Kepler's death). They are about three times longer than the actual story and contain a lot of scientific knowledge Kepler had gained toward the end of his life. It is interesting to see just how close he came to our modern concept of gravity and inertia.
In addition to the explanatory notes there is also a geographic appendix (with more notes attached) which incorporates details of telescopic observations (the telescope had been invented in the meantime). Kepler muses about how the circular structures visible (which we now know are craters) are being constructed by moon dwellers. (We always seem to connect regular geometric features with intelligent work rather than with nature. Think about the Martians constructing canals on Mars or when the first radio signals from Pulsars were received the first thought was about Extra-Terrestials!)
The book was finally published posthumously in 1634. An English language copy of "Somnium" translated by Edward Rosen with a lot of additional commentary is available by Dover Publications, ISBN 0-486-43282-3.
