Follow Markus into the cockpits of a glider over the Swiss Alps and of a fighter jet over Indiana, onto the bridge of a Royal Navy survey ship, to the largest optical telescope on Earth with the Milky Way reflecting on its two huge mirrors, to a non-descript field in the middle of Germany that is home to an ultra-sensitive gravitational wave detector, and into a mysterious world beneath Geneva that houses the World's largest particle accelerator and the detectors that observe the collisions of elementary particles to probe into the building blocks of our Universe.
But this book is not just a collection of personal adventures of the author--only the first two chapters on SOFIA and HMS Enterprise are. Instead it covers, in Seven chapters, a number of topics that Markus Voelter has repeatedly covered in over ten years of recording episodes for the omega tau podcast: aviation and aerospace engineering, astronomy and telescopes, particle physics and large-scale physics experiments as well as models and modeling languages. With 220,000 words, over 150 illustrations (plus lots of pictures online here) and a couple dozen formulas, Markus explains the engineering of the marvelous machines that power modern science.
There's also a video on Youtube where I talk a bit about the book.
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Update 2 April: The Kindle e-book is now available for pre-order on Amazon.
Update 28 March: I have finished writing the book and submitted everything to Kindle Direct Publishing for printing. Unfortunately, due to Covid-19, it will take them 5 weeks to deliver the proofs. Very likely, the publication of the printed book will be delayed. Probably going to publish the EBook first. Pondering ...
The Kindle e-book is now available for pre-order on Amazon, scheduled for release on April 11;
you might want to change to your own local market, it should be available in most.
Originally, I had planned to first publish the soft cover print book. However, because of COVID-19, Amazon is currently unable to deliver proof prints in a timely way, which is why I have decided to publish the book first.
I am tired. It is 4 am California time and I have been awake since early the previous morning, having just arrived in the US from Europe. I am jet-lagged. I am sitting in an old but comfy business-class seat close to the nose of a Boeing 747SP. The SP version of the venerable Jumbo Jet has never been widely used and is even rarer today; thirteen are still in active use at the time of this writing. But the one I am flying on is unique: it is the SOFIA airborne observatory. We are on a ten-hour flight across the US to observe the night sky, and I am on board to record interviews for my omega tau podcast. I have been recording on and off for several hours, and now I'm taking a short break, drinking Coke Zero to try to stay awake for the next few hours. Our landing in Palmdale is scheduled for around 7 am. SOFIA missions are usually planned to return before daylight, because the rising sun might damage the delicate optics if the telescope's door fails to close because of a technical malfunction. There's a plan B -- flying a track that points the telescope, located on the left side of the fuselage, away from the sun. But why take a risk, better to land before sunrise. If the mission requirements dictate landing after sunrise, the mission planners have a software program that tells them which ground heading is safe for the telescope based on the date and time. And which (alternate) runways are available to land with a suitable heading.
- The Making of SOFIA
- Telescope Architecture [Preview ]
- Controlling the Telescope
- Flying SOFIA
- A SOFIA Mission
I don't like being hungry, and I suspect Kyle here feels the same way. We've been standing in front of a deserted terminal building in the harbor of Limassol, Cyprus, for close to thirty minutes. We are trying to get into -- or rather, through -- it so that we can board HMS Enterprise, which is berthed in the harbor. For Kyle getting through won't be a problem, since he is an officer in Enterprise and has the paperwork to prove it. I however am a civilian, and the lady we are talking to cannot quite square a civilian with a military ship. Here's the problem: if we have to wait any longer, we'll miss dinner!
It is mid-December 2017 and I have just flown into Larnaca from Munich. Kyle O'Regan, Navigation Officer Two in Enterprise, met me at the airport and we took a taxi to Limassol. I'm scheduled to spend a week in Enterprise on her trip from Cyprus to Malta to record interviews for omega tau. Even though the Enterprise's crew had filed all the paperwork for their civilian visitor with the Cypriot authorities, things didn't go quite as smoothly as expected.
Kyle, confirming my suspicion that he was also hungry, called the ship on the phone to make sure they would put two portions of turkey and fries aside, ensuring we'd get something whenever we arrived. They promised they would, and we were both relieved. About forty-five minutes and several phone calls by the lady later we were allowed to pass through the terminal building. We crossed the jetty towards the ship and walked up the gangway. A friendly, smiling guard with a rifle welcomed us to the ship. We made our way to the mess straight away, where we were promptly handed our dinner.
Afterwards Kyle showed me where I would live for the week: a two-person cabin I would share with him. He assigned the top bunk to me. His clearly showed that he was an experienced sailor, because it sported his personal feather bed instead of the standard issue bedclothes. It looked very comfy!
After making myself at home Kyle took me to the captain's quarters, where Commander Philip Harper, Captain of HMS Enterprise, welcomed me to the ship. Phil has been in the Royal Navy for 27 years and has served on everything from submarines to both large and small surface vessels. He's the first non-hydrographer to command a Royal Navy hydrographic ship in 220 years. He was kind enough to invite me to the Enterprise to record a podcast episode after an amusing Twitter exchange initiated by a mutual friend, Rainer Kresken. It was great to finally meet him in person.
I had arrived in Enterprise, and I was massively looking forward to the week!
- On the Bridge
- Surveying Equipment
- How Multibeam Sonars works
- The Ship's Systems [Preview ]
- Life on the Ship
- Safety and Exercises
- Driving into Valetta
Ahead of me I can see a beautiful cloud street. I'm flying along the street, at 2.600 meters altitude, with almost 200 km/h, racing “down” the Schwäbische Alb, a low mountain range in the South of Germany. Making very good progress towards my first turn point Titisee-Neustadt on today's cross-country flight, I can see the Black Forrest from almost 100 km away. Visibility is exceptionally good today. On this day in June, the thermals are so powerful, and perfectly stringed along the cloud street, there is no need to circle or even just to slow down to maintain altitude. I am busy, even slightly stressed, looking out the cockpit to see and avoid all those small and hard-to-see oncoming gliders. Everybody is flying the Alb today because of these perfect conditions created by a convergence line. My FLARM, a collision warning system based on peer-to-peer communication between the gliders, is beeping regularly to warn me of gliders I may not be able to see yet. A small display indicates the bearing and elevation of the most “dangerous” ones.
The cockpit is a weird place. It is a pilot's perch, his outlook onto the 100s of square kilometers that serve as a glider pilot's playing field. The view is magnificent, at least when atmospheric humidity is limited and visibility is good, like today. On the other hand it's rather tight: the cockpit walls on the left and right are a few centimeters from my body and the wings extend right out from my shoulders, figuratively. My head is two centimeters below the canopy, my feet, down from my knees, are stuck below the instrument panel. It's almost like a cocoon. You don't get into a glider, you “put one on”. But to me it doesn't really “feel” tight or claustrophobic because of the vast open space right beyond the acrylic glass that is the canopy. The cockpit is also the command center of your aircraft: the soaring computer presents information about terrain, weather and airspace, the radio connects you to fellow pilots and occasionally, to air traffic control. An acoustic variometer fills the air with the ever-important information about climb vs. descent, which you consume subconsciously. The vario's beeping is mixed with the wind noise which, through its intensity, tells you roughly about airspeed. And of course the cockpit has the stick, rudders, the flap handle and various other levers which you use, often also subconsciously, to control and guide the glider. The cockpit is your resting place and picnic area: while you cannot simply stop to rest, there are phases of the routinely many hours-long cross-country flights when you can rest your mind somewhat. Or to eat an apple, a bun or a cereal bar. Or to pee into a bag. After thousands of hours of gliding, and many hundreds of them in this ASG-29, I really feel safe and sheltered in the cockpit. Even though objectively, it's just this small cabin soaring through the heavens.
- Cross-country Gliding
- Glider Physics [Preview ]
- The Future of Gliders
- Wave Flying
- Higher and Faster: the U-2 and SR-71
- Stability and Control
- Flight Control Systems: F-16 and A-320 [Preview ]
- (Flying) Simulators
- Flying in an F-16
If you read the introduction to this book, you will know that I had a relatively untypical time at school. In particular, the physics teachers let us do lots of cool stuff. At one point we were supposed to measure the speed of light. How do you do that? You let light travel a distance, as long as possible, and measure the time. Obviously. The specific experiment involves a laser, a mirror at the end of a long corridor, and a photodiode to detect the reflected laser, plus a way to measure time. We used an oscilloscope to do that: when the laser was triggered, the beam of the oscilloscope started, and the detection of the laser in the diode showed as a peak on the screen. You needed a very high resolution, because the time would be on the order of 0.3 microseconds. The school had one oscilloscope that could do this. And we were allowed to use it. Not a very good idea as it turned out. We cleverly plugged the power chord into an outlet that was right outside the door of a classroom. And it was the slot right before lunch. In order to be at the front of the lunch queue and maximise the usable time during lunch break, everybody sprinted through the school building to the cafeteria when the bell rang. It was actually dangerous to be in the corridors at that time. And a tiny little power chord wouldn't stop anybody. And it didn't. But the oscilloscope was on the ground. And then sent for repair. My “reputation” among the teachers took a hit that day. Also, we didn't get to measuring the speed of light. But no worries, we knew it anyway: c = 299,792,458 m/s in vacuum, and for our purposes also in air.
- Special and General relativity
- Detector Basics [Preview ]
- Passive Seismic Damping
- Thermal Noise and the Q Factor
- Active Damping
- Shot Noise
- Squeezed Laser Light
- Power Recycling Cavities
- Control and Detection
- Five Sigma
- Why Do We Care?
- Future Detectors
The Large Binocular Telescope is at 3.200 meters, on Mt. Graham, a three-hour drive from Tucson, Arizona. Once in the enclosure, the dimensions of the telescope became clear: two giant 8.4 m mirrors mounted next to each other on a common frame. Everything is extremely rigid to avoid bending and vibrations as the telescope moves. Speaking of moving: when it moves, you hear nothing and you feel no rumbling. The telescope is mounted on oil films in azimuth and elevation and is so well balanced that it can be moved with 3 hp electrical motors!
Every large machine or scientific instrument I've visited has this magical moment when you are awestruck by its sheer impressiveness. With SOFIA, the moment came when I first entered the hangar, walking up close to the beautifully polished 747. I literally had to suppress a tear or two, not least because I had been looking forward to this moment for a long time -- - the trip had been in the planning phase for over six months. The opening of the LBT enclosure was another such moment.
It is completely dark in the enclosure (important for calibrating the telescope), only a few dim red lights indicate the status of some some kind of electronic device. We used small flashlights to find our way down to the base of the telescope and forward towards the big sliding doors. It was quite cold, almost freezing. A slight rumble. We are standing in complete darkness, and as I look up, the doors move sideways, revealing a clear, starry night sky like I have never seen before. Turning around, I can see the sky reflected in the two 8.4 meter mirrors. Amazing! The the huge telescope start moving above/behind us with absolutely no sound or vibration. The stars reflected on the mirrors move slowly, and so does the dark shape of the landscape of the planet below us. The whole event was deeply impressive and and clearly drove home the point that this was another masterpiece of engineering and a “spectacular instrument” for science, as Richard called it. He has been involved for more than a decade, from design through construction, first light and -- at the time of recording the podcast -- validation of all of its features.
- The large Binocular Telescope
- LBT Optics
- LBT Instruments [Preview ]
- Other Optical Interferometers
- The Next Generation: the ELT
- Controlling the ELT [Preview ]
- Radio Astronomy
- The 100 meter dish in Effelsberg
- The ALMA Array
- The Event Horizon Telescope
Let's start with model railways. This might be the first time in a child's life where the word “model” is used. In this context, a child probably understands the term to mean “small”: it's a smaller version of a real railway. And being smaller is often a characterising feature of a model because smaller usually means cheaper and faster to build. Of course there are exceptions: models of atoms or other microscopic phenomena are (very much) bigger than the real thing.
But for a model to be a good one it has to be realistic. As a child I was very annoyed if the proportions of a H0 locomotive such as the Deutsche Bahn BR 103 didn't quite resemble those of the real thing. Apart from being a toy, a model that looks like the real thing can be used to visually illustrate something to people who have never seen the original. That is useful, but not very much.
So why do we build models in the first place? We build them because they help us understand something about the real thing. So what else can we do with a model train? We can drive it into a train station and stop, wait a little bit, continue on to the next train station, stop again, and so on. So we can replicate what the real thing is used for. But only to a degree. For example, the proverbial aliens would probably ask themselves why the train stops periodically; after all, the model railway doesn't include people that enter and exit the train when it stops at a station. So the purpose of a real train is not apparent from the model. Unless you know the real thing, like most children, because then you can use your imagination to fill in the missing details such as entering and exiting passengers. The whole thing makes sense then.
Can we use a model of the Stuttgart train station to come up with a scheme for positioning the switches in a way that guarantees that trains never collide? This is actually a non-trivial problem. Train tracks are divided into block sections, and only one train can be in each block. Signals enforce this rule by requesting trains to stop before any block that is already occupied by another train. Any such red signal must be preceded by an advance signal that tells the driver to expect a red signal, so he can slow down. If the driver ignores a red signal, magnets signal this to sensors on the locomotive and it stops automatically. Sensors on the tracks count axles as they enter and leave blocks to detect carriages that are separated from a train and stay back in a block. Flank protection ensures that no switch from a parallel track leads into a protected block from the side, independent of whether a train is allowed onto that parallel track. An interlocking scheme prevents combinations of switch configurations and signal indications that would be dangerous. It's really a complex system, and using models to figure out configurations that are safe and at the same time maximise utilisation of a given set of tracks is a good idea. So could we do this with our model? Assuming we have a faithful replica (same tracks, switches and signals) and we are only interested in the algorithmic aspect of the switching scheme, then yes, the model could be used.
But do we need a physical model to do this? Not really. We can perform the same task with a pen-and-paper model. Or more realistically, with one expressed in software. Software models are great, because they allow us to tune their fidelity: we can model a switch as a binary variable with two states and an immediate change of position. Alternatively we can model the position of a switch as a real number between zero and one, and when we command a change, we can make it change its position slowly from zero to one, simulating the fact that a real switch takes time to change its position. We can add a random element that prevents a position change when commanded to simulate faults. We can simulate system faults (such as icing) by relating the simulated faults of multiple switches that are closely near each other.
So whenever we use a model to understand or predict aspects of the real world we have to be sure that our model considers that particular aspect, that it is able to make a meaningful statement about what we are interested in. This is the most important caveat when using models. In the rest of this section we'll explore models and their use further.
- Mathematical Models
- Numerical Models
- Prediction vs. Explanation
- Statistical Models
- Agents and Emergence
- Model and Experiment
- Meta Models and Languages
- Descriptive vs. Prescriptive Models
- Multi-Level Models
- Implementing Models
- Your own Languages
- Other Terms
Here is how I’d start if I were to write a cold war novel. It was a cold and wet fall day, dark clouds in the sky, fog hiding the ground-bound world. I had just landed at the city’s airport after a three hour flight and when I came landside, I was met by my guide for the day. We exited the airport and got into a VW Golf. We left the airport premises, and drove through the city, eventually arriving at a grey office building. We parked the car, entered the building and checked in at the counter. A slightly annoyed-looking clerk checked my passport, verified my name on a list of pre-announced guests and then handed me a visitor pass: “Make sure you wear this all day, and ensure it’s visible all the time.” Of course.
We left the building and got into the car again to begin a confusing drive: out of the office-style parking lot, through more urban areas, into a more rural landscape, from one village to another. In what turned out to be the last of the chain of villages we drove into a housing area, just to leave that area again via a narrow, curving road. That road abruptly ended at a barrier with a guard shack. An official-looking guy peeked into our car and checked out the credentials of my guide as well as my visitor pass. He opened the gate and we drove through. We parked the car a few dozen meters inside the premises, next to a non-descript building. Exiting the car, we walked towards the building. A guy was standing in front of it having a smoke, probably annoyed at not being allowed to smoke inside on this damp fall day. My guide used her pass to open the door, and we entered the building. From the inside it looked just as boring as from the outside: a cross between a warehouse and a factory building, except that it was almost empty apart from a bunch of technical-looking equipment at the western wall and a huge crane across the top.
After talking for a little while with some of her colleagues in the building, we eventually headed towards and then through another door; there we came against what looked like a gridded cage. My guide and I picked up a bunch of equipment that would allow us to go proceed further into the installation: a helmet and a radiation detector. Both were mandatory for everybody. We also removed two tokens from a registry that kept track of how many people were inside at any time. The facility cannot be started up as long as people are inside. The cage-style section of the room had a rotating door that allowed one single person to pass at a time. To activate the door, my guide needed her passport, but a sensor also scanned her retina to ensure she’s really her―a classical two factor authorization, where one factor is based on a token you possess and the other one uses a non-stealable biological marker. Once through the door we entered a relatively big industrial elevator cabin. My guide selected the lowest floor, and we started our trip down towards a secret world of big machines 50 m below the surface. I was looking forward a lot.
This is how my trip to ALICE started, one of the experiments at the Large Hadron Collider in Geneva, Switzerland. Everything in the story above is accurate except that it was a beautiful sunny day in May, I arrived by train and tram instead of by aircraft, and the building that housed the lift and the crane was actually very “descript”: it had a picture of the ALICE experiment painted on the outside, at 1:1 scale. My guide was Despina Hatzifotiadou, a physicist who is responsible for public outreach at ALICE. We were scheduled to record a podcast episode and to visit the experiment; like the whole LHC, ALICE was offline, undergoing a major upgrade in the 2019-2020 timeframe.
As you probably know, the LHC is the world’s largest particle accelerator. It accelerates heavy particles on a 26 km circular racetrack under Switzerland and France and then collides those particles to investigate the subatomic structure of matter. Four large detectors, or experiments, perform the analysis. In this chapter we’ll look at how the LHC works. But before that we’ll recap the structure of matter.
- The Standard Model
- Particle Colliders
- CERN and the LHC
- Producing the Beam
- The Superconducting Magnets
- Discovering the Higgs
- The other main experiments
- Whats Are we Looking for today
- Future Colliders
With this book Markus Völter masters the balancing act between a great depth of detail in the individual topics and tremendous ease in explaining at the same time, which makes "Once You Start Asking" a pleasure to read. I believe the reason for this unique combination is the author's authentic curiosity. It is this inquiring mind that makes the book something very personal and honest. Markus wants to understand and proceeds meticulously to find out and learn even the finer details that are necessary to understand complex topics. It is our great luck that Markus is not only a passionate and talented questioner, but also a great didact and storyteller. He shares with us what he has experienced and learned on his journey to the most fascinating achievements of our technical world. In the end, admiration remains: for the inventiveness of mankind and for the path Markus has taken, initially with the omega tau podcast and now with this book. We are fortunate to be able to tag along on this journey.
Physicist, University of Duisburg-Essen
Co-creator and co-host of the Methodisch Inkorrekt Podcast
As a former USAF Undergraduate Pilot Training instructor, transport pilot, and current commercial airline pilot for more than 30 years, you'd think I'd know a little something about flying and aerodynamics... but after reading Once You Start Asking, apparently not as much as I thought! Markus has the amazing ability to talk and write about very complex subjects and make them easy to understand; and make you feel like you're right there with him as he flies his glider along the cloud streets, rides aboard the SOFIA airborne observatory, the HMS Enterprise, and more. I've always been impressed with Markus, the accomplished podcaster, but now even more with the talented writer. Buy the book. You will be glad you did.
Captain, Delta Air Lines, Inc.
Creator and host of the Airline Pilot Guy Podcast
Once You Start Asking is a fun, telling, straightforward and engaging narrative about complex topics in science and technology. Markus is a teacher at heart who cannot help but convey his passion for knowledge sharing. One of the best popular science books available, each chapter will make you a richer person and longing for more knowledge.
Davide Sivolella Author of To Orbit and Back Again: How the Space Shuttle Flew in Space and The Space Shuttle Program: Technologies and Accomplishments
Astronomy is a visual science. After all, astronomers can do nothing but observe. The other scientific disciplines have it much easier; they can touch, cut, weigh, and dissect their research objects. But astronomy only has the view to the sky to understand the cosmos. That's why it produces so many impressive images. And that's why astronomers have learned to look more closely than anyone else.
In public, the pictures are usually in the foreground and not without good reason. Apart from the scientific information they contain, the colourful photographs of foreign planets, galaxies and cosmic gas nebulae also have an aesthetic and artistic value. But what is often forgotten about it is the enormous effort that is necessary to get such images.
The instruments of astronomy are as complex as the universe they explore. More than 400 years ago, Galileo Galilei pointed his tiny telescope towards the sky for the first time. We still have telescopes today, but they have almost nothing in common with the devices of that time. In the meantime, gigantic instruments are being used that occupy entire buildings. We send them into space on rockets and we build artificial eyes that can perceive light that is invisible to our human eyes.
Just like the infrared light that SOFIA observes. The acronym stands for "stratospheric observatory for infrared astronomy" and since the stratosphere only begins at a height around 10 kilometres above the Earth's surface, the telescope has to get there somehow. It does this on board an airplane, which sounds like a strange idea but works perfectly, as NASA and the DLR have been demonstrating since 30 November 2010.
Again and again, the modified Boeing 747 flies high up into the sky something happens that's utterly prohibited on passenger flights: a door on the plane opens and the 2.7-meter mirror of the telescope gazes into the cosmos. A lot of work was needed to make it possible to make useful images of the universe. In the book's first chapter, Markus Völter describes the history of SOFIA a a level of detail that is more than commensurate with the complexity of the undertaking. The description of the construction of a telescope may not be as visually captivating as a colorful picture of the universe. But it is just as fascinating.
Florian Freistetter Astronomer, Blogger, Author
This is a book for the crazy ones.
I wish it had been around when I was young, stuck in school, scared of teachers, forced to decode nature and science mostly by myself. How the display of Sharp's 1402 pocket-computer could be addressed pixel-by-pixel, reverse-engineering the binary-system. How a cactus grows from a seed, into two leaves first and only then producing a solid spiky column, discovering that the dicotyledonous birth known from plants also works for cacti. This book would have given me a head-start, an immense boost in my fields of interest, providing enough detail and math to grasp the concepts behind the exciting developments I was fascinated by.
It's not only the chapter about the SOFIA aircraft which is partially written in a revamped "Readers-Digest"-style - a style I loved for its attention to curious details - with transcripts of radio communications, and a description of the order in which the engines are started, beginning with number two and three, because one and four are so far outboard that they would whirl up dirt from the unpaved shoulders of the desert airport SOFIA operates from. It's not only reading about the hunt for the detection of gravitational waves or the Higgs boson and how you ride a telescope. Or a fighter jet. I usually don't care about fighter jets, but together with the illustrations, g-forces, oxygen saturation and the author's feelings, in realized, I do. As I write this, I enjoy the chapter about the role and importance of modeling; I really would have needed this in school!
But best of all - and this is key & killer: this book is based on conversations! Those gave the author plenty of opportunity to ask questions of experts in order to really understand the concepts. This allows hime to pass on in-depth-knowledge, at the perfect level for the curious reader who asks themselves all the time: how the f*** does it all work?
Lothar Bodingbauer Physicist, Radio Journalist, Podcaster
sprechkontakt.at, physikalischesoiree.at, @LoBodingbauer
It has been my great pleasure and privilege to work with Markus on many projects over almost two decades, first with academic publishers and latterly directly. It is perhaps fortunate that our backgrounds and interests mesh quite well. Much of the early work involved software patterns, a subject that continues to fascinate me. But books are one thing; he scared me out of my wits when he asked me to edit his Doctoral thesis. But all was well in the end.
Throughout all this, Markus’ material has stretched my mind, broadened my horizons and given me a lot of enjoyment (we poor editors have to at least try to understand what the subject matter is about), although I never expected him to surprise me again. But with this book, he has. His tentative initial approach (‘The thing is, that this is of course a bit different from my usual purely technical/scientific writing. The reader must be engaged… Would you want to copyedit it? Or is this kind of style not your cup of tea?’) absolutely piqued my interest, and I am so very glad that it did.
This book may be unique: I don't know for sure, but I've not come across anything with its breadth, depth of inquisitiveness, experiential approach and deep understanding of ‘Big Science’. Even Markus wilted a bit at some of it, saying that the LHC material was ‘a bit difficult’ – surely the understatement of the century? For my part, I've never worked on anything so inspirational. It's unsurprising that Markus' material on aviation was merely good, but it was more than that – it had me mentally soaring over the Alps, the Andes and to the edge of space – not to mention wildly distracted to aviation material on YouTube. And a flight with the Thunderbirds? Words fail me – but envy does not.
Although, fortunately, usually they don't. For errors of fact, blame Markus and his reviewers. For errors of grammar, blame me. For weird typography, blame Scrivener. But in the end, don't blame anyone – just enjoy this terrific book.
Steve Rickaby Engineer & (my) Copy Editor