Radioactive alpha decay had been explained in 1928 by Russian physicist George Gamow, which he described as quantum tunneling of alpha-particles (i.e., He-4 nuclei, 2 protons and 2 neutrons) from inside the nucleus, through the strong force barrier (which usually keeps the nucleus together), and finally emerging free. In the case of U-238 transforming to Th-234, the alpha-particle is emitted with about 4.2 MeV of kinetic energy. (This means that they are traveling at about 9.5% of the speed of light, or about 64 million miles per hour. Even though they are traveling fast, they are very light, and therefore are easily stopped - and absorbed - by a thin sheet of paper. In fact, they only travel about 4 cm in air.) Here is one of Ernest Rutherford's early papers - 1899 - describing his experiments on radioactive decay.
Beta decay, on the other hand, was more confusing. The beta particles (now known to be electrons) were emitted with a variety of kinetic energies, prompting Niels Bohr to speculate that the long-held principle of the conservation of energy did not apply to radioactive decay. However, in 1930, Wolfgang Pauli proposed that another particle was emitted along with the electron, which he called a "neutrino," because it was (a) electrically neutral, like the neutron, and (b) very light, like a "little neutron." This particle had not been observed (and would not be directly observed until 1956), but it saved the principle of the conservation of energy.
Then, at Christmas 1933, Enrico Fermi developed a theory of beta decay, based on the quantum theory of the electron developed by Paul Dirac in 1928. As Robert Crease and Charles Mann put it, "The theory was his first and only work on beta decay and was so complete that its description of the phenomenon has remained essentially unchanged to this day. At a stroke, Fermi first accurately described beta decay, first identified the separate nature of its cause, and first predicted most of its essential features."
It wasn't until 1995 that Frederick Reines won the Nobel Prize for his neutrino discovery, and subsequently two other neutrinos were discovered (the mu and tau neutrinos), leading to the 2015 Nobel Prize for the discovery of "neutrino oscillations," in which the different types of neutrinos can change into each other.
Fascinating stuff.
Sunday, November 22, 2015
Saturday, July 25, 2015
The number 32
Sandy Koufax is arguably the best pitcher (ever) in baseball, although he has some competition in the current Dodger star Clayton Kershaw. Koufax wore number 32, and Magic Johnson and a whole host of sports superstars. I've been reading a great book about the Dodgers and I started thinking about player numbers.
The number 32 has some interesting properties, many of which are catalogued here.
One of the weirdest involves the so-called "totient" function φ(n) of 18th century mathematician, Leonhard Euler. It is defined as the number of integers less than or equal to n that are relatively prime to n. For example, φ(1) = 1, φ(2) = 1, and φ(5) = 4. The last is true because all the numbers 1, 2, 3, and 4, are relatively prime to 5. (In this definition, 1 is counted as prime.) There are 7 different numbers for which φ(n) is equal to 32. The first few are n = 51, 64, 68, 80, 96, ... and I'll let you find the other two.
One of the funniest is - Nobody ever says “32-skidoo.”
The number 32 has some interesting properties, many of which are catalogued here.
One of the weirdest involves the so-called "totient" function φ(n) of 18th century mathematician, Leonhard Euler. It is defined as the number of integers less than or equal to n that are relatively prime to n. For example, φ(1) = 1, φ(2) = 1, and φ(5) = 4. The last is true because all the numbers 1, 2, 3, and 4, are relatively prime to 5. (In this definition, 1 is counted as prime.) There are 7 different numbers for which φ(n) is equal to 32. The first few are n = 51, 64, 68, 80, 96, ... and I'll let you find the other two.
One of the funniest is - Nobody ever says “32-skidoo.”
Friday, February 27, 2015
Rivers and Dams
Recently I picked up the book "The Emerald Mile" by Kevin Fedarko, about running the Colorado River, the dams on the river (Glen Canyon Dam particularly), and the great storm in 1983 that almost destroyed the Glen Canyon Dam. I highly recommend it.
The hook of the book is the attempt to run the 277 miles from Lee's Ferry, just below the Glen Canyon Dam, to Pierce Ferry at the Grand Wash Cliffs near Lake Mead in a wooden dory named Emerald Mile. This was attempted several times, but the focus was on the attempt during the 1983 flood. But to tell that story he backs up and covers John Wesley Powell's initial excursion, the outfitting community that has grown up on the river, the dams that block the river, and intimate portraits of some of the river guides.
His writing is good, but sometimes a bit over the top. For example, "His face, which was ovular, was dominated by a hook-boned nose, at the top of which floated a pair of deeply skeptical brown eyeballs." I'm not quite sure how eyeballs can be skeptical. But its enjoyable, and for the most part he gets the technical parts correct. When discussing the river flow and the dam, there's a lot of technical parts, and it's especially interesting to read his discussion of cavitation - the effect of tiny bubbles on the flow of the water through the spillways at Glen Canyon Dam that ended up tearing them apart, and eating through the concrete liner and into the pink sandstone. However, he does make some mistakes. For example, when discussing the blocking of the river by a debris flow, he says, "The flood and the debris fan had narrowed the river to one-quarter its former width, doubled the drop, and increased the speed by a factor impossible to quantify." Of course, it's fairly simple to quantify, using fluid dynamics principles. But I guess the sentence sounds nice.
That book led me to watch the Patagonia documentary, DamNation. Another high recommendation.
This is a beautifully shot look at the history of dams in the US, mostly in the West, and it focuses on the removal of several dams in Washington state. I learned two important facts. First, how many dams there are in the US - over 60,000! And second, how many dams have already been removed. It makes sense that dams have a finite lifetime - for many reasons, not least of which is that the silt that usually flows downstream builds up in the reservoir behind the dam, lowering its utility - and that removal is a logical option. I had just never thought about removing a dam before. As David Montgomery, a geologist at U Washington said, 50 years ago, removing a dam was unthinkable.
One of the most powerful scenes was the description of Celilo Falls on the Columbia River, where native Americans have fished for salmon for (probably) the last 10,000 years [it's one of the oldest settlements in North America]. Those falls were submerged by the reservoir behind The Dalles Dam in 1957.
Addendum: My own river running experience is rather limited. I took a two-day trip down the Stanislaus River in the Sierras when I was a teenager. And I've done three day trips down the Chatooga River in NE Georgia in the past few years. I love the Chatooga because I can camp at Talulah Falls Park, and it's a short drive to the outfitters (SEE) headquarters.
The hook of the book is the attempt to run the 277 miles from Lee's Ferry, just below the Glen Canyon Dam, to Pierce Ferry at the Grand Wash Cliffs near Lake Mead in a wooden dory named Emerald Mile. This was attempted several times, but the focus was on the attempt during the 1983 flood. But to tell that story he backs up and covers John Wesley Powell's initial excursion, the outfitting community that has grown up on the river, the dams that block the river, and intimate portraits of some of the river guides.
His writing is good, but sometimes a bit over the top. For example, "His face, which was ovular, was dominated by a hook-boned nose, at the top of which floated a pair of deeply skeptical brown eyeballs." I'm not quite sure how eyeballs can be skeptical. But its enjoyable, and for the most part he gets the technical parts correct. When discussing the river flow and the dam, there's a lot of technical parts, and it's especially interesting to read his discussion of cavitation - the effect of tiny bubbles on the flow of the water through the spillways at Glen Canyon Dam that ended up tearing them apart, and eating through the concrete liner and into the pink sandstone. However, he does make some mistakes. For example, when discussing the blocking of the river by a debris flow, he says, "The flood and the debris fan had narrowed the river to one-quarter its former width, doubled the drop, and increased the speed by a factor impossible to quantify." Of course, it's fairly simple to quantify, using fluid dynamics principles. But I guess the sentence sounds nice.
That book led me to watch the Patagonia documentary, DamNation. Another high recommendation.
One of the most powerful scenes was the description of Celilo Falls on the Columbia River, where native Americans have fished for salmon for (probably) the last 10,000 years [it's one of the oldest settlements in North America]. Those falls were submerged by the reservoir behind The Dalles Dam in 1957.
Addendum: My own river running experience is rather limited. I took a two-day trip down the Stanislaus River in the Sierras when I was a teenager. And I've done three day trips down the Chatooga River in NE Georgia in the past few years. I love the Chatooga because I can camp at Talulah Falls Park, and it's a short drive to the outfitters (SEE) headquarters.
Wednesday, February 25, 2015
Why "Big Bang" is a bad word
In John Mather's talk last Saturday at Embry-Riddle's Elston Memorial Lecture, he covered all the standard cosmology topics (but focused on his Nobel-prize winning work with COBE, the Cosmic Background Explorer), but also showed some neat videos of how the James Webb Space Telescope will unfold once it gets to the L1 point. You can see one here.
As with all popular talks on the expanding universe, he had to contend with the perennial problem of explaining the current "standard model" of cosmology (the study of the universe and how it came to be the way it is today), known as the ΛCDM model, or the "Lambda Cold Dark Matter" model. It consists of Einstein's equations of general relativity applied to the entire universe, which, in addition to the visible matter (stars, galaxies, dust, etc) is comprised of dark matter (represented essentially by a cold gas) and dark energy (embodied in Einstein's cosmological constant Λ).
Because in every direction we look in the night sky, we see galaxies moving away from us, it is tempting to deduce that we are at the center of the universe. However, it is easy to show that an observer anywhere in the universe would see the same thing, and to draw the conclusion that there is no center. In fact, the so-called Big Bang occurred everywhere simultaneously, and the universe has always been infinite in extent. For this reason, the term "big bang" is really a misnomer, and gives non-astrophysicists the incorrect view that the "explosion" occurred at a single point and moved "outward".
It would be great to rid our lexicon of this term, but unfortunately we are stuck with it (and it clearly shows the weakness of language when describing subjects that are inherently mathematical in nature), and so every popular exposition has to set aside at least some space to explain why this we don't like it. At its core, the standard model of cosmology is based on the expanding space paradigm, in which rather than stuff expanding into already existing space, it is space itself that is expanding. I can do no better than to quote Edward Harrison from his 1993 paper
As with all popular talks on the expanding universe, he had to contend with the perennial problem of explaining the current "standard model" of cosmology (the study of the universe and how it came to be the way it is today), known as the ΛCDM model, or the "Lambda Cold Dark Matter" model. It consists of Einstein's equations of general relativity applied to the entire universe, which, in addition to the visible matter (stars, galaxies, dust, etc) is comprised of dark matter (represented essentially by a cold gas) and dark energy (embodied in Einstein's cosmological constant Λ).
Because in every direction we look in the night sky, we see galaxies moving away from us, it is tempting to deduce that we are at the center of the universe. However, it is easy to show that an observer anywhere in the universe would see the same thing, and to draw the conclusion that there is no center. In fact, the so-called Big Bang occurred everywhere simultaneously, and the universe has always been infinite in extent. For this reason, the term "big bang" is really a misnomer, and gives non-astrophysicists the incorrect view that the "explosion" occurred at a single point and moved "outward".
It would be great to rid our lexicon of this term, but unfortunately we are stuck with it (and it clearly shows the weakness of language when describing subjects that are inherently mathematical in nature), and so every popular exposition has to set aside at least some space to explain why this we don't like it. At its core, the standard model of cosmology is based on the expanding space paradigm, in which rather than stuff expanding into already existing space, it is space itself that is expanding. I can do no better than to quote Edward Harrison from his 1993 paper
From purist point of view one cannot but deplore the expression big bang, "loaded with inappropriate connotations" (McVittie 1974), which conjures up a false picture of a bounded universe exploding from a center in space. In modern cosmology, the universe does not expand in space, but consists of expanding space...And he quotes Willem de Sitter (1931), one of the founders of modern cosmology
The theory of [general] relativity brought the insight that space and time are not merely the stage on which the piece is produced, but are themselves actors playing an essential part in the plot.For those of you who want a more technical explanation, see here, a page from the Physics FAQ, hosted by John Baez.
Monday, February 23, 2015
Fun in the snow
After Kathy, Megan, and Sarah left, Caitlin stayed for a couple more days. We went to the two main palaces in Munich, the Schloss Nymphenburg on the last day of the year, when the building was closed, but the grounds were open. In addition to a huge building, the grounds are extensive, with many walking paths and gardens. On summer days its a popular place to go for Münchner.
And on the previous day we went to the "Munich Residenz," the main palace of the Bavarian royalty, which is now a museum. Also, a portion of the museum houses the treasury - all the crowns and precious jewels that they had collected over the years.
Panorama of the 'summer' palace for the Bavarian royalty, Schloss Nymphenburg. On this day, however, it was covered in snow.
And on the previous day we went to the "Munich Residenz," the main palace of the Bavarian royalty, which is now a museum. Also, a portion of the museum houses the treasury - all the crowns and precious jewels that they had collected over the years.
Crown of Queen Kunigunde (975-1040). It is assumed that she actually wore this crown, but it is not known for sure. The crown was on a "head reliquary" and therefore might have been placed there after her death. It's one of the oldest items in the treasury.
St George slaying the dragon. With lots of jewels. St George is the patron saint of the House of Wittelsbach, which ruled Bavaria from the 1100s until 1918, when they were deposed. He is also the patron saint of the Munich Residenz, and this valuable item is not allowed to leave the Residenz.
Really cool pocket watch from 1620. Unfortunately there was no detailed description, even in the self-guided audio, so I don't know anything about its history. However, if you look closely, on a high resolution image below, the dials denote the following. Top: Lunar cycle and phases of the moon. Right: Standard 12 hour clock. Bottom: Calendar with the day of the month and month of the year. Left: Day of the week. Center: I-II-III-IIII, but I'm not sure what this represents. Anybody?
Friday, February 20, 2015
It's good to be home
After a month of this
I came back to this
I came back to this
The autumn in Munich was very mild, lots of warm days, and only a couple of brief snowfalls that immediately melted. Then, the day after Christmas, we got four days of solid snow, which was good for the family, who wanted to see snow. We also were able to visit Neuschwanstein in snow, and also Salzburg - and, of course, Munich. Most of January, and the beginning of February, it was snowing. Not an overwhelming amount, though, just a few inches every few days. In fact, I enjoyed the snow; there wasn't too much of it, and it looked very nice. A change of pace from Florida. The temperature was pretty steady, right around freezing, but not brutally cold, so my jackets that I had brought with me served their purpose admirably.
The best part was that I met a lot of great people and I'd like to thank them for making my time in Germany worthwhile:
Karl, Philip, Alec, Connor, Sophie, Billy, Will, Timo, Astrid, Luis, Tessa, Sebastian, Helmut, Lukas, Guido, Alexander, Wolfram, Gerald, Dirk, Ruslan, Sandro, Nicole, Aino, Christian, Thomas, Annette, Veronica, Michael, Jack, Klemens, Peter, Carolyn, Merit, Maria, Alexandra, Shyam, Eno, Kevin, Ralph, Steffie, all my students, and last, but not least, Coco.
I can't wait to return!
The best part was that I met a lot of great people and I'd like to thank them for making my time in Germany worthwhile:
Karl, Philip, Alec, Connor, Sophie, Billy, Will, Timo, Astrid, Luis, Tessa, Sebastian, Helmut, Lukas, Guido, Alexander, Wolfram, Gerald, Dirk, Ruslan, Sandro, Nicole, Aino, Christian, Thomas, Annette, Veronica, Michael, Jack, Klemens, Peter, Carolyn, Merit, Maria, Alexandra, Shyam, Eno, Kevin, Ralph, Steffie, all my students, and last, but not least, Coco.
I can't wait to return!
Wednesday, February 18, 2015
Chinese in Berlin?
My airbnb host in Berlin told me an interesting story that I have not had time to confirm. He said that there were four countries that were to divvy up Berlin after WWII: Russia, US, Britain, and China! For some reason, France was not included since they had already "lost." Since China was so far away and didn't want to have to administer an area on another continent, they said Russia could have their region, just give them money. This was why Russia had half of Berlin, and the Allies had the other half. I said that I hadn't heard of that, and he said "if you dig deeply enough on the internet, you'll find it." I took that to mean that he was into conspiracies, you could probably find some whacko espousing this view, but it wasn't true. So far, I haven't been able to find out anything about this.
But the map of Berlin is interesting. It shows the city divided almost exactly in half along a north-south line, except for the city center, the Mitte, cut out and given to the Soviets. This was where my airbnb apartment was, just off of Alexanderplatz, along Alexandrestraße. The BrandenburgerTor is at the west end of this cutout, just inside the Soviet zone.
As can be seen from the entire map of postwar Germany, the US occupation zone included Bavaria. And if you look closely at the photos of the town of Garmisch here, you can barely see barracks that are part of a US installation, one of the few remaining in Germany.
But the map of Berlin is interesting. It shows the city divided almost exactly in half along a north-south line, except for the city center, the Mitte, cut out and given to the Soviets. This was where my airbnb apartment was, just off of Alexanderplatz, along Alexandrestraße. The BrandenburgerTor is at the west end of this cutout, just inside the Soviet zone.
Map of Berlin from the Berlin Wall Memorial, showing the Berlin Wall in red.
Map of the German occupations zones. From Wikipedia.
As can be seen from the entire map of postwar Germany, the US occupation zone included Bavaria. And if you look closely at the photos of the town of Garmisch here, you can barely see barracks that are part of a US installation, one of the few remaining in Germany.
Monday, February 16, 2015
The cable-stayed bridge
"Today...this method is often a civil engineer's first choice for bridges...They go up faster than alternative approaches and cost less because they use less material." - Amy Nordrum, Scientific American, February 2015.
I think the first cable-stayed bridge that I saw was the Sunshine Skyway Bridge across Tampa Bay. I probably saw it in 1988 when I visited Florida for a physics conference (in Hollywood) and I made a trip to Clearwater to visit relatives. Since Tampa Bay is so large, you can see it from a great distance, and it looks very impressive.
The second one I saw was across the Savannah River, near Savannah, Georgia. That one caught me by surprise as we were moving from Washington to Florida in 2001. You don't really see the bridge until you are almost on it, and I wasn't expecting it.
One bridge that I haven't seen, but would like to, is the Santiago Calatrava bridge in Redding, California, across the Sacramento River. Technically, this is a "cantilever spar cable-stayed" bridge, a design that was pioneered by Calatrava and used in some of his other bridges in Spain and Argentina, among others.
The quote at the top is from an article about the new Tappan Zee bridge in New York, which will be a cable-stayed bridge, with eight traffic lanes and will be the widest cable-stay in the world. The article claims that there's a cable-stay under construction in Los Angeles. I can't think of where it might be, except for the Port of Los Angeles, near Long Beach.
A final bridge that I'd like to see, but I didn't get a chance when I was in Germany, is the Millau Viaduct, in France. Of all the photos I've seen, it is the most impressive.
I think the first cable-stayed bridge that I saw was the Sunshine Skyway Bridge across Tampa Bay. I probably saw it in 1988 when I visited Florida for a physics conference (in Hollywood) and I made a trip to Clearwater to visit relatives. Since Tampa Bay is so large, you can see it from a great distance, and it looks very impressive.
Sunshine Skyway Bridge, Tampa Bay, Florida, U.S. At dawn.
The second one I saw was across the Savannah River, near Savannah, Georgia. That one caught me by surprise as we were moving from Washington to Florida in 2001. You don't really see the bridge until you are almost on it, and I wasn't expecting it.
Eugene Talmadge Memorial Bridge, Savannah, Georgia, U.S.
One bridge that I haven't seen, but would like to, is the Santiago Calatrava bridge in Redding, California, across the Sacramento River. Technically, this is a "cantilever spar cable-stayed" bridge, a design that was pioneered by Calatrava and used in some of his other bridges in Spain and Argentina, among others.
Sundial Bridge at Turtle Bay, Redding, California, U.S.
The quote at the top is from an article about the new Tappan Zee bridge in New York, which will be a cable-stayed bridge, with eight traffic lanes and will be the widest cable-stay in the world. The article claims that there's a cable-stay under construction in Los Angeles. I can't think of where it might be, except for the Port of Los Angeles, near Long Beach.
A final bridge that I'd like to see, but I didn't get a chance when I was in Germany, is the Millau Viaduct, in France. Of all the photos I've seen, it is the most impressive.
Millau Viaduct, France.
Friday, February 13, 2015
The usefulness of useless knowledge
The title is supposedly a quote of Abraham Flexner, one of the co-founders of the Institute for Advanced Study in Princeton, that ivory tower where employees are allowed to think about whatever they wish, with no pressure to produce any results whatsoever.
In the January 2015 issue of Physics Today, Oscar Greenberg has an article titled "The origin of quark color," in which he discusses this history of his idea that quarks have three types of color "charge," similar to the two types of electric charge (positive and negative) and the one type of gravitational "charge," i.e., mass. But he starts off philosophically about how "the pursuit of these useless satisfactions proves unexpectedly the source from which undreamed-of utility is derived" (another Flexner quote). He makes the point that quark color was "useless" in this sense. In fact, the same could be said of electric charge and electricity and magnetism in general. Greenberg also repeats that (probably apocryphal) story of Michael Faraday showing one of his electricity and magnetism experiments to a prime minister, who asked "What good is it?" And Faraday replied "I don't know Mr Prime Minister, but one day you will tax it." (see here for some of the history of the quote). Electricity and magnetism has certainly turned out to have "undreamed-of utility" and also to be taxed beyond belief.
When I was a kid, I remember reading about "pure" research and "applied" research, and I was not really sure what kinds of things would fit into the "pure" category. But I guess what I've been doing (see here) can be classified as "pure." Recently, one of my ex-students asked my what I was working on, and I told him about that work on solitons in space plasmas, and he replied "What do you think/hope it will accomplish? Would it create better spacecraft in the future?" I said "Well, at this point it's very close to "pure" research, i.e., we just want to understand the universe in which we live a little better." I guess I was getting a little "philosophical" myself. But I think that you never know how the issues you work on are going to be used (or used for) in the future. It reminds me of the mathematician G.H. Hardy, who said.
Update: Here is the latest on the pure research associated with quark color.
In the January 2015 issue of Physics Today, Oscar Greenberg has an article titled "The origin of quark color," in which he discusses this history of his idea that quarks have three types of color "charge," similar to the two types of electric charge (positive and negative) and the one type of gravitational "charge," i.e., mass. But he starts off philosophically about how "the pursuit of these useless satisfactions proves unexpectedly the source from which undreamed-of utility is derived" (another Flexner quote). He makes the point that quark color was "useless" in this sense. In fact, the same could be said of electric charge and electricity and magnetism in general. Greenberg also repeats that (probably apocryphal) story of Michael Faraday showing one of his electricity and magnetism experiments to a prime minister, who asked "What good is it?" And Faraday replied "I don't know Mr Prime Minister, but one day you will tax it." (see here for some of the history of the quote). Electricity and magnetism has certainly turned out to have "undreamed-of utility" and also to be taxed beyond belief.
When I was a kid, I remember reading about "pure" research and "applied" research, and I was not really sure what kinds of things would fit into the "pure" category. But I guess what I've been doing (see here) can be classified as "pure." Recently, one of my ex-students asked my what I was working on, and I told him about that work on solitons in space plasmas, and he replied "What do you think/hope it will accomplish? Would it create better spacecraft in the future?" I said "Well, at this point it's very close to "pure" research, i.e., we just want to understand the universe in which we live a little better." I guess I was getting a little "philosophical" myself. But I think that you never know how the issues you work on are going to be used (or used for) in the future. It reminds me of the mathematician G.H. Hardy, who said.
"I have never done anything 'useful.' No discovery of mine has made, or is likely to make, directly or indirectly, for good or ill, the least difference to the amenity of the world."And interestingly, much of his work has found applications in science.
Update: Here is the latest on the pure research associated with quark color.
Wednesday, February 11, 2015
Solitons in space plasmas
Along with two of my colleagues, I just finished a paper that should be accepted in the "Journal of Geophysical Research" soon. What's neat about this paper, other than the fact that it's the first application of a technique that was first suggested over 20 years ago, is its sociological history. The ways of science are often serendipitous, and this is a good example.
A few years ago a masters student, Harry, came to me and wanted to write his thesis on solitons (for a more mathematical introduction to solitons, see here, and for a picture of a soliton, see here, and for a history of the observation of the first soliton, see here) in space plasmas, and wanted me to be his advisor. I told him that while I did know a lot about space plasmas, I didn't know much about solitons, and therefore I couldn't guide him in the proper direction, but that I'd be happy to be his advisor and we'd learn about the subject together. This is unusual in that in addition to technical guidance, and advisor usually knows the particular field, and can suggest certain fruitful directions to the student. However, in my experience I've found that my most successful masters students are those that come to me with their own definitive idea, and in addition to learning the subject with them (sometimes from them) I simply give them technical guidance in plasma physics in general. This way they already have motivation, because it's a topic of their choice. I've heard that Feynman was of a similar mind, and didn't want students who came to him and asked what topic they should work on.
In any case, we started, as usual, by reading the literature, and one of the papers that Harry sent me was written by someone who I had shared an office with while a grad student at UCLA. He was an expert on solitons! So I contacted Bob, and after some email exchanges, where he gave Harry and me some advice, I invited him out to Daytona for a visit. He was on a sabbatical at the time, and was able to visit us for a week, during which he gave a departmental colloquium, and also suggested some very good directions for Harry's thesis. Harry duly finished his thesis, graduated, and is now working for Lockheed out in California while we finished polishing up his thesis for publication.
So, in addition to writing a great thesis, I have renewed a friendship that was on a 20-year hiatus, and started a new collaboration. Several of the ideas in Harry's thesis have suggested other problems to work on, and Harry and Bob and I will be pursuing these ideas in the future.
So, what's this neat idea? It's the fact that you can use the inverse scattering transform (IST) to determine whether or not a soliton (or solitons) is embedded in a particular magnetic field profile that has been observed (in our case, by the Ulysses satellite that is in the solar wind). In the first figure below, there's a plot of the magnetic field observed by Ulysses, along with a plot of the soliton that we found using the IST analysis. You can see that they don't match exactly, because there are other waves in the observed magnetic field - not just the soliton - and those waves show up as a difference in the two curves, solid versus dashed.
To see the soliton and the other waves distinctly, we did a numerical simulation and propagated the magnetic field forward in time, and compared that to the soliton moved forward in time. This comparison is shown in the second figure below. Notice that the two curves match much better in the region of the single bump - that's the soliton - but you can also see the waves propagating away from this region. Those are the waves (not part of the soliton) that were initially part of the magnetic field profile.
Normally, given a particular magnetic field, it is in general difficult to tell if there is a soliton embedded in that profile simply by looking. It may resemble a soliton, but that resemblance may simply be masking the fact that there are lots of waves interfering in such a way as to look like a soliton. The IST method, however, gives a definitive answer, although you must run a numerical simulation to see what other waves are embedded in the profile. You can clearly see below that there are some other waves, but that they propagate away at a different speed, and leave the soliton behind.
In any case, we started, as usual, by reading the literature, and one of the papers that Harry sent me was written by someone who I had shared an office with while a grad student at UCLA. He was an expert on solitons! So I contacted Bob, and after some email exchanges, where he gave Harry and me some advice, I invited him out to Daytona for a visit. He was on a sabbatical at the time, and was able to visit us for a week, during which he gave a departmental colloquium, and also suggested some very good directions for Harry's thesis. Harry duly finished his thesis, graduated, and is now working for Lockheed out in California while we finished polishing up his thesis for publication.
So, in addition to writing a great thesis, I have renewed a friendship that was on a 20-year hiatus, and started a new collaboration. Several of the ideas in Harry's thesis have suggested other problems to work on, and Harry and Bob and I will be pursuing these ideas in the future.
So, what's this neat idea? It's the fact that you can use the inverse scattering transform (IST) to determine whether or not a soliton (or solitons) is embedded in a particular magnetic field profile that has been observed (in our case, by the Ulysses satellite that is in the solar wind). In the first figure below, there's a plot of the magnetic field observed by Ulysses, along with a plot of the soliton that we found using the IST analysis. You can see that they don't match exactly, because there are other waves in the observed magnetic field - not just the soliton - and those waves show up as a difference in the two curves, solid versus dashed.
Observed magnetic field components (solid lines) and predicted magnetic field components of a single soliton (dashed lines) deduced from the IST. At time t = 0.
To see the soliton and the other waves distinctly, we did a numerical simulation and propagated the magnetic field forward in time, and compared that to the soliton moved forward in time. This comparison is shown in the second figure below. Notice that the two curves match much better in the region of the single bump - that's the soliton - but you can also see the waves propagating away from this region. Those are the waves (not part of the soliton) that were initially part of the magnetic field profile.
Normally, given a particular magnetic field, it is in general difficult to tell if there is a soliton embedded in that profile simply by looking. It may resemble a soliton, but that resemblance may simply be masking the fact that there are lots of waves interfering in such a way as to look like a soliton. The IST method, however, gives a definitive answer, although you must run a numerical simulation to see what other waves are embedded in the profile. You can clearly see below that there are some other waves, but that they propagate away at a different speed, and leave the soliton behind.
Observed magnetic field components (solid lines) and predicted magnetic field components of a single soliton (dashed lines) deduced from the IST. At time t = 55.2.
If you are interested in reading the entire paper, it's posted on the arXiv, here. The arXiv is a repository of "preprints," papers in draft form before they get published in order to disseminate more quickly than waiting for publication. It's a good place to watch to keep abreast of the latest developments in a particular field.
Monday, February 9, 2015
Nobel Prize Winners I Have Known
Well, not really. More like "Nobel prize winners whose talks I have attended."
The first was Richard Feynman [Physics 1965], back in 1981 or '82. I was a student at Santa Monica College, and a friend took me to a lecture at UCLA by Feynman. At this point, I hadn't taken any physics, or perhaps I was in my first semester, so I didn't understand a thing. From what I know now, he was talking about the two-slit experiment, but to me it was very confusing. The hall was jam packed, though, and I recall sitting on the steps in the aisle. I couldn't figure out what all the fuss was about. Of course, I know now. I also remember where I was when I found out he had died - I was in my TA office in the basement of Knudsen Hall, and I was discussing him with my fellow TAs in 1988.
The second and third were up in Santa Cruz. Hans Bethe [Physics 1967] came to the physics department to give a talk on SN 1987a, so I'm guessing it was in the spring of 1987. He was old, but definitely still very sharp. Around the same time, Linus Pauling [Chemistry 1954, Peace 1962] came to Santa Cruz to give a talk. I don't remember the topic, but I was very impressed at how he was able to switch gears. Apparently, he was scheduled to give a fairly high-level department colloquium, but so many people showed up that the venue had to change at the last minute. He correctly realized that most of the audience would not understand his planned talk - they had just come to see Linus Pauling - so he gave a more popular level talk, on the fly. That, to me, is someone who really knows his subject - and his audience - well.
As a young grad student at UCLA in about 1988, Carlo Rubbia [Physics 1984] came to the department (we had several faculty who worked at CERN) and one of the "events" that was organized was an informal talk between Rubbia and the grad students. It was mostly a question-and-answer session, and I recall that he was rather pompous. But I guess that's just his style, and people have speculated that someone with a less forceful personality would not have been able to get the experiment built that detected the weak intermediate vector bosons.
The next was in 1993. Russell Hulse and Taylor [Physics 1993] had just won the prize in October for the discovery of the binary pulsar from Arecibo in 1974. Hulse at that time was Taylor's grad student, but he had since switched to plasma physics. He happened to be going to the annual plasma physics meeting in November, so they quickly organized a special lecture for him. I don't recall any of the details, but he talked about the history of how he made the discovery.
The next was John Mather and George Smoot [Physics 2006], who gave talks at the April 2007 meeting of the APS (American Physical Society) in Jacksonville. They had just won the Nobel prize in 2006, and I went to that meeting with several students from ERAU. It was mostly to give them experience at a technical conference, but a happy bonus was the joint talk by the Nobelists. They gave a great lecture to a packed, standing room only, audience.
Sometime in 2011 or '12, I think, the Prescott campus organized a lecture by Steven Weinberg [Physics 1979], and they streamed it live to the Daytona campus. Unfortunately, there were only 3 of there to watch it - a disappointing turnout. Apparently, Weinberg was just recovering from an illness, so he didn't actually travel to Prescott, but gave the talk via video from his office at UT. For us in Daytona, it didn't matter, we weren't there in person. But he have a excellent explanation of why the Higgs is a necessary component of the electroweak theory - i.e., the standard model of particle physics - and how it fits into the puzzle, even though its discovery by the LHC hadn't yet been confirmed.
Now, I never met him, nor heard him speak, but John Bardeen [Physics 1956, Physics 1972] has to go on this list, since he's a member of the family! My wife is his first cousin, twice removed. That is, my wife's grandmother is a Bardeen, and she's a first cousin with John. Unfortunately, I never got a chance to meet him. But I have met several of the other incredibly smart Bardeens, including Chris Bardeen.
The reason for this list is that John Mather is coming to speak at ERAU-Daytona on February 20, 2015 at 7:00pm. So, even though I've heard him speak before, I will increase my "Nobel number" by 1.
The first was Richard Feynman [Physics 1965], back in 1981 or '82. I was a student at Santa Monica College, and a friend took me to a lecture at UCLA by Feynman. At this point, I hadn't taken any physics, or perhaps I was in my first semester, so I didn't understand a thing. From what I know now, he was talking about the two-slit experiment, but to me it was very confusing. The hall was jam packed, though, and I recall sitting on the steps in the aisle. I couldn't figure out what all the fuss was about. Of course, I know now. I also remember where I was when I found out he had died - I was in my TA office in the basement of Knudsen Hall, and I was discussing him with my fellow TAs in 1988.
The second and third were up in Santa Cruz. Hans Bethe [Physics 1967] came to the physics department to give a talk on SN 1987a, so I'm guessing it was in the spring of 1987. He was old, but definitely still very sharp. Around the same time, Linus Pauling [Chemistry 1954, Peace 1962] came to Santa Cruz to give a talk. I don't remember the topic, but I was very impressed at how he was able to switch gears. Apparently, he was scheduled to give a fairly high-level department colloquium, but so many people showed up that the venue had to change at the last minute. He correctly realized that most of the audience would not understand his planned talk - they had just come to see Linus Pauling - so he gave a more popular level talk, on the fly. That, to me, is someone who really knows his subject - and his audience - well.
As a young grad student at UCLA in about 1988, Carlo Rubbia [Physics 1984] came to the department (we had several faculty who worked at CERN) and one of the "events" that was organized was an informal talk between Rubbia and the grad students. It was mostly a question-and-answer session, and I recall that he was rather pompous. But I guess that's just his style, and people have speculated that someone with a less forceful personality would not have been able to get the experiment built that detected the weak intermediate vector bosons.
The next was in 1993. Russell Hulse and Taylor [Physics 1993] had just won the prize in October for the discovery of the binary pulsar from Arecibo in 1974. Hulse at that time was Taylor's grad student, but he had since switched to plasma physics. He happened to be going to the annual plasma physics meeting in November, so they quickly organized a special lecture for him. I don't recall any of the details, but he talked about the history of how he made the discovery.
The next was John Mather and George Smoot [Physics 2006], who gave talks at the April 2007 meeting of the APS (American Physical Society) in Jacksonville. They had just won the Nobel prize in 2006, and I went to that meeting with several students from ERAU. It was mostly to give them experience at a technical conference, but a happy bonus was the joint talk by the Nobelists. They gave a great lecture to a packed, standing room only, audience.
Sometime in 2011 or '12, I think, the Prescott campus organized a lecture by Steven Weinberg [Physics 1979], and they streamed it live to the Daytona campus. Unfortunately, there were only 3 of there to watch it - a disappointing turnout. Apparently, Weinberg was just recovering from an illness, so he didn't actually travel to Prescott, but gave the talk via video from his office at UT. For us in Daytona, it didn't matter, we weren't there in person. But he have a excellent explanation of why the Higgs is a necessary component of the electroweak theory - i.e., the standard model of particle physics - and how it fits into the puzzle, even though its discovery by the LHC hadn't yet been confirmed.
Now, I never met him, nor heard him speak, but John Bardeen [Physics 1956, Physics 1972] has to go on this list, since he's a member of the family! My wife is his first cousin, twice removed. That is, my wife's grandmother is a Bardeen, and she's a first cousin with John. Unfortunately, I never got a chance to meet him. But I have met several of the other incredibly smart Bardeens, including Chris Bardeen.
The reason for this list is that John Mather is coming to speak at ERAU-Daytona on February 20, 2015 at 7:00pm. So, even though I've heard him speak before, I will increase my "Nobel number" by 1.
Saturday, February 7, 2015
New Schedule - Greifswald
Regular readers have noticed that this blog has been a mix of German travelogue and (plasma) physics. Also, that - at least during 2015 - I have been posting pretty regularly. In fact, for the last three weeks I've posted something every day. But this is fairly taxing, and as I return to the US, I'm going to post less, and more of the posts will be physics related. Hopefully, they will still be of general interest, because I find them interesting.
I do still have many photos from my travels to post, so those will continue (until I run out), and I plan to post only on MWF. If I feel like it, there will be some weekend posts (like this one) but I'm going to get back to the serious work of my sabbatical (exercising, thinking deeply, and research projects).
Here's one more travelogue/physics post to start off the new schedule.
Gas Metal Arc Welding
The reason I went to Berlin in January (see here, here, here and here) was to visit the Leibniz-Institute für Plasmaforschung und Technologie e.V. (INP), which is a two-hour train ride north of Berlin. One of the professors here at Hochschule München works on gas metal arc welding, among other things, and specifically investigating the parameters of the plasma arc using optical emission spectroscopy.
He was interested in getting a plasma physicist involved in this work, so after several discussions he arranged for me to spend a couple of days visiting INP and learning about the experimental and theoretical techniques that they use. My visit was extremely productive - I learned a lot - and while I was there we outlined a good project for our first collaboration. Hopefully when I get back to the US I will have some time to work on this. I'll be doing something similar to what they already do, where one of their techniques is to invert images like the one above and obtain information about the physical processes (e.g., temperature, density) as a function of position within the arc. This is a kind of "remote sensing" that reveals more information about what's going on in the arc than what you can obtain from just looking. Here, for example, is a result of one of the inversions.
Greifswald
Greifswald is a beautiful small university town. In fact, it has one of the oldest universities in the world. Interestingly, it's the oldest Swedish university. This is because it is located in Pomerania, which used to be a part of Sweden. I got a chance to walk around the city a bit, and one of the physicists took me to a very old church, that we were able to climb to the top and get a good view of the city. I was very taken with this church and here are some photos.
I do still have many photos from my travels to post, so those will continue (until I run out), and I plan to post only on MWF. If I feel like it, there will be some weekend posts (like this one) but I'm going to get back to the serious work of my sabbatical (exercising, thinking deeply, and research projects).
Here's one more travelogue/physics post to start off the new schedule.
Gas Metal Arc Welding
The reason I went to Berlin in January (see here, here, here and here) was to visit the Leibniz-Institute für Plasmaforschung und Technologie e.V. (INP), which is a two-hour train ride north of Berlin. One of the professors here at Hochschule München works on gas metal arc welding, among other things, and specifically investigating the parameters of the plasma arc using optical emission spectroscopy.
High resolution visible light photo of the plasma arc, taken at 1.2 ms after the current was turned on. Here, CO2 is the welding gas, and the emissions you see are from both iron (from the steel welding element) and carbon dioxide.
He was interested in getting a plasma physicist involved in this work, so after several discussions he arranged for me to spend a couple of days visiting INP and learning about the experimental and theoretical techniques that they use. My visit was extremely productive - I learned a lot - and while I was there we outlined a good project for our first collaboration. Hopefully when I get back to the US I will have some time to work on this. I'll be doing something similar to what they already do, where one of their techniques is to invert images like the one above and obtain information about the physical processes (e.g., temperature, density) as a function of position within the arc. This is a kind of "remote sensing" that reveals more information about what's going on in the arc than what you can obtain from just looking. Here, for example, is a result of one of the inversions.
Emission coefficient profiles - as functions of radial position (i.e., assuming cylindrical symmetry) - at different times and for different welding gases. Some are argon, and some are CO2.
Greifswald
Greifswald is a beautiful small university town. In fact, it has one of the oldest universities in the world. Interestingly, it's the oldest Swedish university. This is because it is located in Pomerania, which used to be a part of Sweden. I got a chance to walk around the city a bit, and one of the physicists took me to a very old church, that we were able to climb to the top and get a good view of the city. I was very taken with this church and here are some photos.
Climbing to the top of Dom St Nikolai in Greifswald.
Panoramic view of Greifswald from the top of Dom St Nikolai. If you squint, you can see the Baltic Sea in the far distance.
In this particular church, which is about 700 years old, there are people (saints, presumably) buried under the floor. I knew this was common, but this was the first time that I had seen this in Germany. There were many of these engravings on the stone floor.
The church, like most churches, had a beautiful organ. I only heard two organs playing, one in St Hedwig in Berlin, and the other at the Frauenkirche in München when we went to Christmas Eve mass.
Finally, a beautiful stained glass window. Of all the many churches that I've been to in Germany, this was one of the few that had a nice stained glass window. And this is a huge window, probably 3-4 meters tall. The photo doesn't do it justice, as usual.
Friday, February 6, 2015
3C 273
The "quasi-stellar radio source" 3C 273 and its jet. It is the 273rd object in the Third Cambridge Catalog of Radio Sources.
Fifty-two years ago yesterday, February 5, 1963, Maarten Schmidt figured out a key property of quasars, namely that it was receding from the Earth at 47,400 km/s. Assuming that this recession velocity was due to the expansion of the universe (and not that it was an object within our own Milky Way galaxy that was just moving really fast), and assuming that the Hubble constant was about 95 km/s/Mpc (today, the best value from WMAP is 71.0 ± 2.5 km/s/Mpc ), he estimated the distance to the quasar to be 500 Mpc (a parsec is the distance of an object that has a parallax of one arc second, which is about 30 million million km, or in scientific notation 3 × 1016 m), or 1.5 × 1025 m, or 15 trillion trillion meters. At the time, it was the furthest known object in the universe.
How did he do it? By realizing that the spectral lines observed in the spectrum of this star were redshifted by such an amount that no one had recognized that they were actually the spectral lines of hydrogen. In 1868, Anders Ångström had measured the wavelengths of the hydrogen lines in the visible portion of the spectrum to have the following values.
(It's amazing how accurate he was!) From Schmidt's published paper (which you can read here), he showed that there were not only the three lines in the 4000-5000 Ångström range, but also a magnesium line and a mercury line. But dividing the observed wavelengths (first column, l) by a factor 1.158 (second column, l/1.158) Schmidt obtains the well-known wavelength values (third column, l0). Comparing this third column with Ångström's original measurements above, you can see that they match.
What does the factor 1.158 signify? This is a Doppler redshift that translates into a recessional velocity of 47,400 km/s.
What are quasars? They are now thought to be bright young galaxies, powered by massive black holes at their centers. You can read more about this here.
Update: A detailed history of this historic discover can now be found here. It's interesting to note that the authors were aided by the fact that in 1963 most scientific communication was by letter, and thus has been preserved. It will be interesting for future historians to deal with the almost ubiquitous email communication, and the fact that it is unclear how 'archival' these will turn out to be.
Update: A symposium in honor of Fifty Years of Quasars was held at CalTech. Most of the talks can be watched online here. The talk by Maarten Schmidt is especially interesting - a first hand recollection.
What does the factor 1.158 signify? This is a Doppler redshift that translates into a recessional velocity of 47,400 km/s.
What are quasars? They are now thought to be bright young galaxies, powered by massive black holes at their centers. You can read more about this here.
Update: A detailed history of this historic discover can now be found here. It's interesting to note that the authors were aided by the fact that in 1963 most scientific communication was by letter, and thus has been preserved. It will be interesting for future historians to deal with the almost ubiquitous email communication, and the fact that it is unclear how 'archival' these will turn out to be.
Update: A symposium in honor of Fifty Years of Quasars was held at CalTech. Most of the talks can be watched online here. The talk by Maarten Schmidt is especially interesting - a first hand recollection.
Thursday, February 5, 2015
NOAA weather satellites
Image of Europe as observed by the NOAA-18 weather satellite on January 9, 2015, at 4:51 pm. The red cross denotes the location of Munich.
One of the courses I have just finished teaching is a "project" course in which the engineering students have to do some kind of project, working in a team environment - like they will do when they graduate and get out into industry - give presentations on their progress, and write a final report. Since I'm teaching it, they must speak and write in English - at least when they're interacting with me. This is essential because even in Germany, many of the aerospace companies have their important documentation in English. Of course, the engineers communicate with each other in German, but when they interact with international companies, both spoken and written, they use English.
In this particular course, the students had to solve three tasks: 1) learn enough orbital mechanics to write a computer program that would predict when a particular Earth-orbiting satellite (in this case a NOAA weather satellite) was overhead, 2) build an antenna to receive the (open) signal that the satellite was transmitting, and 3) send that signal to their computer and display the image. Above you see one of the images that one of the teams was able to record.
And below you see the antenna of one of the groups. In their case, they decided to build a "quadrifilar helix" antenna, which consists of four wires, each wrapped in a helical shape. The total length of the antenna is about 1 m, which is one-half of the wavelength of the 137 MHz signal that the NOAA satellites transmit. This is the antenna that received the image above.
A quadrifilar helix antenna on the roof of the R building at Hochschule München.
In order to check that their code for predicting the satellite "pass" was correct, they checked it against the website Heavens Above, which has pass predictions for not only NOAA satellites, but also the ISS, Hubble, and in fact any orbiting object that is tracked. If you're interested in seeing the International Space Station, or Hubble, or Tiangong 1 (China's low Earth orbiter), I recommend that you enter your location in Heavens Above, and go outside the next dusk or dawn, and look up!
Wednesday, February 4, 2015
FC Bayern München basketball
In addition to the well known soccer (football) team "FC Bayern", which plays in the German Bundesliga League, the club also has a professional basketball team also known as FC Bayern, and they also play in the basketball Bundesliga.
We went to one of their games the other night, played against a team from Ljubljana, the capital of Slovenia. The game was played at München's home arena, the Audi Dome. It was the site of the basketball games in the 1972 Olympics, although it has undergone some renovations since then. It holds about 6000 fans, and it was about 2/3 full. But those 4000 made a lot of noise! They definitely back their home team.
The European soccer (fußball) has an interesting structure. First of all, each country has it's own league, or leagues. In Germany, there are three leagues, each at a different level, and each league has about 20 teams. If you do poorly one year - i.e., you finish in the bottom 2 or 3 - you are "relegated" to the next lower league in the following year. On the other hand, if you finish in the top 1-2 of the second league, you can get promoted to the top league for the following year's season. The rules of promotion and relegation are very complicated, and it has as much to do with ability as politics (the top teams wish to remain in the top league).
In addition to league play, though, there is something called "Champion's League." This takes the top teams from all the leagues in Europe (from England to Spain to Russia to Turkey) and they compete in a competition similar in structure to the World Cup. That is, the top 32 teams are placed into 8 Groups of 4 teams; these 4 teams play a double-round-robin competition (with one home and one away game against each of the other teams), and then the top 2 teams from each Group go on to the single-elimination part of the competition, when finally the 'champion' is crowned.
Interestingly, Champion's League games and Bundesliga games take place essentially simultaneously. On Wednesday, FC Bayern might play a Champion's League game against Rome, and then Saturday play a Bundesliga game against Frankfurt.
European basketball teams have something similar. There is a Bundesliga, and something called EuroCup, which has a structure like Champion's League in soccer. FC Bayern is in a group of 4 teams with Ljubljana, and they are doing well. They won the game that we attended - although it was close at the end, and they have won 4/6 of their Group games so far. So they are on track to finishing first in their group, which means that they will have a good seeding in the single-elimination Round of 16.
Panorama of the Audi Dome, from about row 10, just behind the VIP seats. We had to sit there because we were not VIPs, but we were NVIPs.
In addition to league play, though, there is something called "Champion's League." This takes the top teams from all the leagues in Europe (from England to Spain to Russia to Turkey) and they compete in a competition similar in structure to the World Cup. That is, the top 32 teams are placed into 8 Groups of 4 teams; these 4 teams play a double-round-robin competition (with one home and one away game against each of the other teams), and then the top 2 teams from each Group go on to the single-elimination part of the competition, when finally the 'champion' is crowned.
Interestingly, Champion's League games and Bundesliga games take place essentially simultaneously. On Wednesday, FC Bayern might play a Champion's League game against Rome, and then Saturday play a Bundesliga game against Frankfurt.
European basketball teams have something similar. There is a Bundesliga, and something called EuroCup, which has a structure like Champion's League in soccer. FC Bayern is in a group of 4 teams with Ljubljana, and they are doing well. They won the game that we attended - although it was close at the end, and they have won 4/6 of their Group games so far. So they are on track to finishing first in their group, which means that they will have a good seeding in the single-elimination Round of 16.
Action! Bayern is in the dark uniforms, and Ljubljana is in White.
How was the quality of the game? In my opinion, it was about the same quality as a good college game in the US. They don't have NBA-quality players (otherwise they would be playing in the NBA and making a lot more money), but they have good players. In fact, the offense on both teams was pretty good - excellent 3-point shooting, for example, but the defense, especially in the first half, left a lot to be desired. And you could argue that it's easy to have good offense when you're not being defended well, which is true.
Bayern had two American players, one who graduated from U Oregon in 2008 and had been playing in Europe since then, and one who graduated from Santa Clara U in 2009, and also has been on the European circuit. They were the best players on Bayern, but had a solid supporting cast. Ljubljana had no Americans. All in all, it was a fun game!
Bayern had two American players, one who graduated from U Oregon in 2008 and had been playing in Europe since then, and one who graduated from Santa Clara U in 2009, and also has been on the European circuit. They were the best players on Bayern, but had a solid supporting cast. Ljubljana had no Americans. All in all, it was a fun game!
Tuesday, February 3, 2015
Saint Antony
Sometimes this is how I think my students view me when I'm lecturing:
“On hearing the news that some Provinces of that Realm, the realm in question being France, had become infected by this disease, this heretical depravity, as explained several lines above, António de Lemonges left for Toulouse, a city as rich in trade as in vices, and worst of all, a pestilent hotbed of the Sacramental Heretics who deny the real presence of Christ in the Consecrated Host. The Saint was no sooner placed in this den of apostasy than he began to descend into the area of conflicts, only so that he might ascend in the chariot of triumphs. Fired with the burning zeal of God’s glory and the infallible truths of his faith, he hoisted the flags of doctrine on the banners of charity, on the shields of penance the arms of the Cross, and transformed into the Evangelical Trumpet of the Divine Word, he raised voices to eradicate vices. His implacable hatred for the Heretics was matched only by his untiring activity driven by zeal. Everything was sacrificed on the altars of Faith, victims of his cruelty, like someone who with so many truths had exposed life for death his affections for martyrdom. Those Birds of ill omen who, living in the dark night of their errors, only surrender their obstinate pride to the weapons of light, took care to concoct secret poisons against his life, diabolical wiles against his honour, infernal machinations against his reputation, seeking, as far the powers of their malice would permit, to discredit and obscure the lights of so much doctrine, the triumphs of so much Sanctity. St Antony began to preach to the applause and admiration of all Catholics, and all the more so because, recognising that he was a Foreigner, they heard him speak in their own language with such eloquence and ease that he appeared to have become naturalised in an idiom which, like him, had taken root in people’s affections. The news soon spread of the wonderful effect his words were having on Souls, and the Preaching Heretics, once they saw the damage being done to their reputation by this new preacher who was attracting many converts, with that arrogance and presumption so characteristic of this rabble, decided to engage in a mercurial debate with Antony, relying on their specious fallacies to achieve a resounding victory. To achieve their objective, they enlisted the services of a distinguished Dogmatist from Toulouse, the most capable and respected of scholars, named Guialdo, fearless, presumptuous and overbearing, deeply versed in Holy Scripture and with an excellent command of Hebrew, a sharp wit and fiery temperament, and well-prepared for the most testing debates. The Saint did not reject the letter of challenge in order to satisfy the duel of Faith, putting all his trust in God as the only agent of his cause. He fixed the day and the place for the contest. A huge crowd gathered of both Catholics and Sectarians. The Heretic spoke before Antony, for Malice has always prevailed on the world stage, ranting on with vain ostentation about his ill-used learning, and introducing torrents of verbiage with all the loquaciousness of captious syllogisms. The Saint listened patiently to his flood of words, full of artifice, devoid of truth, and then proceeded to refute his depraved errors, with so many quotations from Holy Scripture, enhanced by such clear reasoning, by such convincing arguments and pertinent words that the Heretic’s obstinacy was soon overcome, as much for the worn-out discourses of reason, if he had not held out firmly, as for the diabolical caprices of the will. I shall not go into detail about the subtle arguments with which Antony ennobled this battle of wits, because superior to the narrative, they succumb to the silence of history like the mysteries of fame, suffice it to say that he spoke so wisely that he surpassed himself, his success all the more glorious as it had appeared to be impossible. The perverse Dogmatist found himself humiliated and confounded on seeing himself defeated in the presence of those very same followers who with so much pride had hoped to see his deceptions prevail.”
from “The History of the Siege of Lisbon” by José Saramago, translated by Giovanni Pontiero, pages 240-242.
from “The History of the Siege of Lisbon” by José Saramago, translated by Giovanni Pontiero, pages 240-242.
Monday, February 2, 2015
Charles Townes 1915-2015
One of the neatest astronomical discoveries was the discovery of ammonia molecules at the center of the Milky Way. In 1968, Charles Townes and his colleagues detected the microwave emission at a wavelength of 1.25 cm, and showed that it was due to a cloud of ammonia at 23 K near the galactic center.
Townes won the Nobel Prize in Physics, 1964,
The name "optical maser" never caught on, and it's probably a good thing. Can you imagine? "His optical maser-like focus was on the bottom line."
Charles Townes recently died on 27.Jan.2015, and there is a short obituary here, and a longer one here.
For more than you ever wanted to know about interstellar ammonia, read this review article by Ho and Townes.
Stereo-model of tetrahedral ammonia.
Townes won the Nobel Prize in Physics, 1964,
"for fundamental work in the field of quantum electronics, which has led to the construction of oscillators and amplifiers based on the maser-laser principle."In fact, he had worked on ammonia masers in the laboratory in the 1950s, and proposed the laser in a 1958 paper titled "Infrared and optical masers" with Arthur Schawlow. And it was the very next year, in 1959, that Theodore Maiman built the first laser. Here is a nice article on the history of the laser.
The name "optical maser" never caught on, and it's probably a good thing. Can you imagine? "His optical maser-like focus was on the bottom line."
For more than you ever wanted to know about interstellar ammonia, read this review article by Ho and Townes.
Sunday, February 1, 2015
Erdapfel
Yesterday I went back to Nürnberg to see Behaim's globe, the "Erdapfel." This was the first map of the world, formed into a spherical shape, and was created in 1491, before Columbus's voyage. They also had a few other early globes, one from about 1520 that had a strangely shaped North America just floating in the middle of the ocean.
Unfortunately, photography was not allowed, so I grabbed this image from the web. And this was better than the photo I could have taken anyway, since the lighting on the actual globe was rather poor. Perhaps that was to protect the 500-year-old globe, or perhaps it was because they had moved the glove from its permanent position to a special exhibition. In any case, it was rather hard to see, but you can see a digitized version here.
The last time we were in Nürnberg, before Christmas for the Kriskindlemarkt, I did take a picture of Martin Behaim's statue, which was in Theresienplatz.
The other place I went to was back to the Nürnberg castle. I really enjoyed walking around the grounds. It really feels like you are in a medieval castle. It's built on a hill on on edge of the old city center, surrounded by walls and moats. There was lots of information about the geology of the region, and the rock outcropping upon which the castle was built, but it was all in German... :(
Martin Behaim's Erdapfel.
Unfortunately, photography was not allowed, so I grabbed this image from the web. And this was better than the photo I could have taken anyway, since the lighting on the actual globe was rather poor. Perhaps that was to protect the 500-year-old globe, or perhaps it was because they had moved the glove from its permanent position to a special exhibition. In any case, it was rather hard to see, but you can see a digitized version here.
The last time we were in Nürnberg, before Christmas for the Kriskindlemarkt, I did take a picture of Martin Behaim's statue, which was in Theresienplatz.
Statue of Martin Behaim, creator of the Erdapfel, the earliest globe of the Earth, in Nürnberg's Theresienplatz.
The other place I went to was back to the Nürnberg castle. I really enjoyed walking around the grounds. It really feels like you are in a medieval castle. It's built on a hill on on edge of the old city center, surrounded by walls and moats. There was lots of information about the geology of the region, and the rock outcropping upon which the castle was built, but it was all in German... :(
The front of the Nürnberg castle, as viewed from the approach up the hill from the city center. You can see the natural rock outcropping that was used for defence, and how much higher the castle wall goes. It would have been tough to attack it from this side.
The rear of the Nürnberg castle, wide angle, taken from the Vestnertorbrücke, the bridge leading from the Vestnertor (the Vestner gate), which can be seen at the end of the bridge. On the left you can also see the moat, which is no longer filled with water.
Saturday, January 31, 2015
Saint Hedwig
Of course, when I saw this church's name on the map, I had to visit. It actually has an interesting history, as it is the main cathedral for the Catholic diocese that includes Berlin (I guess the correct term is the seat of the archbishop of Berlin). It was also a good thing, because it turned out that there was a free organ concert that evening, my last evening in Berlin.
I was excited, because the poster for the concert said that some of Arvo Pärt's music would be played. I was introduced to Pärt when I went to a concert at Stetson University about a year ago. It was a duet with piano and tuba - being an old tuba player myself, I had to go. One of the pieces they played was Pärt's "Spiegel im Spiegel." Normally it is piano/violin, but these guys reworked it for piano/tuba. It was excellent. I've since heard it (in a recording) with the standard violin.
The organ player in St Hedwig played "Annum per Annum," by Pärt. I had not heard it before, but I recognized it immediately by the style. I recommend listening to both of these pieces, or anything by Arvo Pärt. It's well worth the time!
Side view of St Hedwig's, showing the domes.
Front entrance of St Hedwig's. There was much construction, as can be seen, in the platz surrounding the cathedral, as is true of much of Berlin.
Organ in St Hedwig's.
I was excited, because the poster for the concert said that some of Arvo Pärt's music would be played. I was introduced to Pärt when I went to a concert at Stetson University about a year ago. It was a duet with piano and tuba - being an old tuba player myself, I had to go. One of the pieces they played was Pärt's "Spiegel im Spiegel." Normally it is piano/violin, but these guys reworked it for piano/tuba. It was excellent. I've since heard it (in a recording) with the standard violin.
The organ player in St Hedwig played "Annum per Annum," by Pärt. I had not heard it before, but I recognized it immediately by the style. I recommend listening to both of these pieces, or anything by Arvo Pärt. It's well worth the time!
Friday, January 30, 2015
Axe of Ahneby
DESY, the Deutsches Elektronen-Synchrotron, is a national accelerator research center in Germany. I was reading a recent issue of their magazine, femto, since there were articles about supersymmetry and grand unified theories. However, those articles were really pretty boring (there's nothing much that you can say about theoretical research programs that have not accomplished anything), and my eye caught a short article near the back about the Axe of Ahneby.
Ahneby is a town in the German state of Schleswig-Holstein in the north, tucked between the Elbe river (and Hamburg) and Denmark. Several Bronze Age axes were found near this town in the 19th century, and recently, using the X-rays from one of their accelerators, DESY scientists showed that one of these axes was a fake! One of the real axes is the 4000-year-old Axe of Ahneby.
Axe of Ahneby
One of DESY's first papers, here, shows the different diffraction patterns resulting from the real axe and from a reproduction. And here is another short paper, explaining the differences.
Finally, here is a news story about the incident.
Thursday, January 29, 2015
Recently on the arXiv
Some interesting papers were posted recently on the arXiv:
- Helge Kragh, a historian of physics, has a nice writeup on Robert Dicke's work on geophysics and the possibility that G might be a function of time. Dicke was a giant in the resurgence of general relativity in the 1950s and 1960s; he almost discovered the cosmic microwave background radiation; and he wrote one of my favorite textbooks: Introduction to Quantum Mechanics, by Dicke and Wittke. Even though this book was written in 1960 it has never gone to a new edition (!) because it's so perfect and concise. If you ever find a copy in a used book store, buy it.
- Kirillov and Levi describe the situation of a particle confined to a saddle - stable in one direction, unstable in the other - and show that by rotation the saddle point can be made stable.
- Several papers on Bell's theorem , quantum nonlocality, and Bell's view of nonlocality. This is always a confusing subject, and whenever I read about it I learn more, but also come up with more questions.
- Alister Graham reviews the history of black holes and how we came to believe that many galaxies (including the Milky Way) have supermassive black holes at their centers. One of the neat pieces of evidence - at least for our galaxy - is an analysis of the stars orbiting this central object. And one of the astronomers working on this problem is UCLA professor Andrea Ghez. Her website shows some cool movies.
Wednesday, January 28, 2015
Honorary Fellow
I am now, officially, an Honorary Fellow of the Munich University of Applied Sciences. And I'm a "Prof. Dr." Look out world!
This morning, the other visiting professor and I had a meeting with the Präsident of the University. He wanted our input on our visit, to see how the visiting fellow program could be improved in the future. It was a good meeting. Hopefully, there will be many more visiting professors, and some even visiting from Hochschule München to other places, like ERAU. I and my faculty mentor - and landlord - Karl, were there. Also, the other professor, Jack, and his mentor, Klemens, was there. Also there was the person from Int'l Programs, Nicole, who has helped us out with so many things - visas, housing, etc.
Then the group of us got our picture taken.
This morning, the other visiting professor and I had a meeting with the Präsident of the University. He wanted our input on our visit, to see how the visiting fellow program could be improved in the future. It was a good meeting. Hopefully, there will be many more visiting professors, and some even visiting from Hochschule München to other places, like ERAU. I and my faculty mentor - and landlord - Karl, were there. Also, the other professor, Jack, and his mentor, Klemens, was there. Also there was the person from Int'l Programs, Nicole, who has helped us out with so many things - visas, housing, etc.
Then the group of us got our picture taken.
From left: mentor Karl Siebold, yours truly, President Michael Kortstock, Fellow "Jack" Lin, mentor Klemens Rother, International Programs representative Nicole Kewitz.
Tuesday, January 27, 2015
Berlin (3)
There are many churches with domes in Berlin. Along with the Reichstag Dome, which of course is not a church, there is the Berliner Dom, Deutscher Dom, and Französischer Dom, among others. Just like Alter Peter, I climbed the Französischer Dom, and got a great view of Berlin. This was the same day that I visited the Reichstag, but the pictures through that dome did not turn out as well as those that were unimpeded.
While the sky was beautiful, the city is not as pretty as Munich. My airbnb apartment was on Alexanderstrasse, just a couple of blocks from Alexanderplatz. The area was mostly block apartment buildings, which gave the area a definite (presumably authentic) cold-war feeling. It is still worthwhile to visit, though, because of all the history that it's been through. It just doesn't feel like a small town, the way Munich does.
Looking east toward Alexanderplatz from the Französicher Dom. The gold-ball topped tower is the radio tower of the city and is in Alexanderplatz, the center of East Berlin. The large, low green dome in the foreground is Saint Hedwig (see next post). Note all the cranes. There was quite a bit of construction going on, which contributed to the industrial feeling.
While the sky was beautiful, the city is not as pretty as Munich. My airbnb apartment was on Alexanderstrasse, just a couple of blocks from Alexanderplatz. The area was mostly block apartment buildings, which gave the area a definite (presumably authentic) cold-war feeling. It is still worthwhile to visit, though, because of all the history that it's been through. It just doesn't feel like a small town, the way Munich does.
Bells inside Französischer Dom. Luckily, they did not ring while I was nearby. However, as I was descending the tower, they did ring. And it was quite loud. I'm glad I was not right next to them. Interestingly, there is an organ consolse visible inside the glass, and you can see the stairs to access the organ on the left. I assume that the organ player wears earplugs, especially if they also ring the bells!
Outside view of the Französischer Dom.
Monday, January 26, 2015
California Dreamin'
Caitlin and I took Kathy, Megan, and Sarah to the Flughafen early in the morning of 30.Dez to catch their 09.30 flight back to the US. It takes about 1 hour to get from Pullach to the airport by S-bahn, and because it was an international flight they had to be there early. In addition, it was cold and snowy, so the plane had to get in line for de-icing, which also takes time.
So we left Pullach at about 06.00, and Caitlin and I decided to have breakfast at the airport. We found a place that served bagels and coffee - one of the first that I had found in Munich (I have since found more), but the entire theme was California surfing. So much so that even one of the tables was inside an old VW van!
Volkswagen van at a restaurant in the Munich airport.
Table inside the Volkswagen van at a restaurant in the Munich airport. Unfortunately we didn't notice that this was a table until after we finished eating, so we didn't get to sit there. But it was a cool idea.
After the airport, we decided to stay in town and do some museum hopping. Specifically, we went to the Munich Residenz, the city palace of the Bavarian royalty. More about that in a future post (although the number of "future posts" that I'm promising seems to be increasing more rapidly than I can write posts, so perhaps it will never happen.)
Sunday, January 25, 2015
Jim Stewart (1941-2014)
The Integral House. Private residence of Jim Stewart, mathematician, textbook author.
My calculus book, handed down to me by my sister way back in 1980, was written by Earl Swokowski. I always liked that book - in fact, I still have it - and I go back and read sections of it from time to time when I need to brush up on a theorem or two. I have never been too critical about whether it was presenting proofs correctly or not. As a physicist, I usually want the answer; I'll leave the rigor to the mathematicians.
Jim Stewart also has written a calculus book, in recent years one of the best selling calculus books in the country. Now, if you write a calculus textbook, or a physics book, or chemistry, or biology, and many schools adopt that book and hundreds of thousands of undergraduates have to buy that book, well you're going to make a lot of money. Very few textbooks reach that level, however, although there are usually one or two in each field that become bestsellers. Sometimes that's because they are also classics (in the field of introductory physics, the "classics" are Sears & Zemansky, starting with their first edition right after WWII continuing to their 13th edition today, and which took a hands-on, practical approach, and Halliday & Resnick, developed in the early 1960s, and which was decidedly more theoretical). But also it could just be that it keeps enough of everyone's favorite topic so that university textbook selection committees find it's the only one they can agree on. I don't know if this happened with Stewart's calculus book, but it has been the case (or so I suspect) with certain physics textbooks.
After making millions with his textbooks, Stewart decided to commission his home, called "Integral House," because of... who knows, his love for math? People have debated the excellence of his calculus books - see the reviews on the amazon.com page for Spivak's calculus book for a taste - but sometimes a book doesn't have to be excellent to be good.
Saturday, January 24, 2015
Water
I always drink water when I am at a restaurant. In fact, I always drink water. Even if I'm drinking something else with my meal, say, a beer, I will usually drink water in addition. In US restaurants, it is customary to brink complimentary water to the table, and refill it continuously. In Germany - probably in Europe - people don't drink water in the same way. In fact, there are no drinking fountains - zip, zilch, nada. Even at the university, Hochschule München, there are no drinking fountains. So I have learned to bring my 1-liter Nalgene bottle with me every day (filled, of course) so that I have something to drink.
In restaurants, also, they do not bring water. In fact, if you ask for water, what you are really doing is ordering a bottle of "mineral wasser." And you'll have to pay for it. And it's expensive. I knew this, but on a recent trip to a restaurant, I forgot. The first thing the waiter does is ask for your drink order (similar to the US), and when we ordered "DunklesWeissbier" (dark wheat beer) he must have asked if we wanted water. I reverted to my old, US, ways, and said yes. Of course, he brought a 750 ml bottle of Acqua Panna, which turned out to cost 5,80 EUR, more than one of the 500 ml beers, which only cost 3,60 EUR.
My advice: bring your own water when you go to a restaurant.
Postscript. You'll notice that there is tax - it's called VAT, value-added tax - and it's 19%, which is a lot, but the tax is included in the price of the items. It's not added on at the end. This makes it very easy to calculate your bill.
In restaurants, also, they do not bring water. In fact, if you ask for water, what you are really doing is ordering a bottle of "mineral wasser." And you'll have to pay for it. And it's expensive. I knew this, but on a recent trip to a restaurant, I forgot. The first thing the waiter does is ask for your drink order (similar to the US), and when we ordered "DunklesWeissbier" (dark wheat beer) he must have asked if we wanted water. I reverted to my old, US, ways, and said yes. Of course, he brought a 750 ml bottle of Acqua Panna, which turned out to cost 5,80 EUR, more than one of the 500 ml beers, which only cost 3,60 EUR.
My advice: bring your own water when you go to a restaurant.
Bill including pizza, bier, and wasser.
Postscript. You'll notice that there is tax - it's called VAT, value-added tax - and it's 19%, which is a lot, but the tax is included in the price of the items. It's not added on at the end. This makes it very easy to calculate your bill.
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