Question of the Week

Jul 172018
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We are all familiar with the appearance of a candle flame. Warm, bright yellow, and formed like a teardrop it nestles up the wick just to reach far out into the empty above it. This behavior can be easily explained by the rise – the convection – of the less dense air that is heated by the combustion around the wick. While colder, more dense air floats inward, the buoyancy of the warm air lets it move upward and away from the combustion zone. However, this process requires buoyancy, which only exists in an environment with gravity. But what would then happen to a flame in zero gravity?

In so-called microgravity, that is an environment with very little gravity like it is present in the Earth’s orbit, there is no convection since there is no definition of a classical “up and down”. The flame therefore looks significantly different and forms a light blue, spherical shape instead of the familiar teardrops. To understand this behavior, one has to consider the chemistry of the combustion as well as the physics of the gas exchange.

In case of the “normal” candle flame, the bright yellow color stems from soot particles that originate in the (non-perfect) combustion. They rise with the hot air and glow yellow in the upper region on the flame. The lower blue-ish region on the other hand is fed by the stream of fresh oxygen-rich air from below. In case of the flame in microgravity, there is no preference for up and down and therefore it assumes a spherical shape. Due to the lack of conversion, the combustion is fed only by (slow) diffusion of the oxygen into and the fuel out of the central combustion zone. This means that the zero-gravity flame burns much slower and does not produce equally distributed soot particles. Thus it is blue, spherical, and produces much more CO and formaldehyde than CO2, soot, and water.

This behavior, and how to extinguish a flame in microgravity, is under investigation aboard on the International Space Station (ISS) in the so-called FLame Extinguishment Experiment (FLEX). It is carried out on small heptane bubbles that are ignited in a controlled atmosphere. The experiment found that such small flame bubbles are not just exotic to look at, but also can pose a threat to space exploration since they can be much more difficult to extinguish. In this way, research on small bubbly flames can thus help making space exploration a bit safer.

A candle on Earth (left) and in microgravity (right): The different combustion patterns are clearly visible. [3, NASA]

— Kai Litzius




May 292018
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Sonoluminescence is a fascinating, mysterious physical phenomenon, that combines the principles of light and sound.

In the year 1934 H. Frenzel and H. Schultes discovered a luminous effect by ultrasonication of water.[1] The defining moment that leads to sonoluminescence is the emergence of a cavitation in the liquid (figure 1). The high frequency ultrasound leads to the formation of bubbles, that are filled with gas and expand and collapse rapidly like a shock wave. Shortly after the collapse, the energy is released in form of sound and a short lightning, which is barely observable with the bare eye and reaches temperatures up to 10,000 K.[2,3]

Figure 1. Schematic illustration of the formation of sonoluminescence (f.l.t.r.): Growth of a gas bubble in a liquid, collapse or implosion of the bubble and emission of light.[4]

In the 1990s, the causes and impacts that lead to sonoluminescence have been intensively investigated but the real cause of this phenomenon remains unresolved even nearly 85 years after its discovery.[5,6] There are different quantum mechanical approaches, but they are highly controversial.[7,8]

Sonoluminescence is not only a physical phenomenon, it does indeed show capability for an academic application, at least in chemistry: in 1991 Grinstaff et al. were able to generate nearly pure amorphous iron by ultrasonication of an iron pentacarbonyl solution in decane. Compared to crystalline iron this compound shows enhanced catalytic activity when used in the Fischer-Tropsch process.[3]

Sonoluminescence also occurs in wildlife: by snapping their claws, pistol shrimp create a sharp stream of water that does not only kill prey but generates a cavitation bubble and thus a short lightning. Scientists call this special phenomenon “shrimpoluminescence”.[9]


— Tatjana Daenzer



[1] H. Frenzel, H. Schultes, Z. Phys. Chem. 1934, 27, 421–424.
[2] B. P. Barber, S. J. Putterman, Nature, 1991, 352, 318–320.
[3] K. Suslick, S.-B. Choe, A. A. Cichowias, M. Grinstaff, Nature, 1991, 353, 414–416.
[4] „Creative Commons“ from Dake CC BY-SA 3.0. ( last access: 15.05.2018.
[5] B. P. Barber, C.-C. Wu, R. L?fstedt, P. H. Roberts, S. J. Puttermann, Phys. Rev. Lett. 1994, 72, 1380–1383.
[6] R. Hiller, K. Weninger, S. J. Puttermann, Science, 1994, 266, 248–250.
[7] C. Eberlein, Phys, Rev. Lett. 1996, 76, 3842–3845.
[8] R. P. Taleyerkhan, C. D. West, J. S. Cho, R. T. Lahey Jr., R. I. Nigmatulin, R. C. Block, Science, 2002, 295, 1868–1873.
[9] D. Lohse, B Schmitz, M. Versluis, Nature, 2001, 413, 477–478.

Apr 012018
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“Dr.” Martin Luther plagiarized in his dissertation

LutherPlag checks

Theology professor Kim Lee-jung of Luther University in Giheung-gu, Yongin, South Korea, reports that he found the doctoral thesis of Martin Luther. The title: Iocorum Encomium (In Praise of Jokes). This discovery is in itself an epochal event. The sensation beyond that: up to 80 percent of the work is plagiarized.

Martin Luther’s is one of the best-researched lives in German history. So far it has been assumed that the reformer never submitted a dissertation, since he never mentioned such an endeavor in his writings, his letters or his diaries.

According to the trilingual press release of South Korean Luther University (see below), theology professor Kim has discovered and examined the dissertation of Martin Luther. The amazing thing is that Martin Luther apparently plagiarized massively in his dissertation. Whole passages are believed to come from a text by his humanist colleague, the Dutch theologian Erasmus of Rotterdam, says Kim.

On his spectacular find and on the content of Luther’s dissertation professor Kim will publish an article in the American Journal of Protestant Theology. In his article he will also address the question: How could such an upright man as Martin Luther do such a thing?

The Korean professor of theology has noticed that countless monuments in Germany refer to the reformer as “Dr. Martin Luther”, whereas in America the academic title is completely absent in his naming. As a reason for this, Kim suspects a cultural preference that arose in Germany during Luther’s lifetime.

“A doctor’s degree seems to be very important to Germans,” he supposes. Even Martin Luther, perhaps the most German of all Germans, may not have resisted this temptation. His example was later followed, among others, by Doktor Faustus, Doktor Allwissend, Dr. h. c. Erich Honecker, Dr. Karl-Theodor zu Guttenberg.

The news has attracted a lot of attention worldwide. Internet activists have set up LutherPlag and run the text through the plagiarism software. Already, it has been said, up to 80 percent of the text consists of plagiarism.

Meanwhile, at Martin Luther University in Halle-Wittenberg, there are unofficial debates going on whether or not to strip Luther of his academic title. This university is the successor of the University of Wittenberg, where Luther submitted his doctoral thesis on 19 October 1512. What would the divestiture mean? Should the title at the dozens of Luther statues in Germany be removed and all the publications on “Dr. Martin Luther” have an erratum attached?


Professor Kim Lee-jung had no idea what consequences his discovery would have. In a telephone conversation with JUnQ, he said: “It is about time, however, that thinking about Martin Luther enters into a postheroic and postmonumental, even into a postdoctoral phase. That’s what I stand for as a scientist, I can do no other.”

Dr. Antje Käßmann for Journal of Unsolved Questions

Mainz, April 1st; 2018



For further information please click here: website.


War der Reformator ein Plagiator?

Dr.” Martin Luther hat in seiner Dissertation abgeschrieben – LutherPlag prüft

Der Theologieprofessor Kim Lee-jung von der Luther University in Giheung-gu, Yongin, Südkorea, berichtet, er habe die Doktorarbeit Martin Luthers gefunden. Der Titel: Iocorum encomium (Lob der Scherze). Diese Entdeckung ist an sich ein Jahrhundertereignis. Die Sensation darüberhinaus: bis zu 80 Prozent der Arbeit sollen abgeschrieben sein.

Die Biographie Martin Luthers gehört zu den am besten recherchierten Leben in der deutschen Geschichte. Bisher ist man davon ausgegangen, der Reformator habe nie eine Dissertation vorgelegt, da er weder in seinen Schriften, noch in Briefen oder Tagebüchern ein solches Bemühen erwähnt habe.

Laut der dreisprachigen Pressemitteilung der südkoreanischen Luther University (siehe unten) hat der Theologieprofessor Kim Lee-jung die Dissertation Martin Luthers entdeckt und untersucht. Das Erstaunliche ist, dass Martin Luther in seiner Dissertation anscheinend massiv plagiiert habe. Ganze Textpassagen sollen aus einer Schrift seines humanistischen Kollegen, dem holländischen Theologen Erasmus von Rotterdam stammen, behauptet Kim.

Über den spektakulären Fund und über den Inhalt der Lutherschen Dissertation wird Professor Kim einen Aufsatz im American Journal of Protestant Theology publizieren. Darin wird er sich auch der Frage widmen: Wie konnte ein so geradrückiger Mensch wie Martin Luther so etwas tun?

Dem koreanischen Theologieprofessor ist aufgefallen, dass die unzähligen Denkmale in Deutschland den Reformator stets als „Dr. Martin Luther” ausweisen, wohingegen man in Amerika auf den akademischen Titel bei der Namensnennung komplett verzichtet. Kim vermutet als Grund eine kulturelle Vorliebe, die in Deutschland zu Luthers Lebzeiten aufkam.

„Die Doktorwürde scheint den Deutschen sehr wichtig zu sein”, schätzt er. Selbst Martin Luther als vielleicht Deutschester aller Deutschen habe wohl der Versuchung nicht widerstehen können. Seinem Beispiel folgten später u.a. Doktor Faustus, Doktor Allwissend, Dr. h. c. Erich Honecker, Dr. Karl-Theodor zu Guttenberg.

Die Nachricht hat weltweit große Aufmerksamkeit erregt. Internet-Aktivisten haben LutherPlag eingerichtet und jagen den Text durch die Plagiatssoftware. Schon jetzt wird von einem bis zu 80-prozentigen Plagiat gesprochen.

Inzwischen wird an der Martin-Luther-Universität zu Halle-Wittenberg inoffiziell diskutiert, ob man Luther den akademischen Grad aberkennen müsse. Diese Universität ist die Nachfolgerin der Universität Wittenberg, wo Luther am 19. Oktober 1512 seine Doktorarbeit eingereicht hat. Was würde die Aberkennung bedeuten? Müsste der Titel von den Dutzenden Lutherdenkmälern in Deutschland mechanisch getilgt werden und all den Publikationen über „Dr. Martin Luther” ein Erratum beigefügt werden?

Professor Kim habe nicht geahnt, welche Konsequenzen seine Entdeckung nach sich ziehen würde. In einem Telefonat mit JUnQ sagte er: „Es ist aber an der Zeit, dass der Umgang mit Martin Luther in eine postheroische und postmonumentale, ja sogar in eine postdoktorale Phase eintritt. Dafür stehe ich als Wissenschaftler, ich kann nicht anders.”


Dr. Antje Käßmann für Journal of Unsolved Questions

Mainz, 01. April 2018



Für weitere Informationen klicken sie bitte hier: website.


Continue reading “Was the Reformer a Plagiarist?” »

Mar 152018
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Probably never, since a Dyson sphere is not a vacuum cleaner of the same-named famous brand. In fact, until now it is just a thought experiment:

In 1960 Freeman J. Dyson published his theory about the “the long-scale conversion of starlight into far infrared radiation” in Science.[1] He states that aliens with further developed technology than ours must have found an advanced way like this to harvest solar energy.

Such a device could be a shell around the system’s sun at a distance of about two earth orbits, a thickness of 2?3 m, and nearly the mass of Jupiter. All the energy emitted by the star could thus be absorbed and harnessed on the inner surface. Of course, one must first exploit an entire planet to obtain all the mass needed for this device –  a huge technical trouble.

But with his hypothesis Dyson also proposed a way to trace intelligent existence in far-away solar systems that was new up to then. Until the 1960s the search for aliens based on the search for extra-terrestrial radio signals. However, a Dyson sphere would appear as a dark object emitting radiation in the far infrared (about 10 µm).[1] Now, instead for only listening to strange radio noise, scanning the sky for abnormalities in the infrared spectrum became also of importance.

Some years ago mankind seemed to be one step closer to discovering a Dyson sphere (or something similar): the light of the star KIC 8462852 shows an immensely changing intensity as if a huge object is regularly passing by. An orbiting planet would be too small to cause such an eclipse. This evokes suspicions about space-factories or cities and even whole Dyson-like devices. But the shadow could probably also be cast by natural causes like the remains of a burst asteroid or an interstellar cloud.[2]

Until we will be able to construct a Dyson sphere millions of years could pass. We first have to develop advanced methods for space-travel and the technology to destruct a whole planet. Not to speak of the energy we will already have consumed on the way.

But then, of course, we might be able to drive our hoovers (or anything else) with energy from a Dyson sphere 😉


— Tatjana Daenzer


Read more:

[1] Dyson F. J., Science 1960, 131, 1667-1668.

[2] (last access 16.02.2018).



Feb 282018
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Conjoined twinning is one of the most fascinating and at the same time devastating human malformations. This is an extremely rare phenomenon. The occurrence is estimated to range from 1 in 50,000 births to 1 in 100,000 births [1], when identical twins are born physically connected to each other. They can be joined anywhere—head, chest, abdomen, hips, and so on [2]. In fact, there is a whole spectrum of cases with different degrees of bodily overlapping: from being joined by a thin sliver of skin to being extensively fused. The “fusion” can be so extensive that in some cases, it is no longer correct to talk about “twins” because there is only one individual with some extra organs [3].

Conjoined twins have been known to exist for centuries, yet there is very little understanding of this phenomenon. Common public questions are: How do conjoined twins live together? How do they eat, walk or manage any other daily routine activities? Do they share thoughts and can they read each other’s mind?

The answers to these questions are indeed different for different pairs of conjoined twins. For example, 27-year old Abigail “Abby” and Brittany Hensel are joined at the torso. They have two hearts, two spines, two sets of lungs, two arms and two stomachs. Below the waist, they are more like one body. Each twin controls her half of their body – Brittany, the left twin, can’t feel the right side of her body, and vice versa. Each twin manipulates one arm and one leg.

As infants, the initial learning of physical processes that required bodily coordination, such as clapping, crawling, and walking, required the cooperation of both twins, even standing up takes total coordination. Now as grown-ups they are incredibly well coordinated with this set-up, able to walk with a smooth gait, dribble a basketball, ride a bike, and even drive a car: both steer and Abigail controls the accelerator with her right foot. The really mesmerizing thing is watching them type on a computer, as both girls’ hands fly over the keys, but there is no verbal discussion of what they are writing [4].

For 98 percent of all sets of conjoined twins, each person has their own separate and distinct thoughts and feelings. But in the case of Tatjana and Krista Hogan [5], which occurs in only one in 2.5 million births, they share neural activity because their skulls are connected.

The girls are still too young to investigate their neurological wiring, but from the MRI scans, doctors have determined that there is a “thalamic bridge” that links one sister’s sensory input to the other, creating a conscious loop. Essentially, if one thinks a happy thought, the other can perceive it. When one sees an image through her eyes, the other receives the image milliseconds later.

With a few tens pairs of conjoined twins across the world today Abby and Brittany, Krista and Tatjana are defying the odds. And a fair answer to all the curious questions can be that they are able to do normal things, even though it takes a lot more effort for them than anyone can imagine.


— Mariia Filianina

  1. Mutchinick, O.M. Conjoined twins: a worldwide collaborative epidemiological study of the international clearinghouse for birth defects surveillance and research, Am J Med Genet C Semin Med Genet. 0, 274 (2011).
  2. Kaufman, M.H. The embryology of conjoined twins, Child’s Nervous System 20, 508 (2004).
  3. Savulescu, J. and Persson, I. Conjoined twins: philosophical problems and ethical challenges, Medicine and Philosophy 41, 41 (2016).
  4. Abby and Brittany: Joined for Life, BBC.
  5. Ryan, D. Through her sister’s eyes: conjoined twins Tatiana and Krista were extraordinary from the beginning. The Vancouver Sun[On-line] (2012). Available:


Jan 082018
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Is Mycelium the Material of the Future?

No, mycelium is not a recently discovered chemical element. It might be the solution to the question of how to replace petroleum-based materials!

Mycelium is the tenuous web of vegetative fungal cells called hyphae that grows in the soilas shown in figure 1.[1] The parts of fungi that we usually see are just their body fruits (mushrooms, chanterelles, shiitake,…). But mycelium forms a much larger network below the surface that can even spread over several thousand square kilometers.[2] It is one of earth’s most important organisms since it helps nature to “digest”, meaning that it decomposes organic material and turns it into compost.[1]

Figure 1: Microscopic image of a mycelium network (size 1 mm · 1 mm).[3]

But can this bio-based material save our planet? The answer to this question could be easier as you might think. Fungal material is renewable, compostable under certain conditions (moisture and the presence of other organisms), fire resistant, moldable, free from volatile organic compounds (VOCs), dyeable and vegan.[4]

Companies like Ecovative and MycoWorks have already started to produce items from mycelium that can find access to our daily life.[4,5]

Ecovative was founded in 2007 and claims to produce more than 450,000 kg of mycelium material per year. They explain the production process on their webpage:

Agricultural waste is seeded with mycelium from mushrooms like Ganoderma. After some time of incubation, the waste is cut into little particles that are filled into a mold with the desired shape. The mycelium grows a few days until it has filled the mold and can be removed. In a last step the solid material is dried to stop the mycelium from growing. From that process packing material and even decoration can be made.[6] Imagine how many things could be substituted that are still petroleum-based and not compostable.

MycoWorks, founded in 2013, is specializing on replacing leather by mycelium – a relieve for our vegan friends. They claim that “…it feels and performs like leather”.[5] Indeed, recently I had the chance to touch a sample of “mycelium leather” and it does feel quite comfortable!

Mycelium as a full substitute for most of our plastic-based everyday products has still a long way to go. Sure, fugus as fancy packing material is not unusual anymore but customers still have to be convinced to wear clothes made from mushrooms. After all, some fungi are responsible for decay and mould. How will it react on the (moist) skin? Can it be washed without any damage to the fabric? How quickly does it decompose?

There must still be made a lot more research and explanatory work until consumers are convinced to take mycelium as an impeccable material. But maybe one day the world will be greener and we will be producing less eternal waste.

– Tatjana Daenzer

Read more:

[1], last access: 15.12.2017, 15:33.
[2] Ingraham, John L.: March of the Microbes: Sighting the Unseen, Harvard University Press, Cambridge 2010.
[3] CC BY-SA 3.0, last access 15.12.2017, 16:52.
[4], last access 15.12.2017, 15:58.
[5], last access 15.12.2017, 16:26.
[6], last access 15.12.2017, 16:09.

Dec 032017
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How will the IT technology develop within the next decade?

Firstly, the term itself refers to the nowadays common praxis to “outsource IT activities to one or more third parties that have rich pools of resources to meet organization needs easily and efficiently” [1, 2]. In other words, one buys the permission to use hardware, network connectivity, storage, and software that is located in a computing center anywhere in the world. It is more or less comparable to other known public utilities such as electricity, water and natural gas [1] and follows the same rule: You pay for what you need, not more.

The private sector is also more and more part of the system. Cloud memory saves personal data and makes it available from any place with an internet connection, file sharing websites are widely used and gained a lot of popularity within the last years. Another kind of cloud computing is especially interesting for research: Branches with high computational needs, e.g. astrophysics, medicine, and large scale facilities like CERN, can save a lot of resources by outsourcing computational power to volunteers. While their PCs are idle, a program starts in the background and performs calculations for the project [3].

The current state of cloud computing is already very impressive, however there is one major goal the IT industry starts to tackle now, namely the so-called Internet of Things (IoT). An example is Near Field Communication (NFC), a set of hardware and software protocols to enable two devices to communicate wireless with each other [4]. It is already part of most modern smartphones and also widely used for contactless payment cards. More and more devices in our daily life will be included in this IoT, resulting in increased connectivity and data flow around us. The idea is to take the cloud and place it everywhere around us, basically creating a fog [5]. This now indeed called “fog-computing” could span a wide range of applications in daily life. From smart houses that adjust the temperature, to refrigerators that tell their user when they are getting empty. An even more spectacular application could be connected to the trend towards self-driving cars. Large IT companies already started to develop cars which do not need a driver any more [6]. What sounds like science fiction could become commonly available within the next decades and opens the path to some great applications of fog-computing. How about a traffic light, which already counts the arriving cars and adjusts its phases according to the traffic volume or tries to prevent accidents by detecting obstacles and pedestrians much faster than any human would be able to? The possibilities are incredible.

However, one also needs to consider possible disadvantages like data safety and the problem of the totally transparent citizen. Moreover, judiciary will require a lot of adjustments and new laws, especially when the computer hardware that processes cloud data is located in another country with different data protection laws. There are a lot of changes to be made, however so far technological progress was never stoppable. We will most likely be able to observe within the next 10 years some of the biggest changes in IT technology and connectivity since the invention of the internet itself.

–Kai Litzius

[1] Hassan, Qusay (2011). “Demystifying Cloud Computing” (PDF). The Journal of Defense Software Engineering (CrossTalk) 2011 (Jan/Feb): 16–21.}
[2] M. Armbrust, A. Fox, R. Griffith, A. D. Joseph, R. Katz, A. Konwinski, G. Lee, D. Patterson, A. Rabkin, I. Stoica, M. Zaharia, “Above the Clouds: A Berkeley View of Cloud Computing”. University of California, Berkeley, Feb 2009.
[4] Cameron Faulkner. ” NFC? Everything you need to know”.
[5] Bar-Magen Numhauser, Jonathan (2013). Fog Computing introduction to a New Cloud Evolution. Escrituras silenciadas: paisaje como historiograf?a. Spain: University of Alcala. pp. 111–126.
[§] Google Self-Driving Car Project Monthly Report – September 2015″ (PDF). Google.

Nov 162017
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Figure 1. Scaling effect of global maps. The circles would all have the same size on the Earth’s surface. [1] Copyright: BY-SA 2.5 (Eric Gaba)

If we think about an earth map, gigantic Asia, Antarctic and North America with Greenland comes up in our mind. However, have you ever thought more about our self-created 2D maps of the earth? Do those maps represent the real sizes of our countries? Are Antarctica and Greenland as big as they seem and Africa in comparison to other continents so small. The answer for most of the 2D maps we are looking at is No! The most maps do not show the true sizes of the countries, because the countries of our round planet were just planed to a 2D paper without the correct scales. Meaning the continents or countries closer to the poles look a lot bigger as they are whereas the ones close to the equator look a lot smaller (see Fig. 1).

How did this happen? Our maps are older as we think. A Belgian geographer and cartographer Gerhard Mercator from 1569 designed those maps we are still looking at. This model is convenient for the seafaring, because you need equatorial azimuthal projections for navigation. In terms of ratios of the countries, the model is indeed sometimes wrong. It does show Greenland and Antarctica totally stretched and therefore bigger as they are. For example, Africa is 14 times larger than Greenland in reality. Madagascar is actually bigger as the United kingdom. Where Ireland also is 3 times smaller than it seems to be on a map of Mercator (see Fig. 2).


Figure 2. Direct comparison of different regions

There are several approaches now on shedding some light on this fact. One webpage showing the optical illusions is called “true size” [4]. Here you can move countries to another region of the earth and their scale will be dynamically adjusted dependent on the local distortion of the map. Another example is given here with a map built using the Cahill–Keyes projection (first proposed by Cahill and refined by Keyes in 1975). In this ensemble, the map provides an easy understanding of the continents with a minimized distortion (Fig. 3). Of course, another possibility to have a quite precise image of our world is to have a globe if you have enough room to have it.

Figure 3. Political world map for 2013 CE using the Cahill-Keyes Projection. Copyright: Duncan Webb CC BY 1.0


— Dania Rose-Sperling

Aug 142017
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Sometimes they come and go with a bang, sometimes they are silent. They glow bright as a lightning in white, yellow, red or blue. They fly freely through the room and some of them even permeate solid matter. They all have in common that they appear mostly during stormy weather, are somewhat spherically shaped and have a lifetime of several seconds.[1] For many centuries people report about observations of lightning balls as depicted in figure 1.

Figure 1: Illustration of a ball lightning from the early 20th century.[2]

Clearly, ball lightnings cannot be the same phenomenon as a strong electric discharge like a bolt lightning since their effect is not as dramatic. A full scientific explanation is not yet found. Do they really exist or are they only the product of frightened people’s minds?

Sure, bolts can cause phosphenes, impressions in the focus of the eye that remain some moments after looking into bright lights.[3] But during the last years scientist came up with some experiments that deliver plausible explanations of their formation:

Abrahamson and J. Dinniss found out that after the impact of a bolt into the soil a cloud of Silicon (Si), Silicon carbide (SiC) and Silicon monoxide (SiO) nanoparticles evaporates and oxidizes in a timespan of several seconds. During this time the energy is released as a bright ball-shaped light.[4]

At the IPP in Garching, Germany, Prof. Dr. Gerd Fu?mann vaporized and ionized a tiny amount of water by an electrical discharge between two electrodes above a water surface. The glowing plasma cloud, called plasmoid, has a spherical or mushroom-like shape (shown in figure 2) and a lifetime below one second.[5] The appearance of these plasmoids is demonstrated in a short video on their web page:

Figure 2: Result of the water discharge experiment from 2014.[6]

Still these experiments lack to explain all the observed properties of a ball lightning: the free movement, the ability to permeate matter and the long lifetime of several seconds. It is plausible that there might occur spherical light phenomena during bolt impacts. An explanation of the rather vivid properties of a ball lightning is yet to come. But maybe they belong to the section of narrative decor.

– Tatjana Daenzer

Read more:

[1] Smirnov, B. M., Phys. Rep. 1987, 152, 177-226.


[3] Peer, J., Kendl, A., Physics Letters A, 2010, 374, 4797-4799.

[4] Abrahamson, J., Dinniss, J., Nature, 2000, 403, 519-521.

[5] Fussmann, G., Phys. Unserer Zeit. 2008, 5, 246-252.



Jul 242017
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Put a raw egg on a flat table, and give it a good spin with two fingers. The egg spins, however, rather slowly because the liquid inside poorly exchanges momentum with the outside shell. Thus, when you spin the egg by applying force to the shell, most of the inside resists the motion and the friction forces between the inside (immobile) and the shell (mobile) will be slowing down the egg’s speed. But if you consider a cooked egg, proteins contained inside the egg are now forming a solid phase that is tightly joint to the shell. In that case, there are no friction forces in the “egg system” and the movement is not slowed down.


In this case now, the only existing friction forces are those between egg and the support (the table) and the air (which can be reasonably neglected). If your initial momentum transfer is strong enough, you observe a strange phenomenon: the spinning egg starts to rotate upright.

The physical concept used to explain this phenomenon is inertia. Spinning ice skaters can reduce their moment of inertia by pulling in their arms, allowing them to spin faster. You can also sit on a swivel chair and spin on yourself. Extend your arms horizontally and you will slow down.  The same is happening with the egg. Friction forces tend to slow down the egg, and decrease overall energy. To save energy, like the skater, the egg stands up and the momentum of inertia consequently decreases.

To spin upright, the egg needs some energy, exactly as one needs some energy to get up in the morning, fighting against gravity. The necessary energy is provided by the rotation itself, and the change of orientation of the egg will only happen if the spinning is fast enough.




Video movement of interia

Bou-Rabee, N. M., J. E. Marsden, and L. N. Romero, A geometric treatment of Jellett’s egg, Angew. Math. Mech. (ZAMM) 85, (2005), 618-642