Fotoeins Fotografie

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Posts from the ‘Science’ category

Deutsches Museum, Muenchen, Munich, Bayern, Bavaria, Oberbayern, Upper Bavaria, Deutschland, Germany, fotoeins.com

Fotoeins Friday around Munich: Deutsches Museum

You cannot possibly take in every exhibit inside the massive Deutsches Museum (German Museum) in a single afternoon or even an entire day. At some point, the mind short circuits, feet will ache, and the stomach sends urgent “I am hungy” messages to the brain. But for a physicist and scientist by training, this museum is a real joy.

With the temporary exhibition “Auf zu neuen Energien” (Onto new forms of energy), I learn about “green power” in Germany, about where in the country solar and wind power is best “collected” or generated. Figuring that out depends on lots of specific meteorological data. The two figures/plots show average annual solar incident radiation at the surface and average annual wind speed at an elevation of 80 metres (typical height of a wind turbine). The sunniest areas indicated with red above are in the southern quarter of the country, and the windiest regions indicated with red below are by the open seas in the north and up in highlands and mountains.

Deutsches Museum, Deutscher Wetterdienst, DWD, annual solar incidence, Muenchen, Munich, Bayern, Bavaria, Oberbayern, Upper Bavaria, Deutschland, Germany, fotoeins.com

Average annual solar incidence, in kilowatt-hours per square metre (1 kWh/m^2 = 3600 kJ/m^2). Courtesy of the Deutscher Wetterdienst (German Meteorological Service), this plot shows how the country’s southern quarter receives the most sun.

Deutsches Museum, Deutscher Wetterdienst, DWD, annual average wind speed, Muenchen, Munich, Bayern, Bavaria, Oberbayern, Upper Bavaria, Deutschland, Germany, fotoeins.com

Average annual wind speed at an elevation of 80 metres, the typical height of a wind turbine. Wind speeds are shown between 3 to 10 metres per second (11 to 36 kilometres per hour). The reddest areas in the northern lowlands by the sea and in highlands and mountains have highest average wind speeds above 7 m/s (25 km/h). Image/plot from Deutscher Wetterdienst (German Meteorological Service).

I made all three photos above on 23 Feb 2017. This post appears on Fotoeins Fotografie at fotoeins DOT com as https://wp.me/p1BIdT-kpM.

Ludwig Boltzmann, Arkadenhof, Universitaet Wien, University of Vienna, physicist, physics, Vienna, Wien, Oesterreich, Austria, fotoeins.com

Fotoeins Friday at Uni Vienna: Ludwig Boltzmann

I’ve highlighted notable physicists who’ve been memorialized within the Arcade Courtyard in the main building of the University of Vienna:

2 Apr: Lise Meitner;
9 Apr: Christian Doppler, Erwin Schrödinger;
16 Apr: Joseph Littrow, Karl Littrow;
23 Apr: Josef Stefan;
30 Apr: Ludwig Boltzmann.

These are all names whose work and discovery form the historical and scientific basis of my university education in the field of physics.


The inscription for physicist and university professor Ludwig Boltzmann reads:

Ludwig Boltzmann, 1844-1906:
Professor of mathematics, 1873-1876;
Professor of theoretical physics, 1894-1900 and 1902-1906.

Buried in Vienna’s Central Cemetery, Boltzmannn’s gravestone includes the equation for entropy in statistical mechanics and thermodynamics.

Boltzmann equation, physics, LaTeX, CodeCogs

Boltzmann entropy equation.

In collaboration with Josef Stefan, the Stefan-Boltzmann Law describes how an object that absorbs all radiation falling on its surface emits radiative intensity (I, radiation energy per unit time per unit area) that’s proportional to the fourth power in temperature T with constant emissivity ε (between 0 and 1) and Stefan-Boltzmann constant σ.

Stefan-Boltzmann Law, physics, LaTeX, CodeCogs

Stefan-Boltzmann Law.

Ludwig Boltzmann was also one of Lise Meitner’s professors and advisors at the university. Meitner would become the 3rd woman to receive a doctorate in physics from the University of Vienna, and would go on to describe the process of nuclear fission.

The university’s historical main building is inside the city’s Old Town which has been inscribed as UNESCO World Heritage Site since 2001. I made the photo above on 16 May 2018 with a Fujifilm X70 fixed-lens prime and the following settings: 1/30-sec, f/5.6, ISO1000, and 18.5mm focal length (28mm full-frame equivalent). This post appears on Fotoeins Fotografie at fotoeins DOT com as https://wp.me/p1BIdT-iGz.

Josef Stefan, Arkadenhof, Universitaet Wien, University of Vienna, physicist, physics, Vienna, Wien, Oesterreich, Austria, fotoeins.com

Fotoeins Friday at Uni Vienna: Josef Stefan

Throughout the month, I’m highlighting notable physicists who’ve been memorialized within the Arcade Courtyard in the main building of the University of Vienna:

2 Apr: Lise Meitner;
9 Apr: Christian Doppler, Erwin Schrödinger;
16 Apr: Joseph Littrow, Karl Littrow;
23 Apr: Josef Stefan;
30 Apr: Ludwig Boltzmann.

These are all names whose work and discovery form the historical and scientific basis of my university education in the field of physics.


The memorial to Josef Stefan (Jožef Štefan) includes a small inscription:

Josef Stefan
Professor of physics, 1863-1893
Born 1835, died 1893

An important physics equation is the Stefan-Boltzmann Law, which describes how an object that absorbs all radiation falling on its surface emits radiative intensity I (radiation energy per unit time per unit area) that is proportional to the fourth power in temperature T; the other two quantities are constants: emissivity ε between 0 and 1, and the Stefan-Boltzmann constant σ.

Stefan-Boltzmann Law, physics, LaTeX, CodeCogs

Stefan-Boltzmann Law.

Both Stefan and Boltzmann are buried in Vienna’s Central Cemetery. Boltzmann’s gravestone includes his entropy equation. Stefan does not have his own grave; instead, his descendants in the Munk family have a gravestone.

The university’s historical main building is inside the city’s Old Town which has been inscribed as UNESCO World Heritage Site since 2001. I made the photo above on 16 May 2018 with a Fujifilm X70 fixed-lens prime and the following settings: 1/60-sec, f/3.2, ISO1000, and 18.5mm focal length (28mm full-frame equivalent). This post appears on Fotoeins Fotografie at fotoeins DOT com as https://wp.me/p1BIdT-iGt.

Joseph Littrow, Karl Littrow, Arkadenhof, Universitaet Wien, University of Vienna, physicist, physics, Vienna, Wien, Oesterreich, Austria, fotoeins.com

Fotoeins Friday at Uni Vienna: Joseph & Karl Littrow

Throughout the month, I’m highlighting notable physicists who’ve been memorialized within the Arcade Courtyard in the main building of the University of Vienna:

2 Apr: Lise Meitner;
9 Apr: Christian Doppler, Erwin Schrödinger;
16 Apr: Joseph Littrow, Karl Littrow;
23 Apr: Josef Stefan;
30 Apr: Ludwig Boltzmann.

These are all names whose work and discovery form the historical and scientific basis of my university education in the field of physics.


A wall plaque memorializes astronomers Joseph Littrow and (his son) Karl Littrow at left and right, respectively. Joseph was director of the Vienna Observatory from 1819 to 1842; Karl succeeded his father as director from 1842 to 1877.

The Littrow crater on the Moon is named after Joseph, but he’s also best known in physics for his optics inventions: the Littrow prism and the Littrow configuration optimizing the performance of a spectrograph with a specially designed diffraction grating.

The university’s historical main building is inside the city’s Old Town which has been inscribed as UNESCO World Heritage Site since 2001. I made the photo above on 16 May 2018 with a Fujifilm X70 fixed-lens prime and the following settings: 1/30-sec, f/2.8, ISO1000, and 18.5mm focal length (28mm full-frame equivalent). This post appears on Fotoeins Fotografie at fotoeins DOT com as https://wp.me/p1BIdT-iGr.

Christian Doppler, Erwin Schroedinger, Arkadenhof, Universitaet Wien, University of Vienna, physicist, physics, Vienna, Wien, Oesterreich, Austria, fotoeins.com

Fotoeins Friday at Uni Vienna: Doppler & Schrödinger

This month I’m highlighting notable physicists who’ve been memorialized within the Arcade Courtyard in the main building of the University of Vienna:

2 Apr: Lise Meitner;
9 Apr: Christian Doppler, Erwin Schrödinger;
16 Apr: Joseph Littrow, Karl Littrow;
23 Apr: Josef Stefan;
30 Apr: Ludwig Boltzmann.

These are names whose work and discovery form part of the historical and scientific basis of my university education in the field of physics.


Shown in the image are memorials to Christian Doppler and Erwin Schrödinger at left and right, respectively. My translation to the inscription on the Doppler memorial inscription reads:

Christian Doppler, 1803-1853:
Professor of physics at Vienna University, 1850-1853.
The Doppler principle has ensured the Doppler name for all time.

With his birth house in Salzburg as backdrop, I briefly describe the physics of the Doppler effect.

The Schrödinger memorial highlights an early 20th-century revolution in science in the form of quantum mechanics: the physics of the atom and its constituents. The well-known equation representing Newton’s 2nd Law, “F = ma”, is to classical mechanics, as the following equation is to quantum mechanics.

Schrödinger equation, physics, quantum mechanics, LaTeX, CodeCogs

The equation on his memorial, and on the gravestone.

This generalized form of the time-dependent Schrödinger equation describes a physical system, represented by ψ, changing with time. I was able to “localize” the final resting place for him and his wife in the alpine Austrian town of Alpbach.

The university’s historical main building is inside the city’s Old Town which has been inscribed as UNESCO World Heritage Site since 2001. I made the photo above on 16 May 2018 with a Fujifilm X70 fixed-lens prime and the following settings: 1/60-sec, f/6.4, ISO1000, and 18.5mm focal length (28mm full-frame equivalent). This post appears on Fotoeins Fotografie at fotoeins DOT com as https://wp.me/p1BIdT-iGo.

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