Sunday , May 16 2021

The Czechs relived Einstein’s famous film The Solar Eclipse

The Association of Universities for Space Research at NASA published a photograph as a prestigious geoscientific film of the day, co-authored by Petr Horálek of the Institute of Physics at the University of Silesia in Opava and Miloslav Druckmüller of the Faculty of Mechanical Engineering of Technology.

Using modern computational methods of image processing, they attempted to reconstruct a solar eclipse image from May 29, 1919, which led to the confirmation of Einstein’s general theory of relativity.

“After more than 100 years, people can see for the first time what this phenomenon in colors was like and what unusual phenomena surrounded the darkened Sun,” Horálek remarked.

Two British expeditions

Einstein began his revolution of thought in 1915 with a series of lectures at the Prussian Academy of Sciences, but was under unpleasant pressure as his strong pacifism and Jewish origins provoked efforts to discredit him. Fortunately, Einstein’s physical theory fell into the hands of British scientists, who decided to confirm it with an experiment on an expedition to observe a solar eclipse.

Reconstructed image of a total solar eclipse of May 29, 1919

Photo: ESO / Landessternwarte Heidelberg-Königstuhl / FW Dyson, AS Eddington, and C. Davidson, P. Horálek / Institute of Physics at Opava, M. Druckmüller / Brno University of Technology

One of the many consequences of general relativity is that light from a distant source can deviate slightly in its trajectory due to the gravity of another material body. According to the general theory of relativity, the Sun should deflect, by its gravitational action, the light of stars passing through its surroundings, which would be reflected in the photograph of stars by their displacement from the Sun. The question was whether theories could be verified in practice.

Scientists at the Royal Observatory tried to do so: they took advantage of a total solar eclipse on May 29, 1919, when a dazzling solar disk was darkened by the moon and faint stars appeared in the constellation Taurus minutes. According to Horálek, these stars should theoretically be a little “different” from the darkened Sun than if our material matrix star were not between them and the observer.

What do we see in the picture?
The dark lunar disk darkens the solar disk, revealing a weak structured solar corona: a plasma plasma envelope of the Sun shaped by its magnetic field. It is also possible to recognize solar magnetic poles (upper left, lower right) and long equatorial coronal rays.
The image is dominated by a pink bulge: a cloud of cooler plasma hovering over the surface of the sun. This giant bulge is very rare during a total solar eclipse and is probably the largest ever captured photographically during an eclipse.
“As for the stars, next to the Sun we can see two clearly at the bottom right, one at the top, one at the far left … The image is a cut of the original plate, so that there are fewer stars, “Horálek told Novinky.

“In the early 20th century, however, there were no digital megapixel cameras, travel agencies and accurate weather forecasts or satellite imagery, so astronomers had to spend a lot of diplomacy and adapt the expedition because the phenomenon could be recorded well enough on the photographic plates, “he explained. Horálek.

There were two expeditions, coordinated by Frank W. Dyson (1868-1939) and Arthur S. Eddington (1882-1944). It was the end of World War I that scientists finally recorded and carefully packed instruments were taken to Liverpool, from where the two expeditions traveled together aboard the steamer Anselm on Saturday 8 March 1919 to Madeira.

One of them, directed by Andrew CD Crommelin (1865-1939), traveled to Sobral, Brazil. Eddington then led an expedition to Prince’s Island in the Gulf of Guinea. Both had problems with clouds during the eclipse, but in the end several fairly high-quality recordings were made on photographic plates, which were subsequently successfully imported into Britain in July and August 1919, all and travel complications.

Eclipse image of 1919 with the highest resolution (with star identification)

Photo: ESO / Landessternwarte Heidelberg-Königstuhl / FW Dyson, AS Eddington and C. Davidson

In the end, the results were excellent and ensured scientific recognition for both the members of the expedition and Einstein himself. The stars surrounding the Sun during the eclipse were bright enough to compare them with their positions on the plates taken later when the Sun was not between them. It turned out that its position deviates up to 1.75 seconds of arc due to the gravity of the Sun.

The originals are lost, we now have a color image

Unfortunately, the original records were lost from this eclipse, but fortunately copies of one of them were made and distributed to observatories around the world.

A copy of Sobral’s film also arrived at the Heidelberg-Königstuhl Observatory in Germany, which recently digitized it. Horálek, in cooperation with the intergovernmental organization European Southern Observatory (ESO), obtained a digitized copy of the original record with the highest possible quality.

“At first glance, it was clear that the image quality was far from the current level and that the scan was scratched and full of dust particles. It is also quite clear that at the time of the eclipse, the clouds were really obstructed. by Sobral, ”he described.

According to him, it was necessary to adjust the digital shape of the glass plate so that some artifacts disappeared and, on the contrary, the real structures of the solar corona stood out. The result was processed by the NAFE program of Professor Druckmüller of BUT. And finally, we also managed to reconstruct the color of the entire image, which was previously only available in black and white.

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