by Staff Writers
Yekaterinburg, Russia (SPX) Jul 27, 2022
For the first time in the history of observations, scientists from the Helsinki and Ural Federal Universities Jarmo Moilanen and Maria Gritsevich have systematized information about all forms of atmospheric halos recorded by mankind at the end of 2021. From numerous sources of data on observations, the history of which includes 4-5 millennia, 119 different forms of atmospheric halo are known today. There are also extra-atmospheric halos and halos that can be seen on various surfaces. An article describing the work carried out and the conclusions reached was published in the Journal of Quantitative Spectroscopy and Radiative Transfer.
In the study, scientists summarized not only the general information regarding the phenomena, but also the conditions necessary for seeing the optical illusions in the atmosphere (the formation of crystals of ice or other minerals), such as temperature and humidity. In addition, the authors of the article identified knowledge gaps in the study of atmospheric halos and outlined promising methods for observing and processing the data. Among them are new digital photography techniques that are being used to improve the quality of detection of atmospheric halos and that lead to the discovery of their new forms.
Scientists have grouped atmospheric halos into commonly observed and rarely seen categories. It is believed that if a certain form of halo is observed at least once a year, it belongs to the first category; halos with a rare light source configuration, orientation, or unusual crystal shape make up only about 1% of all observed halos.
The frequently observed halos are usually formed by the scattering, refraction and focusing of light by hexagonal ice crystals in a disordered, horizontal or vertical orientation. The main sources of light that cause halo are the Sun and the Moon, as well as artificial sources. Rare halos, in turn, are divided into those whose origin has been established, and exotic, those that have not yet been sufficiently studied and are not yet amenable to modeling.
"As a rule, halos are formed as a result of the interaction of light with hexagonal crystals of water ice," says Jarmo Moilanen, author of the article, researcher at the Finnish Geospatial Research Institute, PhD student at the University of Helsinki. "However, some of the documented exotic halos cannot be explained in this way. For example, the mysteries of the origin of elliptical halos and Bottlinger rings have not been solved since their discovery at the beginning of the 20th century. Among the mysterious ones is the so-called Moilanen arc, which I first discovered in 1995."
In the case of exotic halos, science is presumably dealing with anomalous crystal shapes (such as cubic water ice crystals), with their heterogeneity, or with crystals of some other minerals scattered in the air. However, what exactly should be the ice crystals and the paths of the rays that pass through these crystals in order to form a halo of one or another exotic form is still unclear.
"The researchers suggest that the unusual shape of exotic halos is due to anthropogenic factors, such as emissions into the atmosphere or the influence of the strong electromagnetic field of high-voltage power lines, which can disrupt the orientation of ice crystals in the air. To unravel such mysteries, samples of ice crystals, forming exotic halos, were specially collected in the atmosphere, but this experience also gave more questions than answers," says Maria Gritsevich, adjunct professor at the University of Helsinki, senior researcher at the Finnish Geospatial Research Institute and the Ural Federal University.
Finally, the halos formed in the atmospheres of Venus, Mars, Jupiter and their satellites are of interest. Halos have been already extensively documented in the atmosphere of Mars.
"This observation proves that clouds of hexagonal crystals of water ice or other minerals exist in the atmosphere of Mars," says Maria Gritsevich. "There are suggestions that the halos could be formed by carbon dioxide crystals. Monte Carlo modeling of the factors that can lead to the formation of a halo will provide valuable information about the state of the Martian atmosphere."
Atmospheric halos are light scattering phenomena caused by the accumulation of water ice crystals smaller than 10 micrometers in the atmosphere. The combination of the shape of ice crystals (or minerals), their orientation, and the path of light rays through the crystals determines the configuration of the halo, whether it is colored and exhibits white rings, spots, or arcs. In other words, the shape of the halo indicates what types of ice crystals are present in the atmosphere.
The oldest mentions of the halo are from 4 to 5 thousand years old: information about the halo is recorded on cuneiform tablets of the Sumero-Babylonian culture. At the time of Aristotle, at least three halo forms were known. One of the oldest sightings of a halo in Jerusalem dates back to the beginning of the 12th century. By 1820, the number of registered halos was about 20, by 1990 - 60.
Significant progress in documenting the halo has occurred in connection with the proliferation of mobile phones with photo and video cameras. The authors of the article call on the public to record the observed halos and thus contribute to the study of these phenomena and the discovery of new ones.
The missing link to how galaxies evolve
Amherst MA (SPX) Jul 22, 2022
A University of Massachusetts Amherst undergraduate student has contributed significant work regarding the growth of stars and black holes, providing key insight into how they are linked. This new information will allow the James Webb Space Telescope (JWST) to more efficiently untangle how, exactly, galaxies work. Astronomers know that the evolution of galaxies is powered by two processes: the growth of supermassive black holes at each galaxy's center and the formation of new stars. How these proc ... read more
|The content herein, unless otherwise known to be public domain, are Copyright 1995-2022 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. All articles labeled "by Staff Writers" include reports supplied to Space Media Network by industry news wires, PR agencies, corporate press officers and the like. Such articles are individually curated and edited by Space Media Network staff on the basis of the report's information value to our industry and professional readership. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. General Data Protection Regulation (GDPR) Statement Our advertisers use various cookies and the like to deliver the best ad banner available at one time. All network advertising suppliers have GDPR policies (Legitimate Interest) that conform with EU regulations for data collection. By using our websites you consent to cookie based advertising. If you do not agree with this then you must stop using the websites from May 25, 2018. Privacy Statement. Additional information can be found here at About Us.|