The July 22 total solar eclipse, visible from China and India (but not the United States), will be the longest in the 21st century. Teams of scientists from around the world will gather in China to study the corona, the sun's outermost atmosphere, for almost six minutes, unusually long for totality.
Most will be stationed at a 3,000-foot mountain site selected by Prof. Jay Pasachoff, a Caltech and Williams College astronomer and planetary scientist, in Tianhuangping, China, not far from Hangzhou or Shanghai.
The July event will be the 49th solar eclipse that Pasachoff has viewed. A champion of using eclipse observations to study the solar atmosphere, he describes the science of eclipses in the cover story of the international journal Nature (June 11 issue). Pasachoff, who is chair of the International Astronomical Union's Working Group on Solar Eclipses, was invited to write the article as part of Nature's coverage of the International Year of Astronomy.
The article describes the history of eclipse discoveries, such as the element helium and the verification of Einstein's general theory of relativity, as well as current themes in eclipse research.
One recent development in eclipse studies is the new computer capability of bringing out low-contrast features. One such spectacular image, involving processing by Miloslav Druckmüller of the Brno Institute of Technology in the Czech Republic, was selected by Nature for its cover.
The detailed structure of the corona is caused by the sun's magnetic field. Pasachoff's work with Druckmüller and with Vojtech Rusin and Metod Saniga of the solar observatory in Slovakia has led to several joint papers in the Astrophysical Journal on views of the changing corona. The corona changes not only from year to year with the sunspot cycle but also even within minutes, as the scientists saw by comparing their observations from Siberia and Mongolia at the last solar eclipse on Aug. 1, 2008. They plan to extend that work this summer with observations from India, China, and islands in the Pacific.
Pasachoff's team in China includes Bryce Babcock, staff physicist at Williams and several undergraduate students from Williams, where Pasachoff is Field Memorial Professor of Astronomy. He chose the site on a visit over two years ago to southern China together with Naomi Pasachoff, a research associate at Williams, and Beijing scientists Yihua Yan and Jin Zhu.
Pasachoff and his colleagues have been studying, in particular, why the solar corona has a temperature of millions of degrees, much hotter than the sun's surface. They do so by using a special rapid-readout electronic camera and single-color filters chosen to show only coronal gas. They look for oscillations with periods in the range of one second, which would signify certain classes of magnetic waves. The detailed structure of the corona, revealed by imaging in the visible and x-ray regions of the spectrum, and the correspondence of bright coronal regions with sunspot groups, shows that magnetism is the cause of coronal heating and the coronal structure. A competing set of ideas of how the corona is heated to millions of degrees involves ubiquitous nanoflares, that is, relatively tiny solar flares going off all the time.
Studies of eclipses, transits of Mercury and Venus across the face of the sun, and occultations of Pluto and other objects in the outer solar system proceed in tandem. For his eclipse studies, Pasachoff uses a set of electronic cameras provided by NASA's Planetary Sciences Division, primarily for use in studying Pluto and other objects in the outer solar system. His studies of Pluto's atmosphere started with similar cameras that had been provided for eclipse work.
Pasachoff's research this summer, as much of his work in the past, is supported mainly by a grant from the Committee for Research and Exploration of the National Geographic Society.
International Astronomical Union's Working Group on Solar Eclipses: http://www.eclipses.infoWilliams College eclipse expeditions:
Subaru Telescope helps pinpoint origin of ultra-high energy neutrino
16.07.2018 | National Institutes of Natural Sciences
Nano-kirigami: 'Paper-cut' provides model for 3D intelligent nanofabrication
16.07.2018 | Chinese Academy of Sciences Headquarters
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.
Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...
13.07.2018 | Event News
12.07.2018 | Event News
03.07.2018 | Event News
16.07.2018 | Physics and Astronomy
16.07.2018 | Life Sciences
16.07.2018 | Earth Sciences