Looking into the interior of the Earth or the Sun is a bit similar to examining a baby in its mother`s womb using an ultrasound scan. Light cannot penetrate the area, so we make pictures in these cases using sound waves, which human ears cannot hear. With SOHO, ESA has probed deeply into the Sun using the sound-waves principle, and with great success. The future missions, Solar Orbiter and Eddington, will look inside our Sun and other stars, respectively, in a similar way.
Here on Earth, when scientists recorded slight shakes, or seisms, coming from earthquakes even on distant continents, they began to estimate the routes and the changing speeds of the waves passing through the Earth`s interior. This revealed our planet`s molten core. Nowadays, oil prospectors routinely thump the ground to get seismic echoes from deep-lying strata. Scientists combine earthquake records from seismometers worldwide, to make 3D pictures of the rocks far beneath our feet.
Seismology is the study of earthquake waves. Studying solar sound waves is called helioseismology, from helios, a Greek word for Sun. When you transfer your focus onto the stars, as Eddington will do, you are studying asteroseismology. Although the Sun and stars are made of very hot gas rather than rocks, basic principles about deducing the routes and speeds of internal waves still work.
Monica Talevi | alfa
Astronomers see 'warm' glow of Uranus's rings
21.06.2019 | University of California - Berkeley
A new force for optical tweezers awakens
19.06.2019 | University of Gothenburg
From June 25th to 27th 2019, the Fraunhofer Institute for Digital Media Technology IDMT in Ilmenau (Germany) will be presenting a new solution for acoustic quality inspection allowing contact-free, non-destructive testing of manufactured parts and components. The method which has reached Technology Readiness Level 6 already, is currently being successfully tested in practical use together with a number of industrial partners.
Reducing machine downtime, manufacturing defects, and excessive scrap
The quality of additively manufactured components depends not only on the manufacturing process, but also on the inline process control. The process control ensures a reliable coating process because it detects deviations from the target geometry immediately. At LASER World of PHOTONICS 2019, the Fraunhofer Institute for Laser Technology ILT will be demonstrating how well bi-directional sensor technology can already be used for Laser Material Deposition (LMD) in combination with commercial optics at booth A2.431.
Fraunhofer ILT has been developing optical sensor technology specifically for production measurement technology for around 10 years. In particular, its »bd-1«...
The well-known representation of chemical elements is just one example of how objects can be arranged and classified
The periodic table of elements that most chemistry books depict is only one special case. This tabular overview of the chemical elements, which goes back to...
Light can be used not only to measure materials’ properties, but also to change them. Especially interesting are those cases in which the function of a material can be modified, such as its ability to conduct electricity or to store information in its magnetic state. A team led by Andrea Cavalleri from the Max Planck Institute for the Structure and Dynamics of Matter in Hamburg used terahertz frequency light pulses to transform a non-ferroelectric material into a ferroelectric one.
Ferroelectricity is a state in which the constituent lattice “looks” in one specific direction, forming a macroscopic electrical polarisation. The ability to...
Researchers at TU Graz calculate the most accurate gravity field determination of the Earth using 1.16 billion satellite measurements. This yields valuable knowledge for climate research.
The Earth’s gravity fluctuates from place to place. Geodesists use this phenomenon to observe geodynamic and climatological processes. Using...
24.06.2019 | Event News
29.04.2019 | Event News
17.04.2019 | Event News
25.06.2019 | Architecture and Construction
25.06.2019 | Life Sciences
25.06.2019 | Power and Electrical Engineering