The Big Bang is a physical theory that describes how the universe expanded from an initial state of high density and temperature. The notion of an expanding universe was first scientifically originated by physicist Alexander Friedmann in 1922 with the mathematical derivation of the Friedmann equations.
A supervolcano is a volcano that has had an eruption with a volcanic explosivity index (VEI) of 8, the largest recorded value on the index. This means the volume of deposits for such an eruption is greater than 1,000 cubic kilometers.
Sonar is a technique that uses sound propagation to navigate, measure distances (ranging), communicate with or detect objects on or under the surface of the water, such as other vessels.
Sonoluminescence is the emission of light from imploding bubbles in a liquid when excited by sound.
Walter Heinrich Munk was an American physical oceanographer. He was one of the first scientists to bring statistical methods to the analysis of oceanographic data. Munk worked on a wide range of topics, including surface waves, geophysical implications of variations in the Earth's rotation, tides, internal waves, deep-ocean drilling into the sea floor, acoustical measurements of ocean properties, sea level rise, and climate change. His work won awards including the National Medal of Science, the Kyoto Prize, and induction to the French Legion of Honour.
Gerhard M. Sessler is a German inventor and scientist. He is Professor emeritus at the Department of Electrical Engineering and Information Technology of the Technische Universität Darmstadt.
A parametric array, in the field of acoustics, is a nonlinear transduction mechanism that generates narrow, nearly side lobe-free beams of low frequency sound, through the mixing and interaction of high frequency sound waves, effectively overcoming the diffraction limit associated with linear acoustics. The main side lobe-free beam of low frequency sound is created as a result of nonlinear mixing of two high frequency sound beams at their difference frequency. Parametric arrays can be formed in water, air, and earth materials/rock.
Peter Westervelt was an American physicist, noted for his work in nonlinear acoustics, and Professor Emeritus of Physics at Brown University.
The ASA Silver Medal is an award presented by the Acoustical Society of America to individuals, without age limitation, for contributions to the advancement of science, engineering, or human welfare through the application of acoustic principles or through research accomplishments in acoustics. The medal is awarded in a number of categories depending on the technical committee responsible for making the nomination.
In acoustics, microbaroms, also known as the "voice of the sea", are a class of atmospheric infrasonic waves generated in marine storms by a non-linear interaction of ocean surface waves with the atmosphere. They typically have narrow-band, nearly sinusoidal waveforms with amplitudes up to a few microbars, and wave periods near 5 seconds. Due to low atmospheric absorption at these low frequencies, microbaroms can propagate thousands of kilometers in the atmosphere, and can be readily detected by widely separated instruments on the Earth's surface.
Chaotic bubbles within physics and mathematics, occur in cases when there are any dynamic processes that generate bubbles that are nonlinear. Many exhibit mathematically chaotic patterns consistent with chaos theory. In most systems, they arise out of a forcing pressure that encounters some kind of resistance or shear factor, but the details vary depending on the particular context.
Andrea Prosperetti is the Distinguished Professor of Mechanical Engineering at the University of Houston, the Berkhoff Professor of Applied Physics at the University of Twente in the Netherlands and an elected member of the National Academy of Engineering in 2012. He is known for his work in the field of multiphase flows including bubble dynamics and cavitation.
In cosmology, baryon acoustic oscillations (BAO) are fluctuations in the density of the visible baryonic matter of the universe, caused by acoustic density waves in the primordial plasma of the early universe. In the same way that supernovae provide a "standard candle" for astronomical observations, BAO matter clustering provides a "standard ruler" for length scale in cosmology. The length of this standard ruler is given by the maximum distance the acoustic waves could travel in the primordial plasma before the plasma cooled to the point where it became neutral atoms, which stopped the expansion of the plasma density waves, "freezing" them into place. The length of this standard ruler can be measured by looking at the large scale structure of matter using astronomical surveys. BAO measurements help cosmologists understand more about the nature of dark energy by constraining cosmological parameters.
Leonid Maksimovich Brekhovskikh was a Soviet and Russian scientist known for his work in acoustical and physical oceanography.
In acoustics, acoustic attenuation is a measure of the energy loss of sound propagation through an acoustic transmission medium. Most media have viscosity and are therefore not ideal media. When sound propagates in such media, there is always thermal consumption of energy caused by viscosity. This effect can be quantified through the Stokes's law of sound attenuation. Sound attenuation may also be a result of heat conductivity in the media as has been shown by G. Kirchhoff in 1868. The Stokes-Kirchhoff attenuation formula takes into account both viscosity and thermal conductivity effects.
Timothy Grant Leighton was a Professor of Ultrasonics and Underwater Acoustics at the University of Southampton. He is the inventor-in-chief of Sloan Water Technology Ltd., a company founded around his inventions. He is an academician of three national academies. Trained in physics and theoretical physics, he works across physical, medical, biological, social and ocean sciences, fluid dynamics and engineering. He joined the Institute of Sound and Vibration Research (ISVR) at the University of Southampton in 1992 as a lecturer in underwater acoustics, and completed the monograph The Acoustic Bubble in the same year. He was awarded a personal chair at the age of 35 and has authored over 400 publications.
Monita Chatterjee is an auditory scientist and the Director of the Auditory Prostheses & Perception Laboratory at Boys Town National Research Hospital. She investigates the basic mechanisms underlying auditory processing by cochlear implant listeners.
Brian C.J. Moore FMedSci, FRS is an Emeritus Professor of Auditory Perception in the University of Cambridge and an Emeritus Fellow of Wolfson College, Cambridge. His research focuses on psychoacoustics, audiology, and the development and assessment of hearing aids.
Christine Erbe is a German-Australian physicist specializing in underwater acoustics. She is a professor in the School of Earth and Planetary Sciences and director of the Centre for Marine Science and Technology (CMST)—both at Curtin University in Perth, Western Australia. Erbe is known for her research on acoustic masking in marine mammals, investigating how man-made underwater noise interferes with animal acoustic communication.
Wei Rongjue was a Chinese physicist and professor at Nanjing University. In 1952, he was appointed chairman of the physics department at Nanjing University.
