<address id="9fb5l"></address>

        . 24/7 Space News .




        Subscribe to our free daily newsletters



        TIME AND SPACE
        Remembrance of waves past: memory imprints motion on scattered waves
        by Staff Writers
        Washington DC (SPX) Sep 23, 2020

        Illustration of memory effects on wave-matter interaction.

        Wave scattering appears practically everywhere in everyday life - from conversations across rooms, to ocean waves breaking on a shore, from colorful sunsets, to radar waves reflecting from aircraft.

        Scattering phenomena also appear in realms as diverse as quantum mechanics and gravitation. According to Pavel Ginzburg, professor at Tel Aviv University's School of Electrical Engineering, these phenomena become especially interesting when the waves in question encounter a moving object.

        The everyday Doppler effect is familiar - witnessed as the audible shift in pitch that occurs, for example, as a fire engine's siren approaches, passes, and recedes. The idea that the observed frequency of a wave depends on the relative speed of the source and the observer, a popularized aspect of Einstein's theory of relativity, entails cosmic implications for the Doppler effect, particularly for light waves.

        Now, it appears that between relativity and the classical (stationary) wave regime, there exists another regime of wave phenomena, where memory influences the scattering process.

        Memory effect alters the Doppler wave signature
        As recently demonstrated by a team of scientists led by Ginzburg, including lead author Vitali Kozlov and coauthors Sergey Kosulnikov and Dmytro Vovchuk, the Doppler effect can be dramatically altered by memories of prior wave interactions.

        Specifically, when rotating dipoles are arranged to retain a long memory of past interactions with an incident wave, the Doppler signature displays asymmetric peaks in the scattered spectrum. Rather than fading quickly, these long-lasting past interactions affect the present and future evolution of the system under study.

        "The newly discovered memory effect is universal," observes Ginzburg, "It can emerge in a variety of wave-related scenarios - from optics, where lasers are rotating molecules, to astronomy, where rotating dipoles can approximate neutron stars." Although the effect is universal, Ginzburg notes that not every scatterer possesses a long memory.

        "The effect is introduced on purpose, for instance with lumped circuitry in the case of electromagnetic applications," explains Ginzburg. He speculates that the memory effect may contribute to increased efficiency of radar target identification and classification, among other applications, such as stellar radiometry.

        Ginzburg's team set out to answer the question of whether there is "an overlooked interaction regime, which on the one hand does not require relativistic velocities yet on the other hand cannot be straightforwardly explained with classical stationary physics."

        The team chose a simple case of a rotating dipole as a mathematical model that is "capable of describing properties of many real objects, such as quasars in astronomy or rotating blades of a helicopter in radar applications," according to Ginzburg.

        The researchers hope that these newly demonstrated memory effects will be used to advance our understanding of the universe around us and help give rise to new technological applications that take advantage of long-memory materials to imprint motion signatures on scattered waves.

        Research Report:


        Related Links
        International Society For Optics And Photonics
        Understanding Time and Space


        Thanks for being there;
        We need your help. The SpaceDaily news network continues to grow but revenues have never been harder to maintain.

        With the rise of Ad Blockers, and Facebook - our traditional revenue sources via quality network advertising continues to decline. And unlike so many other news sites, we don't have a paywall - with those annoying usernames and passwords.

        Our news coverage takes time and effort to publish 365 days a year.

        If you find our news sites informative and useful then please consider becoming a regular supporter or for now make a one off contribution.
        SpaceDaily Monthly Supporter
        $5+ Billed Monthly


        paypal only
        SpaceDaily Contributor
        $5 Billed Once


        credit card or paypal


        TIME AND SPACE
        Why there is no speed limit in the superfluid universe
        Lancaster UK (SPX) Sep 22, 2020
        Physicists from Lancaster University have established why objects moving through superfluid helium-3 lack a speed limit in a continuation of earlier Lancaster research. Helium-3 is a rare isotope of helium, in which one neutron is missing. It becomes superfluid at extremely low temperatures, enabling unusual properties such as a lack of friction for moving objects. It was thought that the speed of objects moving through superfluid helium-3 was fundamentally limited to the critical Landau v ... read more

        Comment using your Disqus, Facebook, Google or Twitter login.



        Share this article via these popular social media networks
        del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle

        TIME AND SPACE
        NASA's Partnership Between Art and Science: A Collaboration to Cherish

        Israeli tech start-ups take on the Emirates

        ISS may need to evade US Military cubesat

        NASA Goddard's first virtual interns reflect on their summer experience

        TIME AND SPACE
        UK Spaceports form historic alliance

        PLD Space closes new investment in tie-up with Arcano Partners

        Northrop Grumman and NASA donate Shuttle boosters to California Science Center

        US to stop using Russian rocket engine RD-180 in Mid-2020s says ULA

        TIME AND SPACE
        Using chitin to manufacture tools and shelters on Mars

        Study shows difficulty in finding evidence of life on Mars

        China's Mars probe travels 137 mln km

        ERC Space and Robotics Event 2020

        TIME AND SPACE
        China sends nine satellites into orbit by sea launch

        Chinese spacecraft launched mystery object into space before returning to Earth

        China's reusable spacecraft returns to Earth after 2 days

        Mars-bound Tianwen 1 hits milestone

        TIME AND SPACE
        COMSAT expands hardware footprint with new Orbit Communications Systems agreement

        GMV announces the merger of its UK Company and NSL

        Wanted: your ideas for ESA's future space missions

        Satellogic launches 11th satellite to low-earth orbit

        TIME AND SPACE
        Marine sponges inspire the next generation of skyscrapers and bridges

        Could PlayStation 5 and Xbox Series X be swan song for consoles?

        Physicists make electrical nanolasers even smaller

        Microsoft steps up Xbox game with ZeniMax Media buy

        TIME AND SPACE
        How protoplanetary rings form in primordial gas clouds

        Venus is one stop in our search for life

        NASA missions spy first possible survivor planet hugging white dwarf star

        Device could help detect signs of extraterrestrial life

        TIME AND SPACE
        Astronomers characterize Uranian moons using new imaging analysis

        Jupiter's moons could be warming each other

        Atomistic modelling probes the behavior of matter at the center of Jupiter

        Technology ready to explore subsurface oceans on Ganymede











        The content herein, unless otherwise known to be public domain, are Copyright 1995-2020 - 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.


        一晚破了3个处