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Gravitational waves

Each interaction has its particle

For many years, physics has attempted to unite the different theories that explain the world we live in.  The experimental discovery of the graviton and the gravitational wave is a step further in that direction.

There are four fundamental interactions in physics: they are said to be strong, weak, electromagnetic and gravitational.  The first covers the cohesion of atomic cores: the strong interaction is therefore of an extreme intensity but it has a very low range. The second is the weak interaction, which is used to explain radioactivity in particular: its range and intensity are very reduced.   The third and fourth are the most known by a long way as they can be seen in everyday life, whether as light, radiocommunications, gravity or planetary movement. The intensity of the electromagnetic interaction is quite high and its range is infinite; the gravitation interaction is by a long way the weakest of all (almost 10-35 weaker than the electromagnetic interaction) even though it also has an infinite range.  

Each of these interactions is associated with a particle that describes the energy transported by the interaction it represents. These interactions combined with the different material particles (protons, neutrons and electrons) structure matter at the macroscopic scale. These interactions are all the more important because at the atomic scale, matter is essentially composed of a vacuum: if the finger placed on a table does not pass through it, this is partly also due to the effects of these fundamental interactions.

 

Relativity and the notion of space-time warp

It was the general theory of relativity that highlighted the theoretical possibility that a particle transports the energy associated with the force of gravity.

Restricted relativity, a theory published by Einstein in 1905, showed that the length and duration depend on the observer’s reference. In a moving system, time is dilated and length contracted compared to the observer’s. 

The general theory of relativity goes further by hypothesising that weight “warps” space-time.  One of the commonly used images to illustrate this notion is that of an elastic, cross ruled and stretched fabric. If a weight is placed on it, the heavier the weight, the more the fabric will bend; and the more the fabric bends, the more time and lengths will be impacted.   There is an example in a recent American anticipatory film where one of the vessels gravitating near a black hole approaches it. When it moves away, its occupants are much younger than those in the other vessel which stayed at  distance. 

Both the restricted and general theories of relativity were verified experimentally in 1971 (published in Science in 1972) by Hafele and Keating using three synchronised atomic clocks and two commercial airliners.  Two atomic clocks were placed on board two airliners travelling around the world, one travelling east and the other west, the third clock remained on the ground.  According to the restricted theory of relativity, time should have slightly dilated for the airliner travelling east (as the earth rotates from east to west) and on the contrary should have contracted for the airliner travelling west.   Furthermore, aircraft flying at a certain altitude are subjected to a weaker gravity field than the clock that remained on the ground: their time should therefore be accelerated compared to the clock on the ground with differences in the order of a hundred nanoseconds. The theory was verified quite accurately, making it possible to conclude that the two theories of relativity were relevant. 

The effects of relativity are currently regularly taken into account in satellite navigation systems (GPS or Galileo for example) by correcting the time on atomic clocks on board satellites. 

 
Gravitational waves

Gravitational waves, associated with a particle called a graviton, propagate the space-time energy transitions.   These new waves dilate or contract space-time. If we detect electromagnetic waves using antennas that amplify electron movements, gravitational waves can only be perceived using systems that show length variations. However they are difficult to measure as they are of very weak intensity. It is estimated that the order of the length deformation of an object when crossed by these waves is in the order of 0.0000000000001 mm, or 1e-16m! To detect these new waves, highly sensitive receivers had to be developed based on lasers measuring ultra-accurate distances in tunnels several kilometres long on the one hand, and on the other hand it was necessary to focus on ultra-powerful transmitters resulting from extreme phenomena impacting space-time, such as the merging of two stars.

The existence of gravitational waves is now proven and they can be detected, opening up a new era for astronomical observation. In France, this success was rewarded by the 2017 CNRS Gold Medal to the physicists Alain Brillet and Thibault Damour, and by the 2017 Nobel prize for physics, awarded to the physicists Raider Weiss, Barry C. Barish and Kip S. Thorne.

 

 

Les téléphones portables sont une source d’exposition importante aux ondes, bien avant les antennes relais, car ils sont utilisés près du corps. Avec la #5G, l’@ANFR va renforcer ses contrôles et prélèvera 140📱en 2021, (+de 85% du marché 🇫🇷), pour réaliser des mesures de #DAS. https://t.co/ckSdNaiLIU

Des simulations de l’@ANFR évaluent l’exposition du public aux ondes #5G en zone🏙️.Dans tous les cas étudiés, les valeurs simulées sont⬇️au seuil aux limites d’exposition réglementaires en 🇫🇷et sont du même ordre que les niveaux d’exposition des réseaux 4G.https://t.co/KtmUPmGbWK https://t.co/VuLz5BlRW6

Avec l’utilisation d’antennes à faisceaux orientables, la #5G permettra une consommation des données “à la demande” et donc, une exposition aux ondes plus ciblée dans le temps et dans l’espace, contrairement à l’exposition continue engendrée par la 4G.
👉https://t.co/OXpBrtqvZW https://t.co/LIkCIoXuRZ

La consommation de données 📱des 🇫🇷⬆️d’environ 40% chaque année. À ce rythme, le réseau 🇫🇷 #4G sera saturé d’ici 2 ans et l’exposition aux ondes continuera d’⬆️sensiblement, du fait de l’optimisation du réseau #4G pour répondre à cette 📈de consommation. https://t.co/887ASEvBJ8 https://t.co/LUw2X7QCfI

La #5G est à l'heure de l'expérimentation. Quelles sont les agglomérations qui accueillent ces tests ? Découvrez la carte interactive de l'Agence nationale des fréquences https://t.co/1045Imjt10 https://t.co/DBtfEKwv94

L'application Open Barres de l' @anfr est au service des collectivités territoriales. Découvrez le témoignage de Monsieur @ChristianBruyen , Président du Département de la Marne, qui présente à quoi leur sert #OpenBarres sur le terrain. https://t.co/oqo2QnGwzU https://t.co/4MIGhn9RWq

Le groupe finlandais 🇫🇮 @Nokia va fabriquer pour la @NASA ce qui sera le 1er réseau de téléphonie mobile opérationnel sur la Lune 🌒  ! Le réseau #4G «ultra-compact, économe en énergie et résistant aux conditions spatiales» sera déployé dès la fin de 2022. https://t.co/lrAAGVlrS4

Savez-vous que l’exposition aux #ondes électromagnétiques de la #5G est très encadrée en France 🇫🇷 ?
La limite réglementaire est fixée entre 36 V/m et 61 V/m et l’exposition aux ondes avec la 5G est évaluée à un niveau inférieur à 2,3 V/m.
🆕 https://t.co/gerqAr1mRD https://t.co/ArKCwYakrc

Et bientôt, une nouvelle version de la Maison @ANFR 🏡, enrichie de nouveaux objets connectés et avec un nouveau design… » #Restezconnecté https://t.co/vmv7DPY6Zx

The @anfr published a simulation of #wave exposure created by mobile telephony 📱 in dense urban areas taking into account the envisaged changes to #4G and #5G.
Read the full report here : 🆕https://t.co/7DNgHGt2OK https://t.co/6x0z8tGjOC

📶 INAUGURATION 🤳
Demain 👉 Inauguration d'un nouveau site #4G multi-opérateurs #NewDealMobile en @DepVendee en présence de @cedric_o, du @PrefetVendee, de @YvesAuvinet, du Maire de Vouillé-les-Marais, des opérateurs et des élus locaux ➡️ https://t.co/veDREXhgOi https://t.co/d4JCkPlCyw

ANFR a Retweeté

🧐 Le saviez-vous ?

Le site #Cartoradio de l'@anfr permet de voir l'emplacement de presque toutes les antennes radioélectriques en France, de la 2G à la 4G, en passant par la future 5G mais aussi toutes les autres installations comme les radars météo. 📶 https://t.co/iUqqOpYIR1 https://t.co/A8gj8LP8tw

Lors de sa visite du 12 octobre dernier au siège de l’@ANFR, @cedric_o a rappelé le rôle de l’ANFR en matière de contrôle de l’expositions aux ondes et a demandé son renforcement dans le cadre du déploiement à venir de la #5G #transparence 📽️👇
@DGEntreprises
@Economie_Gouv https://t.co/4bOFxt2pQi

The French spectrum agency @ANFR congratulates Paul Milgrom and Robert Wilson for the 2020 #NobelPrize in economics, on their fundamental work on #spectrum auctions. https://t.co/e95aaYrcKW

#TousMobilisés👏 @bouyguestelecom, @orange, @SFR & @free inaugurent le premier site #4G #DCC du #NewDealMobile dans le #Var à Evenos, avec @Laetitiaquilici, Vice-Présidente du @Departement_Var, la Maire de Evenos, les opérateurs et les élus locaux https://t.co/wUm1yu4aCH

L’@anfr prend acte de la mise à jour par la société Sony du téléphone portable Sony Xperia 5 📱, afin de respecter la valeur limite du DAS localisé « tronc ».

▶️https://t.co/RPQ4H8GsQg https://t.co/jABom8jVl1

#CongresANEM
@AnnieGenevard lance les débats [Table Ronde]
Transition #numérique : impact environnemental, énergétique et societal
Avec :
@michel_sauvade
@cedric_o
@sorianotech
@GillesBregant
@bertodiplo
@nicolasguerin68
@DidierCasas
@pacolombani
@arthurdreyfuss https://t.co/BDhz8tUy6m

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