THE LARGE HADRON COLLIDER, SCIENCE IN MOVEMENT

Today, The Grandma has been talking with Joseph de Ca'th Lon about the Large Hadron Collider at CERN, that was powered up in Geneva, on a day like today in 2008.

The Large Hadron Collider (LHC) is the world's largest and highest-energy particle collider.

It was built by the European Organization for Nuclear Research (CERN) between 1998 and 2008 in collaboration with over 10,000 scientists and hundreds of universities and laboratories, as well as more than 100 countries. It lies in a tunnel 27 kilometres in circumference and as deep as 175 metres beneath the France–Switzerland border near Geneva.

The first collisions were achieved in 2010 at an energy of 3.5 teraelectronvolts (TeV) per beam, about four times the previous world record. After upgrades it reached 6.5 TeV per beam (13 TeV total collision energy, the present world record). At the end of 2018, it was shut down for two years for further upgrades.

The collider has four crossing points where the accelerated particles collide. Seven detectors, each designed to detect different phenomena, are positioned around the crossing points. The LHC primarily collides proton beams, but it can also accelerate beams of heavy ions: lead–lead collisions and proton–lead collisions are typically performed for one month a year.

The LHC's goal is to allow physicists to test the predictions of different theories of particle physics, including measuring the properties of the Higgs boson searching for the large family of new particles predicted by supersymmetric theories, and other unresolved questions in particle physics.

The term hadron refers to subatomic composite particles composed of quarks held together by the strong force, as atoms and molecules are held together by the electromagnetic force.

More information: CERN

The best-known hadrons are the baryons such as protons and neutrons; hadrons also include mesons such as the pion and kaon, which were discovered during cosmic ray experiments in the late 1940s and early 1950s.

A collider is a type of a particle accelerator with two directed beams of particles. In particle physics, colliders are used as a research tool: they accelerate particles to very high kinetic energies and let them impact other particles.

Analysis of the byproducts of these collisions gives scientists good evidence of the structure of the subatomic world and the laws of nature governing it. Many of these byproducts are produced only by high-energy collisions, and they decay after very short periods of time. Thus many of them are hard or nearly impossible to study in other ways.

Many physicists hope that the Large Hadron Collider will help answer some of the fundamental open questions in physics, which concern the basic laws governing the interactions and forces among the elementary objects, the deep structure of space and time, and in particular the interrelation between quantum mechanics and general relativity.

Data are also needed from high-energy particle experiments to suggest which versions of current scientific models are more likely to be correct -in particular to choose between the Standard Model and Higgsless model and to validate their predictions and allow further theoretical development.

The collider is contained in a circular tunnel, with a circumference of 26.7 kilometres, at a depth ranging from 50 to 175 metres underground. The variation in depth was deliberate, to reduce the amount of tunnel that lies under the Jura Mountains to avoid having to excavate a vertical access shaft there.

More information: Atlas Obscura

A tunnel was chosen to avoid having to purchase expensive land on the surface, which would also have an impact on the landscape and to take advantage of the shielding against background radiation that the earth's crust provides.

The LHC first went live on 10 September 2008, but initial testing was delayed for 14 months from 19 September 2008 to 20 November 2009, following a magnet quench incident that caused extensive damage to over 50 superconducting magnets, their mountings, and the vacuum pipe.

During its first run (2010–2013), the LHC collided two opposing particle beams of either protons at up to 4 teraelectronvolts (4 TeV or 0.64 microjoules), or lead nuclei (574 TeV per nucleus, or 2.76 TeV per nucleon).

Its first run discoveries included the long-sought Higgs boson, several composite particles (hadrons) like the χb (3P) bottomonium state, the first creation of a quark-gluon plasma, and the first observations of the very rare decay of the Bs meson into two muons (Bs0 → μ+μ−), which challenged the validity of existing models of supersymmetry.

An initial focus of research was to investigate the possible existence of the Higgs boson, a key part of the Standard Model of physics which is predicted by theory, but had not yet been observed before due to its high mass and elusive nature.

CERN scientists estimated that, if the Standard Model were correct, the LHC would produce several Higgs bosons every minute, allowing physicists to finally confirm or disprove the Higgs boson's existence. In addition, the LHC allowed the search for supersymmetric particles and other hypothetical particles as possible unknown areas of physics.

Some extensions of the Standard Model predict additional particles, such as the heavy W' and Z' gauge bosons, which are also estimated to be within reach of the LHC to discover.

More information: Nature

 Science is a way of life.
Science is a perspective.
Science is the process that takes us from confusion
to understanding in a manner that's precise, predictive and reliable
-a transformation, for those lucky enough to experience it,
that is empowering and emotional.

Brian Greene

CERN BECOMES WORLD WIDE WEB PROTOCOLS FREE

The Grandma wants to commemorate an important fact. On a day like today in 1993, CERN announced World Wide Web protocols will be free. It was the beginning of the Internet as we understand nowadays.

The European Organization for Nuclear Research, in French Organisation européenne pour la recherche nucléaire, known as CERN; derived from the name Conseil Européen pour la Recherche Nucléaire, is a European research organization that operates the largest particle physics laboratory in the world.

Established in 1954, the organization is based in a northwest suburb of Geneva on the Franco–Swiss border and has 23 member states. Israel is the only non-European country granted full membership. CERN is an official United Nations Observer.

The acronym CERN is also used to refer to the laboratory, which in 2019 had 2,660 scientific, technical, and administrative staff members, and hosted about 12,400 users from institutions in more than 70 countries. In 2016 CERN generated 49 petabytes of data.

CERN's main function is to provide the particle accelerators and other infrastructure needed for high-energy physics research -as a result, numerous experiments have been constructed at CERN through international collaborations. 

The main site at Meyrin hosts a large computing facility, which is primarily used to store and analyse data from experiments, as well as simulate events. Researchers need remote access to these facilities, so the lab has historically been a major wide area network hub. CERN is also the birthplace of the World Wide Web.

The World Wide Web (WWW), commonly known as the Web, is an information system where documents and other web resources are identified by Uniform Resource Locators (URLs, such as https://example.com/), which may be interlinked by hyperlinks, and are accessible over the Internet.

The resources of the Web are transferred via the Hypertext Transfer Protocol (HTTP), may be accessed by users by a software application called a web browser, and are published by a software application called a web server. The World Wide Web is not synonymous with the Internet, which pre-dated the Web in some form by over two decades and upon which technologies the Web is built.

More information: CERN

English scientist Timothy Berners-Lee invented the World Wide Web in 1989. He wrote the first web browser in 1990 while employed at CERN near Geneva, Switzerland. The browser was released outside CERN to other research institutions starting in January 1991, and then to the public in August 1991. The Web began to enter everyday use in 1993-4, when websites for general use started to become available. The World Wide Web has been central to the development of the Information Age, and is the primary tool billions of people used to interact on the Internet.

Web resources may be any type of downloaded media, but web pages are hypertext documents formatted in Hypertext Markup Language (HTML). Special HTML syntax displays embedded hyperlinks with URLs which permits users to navigate to other web resources. In addition to text, web pages may contain references to images, video, audio, and software components which are either displayed or internally executed in the user's web browser to render pages or streams of multimedia content.

Multiple web resources with a common theme and usually a common domain name, make up a website.

Websites are stored in computers that are running a web server, which is a program that responds to requests made over the Internet from web browsers running on a user's computer. 

Website content can be provided by a publisher, or interactively from user-generated content.

Websites are provided for a myriad of informative, entertainment, commercial, and governmental reasons. The underlying concept of hypertext originated in previous projects from the 1960s, such as the Hypertext Editing System (HES) at Brown University, Ted Nelson's Project Xanadu, and Douglas Engelbart's oN-Line System (NLS). Both Nelson and Engelbart were in turn inspired by Vannevar Bush's microfilm-based memex, which was described in the 1945 essay As We May Think.

Tim Berners-Lee's vision of a global hyperlinked information system became a possibility by the second half of the 1980s.

By 1985, the global Internet began to proliferate in Europe and the Domain Name System (upon which the Uniform Resource Locator is built) came into being.

In 1988 the first direct IP connection between Europe and North America was made and Berners-Lee began to openly discuss the possibility of a web-like system at CERN.

While working at CERN, Berners-Lee became frustrated with the inefficiencies and difficulties posed by finding information stored on different computers.

More information: Web Foundation

On 12 March 1989, he submitted a memorandum, titled Information Management: A Proposal, to the management at CERN for a system called Mesh that referenced to ENQUIRE, a database and software project he had built in 1980, which used the term web and described a more elaborate information management system based on links embedded as text: Imagine, then, the references in this document all being associated with the network address of the thing to which they referred, so that while reading this document, you could skip to them with a click of the mouse.

Such a system, he explained, could be referred to using one of the existing meanings of the word hypertext, a term that he says was coined in the 1950s. There is no reason, the proposal continues, why such hypertext links could not encompass multimedia documents including graphics, speech and video, so that Berners-Lee goes on to use the term hypermedia.

With help from his colleague and fellow hypertext enthusiast Robert Cailliau he published a more formal proposal on 12 November 1990 to build a Hypertext project called WorldWideWeb (one word, abbreviated W3) as a web of hypertext documents to be viewed by browsers using a client-server architecture. At this point HTML and HTTP had already been in development for about two months and the first Web server was about a month from completing its first successful test.

More information: High Performance Browser Networking

This proposal estimated that a read-only web would be developed within three months and that it would take six months to achieve the creation of new links and new material by readers, so that authorship becomes universal as well as the automatic notification of a reader when new material of interest to him/her has become available. While the read-only goal was met, accessible authorship of web content took longer to mature, with the wiki concept, WebDAV, blogs, Web 2.0 and RSS/Atom.

By Christmas 1990, Berners-Lee had built all the tools necessary for a working Web the first web browser (WorldWideWeb, which was a web editor as well) and the first web server. The first website, which described the project itself, was published on 20 December 1990.

The Web began to enter general use in 1993-4, when websites for everyday use started to become available. Historians generally agree that a turning point for the Web began with the 1993 introduction of Mosaic, a graphical web browser developed at the National Center for Supercomputing Applications at the University of Illinois at Urbana–Champaign (NCSA-UIUC).

More information: Web Design

 We mustn't forget we chose the name 'WWW'
before there was even one line of code written.
We could do that because the Internet
as an infrastructure was already there.

Robert Cailliau

MAY 29, 1919: THEORY OF RELATIVITY & A SOLAR ECLIPSE

Albert Einstein

Today, Joseph de Ca'th Lon wants to talk about the theory of the relativity. He's in his native country in Switzerland where the CERN is located.

General theory of relativity is the geometric theory of gravitation published by Albert Einstein in 1915 and the current description of gravitation in modern physics. General relativity is considered as the most beautiful of all existing physical theories. General relativity generalizes special relativity and Newton's law of universal gravitation, providing a unified description of gravity as a geometric property of space and time, or spacetime. In particular, the curvature of spacetime is directly related to the energy and momentum of whatever matter and radiation are present. The relation is specified by the Einstein field equations, a system of partial differential equations.

More information: CERN

Some predictions of general relativity differ significantly from those of classical physics, especially concerning the passage of time, the geometry of space, the motion of bodies in free fall, and the propagation of light. Examples of such differences include gravitational time dilation, gravitational lensing, the gravitational redshift of light, and the gravitational time delay. The predictions of general relativity have been confirmed in all observations and experiments to date. Although general relativity is not the only relativistic theory of gravity, it is the simplest theory that is consistent with experimental data. However, unanswered questions remain, the most fundamental being how general relativity can be reconciled with the laws of quantum physics to produce a complete and self-consistent theory of quantum gravity.

Albert Einstein

Einstein's theory has important astrophysical implications. For example, it implies the existence of black holes, regions of space in which space and time are distorted in such a way that nothing, not even light, can escape, as an end-state for massive stars. There is ample evidence that the intense radiation emitted by certain kinds of astronomical objects is due to black holes; for example, microquasars and active galactic nuclei result from the presence of stellar black holes and supermassive black holes, respectively. The bending of light by gravity can lead to the phenomenon of gravitational lensing, in which multiple images of the same distant astronomical object are visible in the sky. 

General relativity also predicts the existence of gravitational waves, which have since been observed directly by physics collaboration LIGO. In addition, general relativity is the basis of current cosmological models of a consistently expanding universe.

Soon after publishing the special theory of relativity in 1905, Einstein started thinking about how to incorporate gravity into his new relativistic framework. In 1907, beginning with a simple thought experiment involving an observer in free fall, he embarked on what would be an eight-year search for a relativistic theory of gravity. After numerous detours and false starts, his work culminated in the presentation to the Prussian Academy of Science in November 1915 of what are now known as the Einstein field equations. These equations specify how the geometry of space and time is influenced by whatever matter and radiation are present, and form the core of Einstein's general theory of relativity.

Albert Einstein & Georges Lemaître

The Einstein field equations are nonlinear and very difficult to solve. Einstein used approximation methods in working out initial predictions of the theory. But as early as 1916, the astrophysicist Karl Schwarzschild found the first non-trivial exact solution to the Einstein field equations, the Schwarzschild metric. This solution laid the groundwork for the description of the final stages of gravitational collapse, and the objects known today as black holes. In the same year, the first steps towards generalizing Schwarzschild's solution to electrically charged objects were taken, which eventually resulted in the Reissner–Nordström solution, now associated with electrically charged black holes. 

In 1917, Einstein applied his theory to the universe as a whole, initiating the field of relativistic cosmology. In line with contemporary thinking, he assumed a static universe, adding a new parameter to his original field equations—the cosmological constant—to match that observational presumption. By 1929, however, the work of Hubble and others had shown that our universe is expanding. This is readily described by the expanding cosmological solutions found by Friedmann in 1922, which do not require a cosmological constant.

More information: Live Science

Georges Lemaître used these solutions to formulate the earliest version of the Big Bang models, in which our universe has evolved from an extremely hot and dense earlier state. Einstein later declared the cosmological constant the biggest blunder of his life.

Georges Lemaître

During that period, general relativity remained something of a curiosity among physical theories. It was clearly superior to Newtonian gravity, being consistent with special relativity and accounting for several effects unexplained by the Newtonian theory. Einstein himself had shown in 1915 how his theory explained the anomalous perihelion advance of the planet Mercury without any arbitrary parameters, fudge factors. Similarly, a 1919 expedition led by Eddington confirmed general relativity's prediction for the deflection of starlight by the Sun during the total solar eclipse of May 29, 1919, making Einstein instantly famous. 

Yet the theory entered the mainstream of theoretical physics and astrophysics only with the developments between approximately 1960 and 1975, now known as the golden age of general relativity. Physicists began to understand the concept of a black hole, and to identify quasars as one of these objects' astrophysical manifestations. Ever more precise solar system tests confirmed the theory's predictive power, and relativistic cosmology, too, became amenable to direct observational tests.

More information: Space

Time travel used to be thought of as just science fiction, 

but Einstein's general theory of relativity allows for the possibility that we could warp space-time so much that you could go off in a rocket 

and return before you set out.

Stephen Hawking