The World as a Hologram

The Search For The History Of The Universe's Light Emission The light emitted from all objects in the Universe during its entire history - stars, galaxies, quasars etc. forms a diffuse sea of photons that permeates intergalactic space, referred to as "diffuse extragalactic background light" (EBL). Scientists have long tried to measure this fossil record of the luminous activity in the Universe in their quest to decipher the history and evolution of the Cosmos, but its direct determination from the diffuse glow of the night sky is very difficult and uncertain. Very high energy (VHE) gamma-rays, some 100,000,000,000 times more energetic than normal light, offer an alternative way to probe this background light, and UK researchers from Durham University in collaboration with international partners used the High Energy Stereoscopic System (HESS) gamma-ray telescopes in the Khomas Highlands of Namibia to observe several quasars (the most luminous VHE gamma-ray sources known) with this goal in mind. Source: PPARC

Beagle: In het kielzog van Darwin De Nederlandse Publieke Omroep maakt gebruik van cookies. We maken een onderscheid tussen functionele cookies en cookies voor het beheer van webstatistieken, advertenties en social media. De cookies bevatten geen persoonsgegevens en zijn dus niet tot een individu te herleiden. Met de cookies voor advertenties en social media worden mogelijk door derden gegevens verzameld buiten de websites van de Nederlandse Publieke Omroep. Bij instellingen kun je aangeven deze cookies niet te accepteren. Waarom cookies? De Nederlandse Publieke Omroep maakt gebruik van cookies. Klik hier voor meer informatie over cookies en een overzicht van de sites waar je toestemming voor geldt. Cookie instellingen aanpassen? De cookie instellingen voor de websites van de Nederlandse Publieke Omroep zijn te allen tijde te wijzigen. Cookie-instellingen aanpassenAkkoord

Dark Matter: The Larger Invisible Universe | Joe Arrigo PERSPECTIVE Normal matter—you, me, oatmeal, mountains, oceans, moons, planets, galaxies—make up about twenty-percent of the universe; the other eighty-percent is dark matter—star-stuff we cannot see or detect…yet. Why are scientists so certain this enigmatic matter exists? Because the evidence permeates the universe, first observed by Fritz Zwicky, when he measured the motions of galaxies and calculated that there wasn’t enough visible matter to affect galaxies to extent they were being pulled around.WWWFirst, there isn’t enough gravitational force within galaxies to bind and hold them in their current formation; then there is an invisible element that keeps them rotating faster than scientists would expect, clusters of galaxies bend and distort light more than they should, and supercomputer simulations exhibit that clouds of ordinary matter in the early universe did not have enough gravity to create the tight formations of galaxies we now see.

Zomergasten -> Afleveringen -> Robbert Dijkgraaf De Nederlandse Publieke Omroep maakt gebruik van cookies. We maken een onderscheid tussen functionele cookies en cookies voor het beheer van webstatistieken, advertenties en social media. De cookies bevatten geen persoonsgegevens en zijn dus niet tot een individu te herleiden. Met de cookies voor advertenties en social media worden mogelijk door derden gegevens verzameld buiten de websites van de Nederlandse Publieke Omroep. Bij instellingen kun je aangeven deze cookies niet te accepteren. Waarom cookies? De Nederlandse Publieke Omroep maakt gebruik van cookies. Klik hier voor meer informatie over cookies en een overzicht van de sites waar je toestemming voor geldt. Cookie instellingen aanpassen? De cookie instellingen voor de websites van de Nederlandse Publieke Omroep zijn te allen tijde te wijzigen. Cookie-instellingen aanpassenAkkoord

The Theory of Everything | Joe Arrigo PERSPECTIVE The above equation was written by Dr. Michio Kaku, theoretical physicist, who gradu­ated first in his physics class at Harvard, and, when he was in high school built a 2.3 million electron volt atom-smasher in his parents garage. It is an equation for String Field Theory—a theory that may unite The Theory of Relativity with Quantum Theory, into a uni­fied theory called The Theory of Everything. Theoretical physicists are those scientists who work in that twilight zone cutting edge realm be­tween reality and science fiction. For thirty years Einstein sought a unified theory of physics that would integrate all the forces of nature into a single beautiful tapestry. Even he failed. String Theory says that at the subatomic level, there are vibrating strings—that particles like protons, electrons and quarks are nothing but musical notes on a tiny vibrating string, that all the stupendous activities in the universe are born from a sub-atomic loop of energy deep within all matter. © Joe Arrigo

String People: Ed Witten What's the current answer to the question, "What is string theory?" Well, we've understood somehow that there's a more unified picture that mixes up quantum mechanical effects controlled by hbar and string effects controlled by alpha prime. So, there's this M theory story where different string theories are mixed up by dualities. I can't claim that we've gotten to the bottom of it, though. What is M theory? M theory is a name for a more unified theory that has the different string theories, as we know them, as limits, and which also can reduce, under appropriate conditions, to eleven-dimensional supergravity. So M-theory is a name for this picture, this more general picture that will generate the different limits through the different string theories. And likewise, if you ask this observer what happens for strong coupling, the traditional answer was, "Well I don't know." What is K theory and what does it mean for string theory? Why is it so hard to break supersymmetry in string theory?

In a "Rainbow" Universe Time May Have No Beginning What if the universe had no beginning, and time stretched back infinitely without a big bang to start things off? That's one possible consequence of an idea called "rainbow gravity," so-named because it posits that gravity's effects on spacetime are felt differently by different wavelengths of light, aka different colors in the rainbow. Rainbow gravity was first proposed 10 years ago as a possible step toward repairing the rifts between the theories of general relativity (covering the very big) and quantum mechanics (concerning the realm of the very small). The idea is not a complete theory for describing quantum effects on gravity, and is not widely accepted. Nevertheless, physicists have now applied the concept to the question of how the universe began, and found that if rainbow gravity is correct, spacetime may have a drastically different origin story than the widely accepted picture of the big bang. Yet the concept has its critics.

Robbert Dijkgraaf Four things you might not know about dark matter Not long after physicists on experiments at the Large Hadron Collider at CERN laboratory discovered the Higgs boson, CERN Director-General Rolf Heuer was asked, “What’s next?” One of the top priorities he named: figuring out dark matter. Dark matter is five times more prevalent than ordinary matter. Dark matter shows up periodically in the media, often when an experiment has spotted a potential sign of it. Here are four facts to get you up to speed on one of the most exciting topics in particle physics: 1. Illustration by: Sandbox Studio, Chicago At this moment, several experiments are on the hunt for dark matter. In the 1930s, astrophysicist Fritz Zwicky was observing the rotations of the galaxies that form the Coma cluster, a group of more than 1000 galaxies located more than 300 million light years from Earth. The idea of dark matter was largely ignored until the 1970s, when astronomer Vera Rubin saw something that gave her the same thought. 2. 3. 4.

Edward Witten Edward Witten (/ˈwɪtən/; born August 26, 1951) is an American theoretical physicist and professor of mathematical physics at the Institute for Advanced Study in Princeton, New Jersey. Witten is a researcher in string theory, quantum gravity, supersymmetric quantum field theories, and other areas of mathematical physics. Birth and education[edit] Witten was born in Baltimore, Maryland. He is the son of Lorraine (Wollach) Witten and Louis Witten, a theoretical physicist specializing in gravitation and general relativity.[3] Witten attended the Park School of Baltimore (class of '68), and received his Bachelor of Arts with a major in history and minor in linguistics from Brandeis University in 1971. Research[edit] Fields medal work[edit] Witten was awarded the Fields Medal by the International Mathematical Union in 1990, becoming the first physicist to win the prize. In a written address to the ICM, Michael Atiyah said of Witten,[1] M-theory[edit] Other work[edit] Awards and honors[edit]

Dark energy and dark matter Gerard ′t Hooft Name: ′t Hooft, Gerard Postal address: Spinoza Instituut, Leuvenlaan 4 Postbus 80.195 3508 TD Utrecht. Voorts verbonden aan: Institute for Theoretical Physics Universiteit Utrecht Leuvenlaan 4, 3584 CC Utrecht Tel.: +31 30 253 5928 Tel. +31 30 253 1863 Fax: +31 30 253 5937 e-mail: g.thooft@uu.nl Warning: due to severe clogging of this email post box, I can no longer guarantee that received messages will be processed and/or answered.Warning 2: Requests to be recognized as “friend” in social networks such as Facebook or LinkedIn are only considered if they are written with some personal note, not when they seem to come from robots. Discussing Magnetic Monopoles with Rembert Duine Professor Theoretical Physics Click here for lectures (notes, PowerPoint files) Research interests: Gauge theories in elementary particle physics. More and more data concerning the Higgs particle are being registered at CERN. Quantum gravity and black holes . The Hierarchy Problem. Coming up soon: Manned spaceflight to Mars.