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Sunday, 23 July 2017

NASA to Show Technologies at Experimental Aircraft Association’s AirVenture 2017




Visitors to the Experimental Aircraft Association’s 2017 AirVenture in Oshkosh, Wisconsin will see NASA’s latest technologies from across the agency. The annual airshow will be held Monday through Sunday, July 24-30.
This year, the agency will fill the NASA Exhibit Pavilion in Aviation Gateway Park with displays and hands-on activities highlighting NASA’s progress of future aircraft, the International Space Station, Earth science, the solar system, and NASA’s plan for sending astronauts into deep space, including Mars. Visitors to the pavilion also will be able to touch an actual moon rock brought back during NASA’s Apollo missions. NASA also will have more than 20 subject matter experts presenting at the various AirVenture venues and on the flightline. Static displays of a NASA T-38 Talon aircraft, a NASA SR22 research aircraft and a former National Advisory Committee for Aeronautics (NACA) P-63 aircraft.
NASA’s main event will be a special presentation on “New Aviation Horizons: Ready for Flight” on July 27 from 8-9 p.m. CDT in AirVenture’s Theatre in the Woods. Moderated by NASA Acting Chief Technologist, Douglas Terrier, the panel features senior leaders from all four of NASA’s aeronautical research centers talking about their latest work on technologies involved with experimental, or “X”-planes (low boom supersonic and ultra-efficient subsonic) and testing traffic management systems for drones, followed by audience Q&As.
Here is a sampling of the more than 20 AirVenture forum talks involving NASA speakers (all times Central.) For a complete list, visit:

Thursday, 2 June 2016

HIGGS boson

Higgs boson

From Wikipedia, the free encyclopedia
Higgs boson
Candidate Higgs Events in ATLAS and CMS.png
Candidate Higgs boson events from collisionsbetween protons in the LHC. The top event in the CMSexperiment shows a decay into two photons (dashed yellow lines and green towers). The lower event in theATLAS experiment shows a decay into 4 muons (red tracks).[Note 1]
CompositionElementary particle
StatisticsBosonic
StatusA Higgs boson of mass ≈125 GeV has been tentatively confirmed by CERN on 14 March 2013,[1][2][3] although it is unclear as yet which model the particle best supports or whether multiple Higgs bosons exist.[2]
(See: Current status)
SymbolH0
TheorisedR. BroutF. EnglertP. HiggsG. S. GuralnikC. R. Hagen, and T. W. B. Kibble (1964)
DiscoveredLarge Hadron Collider (2011-2013)
Mass125.09±0.21 (stat.)±0.11 (syst.) GeV/c2(CMS+ATLAS)[4]
Mean lifetime
1.56×10−22 s
[Note 2] (predicted)
Decays into
bottom-antibottom pair (predicted)
two W bosons (observed)
two gluons (predicted)
tau-antitau pair (predicted)
two Z-bosons (observed)
two photons (observed)
various other decays (predicted)
Electric chargee
Colour charge0
Spin0 (tentatively confirmed at 125 GeV)[1]
Parity+1 (tentatively confirmed at 125 GeV)[1]
The Higgs boson is an elementary particle in the Standard Model of particle physics. It is the quantum excitation of the Higgs field[6][7]—a fundamental field of crucial importance to particle physics theory,[7] first suspected to exist in the 1960s. Unlike other known fields such as the electromagnetic field, it takes a non-zero constant value almost everywhere. The question of the Higgs field's existence has been the last unverified part of the Standard Model of particle physics and, according to some, "the central problem in particle physics".[8][9]
The presence of this field, now believed to be confirmed, explains why some fundamental particles have mass when, based on the symmetries controlling their interactions, they should be massless. The existence of the Higgs field would also resolve several other long-standing puzzles, such as the reason for the weak force's extremely short range.
Although it is hypothesized that the Higgs field permeates the entire Universe, evidence for its existence has been very difficult to obtain. In principle, the Higgs field can be detected through its excitations, manifest as Higgs particles, but these are extremely difficult to produce and detect. The importance of this fundamental question led to a 40 year search, and the construction of one of the world's most expensive and complex experimental facilities to date, CERN'sLarge Hadron Collider,[10] in an attempt to create Higgs bosons and other particles for observation and study. On 4 July 2012, the discovery of a new particle with a mass between 125 and 127 GeV/c2 was announced; physicists suspected that it was the Higgs boson.[11][12][13] Since then, the particle has been shown to behave, interact, and decay in many of the ways predicted by the Standard Model. It was also tentatively confirmed to have even parity and zero spin,[1] two fundamental attributes of a Higgs boson. This appears to be the first elementary scalar particlediscovered in nature.[14] More studies are needed to verify that the discovered particle has properties matching those predicted for the Higgs boson by the Standard Model, or whether, as predicted by some theories, multiple Higgs bosons exist.[3]
The Higgs boson is named after Peter Higgs, one of six physicists who, in 1964, proposed the mechanism that suggested the existence of such a particle. On December 10, 2013, two of them, Peter Higgs and François Englert, were awarded the Nobel Prize in Physics for their work and prediction (Englert's co-researcher Robert Brout had died in 2011 and the Nobel Prize is not ordinarily given posthumously).[15] Although Higgs's name has come to be associated with this theory, several researchers between about 1960 and 1972 independently developed different parts of it. In mainstream media the Higgs boson has often been called the "God particle", from a 1993 book on the topic; the nickname is strongly disliked by many physicists, including Higgs, who regard it as sensationalistic.[16][17][18]
In the Standard Model, the Higgs particle is a boson with no spinelectric charge, or colour charge. It is also very unstable, decaying into other particles almost immediately. It is a quantum excitation of one of the four components of the Higgs field. The latter constitutes a scalar field, with two neutral and two electrically charged components that form a complex doublet of the weak isospin SU(2) symmetry. The Higgs field is tachyonic (this does not refer to faster-than-light speeds, it means that symmetry-breaking through condensation of a particle must occur under certain conditions), and has a "Mexican hat" shaped potential with nonzero strength everywhere (including otherwise empty space), which in its vacuum state breaks the weak isospin symmetry of the electroweak interaction. When this happens, three components of the Higgs field are "absorbed" by the SU(2) and U(1) gauge bosons (the "Higgs mechanism") to become the longitudinal components of the now-massive W and Z bosons of the weak force. The remaining electrically neutral component separately couples to other particles known as fermions (via Yukawa couplings), causing these to acquire mass as well. Some versions of the theory predict more than one kind of Higgs fields and bosons. Alternative "Higgsless" models may have been considered if the Higgs boson was not discovered.
On 15 December 2015, two teams of physicists, working independently at CERN, reported preliminary hints of a possible new subatomic particle (more specifically, the ATLAS and CMS experiments, using 13 TeV proton collision data, showed a moderate excess around 750 GeV, in the two-photon spectrum): if real, one possibility is that the particle could be a heavier version of a Higgs boson.

On 4 July 2012, the ATLAS and CMS experiments at CERN's Large Hadron Collider announced they had each observed a new particle in the mass region around 126 GeV. This particle is consistent with the Higgs boson predicted by the Standard Model. The Higgs boson, as proposed within the Standard Model, is the simplest manifestation of the Brout-Englert-Higgs mechanism. Other types of Higgs bosons are predicted by other theories that go beyond the Standard Model.
On 8 October 2013 the Nobel prize in physics(link is external) was awarded jointly to François Englert and Peter Higgs "for the theoretical discovery of a mechanism that contributes to our understanding of the origin of mass of subatomic particles, and which recently was confirmed through the discovery of the predicted fundamental particle, by the ATLAS and CMS experiments at CERN's Large Hadron Collider."
Voir en français

Featured updates on this topic

1 Sep 2015 – At the 2015 LHCP conference the collaborations presented for the first time combined measurements of many properties of the Higgs boson

Updates

18 May 2016 – Do recent discoveries mean there’s nothing left? Find out what the future holds for theoretical physics in our final In Theory series installment
17 Mar 2015 – Today the ATLAS and CMS experiments presented for the first time a combination of their results on the mass of the Higgs boson
27 Jan 2015 – Recent publications from CMS use data from the LHC's first run to shed light on the properties of the Higgs boson
12 Nov 2014 – Without a doubt, it is a Higgs boson, but is it the Higgs boson of the Standard Model? Run 2 of the LHC find out, says theorist John Ellis
26 Sep 2014 – In CERN’s 60th year, the first proof of the existence of the Higgs boson earns a Guinness World Record for CERN, ATLAS and CMS
7 Jul 2014 – At ICHEP in Valencia, Spain, all four LHC experiments presented new results from the LHC’s first run. Run 2 physics holds much promise
23 Jun 2014 – Results reported by ATLAS and CMS discuss the decay of Higgs bosons directly to fermions, the particles that make up matter
19 May 2014 – Teach the machines: CERN launches competition to develop machine-learning analysis techniques for Higgs data
31 Mar 2014 – At the Moriond conference CMS presented the best constraint yet of the Higgs boson “width”, a parameter that determines the particle’s lifetime
10 Mar 2014 – On his first trip to CERN since sharing the Nobel prize in physics last year with Peter Higgs, François Englert talks Higgs bosons and supersymmetry

Tuesday, 24 May 2016

Richard Feynman

Richard Feynman  : was a Nobel Prize-winning American physicist, particularly known for his contributions to quantum physics, quantum electrodynamics and particle physics, as well as quantum computing and nanotechnology. During his lifetime, he was one of the best-known scientists in the world, and was a great popularizer of physics through his books and lectures. He was also regarded as something of an eccentric and free spirit, and brought a wicked sense of humour to his work, as exemplified by his well-known quote “I think I can safely say that nobody understands quantum mechanics”.

Richard Phillips Feynman was born on 11 May 1918 in Queens, New York to Jewish parents originally from Russia and Poland. As a child, he was heavily influenced by both his father, Melville, who encouraged him to ask questions to challenge orthodox thinking, and his mother, Lucille, from whom he inherited the sense of humour that he maintained throughout his life. His sister Joan also became a professional physicist.
By his early youth, Feynman described himself as an "avowed atheist". He delighted in repairing radios and demonstrated a talent for engineering from an early age. At Far Rockaway High School in Queens, he excelled in mathematics, and won the New York University Math Championship by a large margin in his final year there.
He was refused entry to his first choice Columbia University because of the "Jewish quota" and attended instead the Massachusetts Institute of Technology, where he received a bachelor's degree in 1939, and was named a Putnam Fellow. He obtained an unprecedented perfect score on the graduate school entrance exams to Princeton University (although he did rather poorly on the history and English portions), where he went to study mathematics and physics along with other luminaries such as Albert EinsteinWolfgang Pauli and John von Neumann. He received a PhD from Princeton in 1942, under his advisor John Wheeler, with a thesis in which he developed an approach to quantum mechanics governed by the principle of “least action”, replacing the wave-oriented electromagneticpicture developed by James Clerk Maxwell with one based entirely on particle interactions mapped in space and time.
During his time at Princeton, he married his first wife, Arline Greenbaum, although she died of tuberculosis just a few years later in 1945. A second marriage, in June 1952, to Mary Louise Bell, was brief and unsuccessful.
While at Princeton, Feynman was persuaded by the physicist Robert Wilson to participate in the Manhattan Project, the wartime US Army project at Los Alamos to develop an atomic bomb. Although not central to the project, he immersed himself in this work, and was soon made a group leader under Hans Bethe, and was present at the Trinity bomb test in 1945. As part of the project, he assisted in establishing the system for using IBM punched cards for computation, and in calculating neutronequations for nuclear reactors. Later, at the US Army’s Oak Ridge facility, he devised safety procedures for atomic material storage, and did theoretical work on the proposed uranium-hydride bomb, which later proved not to be feasible. He also gained a reputation for his pranks and practical jokes, and for his habit of Indian-style drumming out in the desert.
During his time at Los Alamos, Niels Bohr sought him out for discussions about physics, and he became a close friend of laboratory head Robert Oppenheimer, who unsuccessfully tried to lure him to the University of California in Berkeley after the war. Looking back, Feynman thought his decision to work on the Manhattan Project was justified at the time, but expressed grave reservations about the continuation of the project after the defeat of Nazi Germany, and suffered bouts of depression after the destruction of Hiroshima.
After the war, Feynman declined an offer from the Institute for Advanced Study in Princeton, New Jersey, despite the presence there of such distinguished faculty members as Albert Einstein, Kurt Gödel and John von Neumann. Instead he followed Hans Bethe to Cornell University, where he taught theoretical physics from 1945 to 1950. Feynman then opted for the position of Professor of Theoretical Physics at the California Institute of Technology (partly for the climate, as he admits), despite offers of professorships from other renowned universities. He remained there for the rest of his career.
In California, he married for the third time, to an English woman called Gweneth Howarth who shared his enthusiasm for life and spirited adventure. In 1962, they had a son, Carl, and adopted a daughter, Michelle, in 1968. Carl inherited his father’s love of, and propensity for, mathematics and went on to work at a high level in the computer field, particularly in the use of multiple computers to solve complex problems, later known as parallel computing.
Feynman gained a reputation for being able to explain complex elements of theoretical physics in an easily understandable way, and was sometimes referred to as “The Great Explainer”. He opposed rote learning or unthinking memorization, although he could also be strict with unprepared students. His 1964 book “Feynman Lectures On Physics”, which includes lectures on mathematics,electromagnetism, Newtonian physics, quantum physics and even the relation of physics to other sciences, remains a classic. Other lectures and miscellaneous talks were also turned into books, including “The Character of Physical Law”, “QED: The Strange Theory of Light and Matter”, “Statistical Mechanics” and “Lectures on Gravity”.
In December 1959, Feynman gave a visionary and ground-breaking talk entitled "There's Plenty of Room at the Bottom" at an American Physical Society meeting at the California Institute of Technology. In it, he suggested the possibility of building structures one atom or molecule at a time, an idea which seemed fantastic at the time, but which has since become widely known as nanotechnology. He personally offered $1,000 prizes for two of his challenges in nanotechnology, which were claimed by William McLellan and Tom Newman.
He was also one of the first scientists to conceive of the possibility of quantum computers and played a crucial role in developing the first massively parallel computer, finding innovative uses for it in numerical computations, building neural networks and physical simulations using cellular automata.
During his years at Caltech, he worked on, among other things: quantum electrodynamics (the theory of the interaction between light and matter) which he had begun developing at Cornell, and for which he was awarded the 1965 Nobel Prize in Physics jointly with Julian Schwinger and Sin-Itiro Tomonaga; the physics of the superfluidity of supercooled liquid helium and its quantum mechanical behaviour; a model of weak decay (such as the decay of a neutron into an electron, a proton and an anti-neutrino) in collaboration with fellow CalTech professor Murray Gell-Mann; his parton model for analyzing high-energy hadron collisions, which he developed in parallel with Murray Gell-Man’s theory of quarks(although the quark model would be the one to gain general acceptance).
In his work on quantum electrodynamics, he developed an important tool known as Feynman diagrams to help conceptualize and calculate interactions between particles in space-time, notably the interactions between electrons and their anti-matter counterparts, positrons. Feynman diagrams, which are easily-visualized graphic analogues of the complicated mathematical expressions needed to describe the behaviour of systems of interacting particles, have permeated many areas of theoretical physics in the second half of the 20th Century. His ambitious idea was to use the diagrams to model all of physics in terms of particles' spins and fundamental forces, and to explain the strong interactions governing the scattering of nucleons.
He was appointed a foreign member of the Royal Society in 1965, and later won the Oersted Medal for teaching, of which he seemed especially proud. He also became a member of the American Physical Society, the American Association for the Advancement of Science and the National Academy of Science. Later in life, Feynman turned his mind to theories of quantum gravity. Although not developed for the purpose, his Feynman diagrams had became fundamental for developing string theory and M-theory. He was not, however, totally convinced by the theories, and criticized string theorists for “not calculating anything” and for not checking their ideas.
Just two years before his death, Feynman played an important role in the Rogers Commission investigation of the 1986 Challenger Space Shuttle disaster. He developed two rare forms of cancer, Liposarcoma and Waldenström's macroglobulinemia, and died on 15 February 1988 in Los Angeles, shortly after a final attempt at surgery for the former. His last recorded words are noted as “I'd hate to die twice. It's so boring.”

Saturday, 21 May 2016

NASA : Bigelow Expandable Activity Module


Concept image of the Bigelow Expandable Activity Module (BEAM)
This artist's concept depicts the Bigelow Expandable Activity Module (BEAM), constructed by Bigelow Aerospace, attached to the International Space Station (ISS). The BEAM will be launched to the space station later this year.
Credits: Bigelow Aerospace
The Bigelow Expandable Activity Module (BEAM) is an expandable habitat technology demonstration for the International Space Station. Expandable habitats greatly decrease the amount of transport volume for future space missions. These “expandables” are lightweight and require minimal payload volume on a rocket, but expand after being deployed in space to potentially provide a comfortable area for astronauts to live and work. They also provide a varying degree of protection from solar and cosmic radiation, space debris, atomic oxygen, ultraviolet radiation and other elements of the space environment. 
The journey to Mars is complex and filled with challenges that NASA and its partners are continuously working to solve. Before sending the first astronauts to the Red Planet, several rockets filled with cargo and supplies will be deployed to await the crews’ arrival. Expandable modules, which are lower-mass and lower-volume systems than metal habitats, can increase the efficiency of cargo shipments, possibly reducing the number of launches needed and overall mission costs.
Mission Highlights
  • BEAM is scheduled to launch on the eighth SpaceX Commercial Resupply Service mission. After being attached to the Tranquility Node using the station’s robotic Canadarm2, it will be filled with air to expand it for a two-year test period in which astronauts aboard the space station will conduct a series of tests to validate overall performance and capability of expandable habitats.
  • Crews will routinely enter to take measurements and monitor its performance to help inform designs for future habitat systems. Learning how an expandable habitat performs in the thermal environment of space and how it reacts to radiation, micrometeroids, and orbital debris will provide information to address key concerns about living in the harsh environment of space.
  • Following the two-year test and validation period, BEAM will be robotically jettisoned from the space station, leaving orbit to burn during its descent through Earth’s atmosphere—much like many cargo spacecraft do.
  • If BEAM performs favorably, it could lead to future development of expandable habitation structures for future crews traveling in deep space.
  • The BEAM is an example of NASA’s increased commitment to partnering with industry to enable the growth of the commercial use of space. The BEAM project is co-sponsored by NASA's Advanced Exploration Systems (AES) Division and Bigelow Aerospace, which pioneers innovative approaches to rapidly and affordably develop prototype systems for future human exploration missions. The BEAM demonstration supports an AES objective to develop a deep space habitat for human missions beyond Earth orbit. 

More about BEAM

Sunday, 15 May 2016

The WMAP

Wilkinson Microwave Anisotropy Probe :


From Wikipedia, the free encyclopedia
"WMAP" redirects here. WMAP may also refer to either radio station WXNC or WGSP-FM.
Wilkinson Microwave Anisotropy Probe
WMAP spacecraft.jpg
Artist's impression of WMAP
NamesMAP
Explorer 80
Mission typeCMBR Astronomy
OperatorNASA
COSPAR ID2001-027A
SATCAT №26859
Websitemap.gsfc.nasa.gov
Mission duration9 years, 1 month, 19 days
Spacecraft properties
ManufacturerNASA / NRAO
Launch mass835 kg (1,841 lb)[1]
Dry mass763 kg (1,682 lb)
Dimensions3.6 m × 5.1 m (12 ft × 17 ft)
Power419 W
Start of mission
Launch date19:46:46, June 30, 2001[2]
RocketDelta II 7425-10
Launch siteCape Canaveral SLC-17
End of mission
Disposalpassivated
DeactivatedOctober 28, 2010
Orbital parameters
Reference systemL2 point
RegimeLissajous
Main telescope
TypeGregorian
Diameter1.4 m × 1.6 m (4.6 ft × 5.2 ft)
Wavelengths23 GHz to 94 GHz
Instruments
WMAP collage.jpg
NASA collage of WMAP-related imagery (spacecraft, CMB spectrum and background image)

Explorers program
← HETERHESSI →
The Wilkinson Microwave Anisotropy Probe (WMAP), originally known as the Microwave Anisotropy Probe(MAP) was a spacecraft operating from 2001 to 2010 which measured differences across the sky in the temperature of the cosmic microwave background (CMB) – the radiant heat remaining from the Big Bang.[3][4] Headed by ProfessorCharles L. Bennett of Johns Hopkins University, the mission was developed in a joint partnership between the NASAGoddard Space Flight Center and Princeton University.[5] The WMAP spacecraft was launched on June 30, 2001 from Florida. The WMAP mission succeeded the COBE space mission and was the second medium-class (MIDEX) spacecraft in the NASA Explorers program. In 2003, MAP was renamed WMAP in honor of cosmologist David Todd Wilkinson(1935–2002),[5] who had been a member of the mission's science team. After 9 years of operations, WMAP was switched off in 2010, following the launch of the more advanced Planck spacecraft by ESA in 2009.
WMAP's measurements played a key role in establishing the current Standard Model of Cosmology: the Lambda-CDM model. The WMAP data are very well fit by a universe that is dominated by dark energy in the form of a cosmological constant. Other cosmological data are also consistent, and together tightly constrain the Model. In the Lambda-CDM model of the universe, the age of the universe is 13.772±0.059 billion years. The WMAP mission's determination of the age of the universe to better than 1% precision was recognized by the Guinness Book of World Records.[6] The current expansion rate of the universe is (see Hubble constant) of 69.32±0.80 km·s−1·Mpc−1. The content of the universe presently consists of 4.628%±0.093% ordinary baryonic matter24.02%+0.88%
−0.87%
 Cold dark matter (CDM) that neither emits nor absorbs light; and 71.35%+0.95%
−0.96%
 of dark energy in the form of a cosmological constant that accelerates the expansion of the universe.[7] Less than 1% of the current contents of the universe is in neutrinos, but WMAP's measurements have found, for the first time in 2008, that the data prefers the existence of a cosmic neutrino background[8] with an effective number of neutrino species of 3.26±0.35. The contents point to a Euclidean flat geometry, with curvature (\Omega_{k}) of −0.0027+0.0039
−0.0038
. The WMAP measurements also support the cosmic inflationparadigm in several ways, including the flatness measurement.
The mission has won various awards: according to Science magazine, the WMAP was the Breakthrough of the Year for 2003.[9] This mission's results papers were first and second in the "Super Hot Papers in Science Since 2003" list.[10] Of the all-time most referenced papers in physics and astronomy in the INSPIRE-HEP database, only three have been published since 2000, and all three are WMAP publications. Bennett, Lyman A. Page, Jr., and David N. Spergel, the latter both of Princeton University, shared the 2010 Shaw Prize in astronomy for their work on WMAP.[11] Bennett and the WMAP science team were awarded the 2012 Gruber Prize in cosmology.
As of October 2010, the WMAP spacecraft is derelict in a heliocentric graveyard orbit after 9 years of operations.[12] All WMAP data are released to the public and have been subject to careful scrutiny. The final official data release was thenine-year release in 2012.[13][14]
Some aspects of the data are statistically unusual for the Standard Model of Cosmology. For example, the largest angular-scale measurement, the quadrupole moment, is somewhat smaller than the Model would predict, but this discrepancy is not highly significant.[15] A large cold spot and other features of the data are more statistically significant, and research continues into these.