The quantum Hall effect continues to reveal its secrets to mathematicians and physicists. At a lecture in 1939, Paul Dirac said that “pure mathematics and physics are becoming ever more closely connected”.
He went on to say that the two subjects might unify, with “every branch of pure mathematics then having its physical application”. Dirac’s prognosis was, and remains, highly speculative. Today, there is no question of a unification of these fields. Techniques from pure mathematics are used in economics, engineering and finance, but there’s no sense in — nor reason for — these fields becoming one. Calcolare la densità di flusso magnetico con una formula - supermagnete.it. - The effects of magnetic fields. Should we duck?
The most energetic cosmic rays are dangerous because they are ionising radiation. Fortunately, on Earth we have two very effective lines of defence: the Earth’s magnetic field and its atmosphere. If we pass a current down a wire between the poles of a magnet, the wire will move at right angles to both the magnetic field and the current. Similarly, if we fired a beam of electrons into the magnetic field the electrons would move. The Earth’s magnetic field does a similar job.
Some particles in the Belts, the solar wind and cosmic rays, are deflected by the magnetic field to the North and South Poles. Is it safe to go out? Magnetic shield could protect spacecraft. Così era il guscio magnetico primordiale. Il campo magnetico terrestre viene generato nel suo nucleo di ferro liquido da una geodinamo.
Si ritiene che una geodinamo fosse già attiva agli albori della storia della Terra, per poi indebolirsi nei successivi miliardi di anni fino a raggiungere un punto critico 565 milioni di anni fa (immagine a sinistra). Fu a questo punto che iniziò a formarsi il nucleo interno, con conseguente aumento della forza della geodinamo e del campo magnetico (immagine a destra). Crediti: University of Rochester / Michael Osadciw Non erano trascorse che poche centinaia di milioni di anni dalla sua formazione, e già il nostro pianeta aveva messo insieme un’efficace armatura in grado di proteggerlo dalla minacciosa esuberanza solare. Il nostro primo scudo magnetico, stima uno studio uscito ieri su Pnas, risalirebbe infatti ad almeno 4.2 miliardi di anni fa. Un meccanismo differente da quello attuale, dicevamo. Le anomalie del campo magnetico della Terra. La magnetosfera, ossia la regione di Spazio dove agisce il campo magnetico della Terra, e le due strutture a imbuto, le cuspidi polari, che appunto convergono ai poli. | Andøya Space Center.
Hidden Winds on Jupiter May Be Messing with Its Enormous Magnetic Field. Jupiter's magnetic field has changed since the 1970s, and physicists have proved it.
That's not exactly a surprise. Earth's magnetic field, the only planetary field for which we have good ongoing measurements, changes all the time. But the new information is important, because these small changes reveal hidden details of a planet's internal "dynamo," the system that produces its magnetic field.
In a paper published May 20 in the journal Nature Astronomy, a team of researchers looked at magnetic field data from four past missions to Jupiter (Pioneer 10, which reached Jupiter in 1973; Pioneer 11, which reached Jupiter in 1974; Voyager 1, which reached Jupiter in 1979; and Ulysses, which reached Jupiter in 1992). [10 Places in the Solar System We'd Most Like to Visit] They compared that data to a map of the planet's magnetic field produced by the spacecraft Juno, which conducted the most recent and most thorough probe of the giant planet. Researchers confirm Earth's inner core is solid. A new study by researchers at The Australian National University (ANU) could help us understand how our planet was formed.
Associate Professor Hrvoje Tkalčić and PhD Scholar Than-Son Phạm are confident they now have direct proof that Earth’s inner core is solid. They came up with a way to detect shear waves, or “J waves” in the inner core — a type of wave which can only travel through solid objects. “We found the inner core is indeed solid, but we also found that it’s softer than previously thought,” Associate Professor Tkalčić said. “It turns out — if our results are correct — the inner core shares some similar elastic properties with gold and platinum.
The inner core is like a time capsule, if we understand it we’ll understand how the planet was formed, and how it evolves.” Earth’s magnetic field is acting up and geologists don’t know why. Update, 9 January: The release of the World Magnetic Model has been postponed to 30 January due to the ongoing US government shutdown.
Something strange is going on at the top of the world. Earth’s north magnetic pole has been skittering away from Canada and towards Siberia, driven by liquid iron sloshing within the planet’s core. The magnetic pole is moving so quickly that it has forced the world’s geomagnetism experts into a rare move. On 15 January, they are set to update the World Magnetic Model, which describes the planet’s magnetic field and underlies all modern navigation, from the systems that steer ships at sea to Google Maps on smartphones. The most recent version of the model came out in 2015 and was supposed to last until 2020 — but the magnetic field is changing so rapidly that researchers have to fix the model now. The problem lies partly with the moving pole and partly with other shifts deep within the planet.
By early 2018, the World Magnetic Model was in trouble. Mystery of Purple Lights in Sky Solved With Citizen Scientists' Help. Scientists May Have Found The Birthplace Of Magnetic Field Reversals. Observation of Dirac monopoles in a synthetic magnetic field. E' arrivata la tempesta magnetica, più violenta del previsto - Spazio & Astronomia. Dopo quella più debole del 7 settembre, è arrivata ed è stata più intensa del previsto, la tempesta magnetica innescata dalla più potente eruzione solare degli ultimi 11 anni.
Il time-lapse dell'Aurora Boreale dallo spazio. Supermagneti per un minisole - Scientificast. Di solito le unità di misura del Sistema Internazionale sono scelte in modo che una unità sia qualcosa con cui possiamo avere a che fare nella vita quotidiana: un metro, un chilogrammo, un secondo.
Il caos magnetico da cui nasce una stella. Sole 'sbuffa' di nuovo, rischio di una tempesta magnetica - Magnets, all the way down!