Gli astronomi di tutto il mondo osservano in queste ore con allarme il fenomeno - che ha causato aurore anomale fino in Scozia e in Irlanda - innescato da una violenta eruzione solare avvenuta alle ore 3.00 di martedì, che ha già mandato in crisi le comunicazioni in Cina e minaccia di colpire anche linee elettriche e comunicazioni satellitari nel resto del mondo.
Si tratta del più potente fenomeno di questo tipo registrato negli ultimi quattro anni, e un banco di prova importante in vista della gigantesca tempesta solare prevista per il 2012, che potrebbe causare la fine del mondo così come lo conosciamo.
L'esplosione, della potenza di milioni di bombe all'idrogeno fatte scoppiare tutte insieme nella fotosfera della nostra stella, ha distorto tramite tremende ripercussioni magnetiche la ionosfera al di sopra della Cina.
Gli astronomi della Nasa confermano che questa eruzione è la prima di una lunga serie.
Il sole si sta risvegliando.
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venerdì 18 febbraio 2011
sabato 15 gennaio 2011
Il sole è arrivato con due giorni d'anticipo in Groenlandia
Per la prima volta nella Storia, il sole non ha rispettato l'appuntamento con l'alba sulla Groenlandia, levandosi sull'orizzonte con due giorni d'anticipo.
Esperti e scienziati tentano di dare una risposta...
Dal Daily Mail del 14 gennaio
The sun over Greenland has risen two days early, baffling scientists and sparking fears that Arctic icecaps are melting faster than previously thought.
Experts say the sun should have risen over the Arctic nation's most westerly town, Ilulissat, yesterday, ending a month-and-a-half of winter darkness.
But for the first time in history light began creeping over the horizon at around 1pm on Tuesday - 48 hours ahead of the usual date of 13 January.
Climate change? The sun rose in Ilulissat, Greenland, two days early on Tuesday, ending a month-and-a-half of winter darkness. One theory is that melting ice caps have lowered the horizon allowing the sun to shine through earlier
Thomas Posch, of the Institute for Astronomy of the University of Vienna, said that a local change of the horizon was 'by far the most obvious explanation'.
He said as the ice sinks, so to does the horizon, creating the illusion that the sun has risen early.
This theory, based on the gradual decline of Greenland's ice sheet, is backed by recent climate studies.
A report by the World Meteorology Organisation shows that temperatures in Greenland have risen around 3C above average over the last year.
It also reported that December was much warmer than usual with rainfall instead of snow recorded for the first time in Kuujjuaq since records began.
It has even been suggested that the sun's early appearance could have an astronomical explanation.
But Wolfgang Lenhardt, director of the department of geophysics at the Central Institute for Meteorology in Vienna, scotched this theory.
He said: 'The constellation of the stars has not changed. If that had happened, there would have been an outcry around the world.
'The data of the Earth's axis and Earth's rotation are monitored continuously and meticulously and we would know if that had happened.'
E' davvero un'illusione?
E' il nuovo segno di un disastro climatico sempre più tangibile?
Oppure qualcosa sta cambiando a livello astronomico?
domenica 18 ottobre 2009
Un "nastro magnetico gigante" di origine sconosciuta ai confini dell'Eliosfera.
"Questo è un nuovo risultato scioccante" dice il principale inquirente del progetto IBEX, Dave McComas del Southwest Research Institute. "Non avevamo idea che questo nastro esistesse - o che cosa l'abbia creato. Le nostre idee precedenti riguardo all'eliosfera esterna dovranno essere riscritte". [...] "Non può essere una coincidenza, ci sfugge qualche fondamentale aspetto sulle interazioni tra l'Eliosfera e il resto della galassia. I teorici stanno lavorando come pazzi per cercare di capirci qualcosa."
Dal sito della NASA:
October 15, 2009: For years, researchers have known that the solar system is surrounded by a vast bubble of magnetism. Called the "heliosphere," it springs from the sun and extends far beyond the orbit of Pluto, providing a first line of defense against cosmic rays and interstellar clouds that try to enter our local space. Although the heliosphere is huge and literally fills the sky, it emits no light and no one has actually seen it.
Until now.
NASA's IBEX (Interstellar Boundary Explorer) spacecraft has made the first all-sky maps of the heliosphere and the results have taken researchers by surprise. The maps are bisected by a bright, winding ribbon of unknown origin:
"This is a shocking new result," says IBEX principal investigator Dave McComas of the Southwest Research Institute. "We had no idea this ribbon existed--or what has created it. Our previous ideas about the outer heliosphere are going to have to be revised."
Although the ribbon looks bright in the IBEX map, it does not glow in any conventional sense. The ribbon is not a source of light, but rather a source of particles--energetic neutral atoms or ENAs. IBEX's sensors can detect these particles, which are produced in the outer heliosphere where the solar wind begins to slow down and mix with interstellar matter from outside the solar system.
"This ribbon winds between the two Voyager spacecraft and was not observed by either of them," notes Eric Christian, IBEX deputy mission scientist at NASA's Goddard Space Flight Center. "It's like having two weather stations, but missing the big storm that runs between them."
Unlike the Voyager spacecraft, which have spent decades traveling to the edge of the solar system for in situ sampling, IBEX stayed closer to home. It is in Earth orbit, spinning around and collecting ENAs from all directions. This gives IBEX the unique "big picture" view necessary to discover something as vast as the ribbon.
The ribbon also has fine structure--small filaments of ENA emission no more than a few degrees wide. The fine structure is as much of a mystery as the ribbon itself, researchers say.
One important clue: The ribbon runs perpendicular to the direction of the galactic magnetic field just outside the heliosphere, as shown in the illustration at right.
"That cannot be a coincidence," says McComas. But what does it mean? No one knows. "We're missing some fundamental aspect of the interaction between the heliosphere and the rest of the galaxy. Theorists are working like crazy to figure this out."
Understanding the physics of the outer heliosphere is important because of the role it plays in shielding the solar system against cosmic rays. The heliosphere's size and shape are key factors in determining its shielding power and, thus, how many cosmic rays reach Earth. For the first time, IBEX is revealing how the heliosphere might respond when it bumps into interstellar clouds and galactic magnetic fields.
"IBEX is now making a second all-sky map, and we're eager to see if the ribbon is changing," says McComas. "Watching the ribbon evolve--if it is evolving--could yield more clues."
Stay tuned for updates.
Author: Dr. Tony Phillips | Credit: Science@NASA
Dal sito della NASA:
October 15, 2009: For years, researchers have known that the solar system is surrounded by a vast bubble of magnetism. Called the "heliosphere," it springs from the sun and extends far beyond the orbit of Pluto, providing a first line of defense against cosmic rays and interstellar clouds that try to enter our local space. Although the heliosphere is huge and literally fills the sky, it emits no light and no one has actually seen it.
Until now.
NASA's IBEX (Interstellar Boundary Explorer) spacecraft has made the first all-sky maps of the heliosphere and the results have taken researchers by surprise. The maps are bisected by a bright, winding ribbon of unknown origin:
"This is a shocking new result," says IBEX principal investigator Dave McComas of the Southwest Research Institute. "We had no idea this ribbon existed--or what has created it. Our previous ideas about the outer heliosphere are going to have to be revised."
Although the ribbon looks bright in the IBEX map, it does not glow in any conventional sense. The ribbon is not a source of light, but rather a source of particles--energetic neutral atoms or ENAs. IBEX's sensors can detect these particles, which are produced in the outer heliosphere where the solar wind begins to slow down and mix with interstellar matter from outside the solar system.
"This ribbon winds between the two Voyager spacecraft and was not observed by either of them," notes Eric Christian, IBEX deputy mission scientist at NASA's Goddard Space Flight Center. "It's like having two weather stations, but missing the big storm that runs between them."
Unlike the Voyager spacecraft, which have spent decades traveling to the edge of the solar system for in situ sampling, IBEX stayed closer to home. It is in Earth orbit, spinning around and collecting ENAs from all directions. This gives IBEX the unique "big picture" view necessary to discover something as vast as the ribbon.
The ribbon also has fine structure--small filaments of ENA emission no more than a few degrees wide. The fine structure is as much of a mystery as the ribbon itself, researchers say.
One important clue: The ribbon runs perpendicular to the direction of the galactic magnetic field just outside the heliosphere, as shown in the illustration at right.
"That cannot be a coincidence," says McComas. But what does it mean? No one knows. "We're missing some fundamental aspect of the interaction between the heliosphere and the rest of the galaxy. Theorists are working like crazy to figure this out."
Understanding the physics of the outer heliosphere is important because of the role it plays in shielding the solar system against cosmic rays. The heliosphere's size and shape are key factors in determining its shielding power and, thus, how many cosmic rays reach Earth. For the first time, IBEX is revealing how the heliosphere might respond when it bumps into interstellar clouds and galactic magnetic fields.
"IBEX is now making a second all-sky map, and we're eager to see if the ribbon is changing," says McComas. "Watching the ribbon evolve--if it is evolving--could yield more clues."
Stay tuned for updates.
Author: Dr. Tony Phillips | Credit: Science@NASA
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