13/11/2014, 13:21
zakmck ha scritto:ubatuba ha scritto:
ciao zack,tu hai affermato che i piedi sono affondati di qualke cm,mentre da altra parte leggevo che sarebbero affondati di diversi cm.........quale sara'la verita??????
Inizialmente si era parlato di 40 cm. ma si e' trattato di un errore iniziale. Non si tratta comunque di informazioni ufficiali ma di indiscrezioni. Come saprai tra gli accreditati ci sono anche alcuni blogger, tra cui anche la nostra 2di7, e forse qualcuno ha capito e riportato male la misura.
Purtroppo ora pare siano proprio pochi centimetri.
Comunque vediamo cosa diranno alla conferenza pomeridiana, anche se da quello che ho capito il problema maggiore sara' la brevita' del giorno per Philae.
13/11/2014, 13:52
13/11/2014, 15:36
Ufologo 555 ha scritto:
Belle davvero le foto.
13/11/2014, 15:49
13/11/2014, 19:15
13/11/2014, 20:16
14/11/2014, 09:24
The singing comet
Rosetta’s Plasma Consortium (RPC) has uncovered a mysterious ‘song’ that Comet 67P/Churyumov-Gerasimenko is singing into space. RPC principal investigator Karl-Heinz Glaßmeier, head of Space Physics and Space Sensorics at the Technische Universität Braunschweig, Germany, tells us more.
Artist's impression of the 'singing comet' 67P/Churyumov-Gerasimenko. Credit: ESA/Rosetta/NavCam
RPC consists of five instruments on the Rosetta orbiter that provide a wide variety of complementary information about the plasma environment surrounding Comet 67P/C-G. (Reminder: Plasma is the fourth state of matter, an electrically conductive gas that can carry magnetic fields and electrical currents.)
The instruments are designed to study a number of phenomena, including: the interaction of 67P/C-G with the solar wind, a continuous stream of plasma emitted by the Sun; changes of activity on the comet; the structure and dynamics of the comet’s tenuous plasma ‘atmosphere’, known as the coma; and the physical properties of the cometary nucleus and surface.
But one observation has taken the RPC scientists somewhat by surprise. The comet seems to be emitting a ‘song’ in the form of oscillations in the magnetic field in the comet’s environment. It is being sung at 40-50 millihertz, far below human hearing, which typically picks up sound between 20 Hz and 20 kHz. To make the music audible to the human ear, the frequencies have been increased by a factor of about 10,000.
The music was heard clearly by the magnetometer experiment (RPC-Mag) for the first time in August, when Rosetta drew to within 100 km of 67P/C-G. The scientists think it must be produced in some way by the activity of the comet, as it releases neutral particles into space where they become electrically charged due to a process called ionisation. But the precise physical mechanism behind the oscillations remains a mystery.
“This is exciting because it is completely new to us. We did not expect this and we are still working to understand the physics of what is happening,” says Karl-Heinz.
RPC may also be able to help in tracking Philae’s descent to the surface of 67P/C-G on 12 November, in tandem with the lander’s on-board magnetometer, ROMAP .
The sonification of the RPC-Mag data was compiled by German composer Manuel Senfft (http://www.tagirijus.de).
Fonte:http://blogs.esa.int/rosetta/2014/11/11/the-singing-comet/
Larry Grant says:
13/11/2014 at 23:20
Our Earth has a magnetic field, that which orients compasses. What a compass will not tell you is that there are very small variations in the Earth’s magnetic field which take place at frequencies that can be heard as sound if you understand how to convert magnetic field variations into acoustic sound which we can hear.
On Earth a coil of wire about the size of a ‘Hula Hoop’ and a fairly simple amplifier circuit driving a pair of standard headphones or a loudspeaker will let you hear these normal changes in our magnetic field brought about by a myriad of different activities including distant lightning strikes.
Rosetta has a ‘magnetometer’ on board, a very sensitive, accurate and sophisticated magnetic field detector and as it has neared the comet that detector is finding a fairly slow pulsation in the magnetic field surrounding the comet. That pulsation is so slow that if we played it straight as it comes from the detector it would be too low in frequency for us to hear it. We might play it through a sub-woofer and only know it is there because we could see that the woofer speaker cone is slowly moving in an out.
In order to let us hear this sound it has been ‘sped up.’ A length of the recorded signal is simply played back faster and faster with a variable speed playback system until the frequency of it is high enough that we can hear it with our ears. Digital Music synthesizers do this all the time, sample a sound and play it back at various speeds which correspond to the frequencies of musical notes.
While the scientific value of listening is not considered very high because our perception of the sound cannot be easily measured or quantified any negativism toward the value of this experience may be misguided. Our hearing system is seldom given credit for the amazing sophistication required to hear and understand human speech and music.
I have often wished that this conversion to audible frequencies would happen to other phenomena because we contain quite capable pattern and frequency translators which we understand the sounds of conversation and our environment with. We may find that careful use and study of those translators would allow us new methods of analysis of physical parameters beyond or in addition to our other less subjective methods.
Several things stand out about the Rosetta sound and it is incumbent on the producers to state whether any of the sound has been post-produced or modified, especially the curious ambient echo that makes it sound as though the actual sound source is moving around in some kind of large room. At one point the pulsing almost disappears into the echo as though the source is receding from the detector and then it returns, sounding as though it has approached the detector and is positioned right next to it.
If that is entirely the original signal without any modification after speeding it up then it is perhaps much stranger than we appreciate.
My own suggestion is that the source of this signal is something which when entirely understood will change our lives and our civilization at least as much as the discovery and exploitation of electricity has.
Best Regards
Larry Grant
Fonte:http://blogs.esa.int/rosetta/2014/11/11/the-singing-comet/
14/11/2014, 10:37
14/11/2014, 11:37
14/11/2014, 12:19
Ufologo 555 ha scritto:
Belle davvero, anche l'articolo; già, non ci avevo pensato: la Cometa ruota su sé stessa per cui, se non è bene agganciata la sonda, la sbatte al largo, lontano!
14/11/2014, 12:33
14/11/2014, 16:52
15/11/2014, 00:23
15/11/2014, 10:59
15/11/2014, 17:54