Neutrino oscillation( 31 March 2006 Wikipedia)
Neutrino oscillation is a quantum mechanical phenomenon whereby a neutrino created with a specific lepton flavor (electron, muon, or tau) can later be measured to have a different flavor. More specifically, the probability of measuring a particular flavor for a neutrino varies periodically as it propagates. Neutrino oscillation is of theoretical and experimental interest, as observation of the phenomenon implies nonzero neutrino mass.
If you change the way you look at things sometimes, this change, helps you see in different ways that you might not have before? WMAP?
Sounding the Sun: HelioseismologyP.B. Stark
On the other hand, the Sun is essentially transparent to neutrinos, and to acoustic waves. Using acoustic energy, we can "see into the Sun" in a way that is quite similar to using ultrasound to image the interior of the human body.
Oscillations of stars have been recognized since the late 1700s. The complicated pattern of the Sun's oscillation was first observed in 1960 by Robert Leighton, Robert Noyes, and George Simon.
The explanation of the pattern in terms of trapped acoustic waves came in 1970-71 by Roger Ulrich, John Leibacher, and Robert Stein. This explanation predicted certain detailed features of the spectrum of solar oscillations that were confirmed by observations made in 1975 by Franz Deubner.
The Sun is constantly vibrating in a superposition of acoustic normal modes (like the patterns with which a guitar string vibrates, but for a spherical body rather than a string). The characteristic period of oscillation is about 5 minutes. It takes on the order of a few hours for the energy to travel through the Sun. The velocity amplitude of solar p-modes is about 1 cm/s; the relative brightness variation is about 10-7.
Mode lifetimes range from hours to months. Modes are typically excited many times per lifetime.
Let's look at the origins of the images below. Have I described their origin?
See:
The Devil, is in the details of a Mirror World?
While the "true cast" is here? :)
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