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Fraser
2007-Jun-28, 04:19 PM
One time, astronomers thought that only black holes had jets of material pouring out of them. Something to do with the event horizon, and a lack of a solid surface. ...

Read the full blog entry (http://www.universetoday.com/2007/06/28/neutron-stars-have-jets-too/)

Jerry
2007-Jun-29, 04:12 AM
Nothing like this was predicted...by anyone.

Northwind
2007-Jun-29, 05:05 AM
and don't forget the brown dwarfs have them too!

http://www.bautforum.com/showthread.php?t=28239&highlight=brown+dwarf+jets

trinitree88
2007-Jun-29, 09:40 PM
Nothing like this was predicted...by anyone.

Jerry. I disagree. :naughty:That's not true. Asymmetry in weak interactions in all their variations was predicted April 1982....25 years ago. Emission of radiation or particles from a neutron star is a weak interaction. Again, every experiment, every detector, every run. It was routinely ignored, and is now being "discovered". :think:pete.

Nick4
2007-Jul-01, 06:27 AM
I wish i knew how to make or do computer rendering like in the picture for this fourm.

John Mendenhall
2007-Jul-02, 12:16 PM
Asymmetry in weak interactions in all their variations was predicted April 1982....25 years ago. Emission of radiation or particles from a neutron star is a weak interaction. Again, every experiment, every detector, every run. It was routinely ignored, and is now being "discovered". :think:pete.


I'm not familiar with the interaction. A reference or two?

Thanks, John M.

trinitree88
2007-Jul-02, 06:10 PM
I'm not familiar with the interaction. A reference or two?

Thanks, John M.

Weak interactions occur when a particle changes identity, like a pion decaying to a muon...or a muon to an electron....or a neutron to a proton..etc.
Parity has to do with the symmetry of the particle's wave function. If it's axially symmetric (y-axis), then it is assigned even parity. If asymmetric,then it's called odd. Parent particle's parity can be inferred by multiplying the parities, or adding them, of the daughter particles. So, it came as a surprise when the tau, and the theta, with near identical physical characteristics decayed via two schemes....one into two pi mesons, the other into three. If pi mesons are assigned odd parity, then the two parent particles must be different because the two scheme leads to an even-parity parent, whilst the three scheme leads to an odd parity parent.
It had been observed that parity seemed conserved in strong interactions, when Lee and Yang suggested that perhaps it was not conserved in the weak interaction, and then the parent particles were the same. So, they wrote up a paper after a cursory check of the literature. Nobody had ever checked the weak interaction for conservation of parity.
After polarized Co-60 beta decays by Wu, Ambler showed they were right, a subsequent careful check revealed that dozens of experiments in the weak interaction, and even a few in the strong interaction had shown the effect, but nobody had ever looked at the data that way. For the weak interaction, it's every run, every experiment, every lab. In astrophysics if strong fields are present (they are), neutrinos are involved (they are inescapable), and particles are changing identities(such as core collapse neutronization, or neutron decay from strong fields)....then you can expect to see a N-S asymmetry.
see:http://ccreweb.org/documents/parity/parity.html

Wrote a paper on it for the Winter Course in Nuclear & Particle Physics, Bates Linear Accelerator, 91-92, and gave a talk on it at the AAPT Meeting at Vassar in 92.."Parity, Pulsars, and Supernova Remnants". pete

John Mendenhall
2007-Jul-02, 06:35 PM
see:http://ccreweb.org/documents/parity/parity.html

Printed myself a copy of the paper, now I have to read. Be back tomorrow.

trinitree88
2007-Jul-02, 08:30 PM
Printed myself a copy of the paper, now I have to read. Be back tomorrow.

John. You're welcome. An excellent layman's text on the stuff is Martin Gardner's "Mirror Asymmetry and Time Reversed Worlds". He was a columnist for Scientific American for a long time, and does a nice historical treatise of the field. Probably find a copy on www.bookfinder.com. pete.

Jerry
2007-Jul-10, 02:14 PM
Jerry. I disagree. :naughty:That's not true. Asymmetry in weak interactions in all their variations was predicted April 1982....25 years ago. Emission of radiation or particles from a neutron star is a weak interaction. Again, every experiment, every detector, every run. It was routinely ignored, and is now being "discovered". :think:pete.

I didn't know that - thanks!

The other obvious question is black holes: Since the evidence of black holes is accretion rings and jets, if accretion rings and jets can and do occur without black holes forming, how do we know we are dealing with black holes?

trinitree88
2007-Jul-10, 04:28 PM
I didn't know that - thanks!

The other obvious question is black holes: Since the evidence of black holes is accretion rings and jets, if accretion rings and jets can and do occur without black holes forming, how do we know we are dealing with black holes?

Jerry. You're welcome...and that's the million dollar question. At least one ~40 solar mass progenitor left a neutron star though all the theories said it should have been a BH. pete

see:Chandra Press Room :: Neutron Star Discovered Where a Black Hole Was Expected :: November 02, 2005 (http://chandra.harvard.edu/press/05_releases/press_110205.html)