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back to article Doomed Cassiopeia star was sloshed just before deadly supernova blast

The NuSTAR X-ray space telescope has shown the star Cassiopeia A, one of our most recent nearby supernova, was sloshing and bubbling before its final explosive collapse. The glowing remains of Cassiopeia A The glowing remains of Cassiopeia A Scientists have been focusing on Cassiopeia A (Cas A), which is one of the earliest …

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Windows

"Line noise, Mandrake. Internet line noise!"

"When Cas A went supernova, the internal temperature of the star rocketed as it began to collapse, while contained in the cooler outer shell of the reaction. As the compressed neutrinos were formed in the heart of the celestial body they heated the surrounding matter"

Hold on, I think a few things are wrong here.

0) "while contained in the cooler outer shell of the reaction" sounds like english at a first glance, but on second sight turns out to be a nasty pan-galactic dialect most often associated with never-do-wells and chestbusters from Zeta Reticuli. Beware!

1) Neutrinos aren't compressible.

2) They do not tend to heat surrounding matter either.

Anyway, anyone remember Cassiopeia from "Battlestar Galactica", the original series? She was some hot bitch. Rewatching this series makes me realize that she's actually a clueless kid. What's wrong with ME? Oh my god.

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Re: "Line noise, Mandrake. Internet line noise!"

0) "while contained in the cooler outer shell of the reaction"

Typically the corona of a star is far hotter than the core. When this gets reversed, bad things happen.

1) "Neutrinos aren't compressible."

Know that for a fact, do you? You know more than any physicist out there then. I believe, however, this refers to the increased density of the stellar core which slows neutrino exit as there is now just so much matter that they can't help bumping into things on the way out. The compression and fusion of the matter also tends to generate a heckofa lot more neutrinos than otherwise.

3) "They do not tend to heat surrounding matter either."

If there are enough of them, they do. Neutrinos still impact matter, but the events are rare. If enough neutrinos pass through dense enough matter then darn tootin' they'd impart energy to the atmos they impact. That's how we can see them, just by the by. They strike an atom and transfer energy to it which it eventually released as a photon. I.E. "the damned things make matter light up."

Eleventy squillion neutrinos passing through matter that is just this side of violating the pauli exclusion principle will heat the matter in question.

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Re: "Line noise, Mandrake. Internet line noise!"

Hold on, silly you, you should have explored the bible with more intelligence to understand things like these, Perhaps this will help you to find the answers:

http://www.youtube.com/watch?v=z6kgvhG3AkI

No icon, as I cannot believe Ken Ham is just madly crazy nor a "honest" believer, so what remains, a business crook. Give me at lest a puke ikon, a smiling one if possible.

Poor Bill Nye, If I tried to teach a frog to play cards I have a bad feeling I would end up feeling more stupid than the frog. Hard life in the god old USA. (pun with some love).

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WTF?

Re: "Line noise, Mandrake. Internet line noise!"

"Know that for a fact, do you? You know more than any physicist out there then. I believe, however..."

I don't know what to believe anymore.

"Eleventy squillion neutrinos passing through matter that is just this side of violating the pauli exclusion principle will heat the matter in question."

Handwaving does not physics make. I also don't see how the PXP applies here. These neutrinos would definitely all have different states...

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Re: "Line noise, Mandrake. Internet line noise!"

"Handwaving does not physics make. I also don't see how the PXP applies here. These neutrinos would definitely all have different states..."

The PXP is mentioned to give an idea of the density of matter we're talking about. The density of core material in a pre-supernova star is - and please correct me if I'm wrong - just this side of nutronium. Nutronium is what happens when the PXP is overcome. Thus I used a discussion about it not only to attempt to convey the extreme densities I was discussion, but also because it would give those who don't study astrophysics as a hobby something they could look up on Wikipedia.

Researching the PXP should give them an understanding of electron states, how atoms work, how things change at extreme densities and even how materials can heat when exposed to extreme neutrino bombardment. (And how the high density of the material makes neutrino impacts more likely.)

I didn't want to just give the answers, I wanted to provide a brief overview so that others could enjoy the fun of learning and exploration. It's a quirk of mine, especially when it comes to science.

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@DAM

You're right that Pauli doesn't apply to neutrinos, but the physics is a lot more than handwaving - that's what the supercomputers were crunching in this simulation. In a supernova, neutrinos are one of the main ways of transferring the energy generated in the core collapse to the surrounding material. Although they're capable of passing through several light-years thickness of lead, the densities (in the core) are so great and the numbers released (as most of the protons in the core are converted to neutrons) so vast* that huge amounts of energy are transferred causing the explosion that we see.

* An interesting exercise: 19 of the neutrinos emitted by SN1987A were captured in detectors on Earth. Assuming equal emission in all directions, you can estimate the total number involved, by dividing the surface area of a sphere 168,000 light-years in radius by the cross sectional area of the detectors and multiplying by the probability of any given neutrino being captured. The answer is a lot.

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Anonymous Coward

Re: Pauli Exclusion principle

... applies to half integer spin particles. What is the spin of a neutrino?

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Boffin

Re: Pauli Exclusion principle

1/2, so it is a fermion. It's existence was postulated because in beta decay, a proton (fermion) split into a neutron and an electron (both fermions). This violates conservation of angular momentum. Postulating the simultaneous creation of a third particle to carry the surplus spin (or minus the missing spin) solved the problem

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Windows

Re: Pauli Exclusion principle

Trevor: It's a quirk of mine, especially when it comes to science.

I know the feel.

In furtherance of which, an oldish paper (i.e. 2004) explaining the role of neutrinos in core collapse.

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Headmaster

Re: "Line noise, Mandrake. Internet line noise!" @Trevor_Pott

Nutronium does not physics make either, it's a Si-Fi term; "neutron degenerate" matter is the correct name of the stuff found in "neutron stars".

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@Scroticus Canis you have no joy in your soul.

Yes, neutronium is a sci-fi term, but I think everyone is perfectly aware of what's meant by it's use. Neutronium has been a term used to describe the dense matter in a neutron star for longer than "neutron-degenerate matter" and I personally think it has a much nicer ring to it.

Besides, neutron-degenerate matter is so definite. It describes a very specific state of matter. (Assuming you believe that degenerate matter states should be states of matter, but that's a discussion for after you buy me some beers.)

Neutron is less exact. Are we talking about electron-degenerate matter? Proton-degenerate matter? Neutron-degenerate matter? Quark-degenerate matter?

All exist inside a neutron star, and frankly, I haven't the foggiest clue how dense this particular star got before it went boom. Electron-degenerate matter is a certainty, but what else exists in the moments just before the shockwave breaks through?

Nah, I'll stick to Neutronium. It sounds cooler, and it accurately conveys what I'm trying to convey whilst leaving enough uncertainty for me not to get into trouble by not knowing the precise details of the bits that go boom.

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Re: Pauli Exclusion principle

I remember that one! It's the first time I ever read about neutrino heating. Which i hadn't really thought of as a thing before that. Science!

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Re: Pauli Exclusion principle

Here is a handy guide to Neutrino interactions: http://what-if.xkcd.com/73/

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Re: "Line noise, Mandrake. Internet line noise!"

Agree that the words used don't do the best job in conveying the sense. I think what is being suggested here is that each individual neutrino is not compressed but that the group of neutrinos produced in the lower layers of the star are to a degree by the dense material surrounding them.

It seems logical that the further the material falls in towards the star, the more compact it will become, hence the more neutinos it will intercept. I wonder how many neutrinos you have to hit a neutron travelling at, say, .3c with to stop it? Though perhaps you'd break it first...

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Unhappy

Flash vids don't work for many people!

Not just for those with iThings, but also for those whose workplaces have disabled the Flash plugin.

Please try to embed vids in a format which just works. Thanks.

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Windows

Re: Flash vids don't work for many people!

Not missing much. For a re-enactment, just imagine your teenage son's bubblegum exploding on his face. (And a lot more entertaining!)

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Alert

Re: Flash vids don't work for many people! - Your fired!

Ever think that your paid to work when at work rather than watch vids on the internet? Maybe that's why the employers have blocked Flash for those where it is not relevant to their work.

Flash works fine on my iThings which are iMac, Mac Book Air and an ancient PowerBook. Can't be arsed to use the iPad which lurks around the house as it's so limited in many respects.

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Anonymous Coward

Sweet cartesian grid artifacts at the beginning

Is that what those are? I'd never show this video to anybody, I'd be too embarassed.

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Very interesting research

Well timed too with a supernova going off in Messier 82, in reach of small telescopes

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That is a tremendous amount of neutrinos. Thank you for confirming - what I only worked out for myself - about them being spin or angular momentum carriers.

@DAM: Maybe its time to STFU. Then again maybe not.

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I'm going to repost as this is both relevant here and interesting in its own right

"How close would you have to be to a supernova to get a lethal dose of neutrino radiation?"

http://what-if.xkcd.com/73/

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Re: I'm going to repost as this is both relevant here and interesting in its own right

So close to a star that it would be the least of your worries.

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Makes you wonder just how reliable type 1a's are

Sloshing these about could cause a few orders of magnitude difference in their brightness.

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Overly heady headline

I'm still trying to decipher:

"spots your grandparents' hip-joints of the future being made"

I thinks it is supposed to sound cool or rad or dope or sick or whatever but it doesn't make any sense. If you are talking about calcium, it's the same calcium in my hip bones. I don't know how grandparents or joints, for that matter, enter into it. Sometimes you guys try too hard.

Furthermore, nothing was "snapped milliseconds before supernovae blast". A MATHEMATICAL MODEL was deduced from the images which show only the AFTERMATH of the explosion.

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