Powerful Supernova May Be Related To Death Spasms of First Stars 136
necro81 writes "The New York Times is reporting on a discovery from a team of UC Berkley researchers, who may have discovered the brightest stellar explosion ever observed. Observations of the cataclysmic explosion of a 100- to 200-solar-mass star began last September, based on data from the Chandra X-ray Observatory. The researchers believe that the explosion is similar to the death spasms of the first stars in the universe. The super-massive star's collapse is believed to have been so energetic as to create unstable electron-positron pairs that tore the star apart before it could collapse into a black hole — seeding the universe with heavier elements."
Time-lapse video? (Score:2)
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Actually, most of the radiation comes out as neutrinos. Only 1% comes out in forms we can detect at all...
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Not pretending to be anything but an interested layperson, but how does your response square with this excerpt from Wikipedia [wikipedia.org]?
Type I versus Type II
A fundamental difference between Type I and Type II supernovae is the source of energy for the radiation emitted near the peak of the light curve. The progenitors of Type II supernovae are stars with extended envelopes that can attain a degree of transparency with a relatively small amount of expansion. Most of the energy powering the emission at peak light is derived from the shock wave that heats and ejects the envelope.[57]
The progenitors of Type I supernovae, on the other hand, are compact objects, much smaller (but more massive) than the Sun, that must expand (and therefore cool) enormously before becoming transparent. Heat from the explosion is dissipated in the expansion and is not available for light production. The radiation emitted by Type I supernovae is thus entirely attributable to the decay of radionuclides produced in the explosion; principally nickel-56 (with a half-life of 6.1 days) and its daughter cobalt-56 (with a half-life of 77 days). Gamma rays emitted during this nuclear decay are absorbed by the ejected material, heating it to incandescence.
As the material ejected by a Type II supernova expands and cools, radioactive decay eventually takes over as the main energy source for light emission in this case also. A bright Type Ia supernova may expel 0.5-1.0 solar masses of nickel-56,[58] while a Type Ib, Ic or Type II supernova probably ejects closer to 0.1 solar mass of nickel-56.
Thanks in advance for advancing my understanding. Apologies if there is anything akin to an apples/oranges misunderstanding at the base of my query...
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The neutrinos escape the first seconds, long before the weeks the fireball may need to get transparent enough for most radiation.
Re:Time-lapse video? (Score:4, Informative)
"
The core implodes at velocities reaching 70,000 km/s (0.23c),[40] resulting in a rapid increase in temperature and density. Through photodissociation, gamma rays decompose the iron into helium nuclei and free neutrons. The conditions also cause electrons and protons to merge through inverse beta decay, producing neutrons and electron neutrinos. About 1046 joules of gravitational energy are converted into a ten-second burst of neutrinos.[41] These carry away energy from the core and accelerate the collapse, while some neutrinos are absorbed by the star's outer layers and begin the supernova explosion.[42]
The inner core eventually reaches a density comparable to that of an atomic nucleus, where the collapse is halted. The infalling matter then rebounds, producing a shock wave that propagates outward. This expanding shock can stall in the outer core as energy is lost through the dissociation of heavy elements. However, through a process that is not clearly understood, the shock reabsorbs 1044 Joules[a] (1 foe) of energy, producing an explosion.[43]"
You might have stumbled upon this part of the article while getting to the part you quoted. 10^44 joule ->explosion, 10^46 joule -> neutrino burst.
->only 1% is visible.
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Watch out! This kind of language is grossly inappropriate both here and on most Internet forum. Your politeness won't be tolerated for long.
Watch out? (Score:2)
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Your tone was so over-polite it practically seemed to ooze sarcasm.
I was seriously thinking you were trolling, so i was a bit harsher than usual.
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Ok, now I'm the one wandering offtopic...
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Be veeery careful when asking for images on slashdot of anything that explodes, bursts, or has holes in it.
Kinda OT, but I thought I'd say... (Score:5, Funny)
Someone pinch me, I think I'm dreaming.
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If the articles had been about the discovery of a supernova, then I'd agree with you -- but they are about the type of supernova it is, and the implications of that -- which was discovered by the UCal Berkeley guys.
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Oh, Slashdot has already covered the supernova, back in January.
not a dupe [slashdot.org]
What's new is the mainstream media like the new york times finding out about it.
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Oddity (Score:4, Interesting)
I guess they should say "might see if it went supernova soon."
Tom
Re:Oddity (Score:4, Insightful)
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E.L.E (Score:4, Interesting)
Now that's an Extinction Level Event.
"Ooh! Aaah!" dead
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Great. One more thing to worry about with Eta Carradine [wikipedia.org]. Wait, what were we talking about?
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I'm not endorsing this link http://people.roma2.infn.it/~aldo/dar01.pdf [roma2.infn.it] but it does corroborate what I've heard on TV scien
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1.It depends on how much matter is dispersed between us and the supernova(plasma,dust,stars,etc)
2.The estimate of mass and star composition are correct.
3.The mechanism of supernova production is well understood.(not really:the electron-positron pair supernova is new)
4.GRB angle.
http://en.wikipedia.org/wiki/SN_2006gy [wikipedia.org]
Similarity to Eta Carinae
Eta Carinae ( Carinae or Car) is a highly luminous hypergiant star located approximately 7,500 light years from Earth in the Milky Way galaxy. It is est
Pedantry Alert (Score:2)
For example, the question, "Will we survive the blast from Eta Carinae's supernova event?" begs the question that Eta Carinae has had a supernova event. We don't actually know whether or not Eta Carinae has exploded, but the question here assumes that it has and moves on. Begging the question is considered a logical fallacy, because it assumes something without proving it, and then bases further reasoning on that unproven assumption.
You're thinking of "raising th
Re:Oddity (Score:5, Insightful)
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Suppose, shortly after the Big Bang, two good christians synchronized their watches and made a suicide pact for a specific time in the future. As the universe expanded and matter flew apart, one of these people ended on a planet circling the star in question, and the other ended on Earth.
When their watches reach suicide time, and they both kill themselves, do their souls arrive in heaven simultan
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I would guess that everybody that dies arrives in heaven (or hell) at the same time, no waiting for anybody.
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We know information cannot travel faster than the speed of light (or if you prefer, cannot reach outside the light-cone [wikipedia.org] of the event). So if an event "happens" 7500 light years away, did it really happen before the light reaches us? In some sense, an event has not happened until we are inside its light-cone.
Perhaps it "happens" when its light-cone intersects ours? The question with this interpretation is, where does our light-cone start?
T
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How about we ask the 10-legged 8-eyed blue/green alien that got obliterated because his planet was circling that supernova?
Sorry, but these silly smart-sounding 'If a tree in the forest fell, but no one heard it fall, did it really make a sound?'-rhetorical questions irk me. The squirrel on who's head that tree fell doesn't give a crap if it made a sound. Think of the squirrels!
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Since the time for information from the alien about the supernova to reach us is at least as long information from the supernova itself, that doesn't really change the problem, even ignoring the problem of asking.
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Pretty much everything I have ever read about quantum entanglement is careful to point out that it does not enable information to propagate faster than light.
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However, information itself that is limited to the status of the entangled objects can indeed be transmitted FTL. This is partly semantic, since such data is not always considered information per se, since it cannot have meaning outside of the entangled objects.
Re:Oddity (Score:5, Informative)
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Until observed, it's just a probability. However, considering this is Slashdot, I believe the probability of you having both a wife and a mistress is quite low.
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IANAP, but my understanding is that quantum entanglement only allows two remote observers to see the same thing and it works across space and time. No information passes between the observers. As far as either party is concerned, there's only a probability the other one even saw the entanglement event until they talk about it via light speed.
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Cheers!
-l
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Beside
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Sure, that's a reasonable thing to say. But while we're being pedantic, we could also point out that it's all relative. Since the event of the explosion has a space-like separation from the events occurring on Earth now (e.g. the post), the time ordering of the events is different in different inertial frames of reference [everything2.com]. Thus, it may not have happened yet, or it may already have happened, depending on whom you ask (specifically, what reference frame they're in). Still, I'll grant you that in the inst
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You should have consulted Dr. Dan Streetmentioner's "Handbook of 1001 Tense Formations". If you had, you would know that the correct way to phrase the idea would be: "might seeon if it golo supernova insooner".
Eta Carinae (Score:5, Interesting)
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Personally I'd love to see this, provided of course that it wasn't the last thing I ever saw, very briefly.
Re:Eta Carinae (Score:5, Informative)
From here [freeinternetpress.com]:
So it's not too bad, it would probably just miss us.
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If you neglect angular momentum (i.e., for only moderately rotating stars), the current predictions are that pair creation supernovae are the normal mechanism for stars with a low metalicity and immediately pre-supernova mass from about 140 to about 260 solar masses. If you look at the webpage in the
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Re:Eta Carinae (Score:5, Informative)
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Boom? (Score:4, Funny)
Here's the NASA page. (Score:5, Informative)
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Here's the paper about it [arxiv.org].
From the abstract: ... but we argue that any known mechanism ... requires a very massive progenitor star... SN 2006gy is the first supernova for which we have good reason to suspect a pair-instability explosion... SN 2006gy also suggests that the most massive stars can create brilliant supernovae instead of dying ignominious deaths
We report our discovery and early observations of the peculiar Type IIn supernova SN 2006gy... It is not yet clear what powers the enormous luminosity
It's Berkeley (Score:1)
Re:Actually, it's T E X A S (Score:4, Informative)
From the article:
The discovery was made by Robert Quimby, a University of Texas graduate student, who was using a small robotic telescope at McDonald Observatory near Fort Davis, Tex., to troll for supernovasRe: (Score:2)
That's no Supernova (Score:3, Funny)
heavy elements (Score:2)
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I hope you like physics, though. The chart of nuclides can be a bit confusing at first.
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Black hole creation (Score:2)
From my memory (most likely faulty - I'm sure of getting correction from this group ;)) of supernovae processes, I seem to recall that when there's a sudden energy output drop (typically due to running out of one fusion fuel, such as C/N/O in a red giant), stellar collapse begins; this collapse may be halted by increased
Google Reader clips the title (Score:2)
Eta Carinae (Score:3)
200 solar mass possible? (Score:3)
Old News... (Score:4, Funny)
Slashdot, 240 million years behind the times.
(I should probably post this anonymously
RIP Planet Krypton (Score:2, Funny)
How many were killed? (Score:2)
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Re:we should we believe the astrophysicists now? (Score:5, Insightful)
Re:we should we believe the astrophysicists now? (Score:5, Insightful)
Some scientists--and physicists can be especially guilty of this in my experience--place too much faith in their own knowledge and accept the current findings of science as absulute fact. They forget that science is fluid, always changing as new information enters the equation and each answer spawns new questions. Call it arrogance if you want; I think it's something less than that.
In any case, what's the alternative? "God did it"? That may very well be true, but it doesn't answer the question of "how did it happen?"...which is what science seeks to explain.
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Both, I have found, tend to be far too dogmatic in their beliefs on the debate (or, dare I say it, faith).
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One of the key points I'm hoping to raise is the fact that Christians largely do not understand the principles of science and the meanings of many of the words it uses. In our collective ignorance, the Church is often railing against things that don't mean anything close to what we think it
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I hope that answers your scientific questions so that you can quit wasting my tax dollars on pointless research and get back to praising jesus.
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Arrogance would be to say that what they know now is the ultimate truths. Scientific theories are always being re-thought and re-worked. Nobody claims to have all the answers. Sorry, quacks do, but real scientists don't.
Good science provides answers to some fundamental question. In turn
Re:we should we believe the astrophysicists now? (Score:5, Informative)
Isn't this what academic research is (in theory) all about? The search for better understanding, enabling us to revise our theories of how the universe (or some small subset of it) works?
Find the simplest theory that fits all the observations. New data may mean you need a new theory, or that you need to revise your current theory. I don't understand the problem you have, unless it's just with the arrogance of some theorists who claim to have found the answer to Life, the Universe, and Everything. I say, let them be arrogant -- when they are disproved, they'll fall harder for it.
Re:we should we believe the astrophysicists now? (Score:5, Insightful)
After 70 years of computer simulations and observations they failed to predict this new kind of supernova.
Yeah, so? There are infinitely many things that are true which scientists have yet to predict. Why are you under the impression that scientists are supposed to know everything? Even if they did know all the physics involved, you can still only make finitely many predictions in finite time.
Its interesting to read speculations about degenerate lepton gases, but arent they just hand-waving again?
"Again"? When were they "hand-waving" before? About what?
Just goes to show you the arrogance of physicists- they claim answers and grandiose Standard Theories, but are frequently revising them because they mis things like accelerating expansion and 150SM supernova.
That's a feature, not a bug. It's how science works! Physicists claim answers because they have answers. That doesn't mean they have ALL the answers, or they're always right. This is no different in astrophysics than in any other field of physics, or any other science, or in any other field of study, period. People know some things, they can predict some things, and sometimes they miss something or get something wrong. That doesn't mean that nobody knows anything or that experts have nothing useful to say.
(By the way, accelerating expansion was in Einstein's theory from the start, but he took it out because there wasn't any evidence for it at the time.)
I seriously don't understand your point of view, unless (as is likely) it's just flamebait. Every time something new is discovered, do you seriously run around disparaging whole fields of science just because the new thing wasn't predicted ahead of time? Or do you just have some bug up your nose about astrophysicists? It's not like they were even wrong about normal supernovae, they just didn't predict this new kind.
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So, you seem to have gotten this exactly backwards.
As a bit of reading should also make clear, the reason that observations of this type of supernova are rare is that the conditions that favored the formation of stars capa
Re:we should we believe the astrophysicists now? (Score:5, Insightful)
Re:we should we believe the astrophysicists now? (Score:5, Insightful)
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Ha. I just copied that off the bottom of the page, right below your comment.
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Of course. (Score:2)
Compared to this, the Tsar was the equivalent of an ant farting.
Then again, I'm glad it was. Just imagine...