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Posts: 14806
Joined: Dec. 14 2004
From: Washington DC
type 1A supernovae explained.....?
Saw this news on yahoo. Type 1A supernovae have been used traditionally to realize the age and acceleration rate (relative to its age I mean) of the universe because they are the most luminious objects in the universe we know of. So for example the farthest type 1A supernovae observed vs the nearby ones revealed, after a long careful study, that the universe expands faster now then it did in the past....hence it is accelerating.
So it was always thought type 1A supernovae were the result of a binary star systems (binary systems are actually more common in galaxies then lone stars) where one of the stars is dying, is left a white dwarf (shed it's outer layers already), yet it pulls in material from it's close by companion star, and as it's mass increases because of it's accretion disc, it gets too heavy for it's own good and at a critical point its core collapses and explodes. All type 1a thought to be the same, and because that critical mass is always the same for everystar, they use it as a standardcandle for far distance measurements.
So the new info is that after analyzing nearby galazies that had some type 1A's happening, they realized that accretion discs are not the mechanism, rather they result from white dwarf mergers...they actually crash into each other and explode! Like all the time, every type 1A I guess.
So my question now is how does this affect all the data of expansion rates and stuff. I mean if some white dwarfs are more massive then others, or traveling faster or slower before they crash, wouldn't those variables affect the luminosity somehow???? What about at 3 way or more crash of white dwarves and stars in a cluster????
Posts: 3055
Joined: Aug. 30 2008
From: Boston, MA, U.S.A
RE: type 1A supernovae explained.....? (in reply to Ricardo)
quote:
I like B movies and Porn too.
have you seen zombie strippers? it wasn't bad.
oh and of course, the species series. i remember watching the third one, while learning that parilla falseta you taught on flamenco-teacher.com. now every time i play it, i get flashes of a naked chick shooting her tongue through people's skulls.
i'm not even exaggerating. i really do. now i don't watch any t.v. while practicing.
RE: type 1A supernovae explained.....? (in reply to Ricardo)
I thought the only constant in the universe was the speed of light. Physicists probably take the likelihood of error in using any bench mark other than the speed of light in creating their theories. It might take a while for a new consensus to form, but there are some really crazy theories about the possibility of an infinite number of parallel universes casually disconnected from each other, etc., that might not be affected by this latest observation.
RE: type 1A supernovae explained.....? (in reply to Ricardo)
Yeah Ricardo,
That's why you have to take everything that "ice cutting" scientists say with just a pinch of salt....It's interesting...but not Gospel.
For the last 20 years I've been subjected to various Government health warnings and recommendations, followed only a couple of years later by retractions due to new research.
Total rest and lying flat for back pain is good....NO..new research has shown keeping active is better... daily Asprin is good for you, now bad for you.... MMR vaccine for kids can cause them to be be autistic, now 3 years later, (after heaps of kids are infected with measles and possible menangitis) now thought to be totally wrong and bad research..etc, etc, etc....
Man-Made Global Warming is the latest, when only 20 years ago they were predicting a new Ice Age in the UK with the Gulf Stream cutting off, so that there would be Polar Bears walking up and down the frozen-solid River Clyde and nutting local dossers to steal their cans of Special Brew. Now the Sea level is going to rise and swamp us all.
About 10 years ago it was that a very good chance that a giant comet was going to hit the Earth shortly and we would be totally defenceless, plunging the world back to Cave Man times.
In my day it was that there were enough Nuclear Weapons to blow the World up ten times over and that the USSR was going to be the trigger point....unless James Bond could save us.
People have always needed demons and angry Gods since time began.
Generally, IMO a heap of money making opportunities have always arisen from these popular public scares.
A lot of big industry is going to get very rich over pseudo "carbon reduction" schemes and low energy light-bulbs and windmills and petrol/electric cars, while the stockmarkets will go nuts in trading in "carbon credit certificates", which will probably be the next South Sea Bubble and launch us into the next financial crisis in 10 years time when folk realize they are just worthless bits of paper and they have been trading in nonsense.
Meanwhile a lot of folk will get very rich.
That's always been the way IMO.
So I'm not too surprised about the Astrophysicists and Astronomers having a change of heart, that what they believed to be true and taught in all the Universities and handed down to us lesser mortals, could in actual fact perhaps be wrong...
RE: type 1A supernovae explained.....? (in reply to Ron.M)
quote:
ORIGINAL: Ron.M Total rest and lying flat for back pain is good....NO..new research has shown keeping active is better...
I would say yes, but only if the reason for pain is in-activity of the back (like hours of guitar playing). I had an inflammation in the back and cured it away with training.
@Ricardo: "So my question now is how does this affect all the data of expansion rates and stuff". The universe MUST BE expanding, because i feel im becoming fatter and fatter
Posts: 4495
Joined: Aug. 9 2006
From: Iran (living in Germany)
RE: type 1A supernovae explained.....? (in reply to Ricardo)
i think if the mass of those exploding white dwarfs (1A supernovae) are not always the same (as assumed), then the 1A supernovae can't be standardcandles anymore and so all data about the expansion rate of the universe in the past which were based on these standardcandles (and therefore now and in future) could be all wrong. also all data about the rate of dark energy which is the reason for the expansion, should be reconsidered, if this new theory should be correct. imo
Posts: 4495
Joined: Aug. 9 2006
From: Iran (living in Germany)
RE: type 1A supernovae explained.....? (in reply to Ricardo)
just discovered this old article, seams like there were already one (or some) 1a supernovae discovered, from white dwarfs which had more mass than other 1A explosions:
Posts: 357
Joined: Dec. 5 2008
From: New Jersey USA
RE: type 1A supernovae explained.....? (in reply to Ron.M)
The beauty and power and integrity of science and the scientific method, is that, unlike so many other ways of seeking truth, it thrives on new evidence. If the new evidence can be shown to be better/more accurate than the old, then the theory can be refined/expanded to include the new evidence. Mosquitoes really do carry malaria--it isn't just breathing "bad air". If we understand that science is ALWAYS capable of and undergoing correction and further refinement, perhaps we won't be so dismissive of this self-correcting mechanism. If unchanging certainty is what you crave, get into religion.
RE: type 1A supernovae explained.....? (in reply to at_leo_87)
quote:
I like B movies and Porn too.
if you you ever got any questions about those ...that i can help with
quote:
For the last 20 years I've been subjected to various Government health warnings and recommendations, followed only a couple of years later by retractions due to new research.
is panadol still the prefered antidote for radiation ?
quote:
About 10 years ago it was that a very good chance that a giant comet was going to hit the Earth shortly and we would be totally defenceless, plunging the world back to Cave Man times.
the Y2k was the biggest scandal ever....we all expected everything electric to die ? in year 2000 ? hmm i remember alot of people made alot of money from paranoya, there were y2k protected computers and electrical goods beeing advertised... all canned food was sold out...people were building safe houses, buying all kinds of gas masks and safety wear...none of us belived it but we all held our breath for a sec when the clock struck 12 on NY ...just incase ...and i remember the icearenas in my city were booked out emergency services...incase they needed to store alot of dead bodyes in a hurry
quote:
have you seen zombie strippers? it wasn't bad.
yes i have ...thats the best of both worlds lol b grade and some nudity
RE: type 1A supernovae explained.....? (in reply to Arash)
quote:
Ron, actually there is a big difference between astronomy and all the examples you mentioned: these scientists don't do any harm to anybody.
Agreed, Arash,
But that's just because there are no money-making opportunities in it for business and they are probably getting by on a shoestring budget and a lot of aficion and unpaid work by postgrad students etc.
Research groups which come up with results which promote Government policies or provide great marketing opportunities are always well funded.
You can be sure that if a group came up with results which questioned the above or caused problems, their funding would be rapidly withdrawn.
So in that respect, modern science is not on an even playing field when it comes to politics or business.
While I admit and apologise that I was deviating from Ricardo's original post, I was just making the point that I find scientific announcements just "interesting" now, whereas before I used to find them "fascinating".
Posts: 14806
Joined: Dec. 14 2004
From: Washington DC
RE: type 1A supernovae explained.....? (in reply to Arash)
quote:
ORIGINAL: Arash
just discovered this old article, seams like there were already one (or some) 1a supernovae discovered, from white dwarfs which had more mass than other 1A explosions:
As this supernova does not obey the relations that allow type Ia supernovae to be calibrated as standardcandles, and as no counterparts have been found at low redshift, future cosmology studies will have to consider possible contamination from such events.
Seems that the "future" studies have caught up. So if the event was actually a merger, then couldn't we assume some or many of the OLD cosmology studies could be also contaminated? Problem is in the thing I read, they are not asking questions at what was implied by the discovery, just acting like "oh we found the true mechanism". I will wait a while then look it up again for new info, but I am curious why they don't say this is a big deal, something about it I am not understanding maybe in terms of how it affects the standardcandle idea???
Posts: 14806
Joined: Dec. 14 2004
From: Washington DC
RE: type 1A supernovae explained.....? (in reply to kozz)
quote:
ORIGINAL: kozz
quote:
because they are the most luminious objects in the universe we know of
Thats not exactly true...quasars are the most luminous objects. I think you ment stars.
A long time ago they did not know what quasars were. I think now, since they have imaged a quazar (actually a "blazar" which is super bright quasar) that shows a spiral arm structure, that they are pretty solid on what quasars are. A seyfert galaxy is one that has an active nucleus, because it's central black hole is "feeding" on star and dust and gas material, and blasting out at the poles. Seen on edge, a seyfert may appear as a "radio" galaxy that is blasting jets up and down. Seen exactly face on, the jets blasting right twards us, we see a quazar or blazar depending how perfect the orientation is.
From what I understand, and I could be wrong, but what I understand is if a type 1a supernova went off in a seyfert galaxy of any orientation, the explosion will appear as a bright star in the galaxy, so bright in fact it out shines ALL the other stars in the galaxy COMBINED, including the active center. I don't know if one was ever seen in the spiral arms of a blazar or if it would infact be brighter then the nucleus, but point being as a singular event and single object, I was believing that they are the most luminous objects in the universe. But you could be right too that the center is brighter then the single explosion, I don't know for sure, just trying to justify my statement.
Regardless, this new info could change everything about these concepts anyway.
RE: type 1A supernovae explained.....? (in reply to Ricardo)
Hee Ricardo, I am by no means an astronomer, more like a National Geographic / Discovery Channel interpretar....
The thing is, that it is so hard to comprehent what brightness is in the universe. Many many objects in the universe are so enormously bright, that even the weakest placed next to the sun, will make the sun appear black.
But I like your thought, would it change things on measuring.
What I always believed is that things were measured relatively and not in absolute terms, and so it could be explained that it is expanding.
But what will happen in a galaxy far far away? Hmmm, I dont know, but I can imagine that if galaxies / stars gain more mass, it start pulling even more on other objects.... Dont know exactly how to explain but maybe something like this: - you have for very heavy objects - 1 gets to heavy and explodes - but because of the other 3 heavey objects, they start to eat the dust - than 1 explodes again and the other 2 will eat the dust - etc And than maybe the universe starts to contract again.
Untill 1 heavy object is left over, which is gonna implode/explode again, and we have another Big Bang.
But it would take such an enormous time since the distances are so far away....I cannot comprehent it anyway.
I can't proof it, but maybe Buck Rogers can...biep biep de biep.
Posts: 4495
Joined: Aug. 9 2006
From: Iran (living in Germany)
RE: type 1A supernovae explained.....? (in reply to Ricardo)
what i read in some articles, leaves the impression that the data and results about age and size of universe, dark energy, etc. remain nearly unchanged. but i couldn't find a reasonable explanation why. maybe the number of such white dwarf mergers are small or maybe because the data of other "standardcandles"?! like the measurement of temperature fluctuations in the cosmic microwave background, and measurements of the correlation function of galaxies still support the old data and theories (which together with the type 1 supernovae, supported those theories) ! however, i don't understand more than someone who is just a bit interested in this stuff.
this article is also interesting, just found it after posting.
first of all, seams like such different theories about the explanation of those supernovae were already existing and second, there may be different reasons for different explosions, then there is this comment from an astronomer that accreting white dwarf binaries don't have too shine in X-rays at a relatively uniform and steady rate, so the new conclusion could be wrong ! ....and other interesting details in this article too
Posts: 14806
Joined: Dec. 14 2004
From: Washington DC
RE: type 1A supernovae explained.....? (in reply to Arash)
thanks arash, glad to know there are many skeptics on this issue. Damn yahoo for being able to just announce that stuff while I try to check my email. This is like the quark star thing, it will probably die a silent death after more research is done.
RE: type 1A supernovae explained.....? (in reply to Ricardo)
Hi Ricardo
This person: Frans Pretorius wrote a simulator for similar situations and might be able to shed some light on your question. He is doing great work in application of physics involving massive gravitation etc.
His email address is on there and if you want to force a response, make the subject line "Hoezit my ou" which is basically Afrikaans slang for "Howzit going dude". That should at least remind him of home and probably force a response.
RE: type 1A supernovae explained.....? (in reply to Ricardo)
Not that it adds much to what Arash has found out, but this is the abstract to the study. I think that the energy would still be constrained to 2 x the previous limit because each body would have a 1x limit to its mass. Note there are strong caveats to the study so it doesn't settle anything for sure.
cheers, Richard
Nature 463, 924-925 (18 February 2010) | doi:10.1038/nature08685; Received 24 April 2009; Accepted 16 November 2009
An upper limit on the contribution of accreting white dwarfs to the type Ia supernova rate
Marat Gilfanov1,2 & Ákos Bogdán1
1. Max Planck Institut für Astrophysik, Karl-Schwarzschild-Strasse 1, 85741 Garching, Germany 2. Space Research Institute, Profsoyuznaya 84/32, 117997 Moscow, Russia
Correspondence to: Marat Gilfanov1,2 Correspondence and requests for materials should be addressed to M.G. (Email: gilfanov@mpa-garching.mpg.de).
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There is wide agreement that type Ia supernovae (used as standardcandles for cosmology) are associated with the thermonuclear explosions of white dwarf stars1, 2. The nuclear runaway that leads to the explosion could start in a white dwarf gradually accumulating matter from a companion star until it reaches the Chandrasekhar limit3, or could be triggered by the merger of two white dwarfs in a compact binary system4, 5. The X-ray signatures of these two possible paths are very different. Whereas no strong electromagnetic emission is expected in the merger scenario until shortly before the supernova, the white dwarf accreting material from the normal star becomes a source of copious X-rays for about 10^7 years before the explosion. This offers a means of determining which path dominates. Here we report that the observed X-ray flux from six nearby elliptical galaxies and galaxy bulges is a factor of ~30–50 less than predicted in the accretion scenario, based upon an estimate of the supernova rate from their K-band luminosities. We conclude that no more than about five per cent of type Ia supernovae in early-type galaxies can be produced by white dwarfs in accreting binary systems, unless their progenitors are much younger than the bulk of the stellar population in these galaxies, or explosions of sub-Chandrasekhar white dwarfs make a significant contribution to the supernova rate.
Posts: 14806
Joined: Dec. 14 2004
From: Washington DC
RE: type 1A supernovae explained.....? (in reply to marrow3)
quote:
The X-ray signatures of these two possible paths are very different. Whereas no strong electromagnetic emission is expected in the merger scenario until shortly before the supernova, the white dwarf accreting material from the normal star becomes a source of copious X-rays for about 10^7 years before the explosion.........
We conclude that no more than about five per cent of type Ia supernovae in early-type galaxies can be produced by white dwarfs in accreting binary systems,
Thanks for that. It makes sense, their line of thinking how they came up with this. Still not clear on how the actual standardcandle data might be affected by the merging type vs the accreting type...and what about possible multiple mergers, mergers that don't result in explosion, etc etc....
Unless I don't understand white dwarfs enough, my feeling is only 5% then can be used as standardcandles.... again assuming these guys are correct.
Posts: 4495
Joined: Aug. 9 2006
From: Iran (living in Germany)
RE: type 1A supernovae explained.....? (in reply to Ricardo)
don't want to start new off topic threads for these stuff, so i post it here:
now this is something new and really crazy.
we had dark matter, dark energy,,,,,and now we have something called "dark flow" !
this could be the proof of a parallel universe, or if not, then it must be something with an extremely strong gravitation outside our horizon and outside the visible universe.
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