From Daily TechThe Milky Way’s black hole is causing a mess, but isn’t gobbling matter as fast as was thought
One of the most complex and intriguing astrophysical phenomenon is the supermassive black hole. A superdense cluster of mass, the supermassive black hole gobbles up surrounding matter, sucking it into its gravity well. Despite the tremendous importance of these celestial bodies to the structure of our universe, scientists still remain confused about specifics of how they operate.
Supermassive black holes help to shape our universe, but their behavior is still poorly understood
. (Source: PureInsight.org)
It is a well known fact that there is a supermassive black hole at the center of our galaxy, the Milky Way. Dubbed Sagittarius A* (Sgr A*), the black hole is rather weak, due to its inability to successfully capture significant mass. The black hole is bordered by dozens of young stars. It pulls gas off these stars, but is only able to suck in a small percentage of this high velocity stream.
Past estimates put its consumption rate at a mere 1 percent of the gas it pulls away from the stars. Now a new study, using data garnered from the NASA’s Chandra X-ray Observatory, has determined that the black hole is likely eating far less than that figure even — new models indicate it to be consuming a mere 0.01 percent of the gas it sucks off.
Read the rest of the story here.
tallbloke (00:57:59) :
The danger with consensus science, as James F. Evans pointed out above, is that we end up with nonsense like co2 driven climatology. Cosmological hypotheses used to jostle for position, with different possible explanations for the weird and wonderful phenomena we observe
What has happened the last few decades is that Cosmology has gone from being speculative flights of fancy to become a precision science driven by observations and data. ‘Consensus’ science happens when the data become overwhelmingly in favor of one of the many speculations jostling for position such as to leave only one standing. A more appropriate term would be ‘Generally Accepted Science’. The bedrock on which further progress rests. An example is the Heliocentric System where the Earth orbits the Sun, rather than the other way around. There is no ‘danger’ in accepting that.
Everyone here, including you, should be able to live with that without resort to accusations of pseudoscience, zero credibility or any other unpleasantness.
Critique of a theory should be based on real knowledge about it. Not on the shallowness found in ‘alternative’ explanations. In your particular case “We can agree to disagree about whether the conditions for something being regarded as an ‘observation’ have been met here” you could have simply picked the most convincing of the observations and shown that it did not meet established criteria for an ‘observation’ which is all I asked and which is necessary for maintaining that the criteria have not been met. I’ll assume that you are well-versed in the literature on this [otherwise you could not make your statement in the first place] so it should be easy to do what I asked.
kadaka (01:14:04) :
Yet based on the WMAP measurements, the geometry appears flat, with no curvature, to within a 2% error margin.
That is for the overall geometry. Locally, e.g. near a massive body there is a lot of curvature. And in a singularity, infinitely much.
So the hope remains that this universe is not a one-shot event.
One can always hope so [and humans seem to have a yearning for doing so], but so far the prospects look grim.
Bill Tuttle (01:29:20) :
Is this another “the science is settled — there’s no more need to debate” thang?
The debate has shifted from ‘is it there?’ to ‘what is it?’; as simple as that. And THAT debate is raging.
Leif Svalgaard (06:35:03) :
In your particular case “We can agree to disagree about whether the conditions for something being regarded as an ‘observation’ have been met here” you could have simply picked the most convincing of the observations and shown that it did not meet established criteria for an ‘observation’ which is all I asked and which is necessary for maintaining that the criteria have not been met. I’ll assume that you are well-versed in the literature on this [otherwise you could not make your statement in the first place] so it should be easy to do what I asked.
Unlikely we’re going to accomplish this here without bringing in long and trying debate involving people like Narlikar and Arp. We’e tried it before, and it wasn’t pretty. I’m not going to try Anthony’s patience with it.
I’ll elaborate a little bit on the concept of ‘Consensus Science’ and the ‘resistance to acceptance of new ideas’. Three major scientific revolutions can serve as examples: the Heliocentric System, Plate Tectonics, and Big Bang/Dark Matter/Energy. In all cases the ‘ideas’ were not new, going back [approximately] 2000, 300, and 100 years. At the time they were put forward, the data was not compelling enough and other explanations were viable. But in each case, once precision data [and enough of it] began to pile up, the conversion of thought and acceptance of the ideas were swift and the debate quickly abated [there are always die-hards and ignorants so it takes a generation or two to clear the underbrush and get rid off the weeds]. The consensus is always forced upon the community by the data and scientists are a conservative lot who do not easily give up what previously was hard-fought [being forced upon them by earlier data and interpretations], but the data always win in the end, leaving only one viable possibility standing [for the moment]. Every scientist understands this although the public at large may not.
tallbloke (08:01:45) :
Unlikely we’re going to accomplish this here without bringing in long and trying debate involving people like Narlikar and Arp.
Narlikar and Arp have long been passed by the newer data and, indeed, it would be silly to discuss them any further.
The science is settled! Of the well under 10% of the universe’s contents that we can see (visible matter), we know something about it. Of the over 90% of the remaining, we haven’t got a clue – other than that there’s a lot of different pieces of evidence that suggests it must exist.
Anyone interested in wagers as to the presence of intergalactic baryonic dust bunnies being a key part of the dark matter?
OK having read all this I have a problem with the concept of “spacetime”. Time seems only to exist in our minds. We
1) Receive data (through our senses)
2) Interpret and Record data (in our brains)
3) Recall data (brains again)
4) Sequentially analyze data
All of these have been enhanced by electro-mechanical devices that in some ways are superior to brains.
Break the sequence above and time doesn’t exist for an individual. A case reflecting this occurred in 1953 when a 27 year old man had brain surgery to alleviate severe epileptic seizures. An area of the brain was destroyed which helped with problem, but had an horrific side effect. The area destroyed was also the conduit for recordiing observations into memory. After the surgery he could recall events prior to the surgery. Afterwards his recall was on the order of 5 – 6 seconds and he woke up every morning for more than 50 years expecting to see his 27 year old face in the mirror.
Consider what is measured to establish time. We take one rotation of the planet divide it into 24 segments, those into 60 segments, those into 60 segments and so on. We also multiply that rotation by 7, or 28,29, 30, 31 and 365 for calendar purposes. But all we have effectively measured is the earth’s movement and that movement relative to Sol. What is a date? As the real estate agents say, “location, location, location”. If someone wanted to travel back to a specific date and time, say 9:00 AM, 9/10/2001 the earth must be returned to the place it occupied relative to the sun and by extension every thing in the universe would also have to be returned to the position held at that time and date. Every galaxy, star, planet, photon (with or without a Higgs), and neutrino. This being the case how would time travel be possible and how can time be a dimension? In one dimension you can travel back and forth on a line, in two, in various directions on a plane, in 3 in various directions cubically. But you can’t travel in time without being able to move the entire universe. Seems to me that time is nothing more than a way of measuring the motion of the universe and other events relative to the motion of our planet and it’s all in our heads and the storage devices we manufacture.
actuator (09:03:43) :
Time seems only to exist in our minds.
The perception of ‘time’ is in your mind. ‘Time’ as part of spacetime is a very real thing. Instead of a long discussion here, simple google spacetime. The more fundamental concept is that of ‘an event’.
cba (08:32:05) :
Anyone interested in wagers as to the presence of intergalactic baryonic dust bunnies being a key part of the dark matter?
I’ll see your dust bunnies and raise you three synchronised skating turtles.
Leif Svalgaard (20:46:25) :
It seems that there are several tedious posters here that still thinks Einstein was a nut… So, perhaps that was a bad example. How about Eddington: “”The great Arthur Eddington gave a lecture about his alleged deviation of the fine structure constant from fundamental theory. …”
Einstein once allowed as how he may have defined relativity, but he said Eddington was the only man who actually understood it.
Mike
humble grammar pedant
Leif Svalgaard (08:26:57) :
tallbloke (08:01:45) :
Unlikely we’re going to accomplish this here without bringing in long and trying debate involving people like Narlikar and Arp.
Narlikar and Arp have long been passed by the newer data and, indeed, it would be silly to discuss them any further.
A bit like it was silly (and strongly discouraged) to discuss Aristarchus’ heliocentric model after it had been passed by the newer Ptolemaic data and the epicyclic theory based on an Earth centred model?
tallbloke (10:23:01) :
A bit like it was silly (and strongly discouraged) to discuss Aristarchus’ heliocentric model after it had been passed by the newer Ptolemaic data and the epicyclic theory based on an Earth centred model?
What a bunch of nonsense. You have no sense of proportion and knowledge of how astronomy works. I was precisely saying that the idea was old [2000 years], but only became accepted much later [~1600] when overwhelming data made it clear that it was correct after all.
Mike McMillan (10:16:48) :
Einstein once allowed as how he may have defined relativity, but he said Eddington was the only man who actually understood it.
There is an anecdote that a journalist once brought that up with Eddington. He asked: ‘it is said that only three people understand general relativity, do you agree?’. Eddington became pensive, and replied: “I’m trying to think of who that third man might be…”.
Mike McMillan (10:16:48) :
Leif Svalgaard (20:46:25) :
It seems that there are several tedious posters here that still thinks Einstein was a nut… So, perhaps that was a bad example. How about Eddington: “”The great Arthur Eddington gave a lecture about his alleged deviation of the fine structure constant from fundamental theory. …”
Einstein once allowed as how he may have defined relativity, but he said Eddington was the only man who actually understood it.
Einstein stated he wasn’t happy with the prediction or result of the Mercury perihelion experiment. With good reason as it turns out:
“ROZELOT, PIREAUX AND LEFEBRVE (2004)
suggested that the effect on Mercury’s orbit by the internal
shifting of the Sun’s mass may require a re-appraisal of
Eddington’s test and therefore of the veracity of General
Relativity as the best available account of gravity. Mercury is the
innermost of the four terrestrial planets in the solar system,
moving with a high velocity in the sun’s gravitational field. As a
result of slight undulations in this field due to movements of the
sun’s mass within it, the advance in the perihelion of Mercurys’
orbit could be affected. As outlined above, it has also been
conjectured that Mercury and the other planets could contribute to
the dynamic spatial and temporal internal distribution of the sun’s
mass through any or all of the processes summarised above.
The gravitational interaction between the sun and the planets
causes the barycentric motion of the sun, which is non-linear,
stochastic and periodic. There is, therefore, a feedback process
between two non-linear, stochastic and periodic processes: the
internal shifting mass of the sun affecting planetary orbits and the
planetary orbits affecting the internal mass of the sun by shifting it
around, perhaps throughout the entire body of the sun.”
Further discussion getting underway here:
http://tallbloke.wordpress.com/2010/01/10/planetary-solar-theory-a-brief-history/
Leif Svalgaard (10:47:47) :
tallbloke (10:23:01) :
A bit like it was silly (and strongly discouraged) to discuss Aristarchus’ heliocentric model after it had been passed by the newer Ptolemaic data and the epicyclic theory based on an Earth centred model?
What a bunch of nonsense. You have no sense of proportion and knowledge of how astronomy works. I was precisely saying that the idea was old [2000 years], but only became accepted much later [~1600] when overwhelming data made it clear that it was correct after all.
You missed out the bit where the Scions of the then current orthodoxy burned Giodorni Bruno at the stake and banged Galileo Galilei up under house arrest for 20 years and confiscated his telescope.
A tactic still in use 500 years later when Halton Arp was denied telescope time after daring to discover that highly redshifted Quasars were associated with lower redshifted galaxies.
Leif,
I didn’t realize plate tech. went back further than 30 years prior to its acceptance.
As for the helio vs. geo centric cosmologies. It’s even more interesting in the details. The two theories were practically contemporaries. The big gun scientists (or natural philospher) behind the geocentric cosmology was the truly big gun, Aristotle, better known and more capable at straight philosophy compared to natural philosophy. On the heliocentric side, we have Aristarchus, no slouch, but not in the same league reputation wise. Consequently, when it came to prestige, funding, reputation, … one finds the geocentric guys on top from the very beginning and this is crucial.
The geocentric theory proponents had more to overcome in developing their theory for obvious reasons. However, the reputation of the originators, the funding, etc. permitted this to happen and all of the work necessary to achieve a good match between observation and theory went in. With a bit of smoke, elves, and mirrors, the guys managed to determine that by adding epicycles, marvelous results could be achieve that explained everything of importance, but definitely not of everything.
A crucial factor too was the apparent falsification of a key element in the heliocentric case. That is parallax. It wasn’t present, at least in amounts measurable at the time. Actually, it wasn’t measureable 400 years ago either despite the switchover in concensus. Another problem was that the Greek view of perfection considered circles perfect and ellipses imperfect so the notion of elliptical orbits was problematic.
As a consequence of orbits being elliptical, failure to observe parallax of stars with the naked eye and the extra funding (and/or the investment more of effort), the perfecting of theories and the existing prestige and concensus of the geocentric model, it both provided results closer to measurements than did circular orbits around the Sun and didn’t have any really glaring falsification problems. That the Moon had phases wasn’t really a problem but the advent of the telescope brought out that Venus did have phases and Mars, Saturn, and Jupiter did not and the observations of Jupiter brought out that it appeared to have 4 moons that orbited the planet like clockwork.
This is a great example of the scientific method in operation. Progress was made but it took a thousand years plus for things to settle down. Theories were falsified, yet it turned out in the parallax case that it was merely the hypothesis that the universe was far smaller than thought and not with the hypothesis that there should be measurable parallax. With adavancing technology, it was finally possible to make those measurements, in the 19th century?, We have the example of the grossly incorrect theory providing better agreement with observed data than the more correct theory (the one closer to describing what is actually going on), apparently due to greater investment of time / resources used to perfect it. We have the opposition to change to the new theory. And finally, while we have verified that the Earth goes around the Sun, we now know that neither the Sun nor the Earth are the center of the universe, falsifying both of the competing theories. We also have had other theories, some of which have been falsified. We have learned that the universe is not merely the milky way whose center was also thought to be the center of the universe, but also that all sorts of these little nebulae were in fact galaxies like the milky way. And finally, here we sit, fairly comfortable in the theories of the big bang and general relativity, having dispatched the infinite age/sized steady state univervse once and for all (famous last words) and don’t mind so much the cracks in the ediface starting to show up or the bandaides, chewing gum, and bailing wire holding it together. These include dark energy, dark matter, the inflation era, expansion rate increase, the uniformity of WMAP, etc.
Here we have the final rule of the scientific method. Nothing is ever really solved as every question that appears to be answered tends to spawn many more questions that need to be answered and also runs the risk of turning out to be answered (at least in part) incorrectly.
Thinking back to the old Saturday morning movie serials, it looks like we are pretty close to the end of this week’s installment. We’re about due for a doozey of a cliff hanger and the last episode of the series with its ultimate resolution is nowhere in sight. Where will the plot take us next?
Great post cba.
Leif Svalgaard (06:35:03) wrote: “What has happened the last few decades is that Cosmology has gone from being speculative flights of fancy to become a precision science driven by observations and data.”
And, yet, you generally maintain that what was known in 1960, at the birth of the space age, is still at the cutting edge of astrophysics.
And, you still go on about “hot gas” in space, now that is pre-1960 thinking.
There seems to be a contradiction there.
Leif Svalgaard (08:04:40) wrote: “…there are always die-hards and ignorants so it takes a generation or two to clear the underbrush and get rid off the weeds…”
Dr. Svalgaard, have you ever considered the above statement applies to you?
No, not for one second, I’m sure — the die-hards never do — they just pass from the scene.
A so-called “black hole” is a “singularity” with infinite density? And with an infinitely small volume? Such an idea can’t be quantified, it isn’t scientific, rather, it’s metaphysics.
(But such is the power of self-deception in the human species that mathematicians can reify an abstract concept if they can string enough equations together.)
But it’s the only way to theorize that gravity, a weak force in the Universe, can over power light.
And since I’m sure some readers consider me a heretic, why don’t I prove the point:
Relativity is a “thought experiment”, which in reality is a glorified hypothesis.
Einstein disdained actual physical experiments, he gloried in his “thought experiments” — his laboratory was his living room in his two-room apartment in Bern Switzerland.
Science knows that men’s perceptions of physical reality are not the physical reality, itself — the map is not the territory. So repeated experiments are conducted to minimize the problem of Man’s unreliable perception.
How much more unreliable is imaginary perception — “thought experiments”?
No matter how logical, objective, and disciplined the man might be in his attempts at “thought experiments”, it is still fraught with unreliability — such is human nature.
Actually, this is one of the biggest scientific myths out there: General Relativity has been proven many different ways.
Every supposed “confirmation” of General Relativity by way of scientific observation & measurement has an alternative physical explanation.
General Relativity relies on a “thought experiment” that relies on “frame of reference”, namely, Man’s perception is different depending on where his “frame of reference” is located.
But physical reality only has one frame of reference — for a specific time and location there is only one set of physical conditions, an “event”, if you will. There are not multiple realities depending on your “frame of reference”.
This was Einstein’s mistake, he counted “thought experiments” that changed reality by human “frame of reference” as having validity, they don’t.
Example: (One of Einstein’s famous “thought experiments”.)
A man sitting in a falling elevator is weightless by his reckoning.
But he is not weightless, in fact, his weight is what is causing him to fall.
The perception of “weightlessness” for the man as his “frame of reference” is false and a self-deception.
Weight is still acting on his body.
Einstein made the fatal assumption that the man’s perception is reality — it is not.
And this kind of assumption is riddled through General Relativity.
Empirical science strictly depending on observation & measurement while not perfect is the only way for Man to understand his world.
James F. Evans (13:07:20) :
General Relativity relies on a “thought experiment” that relies on “frame of reference”, namely, Man’s perception is different depending on where his “frame of reference” is located.
But physical reality only has one frame of reference — for a specific time and location there is only one set of physical conditions, an “event”, if you will. There are not multiple realities depending on your “frame of reference”.
This was Einstein’s mistake, he counted “thought experiments” that changed reality by human “frame of reference” as having validity, they don’t.
Einsteins point was that you could account for the different ‘viewpoints’ in different frames of reference via the Lorenz Transformation. For that, you need to go to his actual theory rather then his popular book with it’s imperfect analogies.
Einstein was a subtle thinker. This is why he didn’t refer to his own frame of reference in mission control Bern as a rigidly defined thing. He referred instead to the ‘mollusc of reference’.
tallbloke (10:51:23) :
Einstein stated he wasn’t happy with the prediction or result of the Mercury perihelion experiment
Link please.
With good reason as it turns out
No, not at all. As I said there are always people with suggestions left and right. Everybody wants to prove Einstein wrong. Accurate measurements of the Sun’s oblateness [Fivian and Hudson] shows that it is just what we would expect from its rotation rate. Any shifting around of the interior would introduce a quadrupolar moment which is not observed.
James F. Evans (13:07:20) :
And, yet, you generally maintain that what was known in 1960, at the birth of the space age, is still at the cutting edge of astrophysics.
What nonsense. It was also known in 1960 that the Earth was round, and that still holds.
And who conjures up Birkeland?
Dr. Svalgaard, have you ever considered the above statement applies to you?
Of course not. And certainly not the ignoramus bit.
A so-called “black hole” is a “singularity” with infinite density? And with an infinitely small volume? Such an idea can’t be quantified, it isn’t scientific, rather, it’s metaphysics.
A black hole is not a body and has no density nor volume. The singularity is where the tidal forces have no limit. Different thing. Didn’t you read my explanation?
Every supposed “confirmation” of General Relativity by way of scientific observation & measurement has an alternative physical explanation.
Of course. That is true of every physical theory. You can always invent an ad-hoc explanation for anything. The difficult part is to find the one and only alternative explanation that explains every one of GR’s confirmations. None exists to my knowledge.
But he is not weightless, in fact, his weight is what is causing him to fall.
No, if that were so, then bodies of different weights should fall at different rates. Heavier should fall faster, lighter should fall slower, and those with no weight should not fall at all [if weight is what makes them fall – Galileo clarified that for us, by experiment and by thought experiment]. I think you have just disqualified yourself from any serious discussion.
Empirical science strictly depending on observation & measurement while not perfect is the only way for Man to understand his world.
But even with all the observations of modern science, it seems that your understanding of your world is lacking.
But it’s the only way to theorize that gravity, a weak force in the Universe, can over power light.
Light photons that are climbing out of the gravity well of any material body lose energy [become red-shifted]. This has been experimentally observed over and over again with incredible accuracy. We even have to take this into effect by measurements of TSI. The deeper the well, the more energy is lost. With the well deep enough [at a singularity] all energy is lost. Again, you show that you have no idea of what you talking about.
cba (11:06:15) :
I didn’t realize plate tech. went back further than 30 years prior to its acceptance.
Plate tec went by other names: e.g. Continental Drift. Suggestions go as far back as the first maps of the Atlantic Ocean that showed that the East coast of South America looked like a mirror image of the West coast of Africa. Abraham Ortelius (1597), Francis Bacon (1625), even Benjamin Franklin, and others suggested that the Americas were torn away from Europe and Africa.
James F. Evans (13:07:20) :
Einstein disdained actual physical experiments, he gloried in his “thought experiments” — his laboratory was his living room in his two-room apartment in Bern Switzerland.
You are completely off base. You’ve lost me.
So you are excited about a single paper for one hypothesis. But the many proofs for General Relativity aren’t enough.
James F. Evans (13:07:20) :
Every supposed “confirmation” of General Relativity by way of scientific observation & measurement has an alternative physical explanation.
I am certain there are alternate explanations to your plasmoid hypothesis. It looks like you say this single paper is the only proof needed.
Every once in a while I run in to a person that thinks they are smarter than Einstein.
photon without a Higgs (16:12:43) :
I am certain there are alternate explanations to your plasmoid hypothesis. It looks like you say this single paper is the only proof needed.
The paper he cites does not mention, suggest, or demonstrate the presence of plasmoids. That is Evans’ invention.
Leif Svalgaard (15:02:45) :
Any shifting around of the interior would introduce a quadrupolar moment which is not observed.
The constraint on the quadrupole moment (2+-0.4)10^-7 isn’t so tight as to be able to be definite about that. Quite small movements in the dense solar interior would set up much larger flows on the much less dense solar surface.