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.
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James F. Evans (22:49:56) :
Light, the photon, has no mass, therefore, gravity does not act upon light because gravity only acts on objects that have mass.
A photon traveling in empty space has a relativistic mass, which is its energy divided by c2.
When light is transmitted through a layer of magneto-optic material, the result is called the Faraday effect: the plane of polarization can be rotated, forming a Faraday rotator.
The Faraday rotation is of the plane of polarization [and we use this effect to estimate magnetic fields], but does not bend the overall direction in which the photon travels. You think of the photon spiraling around its otherwise straight path.
Einstein predicted that light from a distant object that was gravitationally warped around a massive foreground object would form arcs or even a full circle.
Here are some very nice arcs for you: http://csep10.phys.utk.edu/astr162/lect/galaxies/lensing.html
The faint foreground galaxy would need to be much bigger and brighter in order to accomplish this lensing feat
That is where dark matter comes to the rescue. Lensing is, in fact, one of the very direct ways used to map out the distribution of dark matter.
As to your citation to the Moscow associate professor power point presentation — I’m not inpressed…seems like you are reaching…too far.
Yeah, I was afraid that it would be way over your head, and it apparently was. Perhaps some of the links in the link I gave above will be more accessible to you. You can always ask if there is something you do not understand.
Leif Svalgaard (22:55:52) :
…deviations of the CMB from a perfect blackbody radiation are well understood and were predicted long before they were observed.
That is because you simply do not know the theory. Here is a little bit: http://background.uchicago.edu/~whu/intermediate/intermediate.html
Leif, I’m a historian of science. I know the CMB temperature and anisotropy was more accurately predicted by steady state theorists than it was by the Hubble constant changing Big Bangers of the time.
Hubble himself had strong doubts about Big Bang.
Thanks for the link though. I’ll have a read of where it’s up to. Better the devil you know and all that. 😉
Cheers
The so-called “big bang” — precision science? Not at all.
Hannes Alfven, 1970 Nobel Prize winner, physics:
“I was there when Abbe Georges Lemaitre first proposed this theory,” he recalls. Lemaitre was, at the time, both a member of the Catholic hierarchy and an accomplished scientist. He said in private that this theory was a way to reconcile science with St. Thomas Aquinas’ theological dictum of creatio ex nihilo — creation out of nothing.”
Precision science? An attempt to reconcile faith and science resulting in more faith than science.
tallbloke (23:09:36) :
Since as you say, the empty vacuum of Le Maitre’s day is now full of plasma, ether, hydrogen molecules we can’t see,
That was not what I meant. Rather the vacuum is a seething mass of [virtual] particles popping in and out of existence at incredible frequency. Even after you have removed all the plasma, etc. Go here: http://en.wikipedia.org/wiki/Casimir_effect to learn about the Casimir effect and associated phenomena.
We could make it a competition with annual debates.
This would be silly in the extreme. Like having a public debate about whether the Earth is flat or round, like this one:
guess which one you would be like 🙂
PS. you should really take the trouble to study carefully ALL the material at http://background.uchicago.edu/~whu/intermediate/intermediate.html including the links down the left side. I estimate some six hours of study and thinking would give you an idea what we are talking about, should you be truly interested. If not, well, your loss.
Dr. Svalgaard: So, what you’re really saying is that both “gravity” only galaxy mechanics and gravitational lensing have been falsified, but for the invention of “dark matter”.
“…dark matter comes to the rescue.”
I think you let the cat out of the bag…
James F. Evans (23:28:00) :
Hannes Alfven, 1970 Nobel Prize winner, physics:
“I was there when Abbe Georges Lemaitre first proposed this theory,” he recalls.
BTW, I have often discussed these things with Hannes [“I was there”] and, with all due respect, he was reluctant to accept much of the scientific progress after about 1975. He even doubted that we could measure the Sun’s magnetic field [mostly because we found values that he did not expect, e.g. that it reversed]. No need for you to regress to astronomy of almost a century ago.
tallbloke (23:24:40) :
Leif, I’m a historian of science. I know the CMB temperature and anisotropy was more accurately predicted by steady state theorists than it was by the Hubble constant changing Big Bangers of the time.
Nonsense, link please. The CMB temperature was predicted by the ultimate banger, Gamov.
Hubble himself had strong doubts about Big Bang.
Hubble maintained that “no true expansion exists, and therefore that the redshift represents a hitherto unrecognized principle of nature”, and that is how we see the situation today. The galaxies do not recede through space [i.e. the redshift is NOT a Doppler shift], but partake in a hitherto unrecognized principle of nature, namely the expansion of space itself, with galaxies motionless [apart from the gravitational interactions].
James F. Evans (23:34:46) :
“…dark matter comes to the rescue.”
I think you let the cat out of the bag…
The same way as gravity itself came to the rescue in explaining the movements of planets once the crystal spheres had been shattered. Both ‘gravity’, ‘dark matter, even ‘electricity’ are just words we use for phenomena that we have observed.
BTW, you still owe me a description of an electron and about which branch of plasma physics is your professional field of specialty.
Did you like the nice arcs? or this nice Einstein Ring: http://www.universetoday.com/2008/01/10/hubble-sees-a-double-einstein-ring/
Double, to boot!
tallbloke (23:09:36) :
Since as you say, the empty vacuum of Le Maitre’s day is now full of plasma, ether, hydrogen molecules we can’t see
As I said, this is not what I meant. Let me excerpt a few sentences from the Casimir link:
“The vacuum has a vastly complex structure. The vacuum has, implicitly, all of the properties that a particle may have: spin, or polarization in the case of light, energy, and so on. On average, all of these properties cancel out: the vacuum is, after all, “empty” in this sense”
The clash between classical physics and quantum mechanics is apparent in the above statement, as the energy in the vacuum sums to infinity if we allow oscillators of all possible sizes. Perhaps at the deepest level space is discrete rather than continuous. In a century, schoolchildren will be taught how all this works out.
Leif Svalgaard (23:28:22) :
tallbloke (23:09:36) :
Since as you say, the empty vacuum of Le Maitre’s day is now full of plasma, ether, hydrogen molecules we can’t see, all of which slow light down and redshift it; why are we still in need of unobserved assumptions like “expanding nothingness” and “dark matter”?
That was not what I meant. Rather the vacuum is a seething mass of [virtual] particles popping in and out of existence at incredible frequency. Even after you have removed all the plasma, etc. Go here: http://en.wikipedia.org/wiki/Casimir_effect to learn about the Casimir effect and associated phenomena.
We could make it a competition with annual debates.
This would be silly in the extreme. Like having a public debate about whether the Earth is flat or round, like this one:
guess which one you would be like 🙂
Ahh, back to ridicule already. I think you’ll find it’s the telescope confiscators who are the ‘flat earthers’ if you do your history though.
Anyway, some progress at least. With your theoretical ‘particles popping in and out of existence’ (how cool is that!), and my observed and measured ether drift, we’ll soon be agreeing that space is an electric soup. 😉
Maybe we’ll find the mysterious repulsive force you claim drives the expansion of nothingness there. But then, you are at the same time claiming that space is expanding rather than galaxies moving, and simultaneously having that space filled with theoretical popping particles.
This is a good party trick. Not only having your cake and eating it, but having the remaining portion increase in size too!
Bye for now.
Leif Svaalgard,
Why would you think that public debates on the fudamentals of science would be ‘silly in the extreme’? I am genuinely interested in the chain of thought that gets you to this statement.
Leif Svalgaard (23:51:41) :
tallbloke (23:24:40) :
Leif, I’m a historian of science. I know the CMB temperature and anisotropy was more accurately predicted by steady state theorists than it was by the Hubble constant changing Big Bangers of the time.
Nonsense, link please. The CMB temperature was predicted by the ultimate banger, Gamov.
http://www.astro.ucla.edu/~wright/CMB.html
The first observations of the CMB were made by McKellar using interstellar molecules in 1940. The image at right shows a spectrum of the star zeta Oph taken in 1940 which shows the weak R(1) line from rotationally excited CN. The significance of these data was not realized at the time, and there is even a line in the 1950 book Spectra of Diatomic Molecules by the Nobel-prize winning physicist Gerhard Herzberg, noting the 2.3 K rotational temperature of the cyanogen molecule (CN) in interstellar space but stating that it had “only a very restricted meaning.”
One person did make the connection between McKellar’s 2.3 K and the Universe, and that was [steady state theorist] Fred Hoyle in a 1950 review (1950, Observatory, 70, 194-195) of a book by Gamow and Critchfield (1949, “Theory of Atomic Nucleus and Nuclear Energy-Sources”). Hoyle was one of the three inventors of the Steady State model which was the main competitor to Gamow’s Big Bang model. Hoyle wrote: “[the Big Bang model] would lead to a temperature of the radiation at present maintained throughout the whole of space much greater than McKellar’s determination for some regions within the Galaxy [Anisotropy].” The appendix with Gamow’s cosmological model gives values from which To = 11 K can be computed, which certainly is larger than the observation of 2.3 K. But Hoyle did not consider Alpher and Herman’s paper (1949, Phys. Rev., 75, 1089-1095) which gave two versions of the Big Bang, one with To = 1 K and one with To = 5 K. Thus the uncertainties in the cosmological parameters easily allowed for McKellar’s CN data to be a confirmation of the Big Bang instead of a refutation of it. But none of the participants in this debate ever looked further into the interstellar CN data, and thus the CMB remained undiscovered until 1965. In fact Gamow seemed to conspicuously ignore this discrepancy, and gives To = 50 K in his book “Creation of the Universe” (1955, 1961).
http://wapedia.mobi/en/Cosmic_microwave_background_radiation
Timeline of the CMB
Important people and dates
1941 Andrew McKellar reported the observation of an average bolometric temperature of 2.3 K based on the study of interstellar absorption lines. [nb 6] [16] [17]
1946 Robert Dicke predicts “.. radiation from cosmic matter” at <20 K but did not refer to background radiation [18]
1948 George Gamow calculates a temperature of 50 K (assuming a 3-billion-year old Universe), [19] commenting it “.. is in reasonable agreement with the actual temperature of interstellar space”, but does not mention background radiation.
1948 Ralph Alpher and Robert Herman estimate “the temperature in the Universe” at 5 K. Although they do not specifically mention microwave background radiation, it may be inferred. [20]
1950 Ralph Alpher and Robert Herman re-estimate the temperature at 28 K.
1953 George Gamow estimates 7 K. [18]
1955 Émile Le Roux of the Nançay Radio Observatory, in a sky survey at λ=33 cm, reported a near-isotropic background radiation of 3 kelvins, plus or minus 2. [18]
1956 George Gamow estimates 6 K. [18]
1957 Tigran Shmaonov reports that “the absolute effective temperature of the radioemission background … is 4±3K”. [21] It is noted that the “measurements showed that radiation intensity was independent of either time or direction of observation… it is now clear that Shmaonov did observe the cosmic microwave background at a wavelength of 3.2 cm” [22]
1960s Robert Dicke re-estimates a MBR (microwave background radiation) temperature of 40 K [18]
1964 A. G. Doroshkevich and Igor Novikov publish a brief paper, where they name the CMB radiation phenomenon as detectable. [23]
1964-65 Arno Penzias and Robert Woodrow Wilson measure the temperature to be approximately 3 K. Robert Dicke, P. J. E. Peebles, P. G. Roll, and D. T. Wilkinson interpret this radiation as a signature of the big bang.
So it looks like Alpher and Herman get the laurels for the Big Bangers, and Gamow gets a booby prize for multiple gross mis-estimations.
What was that you said about “predict early, predict often”? 😉
Leif Svalgaard: “Perhaps at the deepest level space is discrete rather than continuous”
In this regard: Do you think loop quantum gravity theory looks promising?
supercritical (01:19:05) :
Why would you think that public debates on the fundamentals of science would be ’silly in the extreme’? I am genuinely interested in the chain of thought that gets you to this statement.
In general such debates would be a good thing [there were actually such debates in the past: http://en.wikipedia.org/wiki/The_Great_Debate ].
The silliness comes in with the particular debate tallbloke proposes, as there is no great schism among astronomers on which to base the debate. There is a need for education of the public [including tallbloke].
Similarly, equally silly would be debates about the age of the Earth, Evolution, Plate Tectonics, and other established facts.
tallbloke (05:27:38) :
I know the CMB temperature and anisotropy was more accurately predicted by steady state theorists than it was by the Hubble constant changing Big Bangers of the time.
It is hard to keep you to the facts. Hoyle did not predict anything, he referred to an observation. Gamow et al. made a real prediction from basic physics.
Espen (05:35:28) :
In this regard: Do you think loop quantum gravity theory looks promising?
There are some good ideas there, but it is too early in the game to tilt one way or the other. Since our current picture of the Universe is driven by observations we are not critically dependent on the theory at the deepest level. In the end, though, that is where the true understanding will come from.
Leif Svalgaard (07:59:19) :
There is a need for education of the public [including tallbloke].
I’m always willing to learn, but never willing to be force fed shallow and inaccurate historical revisionism or false claims of certainty.
Experimentum summus judex – experiment is the ultimate judge.
But I do find theories interesting. – All of them.
However, experiment and observation leading to correct theoretical prediction is king.
http://tallbloke.wordpress.com/2010/01/12/confirmation-of-transmissive-medium-pervading-space/
It’s great that proponents of the Big Bang theory have made some too.
Perhaps in a hundred years we’ll be teaching kids how they were reconciled rather than sweeping one of them under the carpet. I hope so for the sake of science.
Bye for now.
tallbloke (09:11:31) :
I’m always willing to learn, but never willing to be force fed shallow and inaccurate historical revisionism or false claims of certainty.
In that case, you might look in the mirror and reconsider your own inaccurate or unfounded statements.
tallbloke (09:30:08) :
However, experiment and observation leading to correct theoretical prediction is king.
Except the ones you refer to have not held up to modern measurements, e.g.
http://www.mso.anu.edu.au/~charley/papers/CMBDipoleHistory.pdf
The velocity was wrong and the direction as well. You really have to learn a bit about modern astronomy.
tallbloke (09:30:08) :
Perhaps in a hundred years we’ll be teaching kids how they were reconciled rather than sweeping one of them under the carpet. I hope so for the sake of science.
Wrong ideas and inaccurate data are not reconciled nor swept under the rug. They are blissfully forgotten, ignored, and discarded.
Leif Svalgaard (09:49:54) :
Wrong ideas and inaccurate data are not reconciled nor swept under the rug. They are blissfully forgotten, ignored, and discarded.
The measurements Miller made of the Ether Drift in 1926 were not wrong, nor innacurate, and were confirmed in 2002 by Yuri M. Galaev.
THE MEASURING OF ETHER-DRIFT VELOCITY AND
KINEMATIC ETHER VISCOSITY WITHIN OPTICAL
WAVES BAND
The Institute of Radiophysics and Electronics of NSA in Ukraine,
12 Ac. Proskury St., Kharkov, 61085 Ukraine
Furthermore there are other independent confirmations. The non-interferometer coaxial cable experiments of DeWitte (1991) and Torr and Kolen (1984) show results of motion equal to Miller’s 1925 data. In the midst of analyzing the results Cahill concludes: “So the effect is certainly cosmological and not associated with any daily thermal effects, which in any case would be very small as the cable is buried” (Novel Gravity Probe B Gravitational Wave Detection, Flinders University, August 21, 2004, pp. 16-17).
“My opinion about Miller’s experiments is the following. … Should the positive result be confirmed, then the special theory of relativity and with it the general theory of relativity, in its current form, would be invalid. Experimentum summus judex. Only the equivalence of inertia and gravitation would remain, however, they would have to lead to a significantly different theory.”
— Albert Einstein, in a letter to Edwin E. Slosson, July 1925
Those interested are welcome to join rational discussion here:
http://tallbloke.wordpress.com/2010/01/12/confirmation-of-transmissive-medium-pervading-space/
Thank you and goodbye.
tallbloke (10:13:08) :
The measurements Miller made of the Ether Drift in 1926 were not wrong, nor innacurate, and were confirmed in 2002 by Yuri M. Galaev.
I think you are confusing ‘ether drift’ with the dipole component of the CMB. Since relativity is experimentally confirmed over and over, claiming it to be invalid is an extraordinary claim and as such requires extraordinary evidence. What you refer to does not rise to that. If Miller was measuring the solar systems movement through the Galaxy, then to error would be to assume that the Galaxy is stationary in the ‘ether’. Again, your whole edifice on this is the usual pseudo-scientific mish-mash. Educate yourself a bit instead.
Ok, time to weigh in. So lets talk observations. Problems for cosmology
started in earnest with the discovery of Quasars. Note:Quasars were discovered after the Hubble Law which led to the expanding universe. Quasars appear as starlike points in the sky frequently blue in color. They populate regions around spiral galaxies and are an optical and X-ray source. Now to the problem: If one plots apparent brightness against their apparent redshift as one does for other galaxies one gets an unexpected scatter on the diagram not the smooth curve as one gets from plotting other galaxies. Thus it seems quasars do NOT follow the hubble law as do other objects in space. Hence there is no direct indication that quasars are actually at their PROPOSED redshift distances. In fact it has been argued that if Hubble had been given the plots for quasars he and other astronomers would never have concluded the universe is expanding! Quasars are very small compact objects sometimes only a light year across. So if quasars are really at their extreme redshift distances then they must be the most brightest and most energetic objects known to astronomers. So energetic in fact that untestable almost metaphysical mechanisms must be applied to explain the phenomena. On the other hand quasars when placed at their observed distances (in the neighbourhood of nearby galaxies) their brigtness and energies become NORMAL and no special mechanisms need be invoked.
Halton C. Arp’s (who was branded a quasar heretic by the consensus) book of peculiar galaxies contains an outstanding example of the problem of redshift with galaxy NGC7603 (seyfert-very active galaxy). In it you have the main galaxy connected by a luminous bridge to a secondary galaxy. Within the luminous bridge are two more objects. All objects have verry different redshifts: 8700km/s, 117,000km/s, 72,000km/s and 17,000km/s have been measured. According to current redshift understanding all four objects and especially the two located within the luminous bridge should be at wildly varying distances. They are not. This is pretty conclusive observational evidence that there is a NON COSMOLOGICAL COMPONENT to redshift.
The big bang never happened!
Mr. Svalgaard you’re so called watertight physics and precise observations
are a fantasy as are black holes. How do YOU explain this problem or do you claim observational error? Kudos to James Evans and Tallbloke for giving you a hard time!
tallbloke (10:13:08) :
“Since relativity is experimentally confirmed over and over, claiming it to be invalid is an extraordinary claim and as such requires extraordinary evidence. What you refer to does not rise to that. […] Educate yourself a bit instead.
A good [and accessible] place to start is here:
http://einstein.stanford.edu/SPACETIME/spacetime3.html
tallbloke (10:13:08) :
In the midst of analyzing the results Cahill concludes: “So the effect is certainly cosmological and not associated with any daily thermal effects, which in any case would be very small as the cable is buried” (Novel Gravity Probe B Gravitational Wave Detection,
Cahill’s result and his ‘Novel’ theory of gravity predicting a large frame-dragging has been shot down by the Gravity B probe that again has vindicated Einstein. Here is their latest mission status report:
http://einstein.stanford.edu/highlights/hl_021609.html
PS. I regularly attend their seminars as the group is in the same building at Stanford as I.
Brian (10:31:10) :
This is pretty conclusive observational evidence that there is a NON COSMOLOGICAL COMPONENT to redshift.
More than 200,000 quasars are now known and the observational evidence strongly favor cosmological distances. you can learn more about quasars here http://en.wikipedia.org/wiki/Quasar before moving on to more demanding stuff.
One of the best pieces of evidence is the gravitational lensing of quasars by distant galaxies [at cosmological distances] between us and the quasar. Here is a particularly beautiful example:
http://apod.nasa.gov/apod/ap060524.html