- What direction were the polar jets (are they pointing in our direction)?How could they be pointed any other way than generally out of the plane of the galaxy? The average angular motion of 4 million stars has to have an axis similar to the rest of the galaxy, no?
There is a massive, multi-continent/multi-time-zone press conference planned for April 9/10 this week, to announce the results of the Black Hole telescope, attempting to take an image of the supermassive black hole at the center of our galaxy.How might they be able to see that there is an Einsteinian blackhole?
It is a challenging task - if it had been an abject failure, a small press conference would have been adequate...Along with a request for a bigger grant involving more telescopes...
They have taken measurements over a period of months, so any short term variations (on the order of minutes, hours and days) will be turned into a blur.
So, did they:
- Find one black hole, or are there more lurking there?
- Did it (or they) have an active accretion disk?
- Were there polar jets visible?
- What direction were the polar jets (are they pointing in our direction)?
- What is your guess?
See, for example: https://www.abc.net.au/news/2019-04-07/black-hole-first-ever-photograph-could-be-unveiled-this-week/10979244
All will be revealed, this week! Then we can discuss it here...
How could they be pointed any other way than generally out of the plane of the galaxy?That is true if our galaxy were isolated in space.
How might they be able to see that there is an Einsteinian blackhole?With this first crude image, Einstein's theory of General Relativity seems to stand up.
Yes -- i think i have mentioned in New Theories that there might be 8 kinds of blackhole (including dark matter blackholes).Quote from: mad aetheristHow might they be able to see that there is an Einsteinian blackhole?With this first crude image, Einstein's theory of General Relativity seems to stand up.
The low resolution does not get us close enough to the event horizon to see any deviations due to quantum effects.
- In particular, with this 6 billion solar mass black hole, any Hawking radiation would be at an extremely low temperature (which provides a good silhouette against the extremely hot accretion disk).
Polar jets at M87 would of course support my centrifuging of aether theory which i have mentioned in New Theories.At best, they may be not inconsistent with it.
The Wikipedia article mentions that the jet is only seen on one side of the galaxy (our side). A jet on the other side is not excluded, as most of the energy will be directed away from us due to relativistic beaming. It would be hard to see it through the dense population of stars at the center of M87.John Michell in 1783 predicted super massive dark stars that trapped light. He didnt mention GR. He didnt mention a singularity. Stupid i guess.
At radio wavelengths, symmetrical jets are seen.
It also says that the Jet is at right-angles to the plane of the accretion disk.
- And that the accretion disk is gaining about 80 Earth masses per day (as an average)
If you imagine Saturn as a black hole, the Saturn's rings are the accretion disk (around the equator), and the jet scomes out the North and South poles.
So that should halve the number of models you have put on the table....
See: https://en.wikipedia.org/wiki/Messier_87#Jet
It's not an intrinsically complex or relativistic idea (as you have pointed out)The Wikipedia article mentions that the jet is only seen on one side of the galaxy (our side). A jet on the other side is not excluded, as most of the energy will be directed away from us due to relativistic beaming. It would be hard to see it through the dense population of stars at the center of M87.John Michell in 1783 predicted super massive dark stars that trapped light. He didnt mention GR. He didnt mention a singularity. Stupid i guess.
At radio wavelengths, symmetrical jets are seen.
It also says that the Jet is at right-angles to the plane of the accretion disk.
- And that the accretion disk is gaining about 80 Earth masses per day (as an average)
If you imagine Saturn as a black hole, the Saturn's rings are the accretion disk (around the equator), and the jet scomes out the North and South poles.
So that should halve the number of models you have put on the table....
See: https://en.wikipedia.org/wiki/Messier_87#Jet
The wave model for light hadn't taken hold yet either, not until the Thomas Young double slit experiment revealed it in 1801.It's not an intrinsically complex or relativistic idea (as you have pointed out)The Wikipedia article mentions that the jet is only seen on one side of the galaxy (our side). A jet on the other side is not excluded, as most of the energy will be directed away from us due to relativistic beaming. It would be hard to see it through the dense population of stars at the center of M87.John Michell in 1783 predicted super massive dark stars that trapped light. He didnt mention GR. He didnt mention a singularity. Stupid i guess.
At radio wavelengths, symmetrical jets are seen.
It also says that the Jet is at right-angles to the plane of the accretion disk.
- And that the accretion disk is gaining about 80 Earth masses per day (as an average)
If you imagine Saturn as a black hole, the Saturn's rings are the accretion disk (around the equator), and the jet scomes out the North and South poles.
So that should halve the number of models you have put on the table....
See: https://en.wikipedia.org/wiki/Messier_87#Jet
Once you have the understanding of orbits and escape velocities, and a knowledge of the speed of light, you can work out that a big enough (dense enough) thing won't let light escape.
Newton just missed it; he died 1727 but the speed of light was measured in 1728.
I guess John Michell didn't want to speculate about what would happen.
That's sensible of him. At the time, practically nothing was known about how stars worked. They didn't know what they were made of, not what kept them hot.
So what?
Why would you call that "stupid"?
John Michell in 1783 predicted super massive dark stars that trapped lightAbout 12 years after Michell, the French mathematician Laplace independently predicted black holes.
Thanx for that link.Quote from: Mad AetheristJohn Michell in 1783 predicted super massive dark stars that trapped lightAbout 12 years after Michell, the French mathematician Laplace independently predicted black holes.
- 3 years later, Laplace provided a mathematical proof of their possibility.
- His proof shows that he was thinking in terms of light as particles with some velocity.
- The concepts of the energy of a photon and the mass of a photon only arrived with quantum theory, otherwise Laplace could have made a similar prediction based on the energy of light particles.
See: http://www.narit.or.th/en/files/2009JAHHvol12/2009JAHH...12...90M.pdf
The wave model for light hadn't taken hold yet either, not until the Thomas Young double slit experiment revealed it in 1801.I suppose that the wave model would need a smaller mass than the ballistic (corpuscular) model. Based on the wave model suffering a slowing due to the nearness of mass, ie as per Einstein's GR (ie inserting the escape velocity into the equation for gamma). Or is the wave model more complicated than that?
So Michell was also assuming the corpuscular model for light.
I agree with Michell, GR is not needed (alltho i think that GR does come into play)(the nearness of mass slows the photons), & a singularity aint needed (& i dont believe in a singularity).It's not an intrinsically complex or relativistic idea (as you have pointed out)The Wikipedia article mentions that the jet is only seen on one side of the galaxy (our side). A jet on the other side is not excluded, as most of the energy will be directed away from us due to relativistic beaming. It would be hard to see it through the dense population of stars at the center of M87.John Michell in 1783 predicted super massive dark stars that trapped light. He didnt mention GR. He didnt mention a singularity. Stupid i guess.
At radio wavelengths, symmetrical jets are seen.
It also says that the Jet is at right-angles to the plane of the accretion disk.
- And that the accretion disk is gaining about 80 Earth masses per day (as an average)
If you imagine Saturn as a black hole, the Saturn's rings are the accretion disk (around the equator), and the jet scomes out the North and South poles.
So that should halve the number of models you have put on the table....
See: https://en.wikipedia.org/wiki/Messier_87#Jet
Once you have the understanding of orbits and escape velocities, and a knowledge of the speed of light, you can work out that a big enough (dense enough) thing won't let light escape.
Newton just missed it; he died 1727 but the speed of light was measured in 1728.
I guess John Michell didn't want to speculate about what would happen.
That's sensible of him. At the time, practically nothing was known about how stars worked. They didn't know what they were made of, not what kept them hot. So what? Why would you call that "stupid"?
The Wikipedia article mentions that the jet is only seen on one side of the galaxy (our side). A jet on the other side is not excluded, as most of the energy will be directed away from us due to relativistic beaming. It would be hard to see it through the dense population of stars at the center of M87.Most of my kinds of blackholes are probly more properly called dark stars because they are made of dark matter & can have little mass. And i reckon that dark matter resides in the center of all planets etc. My dark matter is very very dense, it is not atomic, it is more like the neutrons in a neutron star.
At radio wavelengths, symmetrical jets are seen.
It also says that the Jet is at right-angles to the plane of the accretion disk.
- And that the accretion disk is gaining about 80 Earth masses per day (as an average)
If you imagine Saturn as a black hole, the Saturn's rings are the accretion disk (around the equator), and the jet scomes out the North and South poles.
So that should halve the number of models you have put on the table....
See: https://en.wikipedia.org/wiki/Messier_87#Jet
I suppose that the wave model would need a smaller mass than the ballistic (corpuscular) model.As is so often the case, you suppose wrongly.
Has (the EHT) given an idea of the (M87 black hole) shape, ie , domed, sphere cone etc ?All it can say is that the silhouette is roughly circular, from our viewpoint.
Yes i am ok with there being a ballistic event horizon, where the ballistic escape velocity is c kmps. Based on the ballistic model being true.I suppose that the wave model would need a smaller mass than the ballistic (corpuscular) model.As is so often the case, you suppose wrongly.
The escape velocity for a ballistic missile at the event horizon is c.
Yet blackholes can , and M87 does have jets which came as a suprise, so the shape of a black hole, and mostly all about them seem to be conjecture and hypothesis. A photo is worth a thousand words, that is if that thousand words are right.Quote from: PetrochemicalsHas (the EHT) given an idea of the (M87 black hole) shape, ie , domed, sphere cone etc ?All it can say is that the silhouette is roughly circular, from our viewpoint.
The prediction of General Relativity is that the event horizon is spherical (maybe with an equatorial bulge if the black hole is rotating rapidly). The observation of M87 is consistent with this theory.
A cone or dome (hemisphere) would not be an expected shape for the event horizon, since some parts are much closer to the central point than others.
A sphere (or an ellipsoid for a rotating black hole) has all points of the event horizon at the location where the escape velocity "to infinity" equals the speed of light, c. These points are all at roughly the same distance from the central singularity.
Where did you get the idea that the jets for this BH came as a surprise? They were detected by the Hubble way back in '99. They were fully expected. Such jets are produced by in-falling material being redirected and accelerated by the the magnetic field of the BH, this all happens well outside the event horizon.Yet blackholes can , and M87 does have jets which came as a suprise, so the shape of a black hole, and mostly all about them seem to be conjecture and hypothesis. A photo is worth a thousand words, that is if that thousand words are right.Quote from: PetrochemicalsHas (the EHT) given an idea of the (M87 black hole) shape, ie , domed, sphere cone etc ?All it can say is that the silhouette is roughly circular, from our viewpoint.
The prediction of General Relativity is that the event horizon is spherical (maybe with an equatorial bulge if the black hole is rotating rapidly). The observation of M87 is consistent with this theory.
A cone or dome (hemisphere) would not be an expected shape for the event horizon, since some parts are much closer to the central point than others.
A sphere (or an ellipsoid for a rotating black hole) has all points of the event horizon at the location where the escape velocity "to infinity" equals the speed of light, c. These points are all at roughly the same distance from the central singularity.
Where did you get the idea that the jets for this BH came as a surprise? They were detected by the Hubble way back in '99. They were fully expected. Such jets are produced by in-falling material being redirected and accelerated by the the magnetic field of the BH, this all happens well outside the event horizon.
The first astrophysical jet was discovered in 1918 by the American astronomer Heber Curtis, who noticed “a curious straight ray … apparently connected with the nucleus by a thin line of matter” in giant elliptical galaxy M87.
Michell in 1783 said that the Sun would be a dark star if its diameter were 497 times greater, based on the density not changing (or the density profile not changing)(whatever).Thanx for that link.Quote from: Mad AetheristJohn Michell in 1783 predicted super massive dark stars that trapped lightAbout 12 years after Michell, the French mathematician Laplace independently predicted black holes.
- 3 years later, Laplace provided a mathematical proof of their possibility.
- His proof shows that he was thinking in terms of light as particles with some velocity.
- The concepts of the energy of a photon and the mass of a photon only arrived with quantum theory, otherwise Laplace could have made a similar prediction based on the energy of light particles.
See: http://www.narit.or.th/en/files/2009JAHHvol12/2009JAHH...12...90M.pdf
Michell using a ballistic calculation said the Sun would be a dark star if 497 times larger (ie 122,763,473 solar masses). My ballistic calculation based on modern numbers says 485.3.
Here i didnt need GR nor a silly singularity.
I allso using ballistics calculated that we would have a dark star if the same size as Earth & 2156 solar masses.
This reduces to 1079 solar masses if i use GR to calculate the kmps of the slowed light near this dark star. Here i inserted the escape velocity into the equation for gamma.
This reduces to 779 solar masses if i assume that the dark star has an atmosphere with n=1.33 (ie like water), ie slowing the escaping light in that proportion.
Anyhow there is no need for GR or for a singularity. And simple ballistics is good enuff.
So, how will we detect whether a blackhole is a Michellian dark star, or is a Laplacian invisible body, or is an Einsteinian blackhole?
Sorry to but-in on this extremely valuable thread, but I wanted to let you all know that Cambridge astronomer Carolyn Crawford is coming onto the Naked Scientists this week to review this story and to update the coverage that it has received.I have a few questions.........
This is an opportunity for us to address some of the outstanding questions highlighted by other news coverage and also to clarify queries that have surfaced from the reporting.
If you would like to suggest some questions that we can put to Carolyn tomorrow as part of the discussion, it would be lovely to hear them.
Is there any way we can know anything related to mass distribution inside the Black Hole?(ie the event horizon?)Einstein's relativity suggests that any matter or radiation passing the event horizon is on a one-way path to a singularity at the center. That means we cannot send a probe to look inside and then report back.
Einstein's relativity suggests that any matter or radiation passing the event horizon is on a one-way path to a singularity at the center. That means we cannot send a probe to look inside and then report back.Might light count as one of these objects ,as I understand that there is a certain radius where light can orbit the BH?
For astronomical bodies with an internal distribution of mass (like a planet), we can investigate the internal distribution of mass by closely tracking the orbit of satellites. We could try a similar experiment with objects orbiting a black hole.
- We would have to try one without an accretion disk, as the friction, turbulence and magnetic fields within the plasma of the accretion disk will also distort the orbits.
I understand that there is a certain radius where light can orbit the BH?Yes, the photon sphere defines the innermost stable orbit for light.
If the Earth was completely spherical,homogeneous and hollow save for a thin crust ,how would orbiting satellites distinguish this from an Earth where the mass was evenly distributed from centre to surface?Newton's shell theorem (https://en.wikipedia.org/wiki/Shell_theorem) states that, to an outside observer, a thin crust is indistinguishable from a singularity of the same mass at the center.
event horizon, implies that the telescope's primary focus, will be an attempt to determine if there exist a curvature to the Universe.Not really,