Physical constant e has dimensioni [electrical charge]
Planck constant h has dimension [energy x time]
joule, erg,energy has dimensiom [mass x velocity squared]
c,velocity has dimension [space/time]
electron mass has dimension [mass]
and so on and so forth
All physical constants have dimensions that can be solved in terms of space,mass, time,electric charge, and Kelvin (temperature), to include thermodynamics
Tullio

OK Tullio:)
Constants and dimensions are a bit abstract concepts.
Normally you have not to deal with that.

Cheers:)

Being a physicist I had to deal with them. But I only took a computer language course at 44 years of age, when working at Elsag in Genoa. I did not understand a word of it, it was PL/1. I was very depresssed, having just separated from my wife, and left two children to her care, as law dictates in Italy. The, one year later, having returned to Milano and found a job at SGS (now STMicroelectronics) as Documentation manager of UNIX boxes designed by Scott McNealy, later SUN boss, I was given a copy of the "White book", the "C" language manual by Kernighan and Ritchie, and started experimenting C programming on my computer. Then in 1985 I was hired by Honeywell, later Honeywell-Bull in UNIX marketing. I wentg also to Israel three times for Honeywheel.
Later I was asked if I accepted the position of manager of the Bull Unix Laboratory at Area Trieste Park in Trieste. Since Trieste is my hometown, I accepted and found myself in charge of an unit with two young graduates, a technician and four stage postgraduate students. I had a Bull RISC minicomputer, really a MIPS computer, two MIPS workstations and two Windows PC, connected to the Internet via the Italian research network, GARR.
I connected to the Free Software Foundation of Richard Stallman and started compiling GNU C 2.2 on it with the K&R C I had, not an ANSI C. I compiled it, compiled TeX 3.20 and the Grass Geographic Information System of the US Army Corps of Engineers. It was the first compilation on a RISC machine and I had to write a report on it.
When Honeywell-Bull would not or could not extend an agreement with Area Science Park, I had to come back home near Milano and started wih a PC, first Windows, then Solaris, then Linux. And soon found BOINC and here I am with 3 computers, 2 Linux and one Windows 10 crunching 6 BOINC projects.Cheers.
Tullio

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Being a physicist I had to deal with them. But I only took a computer language course at 44 years of age, when working at Elsag in Genoa. I did not understand a word of it, it was PL/1. I was very depresssed, having just separated from my wife, and left two children to her care, as law dictates in Italy. The, one year later, having returned to Milano and found a job at SGS (now STMicroelectronics) as Documentation manager of UNIX boxes designed by Scott McNealy, later SUN boss, I was given a copy of the "White book", the "C" language manual by Kernighan and Ritchie, and started experimenting C programming on my computer. Then in 1985 I was hired by Honeywell, later Honeywell-Bull in UNIX marketing. I wentg also to Israel three times for Honeywheel.
Later I was asked if I accepted the position of manager of the Bull Unix Laboratory at Area Trieste Park in Trieste. Since Trieste is my hometown, I accepted and found myself in charge of an unit with two young graduates, a technician and four stage postgraduate students. I had a Bull RISC minicomputer, really a MIPS computer, two MIPS workstations and two Windows PC, connected to the Internet via the Italian research network, GARR.
I connected to the Free Software Foundation of Richard Stallman and started compiling GNU C 2.2 on it with the K&R C I had, not an ANSI C. I compiled it, compiled TeX 3.20 and the Grass Geographic Information System of the US Army Corps of Engineers. It was the first compilation on a RISC machine and I had to write a report on it.
When Honeywell-Bull would not or could not extend an agreement with Area Science Park, I had to come back home near Milano and started wih a PC, first Windows, then Solaris, then Linux. And soon found BOINC and here I am with 3 computers, 2 Linux and one Windows 10 crunching 6 BOINC projects.Cheers.
Tullio

I have that book too Tullio:)
I think that one is edition 2 since it says ANSI C.

DEC PDP-11:)

One of them is Ken Thompson. The other could be Dennis Ritchie. I have also "The UNIX programming environment" by Brian W.Kernighan and Dennis Ritchie.
Tullio

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Constants and dimensions are a bit abstract concepts.
Normally you have not to deal with that.

Cheers:)

some1 who thinks that dimensions & constants r abstract concepts - should not try to read books about Black holes...
or doesn't distinguish dimensions from a dimensionless constants - which is a 3rd grade physics...

it's like trying 2 start Win10 on 8086...
just except that Black holes r there & be astonished by a beauty of it...without any physics!
;)

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non-profit org. Play4Life in Zagreb, Croatia, EU

Carlo Rovelli writes of an "event-horizon telescope" based on a net of radiotelescopes joined in a Very Long Baseline Interferometer to observe the evnt Horizon of Sagittarius A, the black hole at the center of our Galaxy. Its hub is in the Sierra Negra, in Puebla State, Mexico.
Tullio

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Carlo Rovelli writes of an "event-horizon telescope" based on a net of radiotelescopes joined in a Very Long Baseline Interferometer to observe the evnt Horizon of Sagittarius A, the black hole at the center of our Galaxy. Its hub is in the Sierra Negra, in Puebla State, Mexico.
Tullio

A lesson on event-horizon.
https://www.youtube.com/watch?v=yMRYZMv0jRE

Susskind is now researching on a theory by Juan Maldacena and others which puts entanglement basic to the structure of space-time. There is a long article on 'Nature Physics" of November 17 too complex to summarize here.
Tullio

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Susskind is now researching on a theory by Juan Maldacena and others which puts entanglement basic to the structure of space-time. There is a long article on 'Nature Physics" of November 17 too complex to summarize here.
Tullio

The short story.
https://en.wikipedia.org/wiki/ER%3DEPR
From what I understand it only explains the physics of the event horizon.
But what is the physics inside a black hole?

From what I understand, it is a mapping between a 3D "bulk universe" and a 2D surface which encompasses it. This not only in the case of black holes, which is a limiting case, but in all cases. In the black hole case, the 2D surface is the event horizon.All this happens because of entanglement. I had an online discussion on this matter with a physicist (Roberto Battiston) who is now the president of the Italian Space Agency, but he no longer has the time to answer my questions.
Tullio

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It's Black Friday today.
Three years ago, NASA introduced the "Black Hole Friday" as an existential response to American "feast" Black Friday.
https://twitter.com/hashtag/BlackHoleFriday

Milky Way's Second Most Massive Black Hole Found?

Astronomers have detected what could be the second most massive black hole in our galaxy and it may be the missing piece of a cosmic puzzle.

But radio astronomers didn’t directly detect the candidate black hole, rather they spied the whirling gases caught in its powerful gravitational grasp, potentially establishing a new method to track down elusive “intermediate-mass” black holes.

http://news.discovery.com/space/galaxies/milky-ways-second-most-massive-black-hole-found-160116.htm

We don't need two of them.

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Monstrous black hole.

Behemoth Black Hole Found in an Unlikely Place

Astronomers have uncovered a near-record breaking supermassive black hole, weighing 17 billion suns, in an unlikely place: in the center of a galaxy in a sparsely populated area of the universe. The observations, made by NASA’s Hubble Space Telescope and the Gemini Telescope in Hawaii, may indicate that these monster objects may be more common than once thought.

Until now, the biggest supermassive black holes – those roughly 10 billion times the mass of our sun – have been found at the cores of very large galaxies in regions of the universe packed with other large galaxies. In fact, the current record holder tips the scale at 21 billion suns and resides in the crowded Coma galaxy cluster that consists of over 1,000 galaxies.

http://www.nasa.gov/feature/goddard/2016/behemoth-black-hole-found-in-an-unlikely-place

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Monstrous black hole.

Behemoth Black Hole Found in an Unlikely Place

Astronomers have uncovered a near-record breaking supermassive black hole, weighing 17 billion suns, in an unlikely place: in the center of a galaxy in a sparsely populated area of the universe. The observations, made by NASA’s Hubble Space Telescope and the Gemini Telescope in Hawaii, may indicate that these monster objects may be more common than once thought.

Until now, the biggest supermassive black holes – those roughly 10 billion times the mass of our sun – have been found at the cores of very large galaxies in regions of the universe packed with other large galaxies. In fact, the current record holder tips the scale at 21 billion suns and resides in the crowded Coma galaxy cluster that consists of over 1,000 galaxies.

http://www.nasa.gov/feature/goddard/2016/behemoth-black-hole-found-in-an-unlikely-place

No need to travel so far for that story, http://news.berkeley.edu/2016/04/06/supermassive-black-holes-may-be-lurking-everywhere-in-the-universe/

Maybe that is the classical radius. When G.E. Uhlenbeck and S.A.Goudsmit discovered the electron spin in 1925 Wolfgang Pauli objected that the equator of the electron would move at a speed greater than light. The two tried to retract their article to "Annalen der Physik" but it was published on the advice of Paul Ehrenfest The two however never got a Nobel Prize which they amply deserved.
Tullio

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Mysterious 'alignment' of black holes discovered by astronomers

Astronomers have discovered an alignment between a number of gas fountains spewed out by supermassive black holes, possibly shedding new light on the underlying structure of the universe.

Supermassive black holes, often found at the centre of galaxies, regularly eject debris which falls into them, creating huge and super-fast jets of gas.

It seems like a chaotic process, which is why astronomers were so surprised to find around a dozen of these jets appear to be aligned with one another, despite being tens of millions of light years apart.

It's not been proved yet, however. The alignment of the jets was only spotted accidentally, and projects are now underway to take a closer look at the galaxies and explore the idea further.

Oh. It was National Donut Day in the US last friday.
NASA said this.

Enjoying a donut today? We bet it’s not one w/ black hole filling!

Ton's of black holes.

http://www.nasa.gov/feature/jpl/chorus-of-black-holes-sings-in-x-rays
Chorus of Black Holes Sings in X-Rays


The blue dots in this field of galaxies, known as the COSMOS field, show galaxies that contain supermassive black holes emitting high-energy X-rays.


Supermassive black holes in the universe are like a raucous choir singing in the language of X-rays. When black holes pull in surrounding matter, they let out powerful X-ray bursts. This song of X-rays, coming from a chorus of millions of black holes, fills the entire sky -- a phenomenon astronomers call the cosmic X-ray background.

NASA's Chandra mission has managed to pinpoint many of the so-called active black holes contributing to this X-ray background, but the ones that let out high-energy X-rays -- those with the highest-pitched "voices" -- have remained elusive.

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Jeff Steinhauer of the Technion University of Haifa, Israel, says that he has proven the existence of Hawking radiation emanating from a black hole with acoustic waves on a Bose-Einstein condensate at a temperature close to absolute zero. But there are doubts from other scientists. However his experiment does not cost much and is contained in one room only, so his efforts are worth of praise.
Tullio

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