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Harry Costas
Hello Alotmohan

Singularity is a concept for the Big Bang theory.

As for it reality it cannot occur.

But! than again I cannot prove that santa clause is real.

Solid State Universe

But I'd imagine the proper "imaginary"metric for white hole expansion would look like this:

Merry BelatedChristmas.
kaneda
Harry Costas. All large, dense things rotate from moons on upwards. Something as small and dense as a black hole would rotate incredibly fast. If a black hole did not rotate there would be something seriously wrong in our understanding of the cosmos.

Jets from outside the black hole have been explained by magnetic fields, similar to those on the Sun but incredibly more powerful.

We don't know the size of the central mass inside the event horizon. There may be hardly any difference in size between a 10 solar mass BH and a 10,000 solar mass BH central mass.
kaneda
alokmohan. A singularity is a mathematical concept that as Harry points out we have no evidence for in real life. It requires that matter collapses totally to basically nothing but magically the gravity somehow remains.

I have begun to think that the smaller an ultra dense object is, the smaller and more intense is it's gravitational field. I think if any amount of material collapsed into a point source that it's gravitational forces would not be felt any real distance away.
kaneda
SSU. If the formation of a black hole created a worm hole (and a white hole at the other end), then it would basically lose all it's material there and vanish as it eventually fell below the BH minmum mass which would not be too long since WH's are believed to give out huge amounts of energy.

A black hole can be imagined forming when a large enough star collapses but a white hole requires energy from elsewhere to power it. What would cause a white hole to form in a particular place?
Harry Costas
Hello Kaneda

You said

QUOTE
Harry Costas. All large, dense things rotate from moons on upwards. Something as small and dense as a black hole would rotate incredibly fast. If a black hole did not rotate there would be something seriously wrong in our understanding of the cosmos.

Yes we know all spin, but the spin that I'm talking about is extremely fast.
Similarity to a neutron pulsar what we see is the poles pulsating. Not the neutron star. With black holes there are two types one with observale spin and others without. This does not mean the black does not rotate.

QUOTE (->
 QUOTE Harry Costas. All large, dense things rotate from moons on upwards. Something as small and dense as a black hole would rotate incredibly fast. If a black hole did not rotate there would be something seriously wrong in our understanding of the cosmos.

Yes we know all spin, but the spin that I'm talking about is extremely fast.
Similarity to a neutron pulsar what we see is the poles pulsating. Not the neutron star. With black holes there are two types one with observale spin and others without. This does not mean the black does not rotate.

Jets from outside the black hole have been explained by magnetic fields, similar to those on the Sun but incredibly more powerful.

Jets outside of a black hole find their origin from within the matter that makes up the black hole. This matter is an ultra dense degenerated plasma matter. The forces are so great that electron shells have collapsed protons to neutrons, neutrons to quarks, quarks to preon particals. These forces are so great that they prevent any heat loss and prevent light from escaping. It is really a compact star core with the above qualitites. As to the jets formation look up plasma cosmology.

QUOTE
We don't know the size of the central mass inside the event horizon. There may be hardly any difference in size between a 10 solar mass BH and a 10,000 solar mass BH central mass.

Although we cannot see inside a black hole we can determine its mass by the gravitational inflence it has on the surrounding matter , stars and so on.

How to find a black hole
http://pda.physorg.com/lofi-news-black-mass-holes_7420.html

ChaosTheory
QUOTE (Nick+Nov 26 2006, 05:07 AM)
Black holes don't exist.

Yes they do.

Black Holes are deformities in particle radiation/negative energy flux's along a quantum field known as an event horizon.
Solid State Universe
QUOTE (kaneda+Jan 17 2007, 10:20 AM)
SSU. If the formation of a black hole created a worm hole (and a white hole at the other end), then it would basically lose all it's material there and vanish as it eventually fell below the BH minmum mass which would not be too long since WH's are believed to give out huge amounts of energy.

A black hole can be imagined forming when a large enough star collapses but a white hole requires energy from elsewhere to power it. What would cause a white hole to form in a particular place?

Do you have any idea how long it takes to reach infinity?

You won't be around to see it.

Since Black Hole are formed by energy density, I suppose the reverse would be true for White Holes.
AlphaNumeric
QUOTE (Solid State Universe+Jan 17 2007, 07:49 PM)
Do you have any idea how long it takes to reach infinity?

It takes a finite time to hit the singularity of a black hole. The distance is quite finite.
alokmohan
A singularity is a region where-where according to the laws of general theory of relativity-the curvature of spacetime becomes infinitely large,and spacetime ceases to exist.Since tidal gravity is a manifestation of spacetime curvature,a singlalrity is also a region of infinite tidal gravity.thats a region where gravity stretches all objects infinitely along some directions and squeezes them infinitely along others.
Michael Hill
I'm trying this first out because this idiot board has already lost one long message of mine and despite logging in again, I have had to imput a security code. Is dad1 now in charge here?
kaneda
Harry Costas. All black holes spin as far as I know. Is there any evidence they don't?

As far as we know, black hole jets are composed of protons and electrons:

http://www.physorg.com/news79361214.html

You state that both of these (I think you got protons and neutrons mixed up in your explanation) are both crushed inside a black hole so that means the material cannot come from inside. As jets happen in two opposing directions at once, that suggests that the magnetic explanation for their origin is correct. If light cannot escape, matter certainly cannot escape from the inner region.

Compact star core? It is a small sphere of degenerate matter so is not a star core except that it came from one originally.

The article though 2005 seemed a bit dated.
kaneda
SSU. When matter is sucked inside the event horizon of a black hole, it will accelerate to maximum speed (virtually light speed) on it's way to thye central mass.

White holes require a huge energy source which is outpouring energy at an incredible rate. They cannot just form. Black holes form from matter density.
alokmohan
Ima tempted to post.Black holes connect 3D Universe with the higher dimensional Hyperspace. That is the reason why it is critical to watch baby black hole birth and formation to understand the structure of the Hyperspace and the higher dimensions.

Scientists using NASA data are studying a newly recognized type of cosmic explosion called a hybrid gamma-ray burst. As with other gamma-ray bursts, this hybrid blast is likely signaling the birth of a new black hole.

Gamma-ray bursts represent the most powerful known explosions in the universe. Yet they are random and fleeting, never appearing twice. Scientists have only recently begun to understand their nature.

It is unclear, however, what kind of object or objects exploded or merged to create the new black hole. The hybrid burst exhibits properties of the two known classes of gamma-ray bursts yet possess features that remain unexplained.

NASA's Swift first discovered the burst on June 14. Since the Swift finding, more than a dozen telescopes, including the Hubble Space Telescope and large ground-based observatories, have studied the burst.

The unexplained features are associated with virtual particles that belong to higher dimensions. Scientists are watching these particles and their characteristics. It can provide clues to higher dimensions.

kaneda
alokmohan. A singularity is a mathematical concept as is infinity. There is no actual evidence for either.

If spacetime ceases to exist there, how can the curvature of spacetime be infinite?

Since gravity is caused by mater (which you could say bends spacetime), then to have matter crushed out of existence into a singularity suggests that gravity will no longer exist either. Alternatively, if spacetime is infinitely curved, it would suggest that you now have a closed system where all matter, gravity, energy is contained inside it and were you only inches away, you would feel no gravity or radiation from it.

If you had a region of infinite tidal gravity, how could the whole universe stop itself from being pulled into it? Also things will merely be crushed out of existence. You would only have infinite stretching if you had infinite time dilation (ie: something could exist forever), though of course with infinite stretching you could have whole universes between each electron.

I think you'll find tidal gravity causes spacetime curvature rather than the other way around. Also to have tidal gravity I think you would need varying zones of gravity whereas a singularity is one zone of crushing gravity which increases as you approach it.
kaneda
alokmohan. If black holes were connected with hyperspace, or at least operate in a fourth physical dimension it could mean that a hundred million black hole might just look like a million black hole close up based on it's effect on it's neighbours but also have a further gravitational effect over many, many light years through a fourth dimension on stars that would be thought to be far beyond it's gravitational influence.

Old gamma ray bursters are large stars going supernova and then collapsing into a black hole, the gamma signal only lasting upto two seconds.

The hybrid gamma burst lasted 102 seconds:

http://www.nasa.gov/mission_pages/swift/bu...hybrid_grb.html

I would think that is a black hole swallowing a very large star over a "fairly long" time period (maybe two minutes).
alokmohan
Poor chap being gulped.Pity for it.t.
alokmohan
http://www.sciencedaily.com/upi/indhttp://...=ScienceScience daily informs of new black hole&article=UPI-1-20070118-15491500-bc-us-nasa-chandra.xml
Harry Costas
Hello All

Is there a point in giving information on black holes and jets.

People here have there own ideas, regardless of the amount of information on the topics.

I read the above and I have to smile.

I will come back.

Have to take the kids out.

kaneda
QUOTE (Harry Costas+Jan 19 2007, 06:48 AM)
Hello All

Is there a point in giving information on black holes and jets.

People here have there own ideas, regardless of the amount of information on the topics.

I read the above and I have to smile.

I will come back.

Have to take the kids out.

It sounds like you are wondering why you are here? So am I.

You ignore standard theories on black holes in favour of Plasma Cosmology which leaves more questions unanswered than it answers. It seems to be evidence free from your replies so far.
alokmohan
Can you say what is plasmo cosmology/
Harry Costas
Hello All

Some people would like to think what they like to think and so be it.

Kaneda you do not understand where the standard theories originated from and how they are supported.

Take one standard theory and explain to me what you mean. You make statements without support.

Do you want to learn more or are you happy knowing what you know?

Black Holes are missunderstood by many. Its only in the last few years that information as to their workings and evolution and their effect on the surroundings.

AlphaNumeric
QUOTE (Harry Costas+Jan 19 2007, 12:42 PM)
Black Holes are missunderstood by many. Its only in the last few years that information as to their workings and evolution and their effect on the surroundings.

Their workings didn't really begin to be understoof till the mid 60s, with the development of more black hole solutions and coordinates like the Kruskal ones which allow motion across the event horizon to be smoothly described. Still, 40 years isn't really 'recently' (I'm 23, it's a long time to me!). It's only recently we've been able to do detailed computer models of colliding black holes or black hole accretion disk but that doesn't mean a huge amount of work wasn't done in the 60~80s on them.
Harry Costas
Hello All

Plasma Cosmology

Observational confirmation of the Sun's CNO cycle
http://arxiv.org/abs/astro-ph/0512633

Magnetic heart of a 3D reconnection event revealed by Cluster
http://sci.esa.int/science-e/www/object/in...fobjectid=39706

http://public.lanl.gov/alp/plasma/people/alfven.html

Plasma Physics and Astrophysics
Research Papers and Proposals
http://www.plasmaphysics.org.uk/research/

The IEEE, Plasma Cosmology and Extreme Ball Lightning
http://www.holoscience.com/news.php?article=88edua1k

Plasma Cosmology
http://www.matter-antimatter.com/plasma_cosmology.htm

Plasma Theory of Hubble Redshift of Galaxies
http://www.plasmaphysics.org.uk/research/redshift.htm

Theoretical Principles of
Plasma Physics and Atomic Physics
http://www.plasmaphysics.org.uk/

PLASMA UNIVERSE
http://public.lanl.gov/alp/plasma/TheUniverse.html

alokmohan
Can you a short descriptive essay?Which way it stands out and differs from big bang or steadtstate?
alokmohan
ESA's gamma ray observatory Integral has caught the centre of our galaxy in a moment of rare quiet. A handful of the most energetic high-energy sources surrounding the black hole at the centre of the Galaxy had all faded into a temporary silence when Integral looked. This unusual event is allowing astronomers to probe for even fainter objects and may give them a glimpse of matter disappearing into the massive black hole at the centre of our galaxy.

(PressZoom) - The Galactic centre is one of the most dynamic places in our Galaxy. It is thought to be home to a gigantic black hole, called Sagittarius A* ( pronounced 'A star' ). Since the beginning of the Integral mission, ESA's gamma ray observatory has allowed astronomers to keep watch on this ever-changing environment.

Integral has discovered many new sources of high-energy radiation near the galactic centre. From February 2005, Integral began to regularly monitor the centre of the Galaxy, and its immediate environment, known as the Galactic bulge.

Erik Kuulkers of ESA's Integral Science Operations Centre, ESAC, Spain, leads the Galactic bulge monitoring programme. Integral now keeps its high-tech eyes on about 80 high-energy sources in the galactic bulge. "Most of these are X-ray binaries," says Kuulkers.

X-ray binaries are made up of two stars in orbit around one another. One star is a relatively normal star; the other is a collapsed star, such as a white dwarf, neutron star or even a black hole. If the stars are close enough together, the strong gravity of the collapsed star can pull off gaseous material from the normal star. As this gas spirals down around the collapsed star, it is heated to over a million degrees centigrade and this causes it to emit high energy X-rays and gamma rays. The amount of gas falling from one star to the other determines the brightness of the X-ray and gamma-ray emission.

According to the Integral observations in April 2006, the high-energy rays from about ten sources closest to the galactic centre all faded temporarily. Kuulkers excludes the possibility that a mysterious external force is acting on all the objects to drive them into quiescence. "All the sources are variable and it was just by accident or sheer luck that they had turned off during that observation," he says with a smile.
The fortuitous dimming allows astronomers to set new limits on how faint these X-ray binaries can become. It also allows a number of new investigations to be undertaken with the data.

"When these normally bright sources are faint, we can look for even fainter sources," says Kuulkers. These could be other X-ray binaries or the high-energy radiation from giant molecular clouds interacting with past supernovae. There is also the possibility of detecting the faint high-energy radiation from the massive black hole in our Galaxy's centre.

Integral's Galactic bulge monitoring programme will continue throughout this year. The data is made available, within a day or two of being collected, to the scientific community via the Internet from a dedicated webpage at the Integral Science Data Centre ( IDSC ), Geneva, Switzerland. This way, anyone interested in specific sources can watch for interesting changes and trigger follow up observations with other telescopes in good time.

Notes for editors

The findings are accepted for publication in the Astronomy & Astrophysics magazine, in the article titled: "The INTEGRAL Galactic bulge monitoring program: the first 1.5 years
Harry Costas
Hello Alokmohan

Some people want to eat the fruit from the tree rather than growing the tree from its seed.

First thing first get to know the workings of the universe. You need to know how they come about and where they are going.

Star formation.

Supernovas

Compact Star Cores, neutron star, quarks, preon stars (theoretical) and the ultra dense plasma matter that prevents light from escaping (called a black hole, which is not really a hole as so to spaek of, or a hole well, but a dense degereated matter so dence that electron shells cannot exist and light cannot escape.)

I probably posted this before, here it is again

Preon Trinity - A Schematic Model of Leptons, Quarks and Heavy Vector Bosons
http://www.citebase.org/abstract?id=oai:ar...:hep-ph/0208135
http://www.citebase.org/fulltext?format=ap...:hep-ph/0208135

Quarks
http://hyperphysics.phy-astr.gsu.edu/hbase...s/quark.html#c6

Atomic structure
http://hyperphysics.phy-astr.gsu.edu/hbase...ructcon.html#c1

Exchange Forces
http://hyperphysics.phy-astr.gsu.edu/hbase...s/exchg.html#c1

Fundamental Forces
http://hyperphysics.phy-astr.gsu.edu/hbase.../funfor.html#c2

Electron-Positron Annihilation Provides Evidence of Three Colors for Quarks

http://hyperphysics.phy-astr.gsu.edu/hbase...s/qevid.html#c2

Evidence Found for New Form of Ultra-Dense Matter
http://www.space.com/scienceastronomy/astr...ter_020410.html

Astronomers announced Wednesday the discovery of evidence for a new state of matter heavier than any previously known, equivalent in density to stuffing all of Earth into an auditorium

I think the answer to compact star cores and ultra dense degenerated plasma matter which can prevent light from escaping is through the science of the forces within the atom or should I say between the subatomic particals.

The Swarm
http://antwrp.gsfc.nasa.gov/apod/ap050128.html

In respect to the make up of black holes. The seed in many cases is from a large star that has under gone a supernova. The Iron build up is broken down by high energy photons released by the core of the existing star to Helium to hydrogen to protons to neutrons. In smaller stars a neutron core is formed if there is greater amount of neutrons formed, these neutrons are broken down to quarks, creating the next stage, a quark composite and possible a preon quark composite and if sufficient mass is present light will not be able to escape the strong gravitaional, electromanetic and the strong forces that are present in the nucleus of an atom. In actual fact the core is a nucleon large body acting as one.

http://cosmos.swin.edu.au/lookup.html?e=su...burstconnection

The origin of our solar system is from a supernova leaving behind a neutron core composite that created in time a solar envelope.

http://www.omatumr.com/abstracts2006...gsInserted.pdf

Growing Supermassive Black Holes from Seeds
http://pda.physorg.com/lofi-news-black-hol...verse_9824.html
The above link is OK, but reference to the Big Bang has put them on the wrong track.

How to find a black hole
http://pda.physorg.com/lofi-news-black-mass-holes_7420.html

Puny black holes can eject Milky Way's stars
http://space.newscientist.com/article/dn10...r&nsref=dn10020

Keep cool and keep learning.
Take it step by step

If you wish to discuss any subject, please let me know.

One more thing I do not agree with the Big Bang theory, it is a fantasy theory created by the influence of politics and religion and made to be the standard model. Do not take my word on this. Discover it for your self.

I think the universe is endless and recycles.
kaneda

The standard theories came about by observation and experimentation.

So how about you explain Plasma Cosmology? This does not mean that your standard escape clause where you give links to sites and hope I will find something that I agree with there. Even dad1 can give links to sites he does not understand.

I disagree with you so I must be on the wrong track. I hate arguing with people who are always infallibly right. Next pope are you?

Do you actually know anything about plasma cosmology or do you just have some nice links?
kaneda
QUOTE (Harry Costas+Jan 20 2007, 10:13 AM)
Compact Star Cores, neutron star, quarks, preon stars (theoretical) and the ultra dense plasma matter that prevents light from escaping (called a black hole, which is not really a hole as so to spaek of, or a hole well, but a dense degereated matter so dence that electron shells cannot exist and light cannot escape.)

I think the answer to compact star cores and ultra dense degenerated plasma matter which can prevent light from escaping is through the science of the forces within the atom or should I say between the subatomic particals.

From wikipedia:

QUOTE
Plasma is a state of matter where the bonds between parts of the atoms are broken and the pieces, electrons and nuclei, separate. Even though they separate from one another, the electrons and nuclei still pull on each other because of their electric charge. This keeps them from getting too far apart, so the plasma stays together. Because the bonds are broken, the electrons can flow and move, so there are many interesting kinds of waves that can travel in a plasma, especially if there is a magnetic field in it. Magnetic fields make free electrons move in circles, and electric fields make them move in straight lines. Putting both kinds of fields into a plasma makes the electrons and nuclei do very complicated things.

Compare the plasma in plasma cosmology to real plasma.

I'd still like to know how ultra dense degenerated plasma matter can prevent light from escaping without an event horizon.
alokmohan
Degeneration of matter is something we miss.We should discuss.
Harry Costas
Hello Alokmohan

Read up on degenerated matter before you discuss it.

kaneda
Harry Costas. Degenerate matter is very densely packed matter in which even atoms have been broken down into their constituents. There is no movement of particles as would be necessary in a plasma, so a neutron star or black hole is nothing to do with plasma.
alokmohan
QUOTE (kaneda+Jan 21 2007, 06:46 AM)
Harry Costas. Degenerate matter is very densely packed matter in which even atoms have been broken down into their constituents. There is no movement of particles as would be necessary in a plasma, so a neutron star or black hole is nothing to do with plasma.

Degenerate matter is main reason of white dwarf.Degenation if neutrons causes neutron star to collapse.We get black hole.Under high pressure electrons are stuffed in ,they behave as if they are having claustrophobia.
alokmohan
is the most violent thing that can happens in the universe. When Black Holes collide, they generate unimaginable amount of energy.

Initially, each black hole has its own surface, or apparent horizon. However, after a certain time, the black holes merge and form one black hole with a single apparent horizon. Once the black holes have merged, the subsequent behavior of the system is very much like the single distorted black hole system. The black hole oscillates and emits lobes of gravitational radiation. As the vibrations die away, the hole settles down to a single spherically-symmetric black hole.

What we described above is the normal head-on Collisions of Black Holes. But computer simulations predict that there is one in a million chance that accident while head-on Collisions of Black Holes causes destruction of the universe. The destruction of an universe has happened before.

That is the main reason that very advanced extraterrestrial civilization of Type IV eventually escapes into the Hyperspace which holds innumerable universes. The race for escape from eventual destruction does not stop there. They eventually try to escape into the chilled universe that forms the platform for all existence.

---------------------------------------------------------------------------One article I find in indiadaily.The contents seem to be more of scince fiction.Hyper space is not in this universe.We dont know if there are are more than one universe.Black holes colliding is sort ofnormal matter.There is no chance of universe ended.Its nore in the region of science fiction.
kaneda
alokmohan. It is believed that when black holes collide they quitely merge to form a larger black hole. This would be because their event horizons would stop any of the titanic energies from escaping as they merge.

However when a black hole swallows a neutron star or even just a massive star there is considerable leakage as the black hole rips apart the other stellar object and this would produce some of the most violent events we have witnessed (gamma ray bursters, etc).

Hyperspace at present is just theory.
Harry Costas
Hello All

Kaneda said

QUOTE
alokmohan. It is believed that when black holes collide they quitely merge to form a larger black hole. This would be because their event horizons would stop any of the titanic energies from escaping as they merge.

You maybe right.

But than agian have look at these

X-Rays Indicate Star Ripped Up by Black Hole
http://antwrp.gsfc.nasa.gov/apod/ap040224.html

Streaming From A Black Hole
http://antwrp.gsfc.nasa.gov/apod/ap970613.html

Scientists Find Closest Pair of Supermassive Black Holes
http://pda.physorg.com/lofi-news-black-hol...r_65714406.html

===========================================
I think there will be an increase in jet activity from each black hole ejecting matter into space.

alokmohan
Hello all ,gravity waves are real danger.
ChaosTheory
QUOTE (Nick+Dec 1 2006, 03:53 AM)
The extreme of gravity is not a black hole. Light can always escape.

The requirement for a black hole is an event horizon.
You are wrong kjw. Black holes don't exist.

Mitch Raemsch -- Light Falls --

You sir need to sit down, keep quiet, go back to school, and read a science textbook.

We've discussed this OVER AND OVER in the quantum physics section of this forum Nick i suggest you go read it before dulling your brain to make it look like logcal AND scientifical evidence is tried to be proved wrong by someone with such.....

QUOTE
you are wrong kjw, black holes don't exist

outstanding knowledge of this subject.
alokmohan
Nick you are surely joking.The has always been war among scientists doubting existence of black hole.When Scharzchild put up a theory even Einsein denied his own lrgacy.But later on it has been accepted.As analogy I bring continental drift theory.In 1916 theoritically it was sound.Like Scharszchild ggeometry in 1916.Both reemerged in 1960,when scientists came to space age led byUSSR..Western , science was no more granite as thught.Change of time lifted the mental blog and we got black hole.
kaneda
Harry Costas. I did say that a star would not go quietly into a black hole.

Any jet material is from outside the black hole. If one or both of them have accretion discs (not always so as they can consume all nearby fuel), then there would be a large infalling of such material.
kaneda
alokmohan. Despite witnessing some of the most violent events in the universe involving black holes, we have received no gravity waves from them. We have to wonder at their existence.

Nick seems to have left the board now. With no evidence he claimed that black holes did not exist but never gave any reasons and just ignored the evidence they did exist. With just as much evidence he claimed to have proved hyperspheres exist.
alokmohan
I atach this new finging of Chandra.PASADENA, CA, United States (UPI) -- NASA`s Chandra X-ray Observatory has detected evidence of a powerful light echo outburst from the giant black hole at the Milky Way`s center.

National Aeronautics and Space Administration scientists say light echoes are produced when X-ray light generated by gas falling into the supermassive black hole is reflected by gas clouds. While the primary X-rays from the outburst would have reached Earth about 50 years ago, the reflected X-rays took a longer path and arrived in time to be recorded by Chandra last year.

'This dramatic event happened before we had satellites in space that could detect it,' said Michael Muno of the California Institute of Technology in Pasadena. 'So, it`s remarkable that we can use Chandra to dig into the past and see this monster black hole`s capacity for destruction.'

The study will appear in an upcoming issue of The Astrophysical Journal Letter

Harry Costas
Hello All

Black Hole Jets are seen as outside the black hole because man is unable to see the start. Many think that the jet is created by the infalling matter. This is old hat.

The jet is created by the ultra dense plasma within the Black Hole.

Jets are jets pulsar jets to black hole jets they have the same orgin of formation and therefore have the same similar jets.

The difference between a neutron star and a black hole is that the black hole is denser and made up of possibly preon partical composites and because of the inernal forces required to keep these particals together also prevents light from escaping, causing us to call it a black hole because we are unable to see it.

Now! the other definition of a black hole is a WELL with an infinite point call a singularity. This does not exist in my opinion. Its good if you can google and find out why, rather than me telling you so.

A Jet is a Jet, Big or Small: Scale Invariance of Black Hole Jets
http://www.mpa-garching.mpg.de/HIGHLIGHT/2...ight0308_e.html

[20.06] Coronae and Jet Properties of the Black Hole Candidates Cyg X-1 and GX339-4 Over Many Years and Many Decades in Eddington Flux

3C175: Quasar Cannon
http://antwrp.gsfc.nasa.gov/apod/ap010905.html

BHR 71: Stars, Clouds, and Jets
http://antwrp.gsfc.nasa.gov/apod/ap030127.html

http://antwrp.gsfc.nasa.gov/apod/ap060203.html

Micro-Quasar GRS1915 Puffs
http://antwrp.gsfc.nasa.gov/apod/ap971202.html

Neutron Star Imitates Black Hole
http://www.jb.man.ac.uk/news/CircinusX-1/

Many links will tell you that the jets are formed by infalling matter and that what ever goes into a black is lost for ever and that a white hole maybe formed to eject matter out.

In my opinion the key lies in the workings of the ultra dense matter that makes up the black hole.

kaneda
Harry Costas. A black hole comes about because the escape velocity is faster than light which means that NOTHING can escape it.

QUOTE
ultra dense plasma within the Black Hole.

Explain how you can have ultra dense plasma? Plasma is normally a gas like structure where electrons are allowed free movement. In degenerate matter, electrons CANNOT move.

Do you agree with the scientists who found that black hole jets are caused by magnetism (hundreds of billions of gauss) so basically work on the same principle as solar prominences on our sun?

We usually find that the escape velocity of a planet or star is determined by it's mass/density. That is what we believe happens with black holes where the escape velocity is greater than light. While light could be said to be trapped inside an ultra dense material, the surface itself is under no such constriction and at a trillion degrees centigrade would light up much of the nearby universe.

If degenerate matter came out of a white hole from a black hole, it would mean no old black holes because they would all evapourate and that the matter would be distinctive enough to be noted by Earth astronomers for what it was.
alokmohan
http://www.jb.man.ac.uk/news/CircinusX-1/. The post of Jodrell bank is startlig.So long we knew such superluminal jets can come out of a black hole.too technical for me to comment.We have a change of taste.
AlphaNumeric
^ Those jets aren't superluminal, they are ultra relativisitic.
Harry Costas
Hello All

Kaneda said

QUOTE
Explain how you can have ultra dense plasma? Plasma is normally a gas like structure where electrons are allowed free movement. In degenerate matter, electrons CANNOT move.

Do you agree with the scientists who found that black hole jets are caused by magnetism (hundreds of billions of gauss) so basically work on the same principle as solar prominences on our sun?

Kaneda I keep on telling you to research some of these topics.

I want you to look up the different forms of PLasma and than we shall discuss it further. You make statements without knowing the topic.

I have given information before but! you did not take notice.

alokmohan
QUOTE (AlphaNumeric+Jan 24 2007, 12:06 PM)
^ Those jets aren't superluminal, they are ultra relativisitic.

Sorry to request.What is the difference?By the by,what is COROT?
kaneda
QUOTE (Harry Costas+Jan 24 2007, 12:36 PM)
Kaneda I keep on telling you to research some of these topics.

I want you to look up the different forms of PLasma and than we shall discuss it further. You make statements without knowing the topic.

I have given information before but! you did not take notice.

Harry Costas. I have discredited and picked holes in the trickle of information you have given. That is still there for all to see so no point scoring.

I have told you that I do not intend to spend hours in an internet cafe (at my expense) reading information which backs up beliefs of yours which I have shown to be wrong.

I have explained why a black hole has an event horizon and that no matter how densely packed material is, the top layer will still release radiation if it has an escape velocity below light speed (so no event horizon). Your answer was to go read a book.

Apparently your idea of research is that I should read something till I come around to your obviously wrong opinions. Perhaps you should read some books yourself so you can actually answer a question instead of continually dodging them like a politician explaining how he lost an election?
kaneda
alokmohan. In case AN doesn't get back soon, superluminal means faster than light which is impossible. Ultra relativistic means very close to light speed. As to COROT:

http://smsc.cnes.fr/COROT/
alokmohan
Kip Thornes book is good .I keep on reading it.
alokmohan
Sad news.Our galaxy doomed in 2012.First doomsday prediction of galaxy.So pack up your luggage and shift to anoter galaxy.
alokmohan
Sad news.Our galaxy doomed in 2012.First doomsday prediction of galaxy.So pack up your luggage and shift to anoter galaxy.

Collapse of our Galaxy into 3 x 109 km radius Black Hole – a possibility that can end the milky way anytime after 2012 but remote viewers say there are signs of hope
India Daily Technology Team
Jan. 25, 2007

Our Galaxy contains 1000000000 Solar Masses and there are possibilities something can happen that will rock the whole universe. According to some analytic models, 2012 can mark a massive implosion that can end our Galaxy and convert the same into a 3 x 1000000000 km radius Black Hole. It is a massive Black Holes that will open right into the Hyperspace. Such big opening can cause the Universe to collapse very soon.

But there is something going on behind the scene. There is exponential increase in the UFO sighting since year 1800. The numbers keep increasing at very fast rate. According to some remote viewers, the Type IV extraterrestrial civilization in charge of protecting the earth is ready for massive shift of the civilization into safer region in the cosmos. The migration can be out of the universe into some other universe too!

According to some UFOlogists, many Governments are aware of the dangers and have been communicated of the problem that can endanger our Type Zero civilization anytime. The cover ups are designed to calm down people and keep peace and order.

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TECHNOLOGY ARTICLES
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Harry Costas
Hello All

Dooms day

What crap are you talking about?

If the Black Hole at the centre of the MW decided to blow up today it will take over 25,000 years to hit us.

The chances of that are so slim that its not even worth discussing.

In the last 30 years there has been hundreds of dooms day things.

kaneda
I remember being in Calcutta 19 years ago this month and some nut overnight had gone around the central area and pinted up everywhere that the sun went around the earth and not the other way around, and that this was his idea. He had even signed it.

Down south, I came across a young westerner who had gone native and listened to Yogi somecrap or other's reachings and every second word he said was "cosmic".

A lot of very strange ideas come out of India.

The article doesn't mention the legendary dark matter which accounts for multiples of that number of solar masses. Then again, dark energy may come to the rescue and actually blow the galaxy all across the cosmos instead. Doh!
alokmohan
And the p resent poster is Indian.I never heard this web.Got it from google :
alokmohan
New cosmological computer simulations produced by a team of astronomers from Northwestern University, Harvard University and the University of Michigan show for the first time that supermassive black holes (SMBHs), which exist at the centers of nearly all galaxies, often come together during triple galaxy interactions.

Frederic Rasio, a theoretical astrophysicist and professor of physics and astronomy in the Weinberg College of Arts and Sciences at Northwestern University in Evanston, Ill., presented the findings at the meeting of the American Astronomical Society in Seattle.

The theoretical results are of special interest because of the recent discovery by astronomers at the California Institute of Technology of a possible triple quasar, findings that were also reported at the Seattle meeting.

"SMBHs become visible as quasars when they accrete large quantities of gas from their host galaxies, releasing prodigious amounts of energy in radiation," said Rasio. "The observation of three quasars in very close proximity shows that the kinds of interactions predicted by our computer simulations are indeed taking place, even in the nearby, present-day universe."http://www.astronomy.com/asy/default.aspx?c=a&id=5087

The existence of binary SMBHs, formed when two galaxies come together, that merge and bring together their central SMBHs, has been discussed by astronomers for many years. The new work reported by Rasio shows that interactions between three SMBHs are also quite frequent, occurring perhaps up to a few times per year within the observable universe. While the merger of a binary SMBH following the collision between two galaxies simply leads to the formation of a bigger SMBH at the center of a bigger galaxy, triple black hole interactions can be much more violent and interesting.

"Three is so much better than two because the dynamics of three gravitationally interacting bodies is chaotic, as opposed to the much more regular motion of two bodies simply orbiting each other," said Rasio.

These violent triple interactions were especially frequent at early cosmological times, when our universe was only about one-tenth of its present age, and galaxies were smaller and collided much more frequently than today. At that earlier epoch, galaxies were living in a very crowded environment, as the universe had yet to expand to its present size. Smaller galaxies merged together to form some of the much bigger galaxies we see today. Although slower today, this process is ongoing. Even our own galaxy, the Milky Way, will experience a "major merger" event when it collides with its nearest neighbor, the Andromeda galaxy, in about three billion years.

Triple encounters of SMBHs often end in the complete coalescence of an SMBH pair, guaranteeing a high cosmic merger rate of black holes. They can also lead to SMBH binaries being kicked out of their parent galaxies and wandering "naked" through the universe.

"Triple black hole systems undergo complex, chaotic interactions often ending in the high-velocity ejection of one component, often straight out of the host galaxy," said Loren Hoffman, a doctoral student at Harvard and a member of the research team.

"The detection of wandering black hole binaries flying in empty space would give us a unique signature of triple interactions in the early universe," said team member Marta Volonteri, assistant professor of astronomy at the University of Michigan. "Gravitational waves emission seems to be the only way of spotting these wandering binaries."

Merging SMBH binaries are key sources of gravitational radiation that astronomers hope to detect with future observatories such as the Laser Interferometer Space Antenna (LISA), a billion-dollar joint venture of NASA and the European Space Agency, which is currently in a design phase and is expected to begin observations in or around 2017.

In addition to Rasio, Hoffman and Volonteri, the research team includes Stefan Umbreit, a postdoctoral fellow at Northwestern
alokmohan
stronomers have discovered the strongest evidence yet found indicating that matter is being ejected by a medium-sized black hole, providing valuable insight on a process that may have been key to the development of larger black holes in the early Universe. The scientists combined the power of all the operational telescopes of the National Science Foundation's National Radio Astronomy Observatory (NRAO) to peer deep into the heart of the galaxy NGC 4395, 14 million light-years from Earth in the direction of the constellation Canes Venatici.

"We are seeing in this relatively nearby galaxy a process that may have been responsible for building intermediate-mass black holes into supermassive ones in the early Universe," said Joan Wrobel, an NRAO scientist in Socorro, NM. Wrobel and Luis Ho of the Observatories of the Carnegie Institution of Washington in Pasadena, CA, presented their findings at the American Astronomical Society's meeting in Seattle, WA.

Black holes are concentrations of matter so dense that not even light can escape their powerful gravitational pull.

This VLBI image of the inner region of galaxy NGC 4395 shows extended radio emission that indicates suspected outflow powered by an intermediate-mass black hole. Wrobel & Ho/NRAO/AUI/NSF
The black hole in NGC 4395 is about 400,000 times more massive than the Sun. This puts it in a rarely-seen intermediate range between the supermassive black holes at the cores of many galaxies, which have masses millions to billions of times that of the Sun, and stellar-mass black holes only a few times more massive than the Sun. Energetic outflows of matter are common to both the supermassive and the stellar-mass black holes, but the new radio observations of NGC 4395 provided the first direct image of such a suspected outflow from an intermediate-mass black hole.

The outflows presumably are generated by little-understood processes involving a spinning disk of material being drawn toward the black hole at the disk's center.

"An outflow from a black hole can regulate its growth by pushing back on material being drawn toward it. This is an important aspect of black hole development. Our observations offer new and unique information on how this process works for intermediate-mass black holes," Ho said.

"Intermediate-mass black holes may have been the starting points for the supermassive black holes that we now see throughout the Universe. By studying this contemporary analog to those earlier objects, we hope to learn how the less-massive ones grew into the more-massive ones," Wrobel explained.

The black hole in NGC 4395 was added to a small number of known intermediate-mass black holes in 2005, when a research team led by Brad Peterson of the Ohio State University calculated its mass based on ultraviolet observations. Other ultraviolet and X-ray observations gave tantalizing hints that material might be flowing outward from the black hole.

"Fortunately, this object also is detectable by radio telescopes
kaneda
QUOTE (Harry Costas+Jan 24 2007, 12:36 PM)

Kaneda I keep on telling you to research some of these topics.

I want you to look up the different forms of PLasma and than we shall discuss it further. You make statements without knowing the topic.

I have given information before but! you did not take notice.

Another master of empty words who has failed to answer any questions, despite all his empty boasting.

Considering all the spiral galaxies (like ours) we can observe with super massive black holes at their centre which have not suddenly collapsed, I think we are safe.
alokmohan
Frankly we are researching in our own way.There is so much to know.Debate is there whether black hole exists.Einstein was father of of black hole,even he thoght is too bizarre.It shook our cherished beliefs just as continental drift theory.But here it stands out.We are fighting it out.
kaneda
alokmohan. When I first heard of black holes decades ago I didn't believe in them but the evidence builds up and you either believe it or become a denier. Escape velocity from a neutron star is about 2/3 light speed and most deniers will accept that but somehow believe that a much denser black hole does not have a higher escape velocity.
alokmohan
When S.Charasekhar first said a white dwarf too big will collapse on itself ,Eddington laughed away the idea in open conference and he had to sort of leave Britain with disgrace.He shook cherishen beleif of scientists.Scientists are not that scientific minded.Eddington admitted that Chandras calculation were correct but nature would prevent such a cllapse.As if Eddinton discussed with nature.
kaneda
There is a lot of jealousy in science and rigidity which finds it difficult to accept new ideas.
alokmohan
Not jealously only.Man likes to keep his cherished belief.In 1916,black holes were established.In 1916 continental drift theory was well established.But scientists had a mental block.When sputnick went,vanity of all knowing scientific establishment vanished in thin air and accepted reality and embraced both new concepts.
kaneda
There are indeed many cherished beliefs in science which are not supported by fact but only by informned speculation. They may be 100% true, they may be 100% false. We don't know but for the moment, they are judged as true. This kind of thinking unfortunately straighjackets the scientific community so that everything must be "peer reviewed" before even being considered as "worthy of thought".
alokmohan
Einstein did not beleve his own equations.He though black holes are bizzare.He disc arded Schwarschild on ground that all mathematics is correct,but there must be l law of nature that will prevent formation of black holes,when in fact there is none.Was he all that rational?
kaneda
Alokmohan. Like the rest of us, Einstein was fallible. Even Hawking gets it wrong occasionally and Bill Gates's personal computer crashes. I think that people like Einstein can be too constrained by their teachings and not dare to think; "What if....?"
alokmohan
It is not a personal matter of Einstein.When Chandra woked out that heavy star may collapse on itself Eddington resisted,who was supposed to be giant of his age.When Wegene theory of continenal drift he was single handed.In 1926,both were in this state.There was a ego boosting of European science.In 1957 Soviet science succeeded and they knew that Western science was not resting on granite rock as they thou ght
alokmohan
Black hole and degenearation of matter are inseperable I can say.When we analysed sirius B i aws seen to have densit 61000 times that of Platium.At Eddingtons time it was beyond conceptio to have a thing 61000 times heavier than platinum.THIS WAS MYSTERY SINCE WE KNEW DENERATIN.
alokmohan
Degenearate netrons make neutrn star.At Chandra time ,when he talked of white dwarf.neutron stars were not knownJames Chadwik got netron star.
alokmohan
The best book I have read is Kip Thornes black hole.He has covered every aspect of black hole in 500 pages or so.As you read it you are enthralled ,You are as if i n Hades,an imaginary black hole.You are aware of limits of physics at present .In black hole,at singularity we want new physics.John Wheler is the way out.
kaneda
alokmohan. Most of the atom is space, like peas orbiting a football around a thousand feet away. Take that away and you have neutron stars where everything can be packed into a much smaller space. These are believed to be just neutrons and not crushed beyond that point. In a black hole, even these have been crushed to no one is yet sure what. I don't see any reason for new physics at this point since hot is still hot, mass is still mass and magnetism is still magnetism, etc.

I don't think singularities exist. I think such a point source would bend space in on itself and even standing a few feet away from it, you would feel neither gravitation or radiation forces from it. There is probably a ball of quarks or something smaller inside. Quarks are thought to be about 1/1000th size of a proton (a bit bigger than an electron) so I would think these were an ideal candidate for black hole material, along with electrons.
alokmohan
Big bang started from singularity.Black holes do exist and at center you have a singularity.It all started since Einsteins time.Schwarchid was first to state it.
kaneda
alokmohan. A singularity is a concept, a point source which claims infinite density and anything which uses the word "infinite" belongs in mathworld. Presumably if a large star was crushed down to super strings, that would still end up bigger than a singularity.

A neutron star (11 miles across) has an escape velocity of about 2/3 of light speed. If you crush neutrons down to protons and electrons, then crush the protons, each has 3 quarks in enough room for 1,000 quarks, so I think a black hole could be just the next stage where you have quarks, electrons and some other similar sized particles in a small ball maybe a hundred yards across with an event horizon as it's escape velocity is now above light speed.

Note. An actual singularity would be ultimately stable and never change or inflate/expand as in the big bang.
alokmohan
Very intense, low-frequency, gravitational wave sources can be expected from gravitational waves associated with the merger of massive black holes.

Scientists have long argued that massive black holes are inevitable in the cores of young galaxies. There is very strong evidence that such black holes exist in many objects, with masses ranging from 106 to 109 solar masses. Galactic mergers are likely to give rise to such black hole mergers. So one estimate of the rate of powerful gravity wave events can be obtained by estimating the rate of Galactic mergers. For large galaxies with central black holes, scientists have estimated this rate at about one per century. This does not include the far more frequent mergers of smaller Galaxies for which central black holes have not been confirmed. It is very clear now that the events in the cosmos are well coordinated through the use of very intense low-frequency gravitational wave sources in higher dimension. Gravity detectors in 3D Spatial dimension fail to detect the intense gravity waves.

It is also clear that a central command and control structure guides these gravity wave clusters to influence the universe in every part. Black hole collisions are the only opening for us to view the higher dimensions and the gravity wave clusters.

It seems that the higher order type IV extraterrestrial civilization is in control from the Hyperspace.

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kaneda
alokmohan. We see about one gamma ray burster a day and GMB's are believed to be associated with black holes. They are extremely violent events and should give off gravity waves (if they exist) but so far we have never detected any. Gravity propagates at the same speed as light so gravity waves should arrive at the same time as EMR.

Having said that, it is possible that the intervening galactic medium could soak up gravity waves so we may never detect any except from "close up".
alokmohan
Gravity waves are feeble,we dont feel impact for very small things.
alokmohan
Gravity wave is important.We should take protective measures.
Nick
Gravity waves once emitted should roam around the universe forever because they are not absorbable like an electromagnetic wave would be.
AlphaNumeric
Yes they are. EM waves are absorbed and emitted by anything with EM charge. Gravity waves would be emitted and absorbed by anything with mass. That's how you detect them, they use some of their energy to move matter, such as your signal sensors. Since energy is conserved in such a process, the wave would weaken slightly. Hence, they could be absorbed by they passed through enough matter just like radioactivity is stopped by enough material.
Grumpy
alokmohan Posted on Feb 2 2007, 12:00 PM
QUOTE
Big bang started from singularity.Black holes do exist and at center you have a singularity.It all started since Einsteins time.Schwarchid was first to state it.

I want to propose a question.

As a particle approaches a black hole event horizon, the acceleration causes the time the particle experiences to slow down from the experiences of matter not in the gravity well. The black hole actually warps space/time into a smear spread over the EH. Everything that has ever fallen into the hole is still falling(Not according to it's own view but to the view of the universe), It will take billions or even trillions of years(as experienced by us, in the universe) for that particle to move appreciably. It is even possible that the black hole will evaporate(Hawking radiation) before a singularity could be formed. Or it might break down to the quark level with graduated "layers of scale"((molecular, atomic, neutronic and quarkish,+????))of the slowly(to us) falling matter.

Am I missing something here???

Grumpy
AlphaNumeric
QUOTE (Grumpy+Feb 6 2007, 02:58 AM)
It is even possible that the black hole will evaporate(Hawking radiation) before a singularity could be formed.

When a BH forms, the matter gets smaller and smaller until the space-time curvature reaches a point where light can't escape. At that moment, the EH forms, cutting the matter off from the outside universe.

Now from the matter's point of view, time continues normally and it gets crushed into a singularity. From our point of view, watching from afar, we saw a dense collection of matter which was NOT a singularity suddenly get shrouded by an event horizon. We never saw the singularity form, but you don't need a singularity for an event horizon. From our point of view we still see the event horizon which is a pretty big sign you'd be in trouble if you got too close. Hence we don't have to see the singularity form to experience all the effects of a black hole.

As for infalling matter, you're right, we never see anything actually cross into the black hole, but we find we can never get that material back either and the gravitational effect of the BH is just as if that matter was apart of it, so while you see optical effects due to light distortion, make no mistake, a singularity will still shred you to bits if you get too close.
fivedoughnut
Alphanumeric etc,

What are your thoughts on endo event horizon energy transit?; chronorecursion to white hole big-bang scenario?

AlphaNumeric
QUOTE (fivedoughnut+Feb 6 2007, 03:38 AM)
chronorecursion to white hole big-bang scenario?

Potato elephant spanner foot? Car noodle wiffle top.

Err.. sorry, having read that sentence of yours, I thought the point of the discussion was to put random words together. Or do you actually think that sentence has a well defined meaning?
fivedoughnut
QUOTE (AlphaNumeric+Feb 6 2007, 02:49 AM)
Potato elephant spanner foot? Car noodle wiffle top.

Err.. sorry, having read that sentence of yours, I thought the point of the discussion was to put random words together. Or do you actually think that sentence has a well defined meaning?

attempting lucidity factor 3:

Ok, matter is crushed beyond the concentration necessary for EH formation ..... following so far? ...... @ this boundary, all time occurs in a nothing of a second, right! ..... all I'm suggesting is condensation of matter beyond this point may create a negative time gradient .... this is basic stuff alpha'c .... just wanted to know your thoughts.
alokmohan
Negative time gradient?I dont understand.Help me out.
alokmohan
Loosely speaking, a black hole is a region of space that has so much mass concentrated in it that there is no way for a nearby object to escape its gravitational pull. Since our best theory of gravity at the moment is Einstein's general theory of relativity, we have to delve into some results of this theory to understand black holes in detail, but let's start of slow, by thinking about gravity under fairly simple circumstances.
Suppose that you are standing on the surface of a planet. You throw a rock straight up into the air. Assuming you don't throw it too hard, it will rise for a while, but eventually the acceleration due to the planet's gravity will make it start to fall down again. If you threw the rock hard enough, though, you could make it escape the planet's gravity entirely. It would keep on rising forever. The speed with which you need to throw the rock in order that it just barely escapes the planet's gravity is called the "escape velocity." As you would expect, the escape velocity depends on the mass of the planet: if the planet is extremely massive, then its gravity is very strong, and the escape velocity is high. A lighter planet would have a smaller escape velocity. The escape velocity also depends on how far you are from the planet's center: the closer you are, the higher the escape velocity. The Earth's escape velocity is 11.2 kilometers per second (about 25,000 m.p.h.), while the Moon's is only 2.4 kilometers per second (about 5300 m.p.h.).

Now imagine an object with such an enormous concentration of mass in such a small radius that its escape velocity was greater than the velocity of light. Then, since nothing can go faster than light, nothing can escape the object's gravitational field. Even a beam of light would be pulled back by gravity and would be unable to escape.

The idea of a mass concentration so dense that even light would be trapped goes all the way back to Laplace in the 18th century. Almost immediately after Einstein developed general relativity, Karl Schwarzschild discovered a mathematical solution to the equations of the theory that described such an object. It was only much later, with the work of such people as Oppenheimer, Volkoff, and Snyder in the 1930's, that people thought seriously about the possibility that such objects might actually exist in the Universe. (Yes, this is the same Oppenheimer who ran the Manhattan Project.) These researchers showed that when a sufficiently massive star runs out of fuel, it is unable to support itself against its own gravitational pull, and it should collapse into a black hole.

In general relativity, gravity is a manifestation of the curvature of spacetime. Massive objects distort space and time, so that the usual rules of geometry don't apply anymore. Near a black hole, this distortion of space is extremely severe and causes black holes to have some very strange properties. In particular, a black hole has something called an 'event horizon.' This is a spherical surface that marks the boundary of the black hole. You can pass in through the horizon, but you can't get back out. In fact, once you've crossed the horizon, you're doomed to move inexorably closer and closer to the 'singularity' at the center of the black hole.

You can think of the horizon as the place where the escape velocity equals the velocity of light. Outside of the horizon, the escape velocity is less than the speed of light, so if you fire your rockets hard enough, you can give yourself enough energy to get away. But if you find yourself inside the horizon, then no matter how powerful your rockets are, you can't escape.

The horizon has some very strange geometrical properties. To an observer who is sitting still somewhere far away from the black hole, the horizon seems to be a nice, static, unmoving spherical surface. But once you get close to the horizon, you realize that it has a very large velocity. In fact, it is moving outward at the speed of light! That explains why it is easy to cross the horizon in the inward direction, but impossible to get back out. Since the horizon is moving out at the speed of light, in order to escape back across it, you would have to travel faster than light. You can't go faster than light, and so you can't escape from the black hole.

(If all of this sounds very strange, don't worry. It is strange. The horizon is in a certain sense sitting still, but in another sense it is flying out at the speed of light. It's a bit like Alice in "Through the Looking-Glass": she has to run as fast as she can just to stay in one place.)

Once you're inside of the horizon, spacetime is distorted so much that the coordinates describing radial distance and time switch roles. That is, "r", the coordinate that describes how far away you are from the center, is a timelike coordinate, and "t" is a spacelike one. One consequence of this is that you can't stop yourself from moving to smaller and smaller values of r, just as under ordinary circumstances you can't avoid moving towards the future (that is, towards larger and larger values of t). Eventually, you're bound to hit the singularity at r = 0. You might try to avoid it by firing your rockets, but it's futile: no matter which direction you run, you can't avoid your future. Trying to avoid the center of a black hole once you've crossed the horizon is just like trying to avoid next Thursday.

Incidentally, the name 'black hole' was invented by John Archibald Wheeler, and seems to have stuck because it was much catchier than previous names. Before Wheeler came along, these objects were often referred to as 'frozen stars.' I'll explain why below.

Back to Black Hole Question List

How big is a black hole?
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There are at least two different ways to describe how big something is. We can say how much mass it has, or we can say how much space it takes up. Let's talk first about the masses of black holes.

There is no limit in principle to how much or how little mass a black hole can have. Any amount of mass at all can in principle be made to form a black hole if you compress it to a high enough density. We suspect that most of the black holes that are actually out there were produced in the deaths of massive stars, and so we expect those black holes to weigh about as much as a massive star. A typical mass for such a stellar black hole would be about 10 times the mass of the Sun, or about 10^{31} kilograms. (Here I'm using scientific notation: 10^{31} means a 1 with 31 zeroes after it, or 10,000,000,000,000,000,000,000,000,000,000.) Astronomers also suspect that many galaxies harbor extremely massive black holes at their centers. These are thought to weigh about a million times as much as the Sun, or 10^{36} kilograms.

The more massive a black hole is, the more space it takes up. In fact, the Schwarzschild radius (which means the radius of the horizon) and the mass are directly proportional to one another: if one black hole weighs ten times as much as another, its radius is ten times as large. A black hole with a mass equal to that of the Sun would have a radius of 3 kilometers. So a typical 10-solar-mass black hole would have a radius of 30 kilometers, and a million-solar-mass black hole at the center of a galaxy would have a radius of 3 million kilometers. Three million kilometers may sound like a lot, but it's actually not so big by astronomical standards. The Sun, for example, has a radius of about 700,000 kilometers, and so that supermassive black hole has a radius only about four times bigger than the Sun.

Back to Black Hole Question List

What would happen to me if I fell into a black hole?
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Let's suppose that you get into your spaceship and point it straight towards the million-solar-mass black hole in the center of our galaxy. (Actually, there's some debate about whether our galaxy contains a central black hole, but let's assume it does for the moment.) Starting from a long way away from the black hole, you just turn off your rockets and coast in. What happens?

At first, you don't feel any gravitational forces at all. Since you're in free fall, every part of your body and your spaceship is being pulled in the same way, and so you feel weightless. (This is exactly the same thing that happens to astronauts in Earth orbit: even though both astronauts and space shuttle are being pulled by the Earth's gravity, they don't feel any gravitational force because everything is being pulled in exactly the same way.) As you get closer and closer to the center of the hole, though, you start to feel "tidal" gravitational forces. Imagine that your feet are closer to the center than your head. The gravitational pull gets stronger as you get closer to the center of the hole, so your feet feel a stronger pull than your head does. As a result you feel "stretched." (This force is called a tidal force because it is exactly like the forces that cause tides on earth.) These tidal forces get more and more intense as you get closer to the center, and eventually they will rip you apart.

For a very large black hole like the one you're falling into, the tidal forces are not really noticeable until you get within about 600,000 kilometers of the center. Note that this is after you've crossed the horizon. If you were falling into a smaller black hole, say one that weighed as much as the Sun, tidal forces would start to make you quite uncomfortable when you were about 6000 kilometers away from the center, and you would have been torn apart by them long before you crossed the horizon. (That's why we decided to let you jump into a big black hole instead of a small one: we wanted you to survive at least until you got inside.)

What do you see as you are falling in? Surprisingly, you don't necessarily see anything particularly interesting. Images of faraway objects may be distorted in strange ways, since the black hole's gravity bends light, but that's about it. In particular, nothing special happens at the moment when you cross the horizon. Even after you've crossed the horizon, you can still see things on the outside: after all, the light from the things on the outside can still reach you. No one on the outside can see you, of course, since the light from you can't escape past the horizon.

How long does the whole process take? Well, of course, it depends on how far away you start from. Let's say you start at rest from a point whose distance from the singularity is ten times the black hole's radius. Then for a million-solar-mass black hole, it takes you about 8 minutes to reach the horizon. Once you've gotten that far, it takes you only another seven seconds to hit the singularity. By the way, this time scales with the size of the black hole, so if you'd jumped into a smaller black hole, your time of death would be that much sooner.

Once you've crossed the horizon, in your remaining seven seconds, you might panic and start to fire your rockets in a desperate attempt to avoid the singularity. Unfortunately, it's hopeless, since the singularity lies in your future, and there's no way to avoid your future. In fact, the harder you fire your rockets, the sooner you hit the singularity. It's best just to sit back and enjoy the ride.

Back to Black Hole Question List

My friend Penelope is sitting still at a safe distance, watching me fall into the black hole. What does she see?
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Penelope sees things quite differently from you. As you get closer and closer to the horizon, she sees you move more and more slowly. In fact, no matter how long she waits, she will never quite see you reach the horizon.

In fact, more or less the same thing can be said about the material that formed the black hole in the first place. Suppose that the black hole formed from a collapsing star. As the material that is to form the black hole collapses, Penelope sees it get smaller and smaller, approaching but never quite reaching its Schwarzschild radius. This is why black holes were originally called frozen stars: because they seem to 'freeze' at a size just slightly bigger than the Schwarzschild radius.

Why does she see things this way? The best way to think about it is that it's really just an optical illusion. It doesn't really take an infinite amount of time for the black hole to form, and it doesn't really take an infinite amount of time for you to cross the horizon. (If you don't believe me, just try jumping in! You'll be across the horizon in eight minutes, and crushed to death mere seconds later.) As you get closer and closer to the horizon, the light that you're emitting takes longer and longer to climb back out to reach Penelope. In fact, the radiation you emit right as you cross the horizon will hover right there at the horizon forever and never reach her. You've long since passed through the horizon, but the light signal telling her that won't reach her for an infinitely long time.

There is another way to look at this whole business. In a sense, time really does pass more slowly near the horizon than it does far away. Suppose you take your spaceship and ride down to a point just outside the horizon, and then just hover there for a while (burning enormous amounts of fuel to keep yourself from falling in). Then you fly back out and rejoin Penelope. You will find that she has aged much more than you during the whole process; time passed more slowly for you than it did for her.

So which of these two explanation (the optical-illusion one or the time-slowing-down one) is really right? The answer depends on what system of coordinates you use to describe the black hole. According to the usual system of coordinates, called "Schwarzschild coordinates," you cross the horizon when the time coordinate t is infinity. So in these coordinates it really does take you infinite time to cross the horizon. But the reason for that is that Schwarzschild coordinates provide a highly distorted view of what's going on near the horizon. In fact, right at the horizon the coordinates are infinitely distorted (or, to use the standard terminology, "singular"). If you choose to use coordinates that are not singular near the horizon, then you find that the time when you cross the horizon is indeed finite, but the time when Penelope sees you cross the horizon is infinite. It took the radiation an infinite amount of time to reach her. In fact, though, you're allowed to use either coordinate system, and so both explanations are valid. They're just different ways of saying the same thing.

In practice, you will actually become invisible to Penelope before too much time has passed. For one thing, light is "redshifted" to longer wavelengths as it rises away from the black hole. So if you are emitting visible light at some particular wavelength, Penelope will see light at some longer wavelength. The wavelengths get longer and longer as you get closer and closer to the horizon. Eventually, it won't be visible light at all: it will be infrared radiation, then radio waves. At some point the wavelengths will be so long that she'll be unable to observe them. Furthermore, remember that light is emitted in individual packets called photons. Suppose you are emitting photons as you fall past the horizon. At some point, you will emit your last photon before you cross the horizon. That photon will reach Penelope at some finite time -- typically less than an hour for that million-solar-mass black hole -- and after that she'll never be able to see you again. (After all, none of the photons you emit *after* you cross the horizon will ever get to her.)

Back to Black Hole Question List

If a black hole existed, would it suck up all FROM SCIENCE DAILY.
kaneda
Grumpy. Something falls into a black hole, it is over in an instant. Light escaping the particle will do so until suddenly it vanishes at the EH cutoff point. I think the idea of time dilation is that the object experiences time slower but to outside (stationary) observers, they experience the thing moving in normal time.

Interesting quote from someone on BBC World this morning (I only caught the end of it) talking of an accelerator: Light is accelerated so fast that it can reach the Moon in less than a second.
fivedoughnut
QUOTE (alokmohan+Feb 6 2007, 04:46 AM)
Negative time gradient?I dont understand.Help me out.

Ok, as matter condenses below the event horizon, it has been postulated that the magnitude of negative time will increase exponentially, thus creating a gradient.
AlphaNumeric
QUOTE (fivedoughnut+Feb 6 2007, 04:00 AM)
Ok, matter is crushed beyond the concentration necessary for EH formation ..... following so far?  ......

Fine up to there.
QUOTE (fivedoughnut+Feb 6 2007, 04:00 AM)
@ this boundary, all time occurs in a nothing of a second, right! ..... all I'm suggesting is condensation of matter beyond this point may create a negative time gradient
Complete nonsense.

A pressure gradient is the changing of pressure in terms of another variable (typically position). One place is experiencing higher pressure than another place, creating a flow from one to the other. That description doesn't carry over to time and black holes. There's no 'flow' of space-time, it's static. Objects experience different passages of time at different points but saying "negative time gradient" is an erroneous statement.
alokmohan
I understand there is no negative time gradient?
fivedoughnut
QUOTE (AlphaNumeric+Feb 6 2007, 09:23 AM)
but saying "negative time gradient" is an erroneous statement.

Alphanumeric,

Sure, it's simply a case of knowing the right easily understood terminology ..... try this:
As you pass beneath an event horizon deeper into the gravitational well, my resplendent common sense tells me that this might create a duality affect where the observer enters a strange relativistic frame where his clock is seen to tick on as per usual, whilst external events run both forwards and increasingly backwards, like the unification of a forward and backward reality ...... hope this is all crystal clear now

p.s Sorry, really overstepped the mark when I asked for your thoughts ..... I apologize if I've embarrassed you.
fivedoughnut
QUOTE (alokmohan+Feb 6 2007, 10:46 AM)
I understand there is no negative time gradient?

"no negative".... Hey dude so we're in agreement

AlphaNumeric
QUOTE (fivedoughnut+Feb 6 2007, 02:21 PM)
Sure, it's simply a case of knowing the right easily understood terminology ..... try this:

Yes, you should try learning that terminology some day.
QUOTE (fivedoughnut+Feb 6 2007, 02:21 PM)
really overstepped the mark when I asked for your thoughts ..... I apologize if I've embarrassed you.
How would you displaying a complete lack of understanding of relativity embarass me?
Nick
There may be no negative time or time reversal but there surely is time slowdown. And if there is a slowdown there must be an absolute fastest time from which to begin this slowdown.
AlphaNumeric
Not really. The photon has no sense of time at all and all objects with mass have 'personal clocks' which tick at rates dependant on their velocity. The faster they move (relatively speaking obviously), the slower their watch ticks from an observer's point of view, but given their velocity can get arbitrarily close to c but not reach it, there is no upper bound on the ratio of the clock ticks between them and the observer.

Just look at this graph of gamma (which is the ratio of clock ticking)

It increases without bound, because the point v=c isn't in the domain. This is akin to saying "There's no largest element in the interval [0,1)".
Nick
The photon waves in both space and time. It waves in the fastest time.
fivedoughnut
QUOTE (AlphaNumeric+Feb 6 2007, 06:57 PM)
Yes, you should try learning that terminology some day.
How would you displaying a complete lack of understanding of relativity embarass me?

Alphan'c,

Actually I was initially quite correct with "negative time gradient"; I thought I'd roll over and humour you when your pram started rocking as it does when you're clearly threatened. All I asked was a friendly what do you think?; you replied quite predictably with rattle banging negativity; time and time again when challenged with "well what do you think?" it's the same old scenario; I've you sussed mate; If you possessed the merest yocto-modicum of actual thought processing ability you might have had an answer for me; a crap answer, but an answer nevertheless .... I certainly lack the fine art of text book regurgitation relativity-wise, granted, however, by embarrassment I was referring to my clear unveiling of your gross incapacity for individual thought .... i.e, you're nothing more than a friggin 'ask Jeeves' program.

p.s "Pretty Polly", "Pretty Polly", "Pretty Polly".

alokmohan
Idigress a bit.Please know if you dont know that black holes are bald.No hair.Means they have only three propertes .Mass ,spin and angular momentum.So dont show the poor chap a comb.
kaneda
In theory, if matter moved fast enough, time/change would stop for it but there would be no faster speed (faster than light speed) so no reversal (negative time gradient).

The fact that light can red or blue shift suggests that it is affected by "time".