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#26 2003-04-06 19:13:57

dickbill
Member
Registered: 2002-09-28
Posts: 749

Re: Singularity - Black Holes, Gamma Rays, Magnetars, etc

I am not an expert like you guys Robert and BGD, but you said that time is one dimension only, not fractional. Is it absolutely sure ?
Again I am not physician, but did you read my post about the billiard earlyer on in this thread ? it seems that the arrow of time is more or less stronger depending on the content of information of the system, then, maybe, time is an effect like gravity...

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#27 2003-04-06 19:53:14

RobertDyck
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From: Winnipeg, Canada
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Posts: 7,836
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Re: Singularity - Black Holes, Gamma Rays, Magnetars, etc

I am not an expert like you guys Robert and BGD, but you said that time is one dimension only, not fractional. Is it absolutely sure ?
Again I am not physician, but did you read my post about the billiard earlyer on in this thread ? it seems that the arrow of time is more or less stronger depending on the content of information of the system, then, maybe, time is an effect like gravity...

I've made a few typo's in my time on this board, but this one was just too funny. You said you're not a "physician"; did you mean physicist? Physician is a medical doctor.

Time as a fractal... interesting. That could explain time dilation. However, I'm more inclined to think there is a rotation going on so that as an object increases its speed toward the speed of light, that reduces passage of time within the object. The reason the speed of light cannot be exceeded is that passage of time within the object has completely ceased, so the rotation is complete. But does the same thing happen within the influence of a massive object like a planet? Einstein said there is no difference between gravity and acceleration, so they should equate. Does time dilation create fractal time? That could produce some interesting random effects, especially at very close to the speed of light or within the event horizon of a quantum singularity.

By the way, the event horizon is the distance from the quantum singularity where the escape velocity is greater than the speed of light. Since nothing can travel faster than the speed of light, no light can get out from that "shell" around the quantum singularity. However, the "shell" is just a mathematical distance from the quantum singularity; there is nothing solid about it. From the outside the event horizon would appear black, but anything falling in would heat up and emit a lot of light and radiation until it passed through the event horizon. Within the event horizon there is nothing fundamentally different; gravity tides would be extreme and tend to tear everything apart, speed of everything orbiting the quantum singularity would be extremely fast, and time dilation would be extreme so passage of time for anything inside would be slow. As you get very close to the quantum singularity, however, these random effects would also get extreme.

Inside the singularity all dimensions are separate from ours. Its dimensions are discontinuous from ours. That means there may be a new dimension of time within the pocket universe that is within the quantum singularity, so passage of time within that universe may have no relation to time in ours. The quantum singularity would be a mathematical point with no size at the center of the event horizon, but within it could be an entire universe.

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#28 2003-04-06 22:16:40

dickbill
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Registered: 2002-09-28
Posts: 749

Re: Singularity - Black Holes, Gamma Rays, Magnetars, etc

did you mean physicist? Physician is a medical doctor.

Time as a fractal... interesting. That could explain time dilation. However, I'm more inclined to think there is a rotation going on so that as an object increases its speed toward the speed of

Physicist... sorry.

No, I don't mean time has a fractal dimension. It has nothing to do with time dilatation and relativity either. I was refering to the billiard experiment. I don't remember where I picked up that example, Hawkings maybe ? not sure. Those posts are so long that I guess you havn't read it. So here it is, again:

Imagine you record with a camera 2 pool billiards balls. But you don't see the players in the camera. You just see one ball moving on the table in straight line until it hits the second ball, which then starts to move while the first ball has been stopped.
You show this movie to somebody, in forward or reverse direction.
With only the information contained in the movie, can this person decide if the movie is actually displayed forward or reversed ? no, in both direction, in the past or the future, the movie is exactly the same.
Do the same experiment with 3 billiards balls and 2 players, always invisible, so now you have 2 balls converging towards one immobile ball. Show the movie again in either sense, the person who watch is still incapable to decide which sense is the right one.
Only when you add more balls, the spectator becomes more and more aware of the probability of the events involved. 10 balls converging to hit a single immobile ball is much more difficult and so improbable than the reverse.  It also requires 10 players instead of one. So, based on this quantitative difference, the spectator is now able to decide if you had showed the movie in the right or reverse direction. But he still cannot be absolutely sure.

You see that the arrow of time points in the direction of the entropy increasing, as said S. Hawkings. The arrow points  from the less likelly to the more likelly. The less disorder to the more disorder. It seems that the arrow of time can be more or less strong depending of the entropic evolution of the system. But it's only a quantitative difference and it involves the observator in addition.

so if a system displays little information content (like a black hole from the outside maybe ?), the entropy variation should be very low or null, and so, based on the thermodynamic definition of the time, we are unable to decide if the system evolutes in one temporal direction or the other.

I believe that all physical laws are infeoded to the 2nd principle of thermodynamic, and so there is no physical force in the universe wich would generate more order than disorder and nobody knows why, this principle is not derived from any other physical principle. (Life is supposed to work by exporting disorder outside the living system and globally, life creates more disorder than oder). We see that the perception of time is dependant of the direction of the created disorder. In addition, to be able to exist, time needs an information content, which itself needs an observator. so I don't know which influences who.

Then, is time a real dimension, or should the physicists replace the "time" dimension by entropy variation, in their equation ?
That would mean including an information content and an observator.

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#29 2003-04-07 07:20:21

RobertDyck
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From: Winnipeg, Canada
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Re: Singularity - Black Holes, Gamma Rays, Magnetars, etc

It has often been said that time is a dimensions, but with Relativity it has been described as a dimension like any other. The question is just what makes time, time. Why does time "pass"? Movement over distance requires time. A billiard ball can be viewed as a cylinder extruded into the 4th dimension. It bends and touches another such 4-dimensional cylinder at one point. But time passes very slowly within an object moving at close to the speed of light. But what is "time" and how can it pass slowly? Perception of time by humans is a result of chemical interactions within our body that cause propagation of nerve signals. So a spacecraft moving close to the speed of light results in the waves that make up subatomic particles within that spacecraft moving very slowly. If the spacecraft could achieve the speed of light, the waves of the matter within that spacecraft would stop. Why? There is a lot more to time than entropy.

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#30 2003-04-07 08:16:52

dickbill
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Posts: 749

Re: Singularity - Black Holes, Gamma Rays, Magnetars, etc

There is a lot more to time than entropy.

I agree with that. But if you addition the entropic consideration, the relativistic effects and the quantic effects of undetermination, it seems that time is very flexible and "relative" to many variables. So maybe time is more like an effect, or an approximation,  and is not the good variable to introduce in the equations.

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#31 2003-04-08 09:56:59

Palomar
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From: USA
Registered: 2002-05-30
Posts: 9,734

Re: Singularity - Black Holes, Gamma Rays, Magnetars, etc

The result is a set of waves operating over curved space that is warped in at least 7 dimensions. The waves keep getting curved and reflected back upon themselves. So each wave is altering the path of the other waves, resulting in the waves getting caught on each other.

*Robert describes to a "T" what's going on inside Cindy's brain as she is trying to process all this information!   yikes 

Okay, I have read your first post Robert.  I'll go on to the 2nd one and might have questions. 

Side note:  I have seen a book entitled _Introducing Fractal Mathematics_...I guess that would be my starting point in that particular regard.  ::oh my aching head::

--Cindy   :laugh:


We all know [i]those[/i] Venusians: Doing their hair in shock waves, smoking electrical coronas, wearing Van Allen belts and resting their tiny elbows on a Geiger counter...

--John Sladek (The New Apocrypha)

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#32 2003-04-09 13:09:52

Palomar
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From: USA
Registered: 2002-05-30
Posts: 9,734

Re: Singularity - Black Holes, Gamma Rays, Magnetars, etc

RobertD:  "Here is a simple visualization to help explain dimensions: draw a line on a chalk board (or white board). Now draw a line perpendicular to it so the second line crosses the first at 90?. The first line is in one dimension and you can measure the number of inches or centimetres any point is from the crossing point. The second line is in a second dimension and has a second number distance from the crossing point. Any point on the board has an X and Y coordinate; that is the distance "up" from the horizontal line, and a distance "across" from the vertical line. These are 2 dimensions of a plane. Now draw a line that is perpendicular to both of the others so it is 90? to both of them. The only way to do that is to draw it out from the board. This is the 3rd dimension, often designated by the letter Z. Now try to draw a line that is perpendicular to the previous 3 lines. You can't do it. That would require 4 dimensions of space. Our experience only has 3 dimensions. However, bozons (protons and neutrons) have more than 4 dimensions of space-time. The strong and weak nuclear forces operate over other dimensions."

*Erm...I got lost on trying to "draw a line that is perpendicular to both of the others so it is 90? to both of them..."  Mind refuses to cooperate with what hand wants to draw, what can I say?  I can't visualize it.  And I guess whoever told me a long time ago that dimensions are like the layers of an onion was wrong...?

RobertD:  "Fractal mathematics is interesting. Visualize a single line drawn on a chalk board. That line has 1 dimension. Now draw a wiggly line. That line has more than 1 dimension, but less than 2 dimensions. Now make the wiggles larger and more complicated, but keep repeating the wiggle pattern. That line has still more dimensions but it is still less than 2. The line becomes steadily more wiggly and the wiggles become more complicated as the dimension fraction become larger. When the number of dimensions becomes 2, the wiggles merge so the line becomes a plane and fills the entire board. If you continue to increase the number of dimensions beyond 2,"

*I understood this!  smile

RobertD:  "Einstein's theory of relativity states that a theoretical spaceship that travels ever faster, approaching the speed of light, will become shorter in the direction of travel. If the spacecraft could reach the speed of light it would shorten so it has zero length.  I believe this is due to the fact that the dimension of travel is literally collapsing as you accelerate close to the speed of light. If you could travel at exactly the speed of light, your spacecraft would become a 3-dimensional space-time object in our 4-dimensional space-time universe."

*Would organic beings cease to exist at that point, even if the spaceship could survive somehow?

RobertD:  "An electron travels close to the speed of light, so this is why it has one dimension almost completely collapsed. If a spacecraft could travel as fast as an electron, it would experience quantum tunnelling and other random effects just as an electron."

*So then is there really such a thing as death, or the end of matter?  If every thing exists at at least a 1-dimensional level, it will always exist in some form or another, right?  I'm trying to bring this back to the original question:  Can mass ever be destroyed ("crushed out of existence") as we define those terms?  Any thing which exists must exist in at least 1 dimension, there is NO nondimension/0 dimension...right?

I'm probably "way out there" now.  Do my questions make sense, Robert, or will you suspect me of ingesting psilocybin before I posted this?  I'm trying to ask coherent, logical questions but I'm unsure of how to phrase them exactly...?  We necessarily likely have a communication gap going on here, due to my difficulty in grasping these concepts, and I'm trying to keep that gap as narrow as possible.  sad

--Cindy


We all know [i]those[/i] Venusians: Doing their hair in shock waves, smoking electrical coronas, wearing Van Allen belts and resting their tiny elbows on a Geiger counter...

--John Sladek (The New Apocrypha)

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#33 2003-04-09 14:21:43

RobertDyck
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From: Winnipeg, Canada
Registered: 2002-08-20
Posts: 7,836
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Re: Singularity - Black Holes, Gamma Rays, Magnetars, etc

*Erm...I got lost on trying to "draw a line that is perpendicular to both of the others so it is 90? to both of them..."  Mind refuses to cooperate with what hand wants to draw, what can I say?  I can't visualize it.  And I guess whoever told me a long time ago that dimensions are like the layers of an onion was wrong...?

You understand, exactly. The point is drawing a line perpendicular to the other two lines cannot be done... unless you draw the line in mid-air directly out from the chalk board. The line for the 3rd dimension would have to be represented by a stick with one end attached to the chalk board at the crossing point of the other two lines.

Would organic beings cease to exist at that point, even if the spaceship could survive somehow?

Organic beings would be squished along with the spaceship. They wouldn't necessarilly die, but time would stop for all beings inside the ship as well as the ship itself. The only way to restore the organic beings would be to restore their 3rd dimension by slowing down the spaceship. How do you control any onboard engines if time for the ship has stopped? Control to slow down the ship would be quite a challenge.

So then is there really such a thing as death, or the end of matter?  If every thing exists at at least a 1-dimensional level, it will always exist in some form or another, right?  I'm trying to bring this back to the original question:  Can mass ever be destroyed ("crushed out of existence") as we define those terms?  Any thing which exists must exist in at least 1 dimension, there is NO nondimension/0 dimension...right?

Correct. Energy can be converted to matter, matter can be converted to energy. Everytime you make a change the organization will become more random (increasing entropy). However, mass/energy cannot be destroyed. In fact, the total mass of a quantum singularity does not change; it just becomes very, very dense.

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#34 2003-04-10 11:07:42

Palomar
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From: USA
Registered: 2002-05-30
Posts: 9,734

Re: Singularity - Black Holes, Gamma Rays, Magnetars, etc

Would organic beings cease to exist at that point, even if the spaceship could survive somehow?

Organic beings would be squished along with the spaceship. They wouldn't necessarilly die, but time would stop for all beings inside the ship as well as the ship itself. The only way to restore the organic beings would be to restore their 3rd dimension by slowing down the spaceship. How do you control any onboard engines if time for the ship has stopped?

*Thanks Robert.  smile  And speaking about stopping time, I've read some place (here or in a book, I can't recall which) that the closer to the speed of light a spaceship could travel, the larger its mass would become...and upon reaching light speed its mass would fill the entire universe; which is why travel beyond the speed of light is impossible -- because an object cannot become larger than the universe.  I believe I've recalled that correctly.

Time for the spaceship stops.  But wouldn't -all- time throughout the universe stop as well?  I recall a piece of (supposed)  history which claims to have recorded (thousands of years ago) that the sun "stopped" one day for a period of many hours; it remained stationary in the same position in the sky for many hours, then finally began moving toward the west again.  This event was supposedly recorded by historians and scientists at the time.  What could have caused this, if it were true?  What if a space-faring race of beings pushed the light-speed envelope and the universe stood still for those hours...but I should think humans, as part of the universe, would have "stopped" on that occasion as well.

Yeah, I know how this may sound, but it came to mind so what the heck; I'll run with it.

--Cindy


We all know [i]those[/i] Venusians: Doing their hair in shock waves, smoking electrical coronas, wearing Van Allen belts and resting their tiny elbows on a Geiger counter...

--John Sladek (The New Apocrypha)

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#35 2003-04-10 15:34:19

RobertDyck
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From: Winnipeg, Canada
Registered: 2002-08-20
Posts: 7,836
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Re: Singularity - Black Holes, Gamma Rays, Magnetars, etc

the closer to the speed of light a spaceship could travel, the larger its mass would become...and upon reaching light speed its mass would fill the entire universe; which is why travel beyond the speed of light is impossible -- because an object cannot become larger than the universe. ...

Time for the spaceship stops.  But wouldn't -all- time throughout the universe stop as well?  I recall a piece of (supposed)  history which claims to have recorded (thousands of years ago) that the sun "stopped" one day for a period of many hours; it remained stationary in the same position in the sky for many hours, then finally began moving toward the west again.  This event was supposedly recorded by historians and scientists at the time.  What could have caused this, if it were true?  What if a space-faring race of beings pushed the light-speed envelope and the universe stood still for those hours...but I should think humans, as part of the universe, would have "stopped" on that occasion as well.

You're correct on both points. As you increase a moving object close to the speed of light, its mass increases. According to relativity, to achieve the speed of light it would have infinite mass, which would require infinite energy to accelerate it that last little bit. Ok, not going to happen. However, close to the speed of light can happen, and interesting random effects should happen. Could you quantum tunnel the entire spacecraft forward? Hmmm.

As for stopping the sun, that would require stopping the rotation of the Earth. The Earth is really, really big. I don't think you could stop it; call me skeptical. If an alien spacecraft had achieved the speed of light, time inside the spacecraft would stop. It wouldn't affect the rest of the universe. If time on Earth stopped, the people would stop as well so no one would notice anything happened.

Hmm. The magnetic poles of the Earth reverse every 22,000 years, and the core rotates faster than the rest of the Earth. What would happen if the fluctuations slowed the Earth's rotation? Naw! The mass of the Earth is far too big to stop, and equally big to restart. If you were able to stop it, all the objects on the Earth would experience whip-lash. Imagine lakes splashing out of their basins, oceans pouring across continents, and people trying to grab the nearest tree. I could see it getting cloudy for a few hours, but not stopping the sun.

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#36 2003-04-11 11:27:01

Palomar
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From: USA
Registered: 2002-05-30
Posts: 9,734

Re: Singularity - Black Holes, Gamma Rays, Magnetars, etc

Could you quantum tunnel the entire spacecraft forward? Hmmm.

all the objects on the Earth would experience whip-lash.

*Would you care to outline what could/would happen if the ship could "quantum tunnel forward"?  What would be the result for them?  Where would they then end up at?

{{Whiplash!!}}  smile  LOL!  Yeah.  Thanks for acknowledging ::where:: I was coming from with that last post.  I know it sounded kind of "out there" and I almost didn't ask...but given "anything is possible" (or very nearly so), I thought I'd go ahead anyway.

Thanks, George, for the link.

The following link will be old hat to lots of folks here, I suppose, but I found this "Black Hole FAQ" on the net; it also discusses (albeit briefly) white holes and worm holes:

http://cosmology.berkeley.edu/Education/BHfaq.html

--Cindy


We all know [i]those[/i] Venusians: Doing their hair in shock waves, smoking electrical coronas, wearing Van Allen belts and resting their tiny elbows on a Geiger counter...

--John Sladek (The New Apocrypha)

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#37 2003-04-12 11:11:25

Palomar
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From: USA
Registered: 2002-05-30
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Re: Singularity - Black Holes, Gamma Rays, Magnetars, etc

*I'm going to put this here, since it relates to the first person to describe black holes and, in that regard, is on-topic for this thread.  He also played violin with William Herschel:

http://www2.exnet.com/1996/02/20/science/science.html

--Cindy


We all know [i]those[/i] Venusians: Doing their hair in shock waves, smoking electrical coronas, wearing Van Allen belts and resting their tiny elbows on a Geiger counter...

--John Sladek (The New Apocrypha)

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#38 2003-04-17 07:25:41

Palomar
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From: USA
Registered: 2002-05-30
Posts: 9,734

Re: Singularity - Black Holes, Gamma Rays, Magnetars, etc

Now, that concludes our lesson, ladies and gentlemans. Questions and constructive criticism is always welcomed.

*Hi BGD.  I read your post.  I don't have any questions or comments...basically because quite a bit of it is "over my head."  But thanks for your input.  smile

--Cindy


We all know [i]those[/i] Venusians: Doing their hair in shock waves, smoking electrical coronas, wearing Van Allen belts and resting their tiny elbows on a Geiger counter...

--John Sladek (The New Apocrypha)

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#39 2003-11-30 18:42:46

Palomar
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From: USA
Registered: 2002-05-30
Posts: 9,734

Re: Singularity - Black Holes, Gamma Rays, Magnetars, etc

*I recalled the following article (below) to memory a few days ago (originally posted by me in the original "New Discoveries" thread), and am wondering...how is it possible that a black hole can have such motion?  I thought they were either absolutely stationary or nearly so?

My original post: 

"Posted: Mar. 28 2003, 09:24   

Talk about weird; I've never heard of a "runaway black hole" before.  And it's heading in our direction...{gulp}  Let's just hope the astronomers are right, and we Terrans have nothing to fear from it.  tongue

Read me"

A portion of that article:  "Such 'cannonball' black holes were predicted in theory, but 'GRO J1655-40 is the first one that has been found in the real universe,' Mirabel said."

Again, I'm wondering how a black hole can move about (I thought they were stationary or nearly so)?  And what may that be doing to the "fabric" of space-time?

Interesting critters...

--Cindy


We all know [i]those[/i] Venusians: Doing their hair in shock waves, smoking electrical coronas, wearing Van Allen belts and resting their tiny elbows on a Geiger counter...

--John Sladek (The New Apocrypha)

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#40 2004-03-30 07:47:13

Palomar
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From: USA
Registered: 2002-05-30
Posts: 9,734

Re: Singularity - Black Holes, Gamma Rays, Magnetars, etc

*I recalled the following article (below) to memory a few days ago (originally posted by me in the original "New Discoveries" thread), and am wondering...how is it possible that a black hole can have such motion?  I thought they were either absolutely stationary or nearly so?

My original post: 

"Posted: Mar. 28 2003, 09:24   

Talk about weird; I've never heard of a "runaway black hole" before.  And it's heading in our direction...{gulp}  Let's just hope the astronomers are right, and we Terrans have nothing to fear from it.  tongue

[http://www.cnn.com/2002/TECH/space/11/2 … index.html]Read me"

A portion of that article:  "Such 'cannonball' black holes were predicted in theory, but 'GRO J1655-40 is the first one that has been found in the real universe,' Mirabel said."

Again, I'm wondering how a black hole can move about (I thought they were stationary or nearly so)?  And what may that be doing to the "fabric" of space-time?

Interesting critters...

--Cindy

*Here we go again.  I came across this old article (4 years dated) at Astropix the other day:

[http://antwrp.gsfc.nasa.gov/apod/ap000119.html]Big Black Hole Floats By 

How is this possible?  How do these things move?  It seems these two instances are of stellar black holes being attracted by the gravitational pull of supermassive black holes?   ???  I can't think of what else would be strong enough, gravitationally speaking, to induce them to move besides the gravity of a supermassive black hole...but of course, I'm not a scientist.

Again, I thought black holes were generally stationary. 

***

Interesting and new article from space.com; they may also be (at least some of them) neutron stars:

[http://www.space.com/scienceastronomy/R … 40330.html]Bevy of Black Holes in Andromeda Galaxy

--Cindy


We all know [i]those[/i] Venusians: Doing their hair in shock waves, smoking electrical coronas, wearing Van Allen belts and resting their tiny elbows on a Geiger counter...

--John Sladek (The New Apocrypha)

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#41 2004-03-30 12:28:37

SBird
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Re: Singularity - Black Holes, Gamma Rays, Magnetars, etc

The thing to remember about black holes is that they're not THAT exotic.  A black hole of 6 solar masses (as this one is) moves around just like any star what weighs the same does.  If it were to go past the sun (a Bad Thing for us), the sun would be thrown around pretty badly by the gravitational sling but the black hole would as well.  The REALLY BIG black holes at the center of a galaxy often can mass over 1 billion solar masses.  Those don't move too much. 

If the sun were to collapse into ablack hole right now, the orbits of the planets would be completely unchanged.  The big difference is that with the sun, once you hit the surface, the gravitational attraction gies down the further in you go because you now have bits of the Sun behind you pulling upwards.  A black hole, having no radius lets you just keep falling and falling inwards as gravity goes up by the inverse square law indefinately.

Of course, black holes are not a proven thing.  The standard model posits no forces that can hold up matter at the densities found in ablack hole.  However, we know that the Standard model is broken.  Therefore, 'black holes' could actually be some form of very compact degenerate matter that has such high gravitational density that it looks like a black hole from here.  Until we can actually observe a black hole from up close, they remain conjectural objects.

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#42 2004-03-30 13:46:25

Palomar
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From: USA
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Posts: 9,734

Re: Singularity - Black Holes, Gamma Rays, Magnetars, etc

Of course, black holes are not a proven thing.  The standard model posits no forces that can hold up matter at the densities found in ablack hole.  However, we know that the Standard model is broken.  Therefore, 'black holes' could actually be some form of very compact degenerate matter that has such high gravitational density that it looks like a black hole from here.  Until we can actually observe a black hole from up close, they remain conjectural objects.

*Well, thank you for that reminder; I needed it.  I have an unfortunate tendency to interpret things literally (a habit I'm trying to fix).

It (conjecture) is also sometimes difficult to keep in mind when the authors of these articles make it sound like they are anything but conjectural, and *are proven.*  :-\

As for exotic...it's in the mind of the beholder.  wink

--Cindy


We all know [i]those[/i] Venusians: Doing their hair in shock waves, smoking electrical coronas, wearing Van Allen belts and resting their tiny elbows on a Geiger counter...

--John Sladek (The New Apocrypha)

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#43 2004-03-30 14:31:30

SBird
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Re: Singularity - Black Holes, Gamma Rays, Magnetars, etc

There tends to be a tendency for layperson science books to make things look more concrete than they actually are.  For example, many books about quantum physics talk about a particular theory for explaining the wave/particle duality as if it's well understood.  The fact is that 80 years after the fact, we really still don't understand this problem at all.  It's unfortunate that layperson science is done this way since it tends to get people confused.

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#44 2004-03-30 18:23:49

dicktice
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From: Nova Scotia, Canada
Registered: 2002-11-01
Posts: 1,764

Re: Singularity - Black Holes, Gamma Rays, Magnetars, etc

SBird wrote: "Of course, black holes are not a proven thing.  The standard model posits no forces that can hold up matter at the densities found in a black hole.  However, we know that the Standard model is broken.  Therefore, 'black holes' could actually be some form of very compact degenerate matter that has such high gravitational density that it looks like a black hole from here.  Until we can actually observe a black hole from up close, they remain conjectural objects."

Now, as a self-proclaimed scientist, he could have been less equivicating regarding black holes. We laypersons are just longing for someone to bring us up to date about black holes, and what does he say? Stated elsewhere: "They aren't all that exotic," but (above) they're not a proven thing, break the Standard model (whatever that is), remain conjectural until we can observe them up close, in spite of having no radius (dimensionless?). Not a clear lecture--I know he can do better.

Cindy wrote: "I have an unfortunate tendency to interpret things literally."

Please don't change, because your enthusiasm for the great adventure itself tends to bring out the best in those of us who keep on attempting to explain the presently unexplainable, and recommend doing the currently undoable.

Here's a sample layperson question, that comes to mind after reading SBird's posts: If black holes are spaced between stars, as are the visible stars, with no visible acretion disc to observe (if such can be posited, i.e., not observable from any distance until it's too late to avoid being swallowed up) I'd think of that literally as a threat to interstellar voyaging.

My own take is that roving black holes hopefully don't develop out there, where matter is sparce between stars.

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#45 2004-03-30 20:45:22

SBird
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Re: Singularity - Black Holes, Gamma Rays, Magnetars, etc

??? ?
I must admit, dicktice, that I'm not entirely certain I've gotten the meaning of your last post - I apologize for any further confusion ahead of time.  From what I gather, you would have liked to have seen a more detailed and easier to understand version of what I had just posted.

I'd like to have done that but I'm grabbing time at work and therefor don't have sufficient time to write a full description that would do the subject justice.  To have done so would require a message three times as long.  I don't have time right now to sufficently update the previous message but I will answer your last question:

There are no reasons for black holes to be in areas near stars.  They are capable of having momentum and traelling around.  However, as far as astrogational hazards, they're a non-issue.  They're a tiny target to hit and any black hole to be massive enough to be a danger would distort light around it, making it visible.  I'd be much more concerned about small bits of space debris.

As for being literal, there's no problem per se with that but it does tend to get one in trouble when dealing with modern physics.  Things like relativity and quantum physics behave in ways that are different from our every day experience.  Pop sci books that try to make subject approachable tend to treat the subject matter in a very literal manner that makes it look less intimidating.  While this is a noble goal, the problem is that one's understanding of the subject is often rather incorrect as a result. 

Learning about science from sources like that is OK but only if you know to take the explanations with a grain of salt.  The truth is often rather complicated and difficult to get a good understanding of.  Heck, there are fundamental portions of physics that science has a very poor grasp of.   In truth, it should be intimidating but that's nothing to be ashamed about.  These are problems that the best minds of the human race have unsuccessfully beaten heads against.

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#46 2004-03-30 21:18:24

Mark Friedenbach
Member
From: Mountain View, CA
Registered: 2003-01-31
Posts: 325

Re: Singularity - Black Holes, Gamma Rays, Magnetars, etc

SBird: Of course, black holes are not a proven thing.  The standard model posits no forces that can hold up matter at the densities found in a black hole.  However, we know that the Standard model is broken.  Therefore, 'black holes' could actually be some form of very compact degenerate matter that has such high gravitational density that it looks like a black hole from here.  Until we can actually observe a black hole from up close, they remain conjectural objects.

They're effects (which are plenty) have been observed on numerous occations.  Recently they've even been observed directly via Hawking radiation.  Black Holes are certainly real 'proven' things.

As for the standard model (which, for the laypersons here, is the name given to the current state of quantum theory), it is 'broken' because it does not include the force of gravity.  Yes, the standard model can't explain black holes, but general relativity can.  And in some cases, general relativity and the standard model can be used together to describe the properties Black Holes have, with great success.  This is what Hawking has done.

Cindy: I have an unfortunate tendency to interpret things literally.

Just remember that all these metaphors we use are metaphors, and they can be misleading.  My best advice is to be very careful when you interpret these metaphors.  Look for the underlying truth behind it, and don't push the analogy too far.

But most of all, ask questions!  big_smile

dicktice: Here's a sample layperson question, that comes to mind after reading SBird's posts: If black holes are spaced between stars, as are the visible stars, with no visible acretion disc to observe (if such can be posited, i.e., not observable from any distance until it's too late to avoid being swallowed up) I'd think of that literally as a threat to interstellar voyaging.

You needn't worry.  If nothing else the gravitational effects of the black hole would be very visible.  But black holes do have acretion disks as a result of how they are usually formed, and can maintain them even interstellar space (remember, space isn't totally empty).  Black Holes are also directly observable via Hawking radiation, so they're actually pretty easy to spot these days.

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#47 2004-03-31 03:33:26

SBird
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Registered: 2004-03-10
Posts: 490

Re: Singularity - Black Holes, Gamma Rays, Magnetars, etc

I'd like to see the reference for this observation of Hawing radiation from a black hole.  The observable radiation from such a process is so small that it sould be unobservable unless you have a black hole in a laboratory.  There is no way that a standard solar mass black hole would have hawking radiation observable to a telescope.  A black hole of that amount of mass has Hawking radiation cooler than the cosmic background radiation.  Heck, even if you had the black hole sitting right in front of you in a laboratory, it's unlikely that you could detect the Hawking radiation coming off of it.

As for general relativity and black holes, yes, relativity does explain what happens to mass as it goes to a singularity - somwhat.  Relativity breaks down at the point of a singularity and therefore can't be said to explain what happens there.

Furthermore, relativity says *nothing* about the matter involved in the formation of a black hole.  Things like the Pauli exclusion principle are purely a subset of quantum mechanics.  We know that normal matter is kept from collapsing by the repulsion of electrons of the same quantum state.  In neutron stars, nucleon degeneracy does the same task.  Preesent theory assumes that at higher levels of pressure, matter then completely collapses into a black hole.  This is not known for certain.  It's the most likely explanation and the one I believe in but there is no proof for it. 

For all we know, a star of > 3.5 solar masses collapses into another state of matter such as a quark soup or other more exotic things.  Such a material would warp light, create a violent accretion disc and deflect nearby star trajectories just like a black hole.  From the distances we are observing these objects, they would look just like black holes.

Remember, noone's actually gotten close enough to a black hole to observe an event horizon.  We just see large gravitational masses that appear to be a point source.  According to current theory, the matter in such an astronomical body must be a black hole since it 'must' have collapsed into a singularity.  We do not know that with certainty.

Do I believe that black holes exist?  Yes.  Present theory seems to indicate that there are no stable degenerate matter states that can prevent a black hole from collapsing into a singularity.  Do I KNOW that black holes exist?  No, and neither does anyone else.

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#48 2004-03-31 06:38:41

Mark Friedenbach
Member
From: Mountain View, CA
Registered: 2003-01-31
Posts: 325

Re: Singularity - Black Holes, Gamma Rays, Magnetars, etc

I'd like to see the reference for this observation of Hawing radiation from a black hole.  The observable radiation from such a process is so small that it sould be unobservable unless you have a black hole in a laboratory.  There is no way that a standard solar mass black hole would have hawking radiation observable to a telescope.  A black hole of that amount of mass has Hawking radiation cooler than the cosmic background radiation.  Heck, even if you had the black hole sitting right in front of you in a laboratory, it's unlikely that you could detect the Hawking radiation coming off of it.

You're absolutly right.  The article I was thinking of I read a few years back in discover magazine, but clearly I must be remembering wrong.  You are correct about Hawking radiation.

As for general relativity and black holes, yes, relativity does explain what happens to mass as it goes to a singularity - somwhat.  Relativity breaks down at the point of a singularity and therefore can't be said to explain what happens there.

Furthermore, relativity says *nothing* about the matter involved in the formation of a black hole.  Things like the Pauli exclusion principle are purely a subset of quantum mechanics.  We know that normal matter is kept from collapsing by the repulsion of electrons of the same quantum state.  In neutron stars, nucleon degeneracy does the same task.  Preesent theory assumes that at higher levels of pressure, matter then completely collapses into a black hole.  This is not known for certain.  It's the most likely explanation and the one I believe in but there is no proof for it. 

For all we know, a star of > 3.5 solar masses collapses into another state of matter such as a quark soup or other more exotic things.  Such a material would warp light, create a violent accretion disc and deflect nearby star trajectories just like a black hole.  From the distances we are observing these objects, they would look just like black holes.

Remember, noone's actually gotten close enough to a black hole to observe an event horizon.  We just see large gravitational masses that appear to be a point source.  According to current theory, the matter in such an astronomical body must be a black hole since it 'must' have collapsed into a singularity.  We do not know that with certainty.

You are right that we do not know what the internal structure of a black hole is (if it has any).  But we have observed event horizons.

Here's how: Accretion matter falling into a neutron star heats up.  When it strikes the surface it's gained so much momentum that a thermonuclear explosion results.  We see this as a large x-ray burst.  Once neutron stars exceed a certain size we still see the heating, but not the burst.  The conclusion is that the star has become so massive that its gravity traps the light of the explosion.  This cut-off point in size is about what we'd expect for the transition to a black hole.  Therefore what we're observing is the event horizon of a black hole.

There have been other experiments to show the existance of black holes, I'm sure.  This is the one I'm the most familiar with.  My point is that black holes, objects so massive that they possess an event horizon, do exist, and are not a matter of belief or untested theory.  But I think we're really in agreement over this aren't we?

I apologize for hijacking the thread over such a nitpicky point.  I guess given the title of the thread I should have realized you were talking about singularities and not black holes in general.   smile

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#49 2004-03-31 09:37:55

Palomar
Member
From: USA
Registered: 2002-05-30
Posts: 9,734

Re: Singularity - Black Holes, Gamma Rays, Magnetars, etc

Cindy wrote: "I have an unfortunate tendency to interpret things literally."

Please don't change, because your enthusiasm for the great adventure itself tends to bring out the best in those of us who keep on attempting to explain the presently unexplainable, and recommend doing the currently undoable.

*Thank you for those kind words, dicktice.  Mark encourages asking questions -- for me, easy enough (I'm insatiably curious!)  smile

I posted the following a year ago, in the original "New Discoveries" thread (now buried way, way down in the Science & Technology folder; it took me a while to relocate it), which was prior to this thread being established.

I -very rarely- repost information, by the way. 

I wrote it in the context of "proven," although perhaps the program was a bit more speculative (it's been a year now...).  Anyway, I did my best to relate the documentary:

It was a fascinating documentary my husband and I watched:

"The beauty of the interplay between destruction and creation was evident in a Discovery Channel television program I watched this evening, originally airing on the Science Channel (which my cable company unfortunately doesn't provide...I'll have to give them a little ring-a-ling on the telephone).

The program was titled "Supermassive Black Holes."  If you haven't seen it, here's the run-down (to the best of my ability):

*Every galaxy yet examined for a black hole has been found to have one at its center; apparently every galaxy has one at its center.

*Black holes are proportionate in size to its "host" galaxy.

*Scientists sought to determine the "which came first, the chicken or the egg?" dilemma with regards to black holes and their "host" galaxies.  Data to date leans in great favor to the certainty that black holes are formed first; that at the beginning of our universe gasses compressed to such a point, finally collapsing, that black holes formed from them.  The gravity from the black holes begins to agitate the gases around them, superheating them (quasars).  The black holes suck these gases in, the violence of the "feeding" and superheating of surrounding gases creating stars -- and hence galaxies.  [::edit::  The documentary showed this process as a gentle explosion, like the upshoot of a geyser]. Jets of energy from a quasar can extend thousands of light-years into space; this energy pushes surrounding space away from the quasar/emerging galaxy. 

*When the superheated gas is consumed from the quasar (which then is gone, of course), the black hole becomes dormant -- but not necessarily permanently dormant; an astronomer in Hawaii believes she has data showing that the black hole at the center of our galaxy has begun "feeding" again, albeit mildly -- gobbling up some stray, nearby gases and that it is nothing for us to be alarmed about; we are approximately 24,000 light years from the black hole.

*I've heard this item before:  The Andromeda galaxy -- the galaxy nearest to us -- is moving toward us at 250,000 miles an hour.  An astronomer has done extensive calculations:  In roughly 3 billion years, Andromeda will collide with our galaxy; its black hole will merge with ours...and Earth and our companions in the Solar System will be toast from the intense radiation, stellar explosions, etc.  According to his calculations, we're going out with a bang. 

It was a spectacular program; I could watch and soak up stuff like this for hours.  If you get a chance, do watch."

--Cindy


We all know [i]those[/i] Venusians: Doing their hair in shock waves, smoking electrical coronas, wearing Van Allen belts and resting their tiny elbows on a Geiger counter...

--John Sladek (The New Apocrypha)

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