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 chrono1985
Joined: 11/20/2004
Msg: 155
Black holes...help!Page 8 of 9    (1, 2, 3, 4, 5, 6, 7, 8, 9)
The whole reason they are called holes instead of spheres is simple once you read into what's Hawkin's explanation of how they form. Specifically the section describing the part where a star falls through it's own event horizon (center of gravity for all intents and purposes). So much mass builds up in such a unimaginably small point of space that it literally punches a hole in space (and as theorized time as well).

I never really followed well with the idea that black holes lead to white holes in another space/time (read as and or). I think they are a replication mechanism. A black hole forms and begins to take in matter/energy, but the point where that matter/energy is being collected is fixed in both spatial and chronological coordinate. Eventually the stream connecting our universe to that point is severed and it explodes into a new universe. Don't confuse that though with the stream being a tunnel backward in time, as all the matter in our universe would have moved past that point the instant it formed. This isn't to say it's an infinite cycle though, eventually the matter would be to dispersed to be collected by even ultra massive black holes. It could not even be exploding but instead be a universe at the core of the black hole, since the matter would be more tightly during the start of a universe it would make sense that more black holes could form during that time and thin it out enough for it to cool the point that our universe has.
 abelian
Joined: 1/12/2008
Msg: 156
Black holes...help!
Posted: 1/28/2009 3:43:12 PM

The reason that escape is immpossible is because the curvature of the space beyond the Event Horizon. In other words, the Event Horizon is the threshold where space is so inwardly curved (collapsed) that nothing can escape.

Unless you are trying to say that the future pointing timelike trajectories inside the horizon all end on the singularity, then what you are saying makes no sense and contradicts your own use of the term Killing field. A Killing field preserves the isometries of the metric, which for an observer inside the horizon, means the singularity is in his future, since where the metric says it is. The singularity is NOT a location in space. It's all of space and it's located in the future of an observer who crosses the horizon. The horizon is in the past of an observer inside the horizon. You can easily see this just by looking at the interior Schwarzschild metric. Inside, the radial coordinate, r, is timelike and therefore r is the time coordinate, not a spatial coordinate.

First: Both 'spin.' In "static" models things are distorted because we do not exist in a static Universe (or Multi-Verse, for that matter).

Both do not spin. The schwarzschild black hole is the solution for spherically symmetric matter distribution in a static spacetime. (i.e., the spacetime is eternal and nothing ever changes.) Hence, schwarzschild black holes do not exist in this universe, despite being useful approximations. If you want to dispute that, write down the Schwarzschild metric and point out the term(s) containing the angular momentum.


Second: Kerr's Theory matches better to what has been observed. From what I understand, these two models are not radically different or otherwise incompatible. Don't forget that Kerr's work was done years after Schwartzchild postulated his theories.


The reason they aren't incompatible is that a Schwarzschild black hole is the limiting case of a Kerr black hole in the limit that the angular momentum goes to zero. Neither are ``theories.'' Both are the exact solutions to the field equations in general relativity for two specific matter distributions. The theory is the General Theory of Relativity. Black holes are merel a specific result.
 oregonmeetsmesa
Joined: 9/22/2005
Msg: 157
Black holes...help!
Posted: 1/28/2009 4:34:00 PM
Still sounds like alot of differing theories, as if any of you could possibly prove your correct and since the closet believed to be a black hole from observations of strong X-ray emission is Cygnus X-1, located about 8000 light years away. Cyg X-1 being an ordinary star that is believed to be orbiting a black hole. There are other nearby candidates for black holes which include : GRO J0422+32 =V518 also A0620-00 = V616 Mon and also XTE J1118+480

So much of science and even anthropology is theories yet still the strong arguments exist,each scholar ready to disprove the other with a theory.

Mine and others opinion is no better or worse than any of yours, yet mine and other are quickly discounted as you try to prove to me using more theories and until you send something through, if there even is a through ,if there even is a hole,then the theory is nothing more than that,ones opinion,that is all.

The emission of strong X-rays could be from some other source,as if you have concrete proof on the only way to get strong X-ray emissions is ...........?

So many theories in recent history are proven as inaccurate as soon as new data disproves the former theory,I can think of dozens of examples off the top of my head.I can remember so many things taught to me as fact that actually turned out merely theory,and on some of the examples I have in the last 30 years ,ones I had been graded on only to have had modern discovery proving the theory incorrect,whether it was the nothing could exist in 800 degree water or cold fusion was absolutely impossible(progress is being made on the latter) I have found many a brilliant scholars throughout history has been shown his theory was incorrect thus making it hard to fight to passionately here.

Reminds me of when two multiple degree d doctors are put into a debate,each one author to many books,each one a leader in the same field,yet there conclusions are polar opposites.

Nonetheless theories are fascinating and its wonderful when one becomes proven and true.Think whats learned about theories is not to take them to seriously ! Even my hero Hawkins is under attack by some pretty good new theories.
 abelian
Joined: 1/12/2008
Msg: 160
Black holes...help!
Posted: 2/18/2009 10:20:42 AM
If you think this is in error show the proof that it is wrong.


I've already done that. In addition, since the photon is massless, you can't apply an expression like, F = GMm/r^2. That expression is only suitable for a Galilean universe in which the only way to have a massless particle is for it to propagate at an infinite velocity. Your reasoning is based on hacking and patching parts of incompatible theories together. I gave you a reference to for this already. Photons propagate along null rays. Take the metric for the interior, consider rays with ds^2 = 0 and you'll discover that all future pointing null and timelike trajectories have decreasing r. That means that when you are inside the black hole, the horizon is in your past and the singularity is in your future. Unless you know how to turn around in time, your future awaits you at the singularity.
 abelian
Joined: 1/12/2008
Msg: 162
Black holes...help!
Posted: 2/18/2009 5:23:46 PM
No you did not. You have argued. But shown no proofs here or there.

Yes, I have. In fact, the post you inclded in your reply has all the information you need. Write down the schwarzschild metric and do a little arithmetic. If you're up to disputing general relativity, you ought to at least be able to understand it enough to know what the metric tells you.


A photon has a mass as per fh/c^2.

That is not a mass. That is a momentum and you cannot use it as a mass the way you are trying to use it.


A high energy photon (gamma ray) in passing through other matter can turn into a electron (which has a rest mass) and a positron (which has a rest mass) pair. Photons have mass - but not a rest mass.


If you do the calculation, you'll discover that a photon cannot turn into an e+e- pair. It requires 2 photons. I've built a gamma ray detector that performs such a conversion, so I'm very familiar with how it works. The second photon is the virtual photon from the field of a heavy nucleus, like Pb.

If you think you can get pair production from a single photon try calculating it and you'll discover you cannot conserve energy and momentum precisely because the photon is massless.
 stargazer1000
Joined: 1/16/2008
Msg: 164
Black holes...help!
Posted: 2/18/2009 9:03:13 PM
You know, it's amazing the half-heard facts that people take to be the whole story and get repeated in these discussions. So here's a little black hole physics from an enthusiastic amateur astronomer.

First of all, they exist and their effect has been observed. They represent a stellar evolutionary end-point in that the mass of a star has contracted to virtually infinite density and the gravity well has become so steep as to be unscalable even by electromagnetic forces - photons.

Either that, or in the case of galactic black holes, have the mass of millions of stars, again contracted to infinite density.

Stellar-mass black holes have been observed and one of the most famous ones is Cygnus X-1, a source of X rays. A star was observed spectroscopically to be orbiting another stellar mass object but that second object couldn't be observed. Two stars orbiting one another can be discerned by their individual spectra so it had to be orbiting something invisible. It was also eating mass from the visible star and emitting xrays. The original term for it was "black star" but, after Einstein, black hole came to be preferred term.

And there's numerous instances of galactic black holes. Our own galaxy's center has been observed to have stars revolving around a central mass and speeds that should have them easily flying out of our galaxy. And we're talking a region of space no larger than a few times our own solar system. The speed of those stars tell of a mass millions of times that of our sun. That can only be one thing. A black hole.

Galaxy M87 at the centre of the Coma-Virgo cluster has something that is creating a massive jet. If a black hole is eating, it would create an disc of material that was being accreted into the black hole. Conservation of motion causes the material to revolve around the event horizon before falling in. This sets up tremendous friction which generate great heat and magnetic fields which twist, collimating a giant jet of material to be shot out of either poles of the system. Black hole environments are very dynamic places.

Then there's quasars - the active center of galaxies. The brightest one is 3c 273 in Virgo. It's dim but I have seen it in my telescope. Distance: about 2 billion light years.

Oh, by the way, someone mentioned gravity. No, you don't fall at the speed of light if you fall off a chair. However, gravity waves travel outward from objects in space rotating around one another at the speed of light. That's Relativity for you. Information is restricted to c. Darn that Einstein guy!
 abelian
Joined: 1/12/2008
Msg: 171
Black holes...help!
Posted: 2/24/2009 5:25:47 AM

Your metric is called a Gauge Scalar.

A metric corresponds to a spin 2. A scalar is a spin 0.
 AtomicGogol
Joined: 4/4/2008
Msg: 177
view profile
History
Black holes...help!
Posted: 12/10/2009 8:33:02 PM
I believe you're spot on, mtnbike. I for one would like to know if naked singularities will ever be found. Black holes seem to me to be a flaw in general relativity because of their infinite nature. Further refinement of quantum gravity theory and any observation of a naked singularity would clear it up a lot, wouldn't it?
 scorpiomover
Joined: 4/19/2007
Msg: 179
view profile
History
Black holes...help!
Posted: 12/17/2009 5:39:56 PM

thus it would be a black shpere not hole...?
It's a sphere. But any light that reaches the event horizon, never leaves. That makes it appear black against the blackness of space, only that because it also absorbs all the light behind it, you cannot see any stars there, even when there are some behind it. Even if a comet passes behind one, too far away from the event horizon to be trapped, you'll see it moving along, then suddenly it will disappear, and then a few minutes later, it will re-appear, as if it was travelling the same route all alone, and it passed through a giant "black hole". So all you see is a black hole in the sky, a place devoid of any stars, planets, comets, meteors, asteroids, whatever. It looks like a black hole to us. So that's what we call it, a black hole.
 AtomicGogol
Joined: 4/4/2008
Msg: 180
view profile
History
Black holes...help!
Posted: 12/17/2009 9:19:11 PM
Surely a 1-dimensional point of infinite density is scientifically flawed. Does anyone here have a say on this?
 desertrhino
Joined: 11/30/2007
Msg: 181
view profile
History
Black holes...help!
Posted: 12/17/2009 9:40:19 PM
I don't understand why you say a black hole is 1-dimensional and has infinity density. This would only be true of a zero mass black hole.

Otherwise: (math borrowed from: http://www.physicsforums.com/archive/index.php/t-143096.html)

The density required to create a black hole can be given by p = 3M/4piR^3
From Schwarzschild equation the radius of a black hole in relation to its mass is given by R = 2GM/c^2.
Substituting this into the previous equation, we obtain p = 3c^6/32piG^3M^2

Therefore - p is inversely proportional to the mass squared of the black-hole. The greater the mass, the less the required density.
 aremeself
Joined: 12/31/2008
Msg: 183
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History
Black holes...help!
Posted: 12/18/2009 7:20:39 PM
are black holes theorised to be necessary for the functioning of galaxies?

why? and how?
 stargazer1000
Joined: 1/16/2008
Msg: 185
Black holes...help!
Posted: 12/19/2009 6:57:17 PM
There does seem to be a mass ratio relationship between galactic center black holes and the mass of their central cores. It is thought central black holes were fundamental to the formation of galaxies.
 aremeself
Joined: 12/31/2008
Msg: 186
view profile
History
Black holes...help!
Posted: 12/19/2009 8:50:05 PM
maybe its been recommended already, but an interesting little read is the end of everything.

It will probably turn out that black holes, or whatever they are, are necessary to keep the galaxies in some kind of balance or whatever.
something necessary to keep things in there proper orientation a few millennia longer from that supposed eventual end. [entropy?]
 desertrhino
Joined: 11/30/2007
Msg: 188
view profile
History
Black holes...help!
Posted: 12/30/2009 9:36:20 PM
Yep, ignorant ramblings of enlightened special knowledge are FAR easier than getting a real education and learning what the heck you're talking about.

Haramein is making money by preying on the ignorant and semi-educated, SOUNDING like he's saying something meaningful, when he is, in fact, just spouting pseudo-scientific gibberish. But that horse has been beaten to death already.
 Page 2u
Joined: 1/30/2008
Msg: 189
Black holes...help!
Posted: 1/2/2010 9:10:43 AM

Haramein is making money by preying on the ignorant and semi-educated, SOUNDING like he's saying something meaningful, when he is, in fact, just spouting pseudo-scientific gibberish. But that horse has been beaten to death already.


Yup the horse has been beaten to death—problem is the people beating the horse are donkeys, and who cares if you can’t make them drink—

If you’re interested in playing with Haramein theories and taking it a step further –ie. Into the black hole, check out Rodin coil—Now I’m no physicist nor am I particularly good at math, but I am an experienced mechanical designer. Unlike all the other theories this direction can be proven in practical / tactile experiments.

Possibly the black hole is a sphere – a toridial flow falling back onto itself..
124875—is the key, period doubling.
 abelian
Joined: 1/12/2008
Msg: 198
Black holes...help!
Posted: 5/15/2011 6:22:58 AM
Can black holes explode at some point?

No, but black holes can evaporate. They will evaportate faster as they get smaller and the smaller they are, the hotter they are.

Also, can black speres have "galaxies" and "universes" even in its sphere?

In principle, yes, although the size of the black hole would have to be enormous. What you are calling ``its sphere'' is the region of spacetime bounded by the event horizon. The event horizon is the boundary such that once anything crosses it, it must move toward the singularity and cannot return to any point outside the horizon. However, there is nothing special about the horizon other than that. The gravitational field at the horizon could be the same as the earth's gravitational field if the black hole was large enough. (Off the top of my head, I think this is about 10^42 solar masses - a 10 with 42 zeroes behind.) If you were to fall into one that large, as you crossed the horizon, you would feel nothing any different than you would feel free falling on earth.

Black holes are not dense. There is plenty of space inside. The matter all ends up at the singularity.
Can someone explain just how can a black hole evaporate if it is so dense after consuming matter for centuries (it could be for thousands of years too) ...

That is actually quite difficult to explain in a simple way. To do so, requires relativistic quantum field theory. However, a somewhat oversimplified explanation is the following:

In a region of spacetime where there is no matter, no gravitational field, you have nothing but empty space. The space is not really ``empty.'' Particles and antiparticles are created in pairs and anihilate with each other all the time. This is called the quantum vacuum state. These particle pairs are created and anihilated very quickly, so that they have no effect on anything. They can't without violating conservation of energy. (They do play a role in quantum field theory, but for this purpose, that is not germane.)

On the other hand, at the horizon of a black hole, things are different. If a particle anti-particle pair is created at the horizon, one member of the pair may escape the gravitational field, in which case, the other must fall into the black hole. To conserve energy, if the outgoing particle has a positive enery (which it must), the ingoing particle must have a negative energy. That negative energy decreases the mass of the black hole. (One might equally well ask why the negative energy particle in the pair always falls inside. The answer is that the explanation is that isn't quite how it works and a detailed explanation would fix this minor defect, but then making clear what's really happening would get mathematically complicated.) Suffice it to say that if you treat the particles and anti-particles correctly in a curved spacetime, it doesn't matter which falls in. All that matters is that one member of the pair crosses the horizon and one does not. )

Since photons are massless, photons will be the most likely types of particles produced, in which case, the blcak hole evaprorates by producing ordinary electromagnetic radiation. It's actually a perfect blackbody and produces a blackbody radiation spectrum. However, the temperatures of even a pinhead sized black hole are so low that, the radiation would extremely difficult to observe and the time required for it to evaprorate would exceed the lifetime of the universe.

Once "evaporated" what is the contents of the "molecules" once evaporated?

Photons. In principle, other particles could be produced, but the heavier the particle, the less likely it is to produce them. There are some other factors that would surpress heavier particles even more.
 chrono1985
Joined: 11/20/2004
Msg: 200
Black holes...help!
Posted: 5/15/2011 7:44:32 AM
One concept of a black hole you rarely hear about, which is yet another function of them that media like to ignore. Even space falls into a black hole. This is why light can not escape, because the space it's falling toward is falling at the same rate. It's like if you jumped off your chair and all of a sudden the ground started to fall, so that you were always 1ft above the ground.

The disc you see on a black hole with spin is formed by that key component of a black hole. It occupies the area called the ergosphere, an area where space is pull along with the black hole. Anything falling through that space now must travel the curvature of space formed by the rotation of the black hole. Keep in mind though that not all black holes spin.
 abelian
Joined: 1/12/2008
Msg: 206
Black holes...help!
Posted: 5/17/2011 7:23:40 AM
A star is born. It burns itself out and collapsing on itself.

A star dies...

Although this explains the process by which a black hole is formed and the conditions required for it to happen, it really only explains black holes as one possibilty for the end of a star's life. It really doesn't explain what a black hole is. Gravity is what holds the earth together. The pressure is very large as you go closer to the eath's center. As the earth formed, the pressure increased and the pressure from gravity heated the center faster than the heat could escape, so the earth gets hotter as you go toward the center.

If the earth were much larger (i.e., more massive), that pressure would be much higher and the earth would be hotter. If the earth was massive enough, the pressure would be large enough and themperature hot enough that molecules could not form (except perhaps, close to the surface). (Put a diamond in a fire and you'll vaporize it, for example.) If the earth is larger and more massive still, the atoms will be stripped of their electrons and nuclei will collide and fuse, giving off a great deal of heat. Now you have a star. The intense heat creates a great deal of pressure and that pressure prevents the star from being compressed into cold lump of matter. But, eventually, the the lighter elements have all fused into heavier elements and the heaviest element that can be formed by fusion while still producing energy, is iron. If the star merely burned itself out (and some do), you you'ld have a cold lump of matter, held together by gravity. The only thing that prevents the lump of matter from collapsing into something smaller is the stability of matter that requires quantum mechanics to explain. (cf the Pauli exclusion principle.)

Quantum mechanics allows one to calculate how much pressure is required to overcome If the star is larger still then gravitational pressure will crush the matter still further and if the star is large enough, nothing can stop gravity from causing the matter to collapse completely to a simgle point. This is a black hole. The event horizon is the region where nothing can escape the gravitational field of the matter that collapsed to form the black hole. In principle, black holes could form in other ways, (like high energy collisions of particles) but the death of massive stars is the only simple way to get some matter close enough together for gravity to be strong enough to overcome everything else.

I am still trying to figure out that when you look at the sky it is like reading yesterday's newpaper... Well, not really yesterday's but millions of yesterdays ago...

As a first approximation, this is straight forward to understand. Light proagates at a finite speed, so it takes time for light to reach you, even if you're looking at your hand. It's not a long time in that case, but you're still seeing your hand a few nano seconds in the past. If you're looking at something that is so far away that it took a year for the light to reach you, what you are seeing happened a year ago, not right now.

However, this inevitably leads one to think that the speed at which light travels is relevant and that there really is a non-ambiguous way to define ``right now'' such that if one could travel faster than light, one wouldn't be constrained to observing what is in the past. The real explanation is that there is no unambiguous definition of ``right now'' because in special and general relativity, the entire geometry of spacetime is not what you think it would be based on the kind of geometry one learns in high school. This is not hard to explain to someone in a one-on-one setting with a pen and paper available to draw pictures, but translating the pictures to text makes it seem incredibly difficult unless one already understands enough geometry and algebra to not be intimidated by equations and one has some ability to see how those equations relate to physical things.

In particular, most people are familiar with the pythagorean theorem for a right triangle, c^2 = a^2 + b^2. That works ok for objects in space, but once you throw time into the picture and treat time as just another direction in space (i.e., spacetime), the pythagorean theorem is different if one of the ``legs'' of a triangle is along an exis in time, i.e., if the distance in time is b, then it becomes c^2 = a^2 - b^2. The best not-all-that-technical book that will make this clearer is ``Spacetime Physics,'' by Taylor and Wheeler.

Fascinating really...

Yep. I became a physicist because it is fascinating enough that I'd not trade what I've learned for anything, even sex and I'd say that sex has to be number two on the list.

What if our sun becomes a black hole. All the planets, gases and dust would be sucked in it right? Would that be possible?

Apart from no longer receiving light and heat from the sun, nothing, at least not at distances far away from the sun (meaning any distance further than the radius of the sun as it is now. There's nothing special about black holes (apart from what happens inside the horizon). If the sun were to become a black hole, the black hole woud have a radius of 1.5 km (a bit less than a mile, or just under 2 miles in diameter). The gravitational field of the sun on the earth and planets would be exactly the same because the graviational field of any object at a distace greater than the size of that object is exactly what it would be if all of the mass were concentrated at a point.


For anyone interested inthe jets emitted by accretion discs surrounding massive rotating objects, here's a good explanation of the best model that exists, at this point in time:

http://www.physics.purdue.edu/~mlister/articles/meier2001_sci_291_84.pdf
 abelian
Joined: 1/12/2008
Msg: 207
Black holes...help!
Posted: 5/17/2011 7:53:18 AM
Reading about the ergosphere, it appears that at the points that the jet streams are emitted, the ergosphere perfectly matches the boundary of the event horizon..

The reason for that is the speed of rotation at the points along the rotation axis is zero. Spin a globe and you'll notice that the speed at which points on the equator move is faster than points nearer to the poles. The ergosphere is a consequence of the rotation, so at the two points where the poles occur, there is no ergosphere. The ergosphere is largest at the equator and becomes smaller as you move toward north or south the poles.

There are actually two horizons in a rotating black hole. The outer horizon is similar to the horizon of a non rotating black hole. The inner one is much more interesting. Look up Kerr black hole, or Kerr metric.

Does this mean that, assuming something could power through the jet stream (impossible I know, but hypothetically), it would be able to reach the event horizon without being pulled down into the accretion disk?

The accretion disc is nothing but matter that is spiralling into a massive, rotating body because it's velocity isn't great enough to allow it to stay in a stable orbit, like a satellite that falls back to the earth. If you want to know why particles are pushed down into a disc, again, picture a globe except this time, picture a stiff wire that rund from the north to the south pole along a meridian and on this wire there is a bead which can slide back and forth between the poles. Start with the bead at either pole and spin the globe. The bead will slide toward the equator.

What is orbiting black holes and neutron stars are charged particles. Moving charges produce electrical currents which produce magnetic fields. Here are some pictures:

http://www.physics.purdue.edu/~mlister/articles/meier2001_sci_291_84.pdf

Notice the currents around the rotating object are ``tightest'' at the equator, like a solenoid that is wound tightly on a small diameter at the center and more loosely with larger and larger radii as one moves toward the poles. Unlike the stiff wire on the globe which constrains the bead, charged particles follow field lines (look up Lorentz force), hence if the particles move fast enough, they will follow the field lines in the directions ofthe poles but since the field lines bend away from the poles instead of toward the poles, the particles will escape in directions along the rotation axis.

Keep in mind though that not all black holes spin.

All physically realistic black holes spin. The solution for a non-spinning blackhole is obtained by assuming that the spacetime is static, i.e., it looks the same wheter you go forward or backward in time, so a Scwarzchild black hole is eternal - it has always existed and always will exist. It can only be an approximation to a real black hole, however it's an exact solution to the field equations and it is also a really good approximation to more realistic black holes outside the horizon, so one typically uses it to obtain the basic features of any black hole. The difference only matters if you want to know really detailed information about regions where the gravitational fieds are very strong.



 abelian
Joined: 1/12/2008
Msg: 209
Black holes...help!
Posted: 5/19/2011 4:35:17 PM
Now, does a beam of light slow down if it does not bounce off of anything?

No, but neither does a rock if you throw it in outer space.

I understand the concept of speed of light but can a light beam travel at the speed of light forever?

Light can only propagate at the speed of light. (It travels slower in a medium, like a crystal, but I assume you mean in free space. Why it travels slower in a medium isn't really relevant to the question you're asking.)

Does a beam of life "die" off after a period of time?

That depends on what you mean by a ``beam'' of light. However, let's cover the possibilities. First, consider all of the light emitted from the surface of the sun. Picture an imaginary spherical surface drawn completely around the sun. All of the light that crosses that spherical surface at a given instant will have some total intensity. Call it I. Now picure a much much bigger sphere drawn around the sun. All of the light that crossed that first surface will, at some later time, also cross the surface of that much larger sphere (unless something in beween is blocking it which we will assume there is not.) The total intensity must therefore be the same as the intensity of light that crossed the smaller spheere. However, the larger sphere has a much larger surface area, so the light is more spread out. In that sense, if you take a piece of paper that's 1 ft by 1 foot square, the intensity of the light that lands on that 1 square foot of paper if you are a foot away will a lot greater than if you are 100 feet away.

So, if you were to create a light beam by putting up a big screen with a hole in it, the beam would diverge, but the total intensity of the beam would be the same no matter how far it travels. It would just be spread out over a larger area. A laser on the other hand is slightly different. Laser light it produced in such a way that the beam doesn't diverge very much. If you picture a laser which could produce a perfect beam of light that didn't diverge, the intensity would be the same no matter how far the beam traveled.

If a beam of light does not slow down then speed of light is sort of like a constant.

Well, it's not sort of like a constant. It is exactly a constant. In fact, it's known to a constant with such great precision that a distance of 1 meter can be defined to much greater precision by measuring how far light travels in a specific time interval with much greater precision than using the platinum bar that used to define the meter.


Can a burst of light from a sun slow down at some point?

No.

Can a burst of light penetrate any sphere in rotation in a direct line sort of speak?

I don't understand this question.

Can a burst of light lose its strength the longer it is travelling without bouncing off of any space matter?

No. It can't even slow down by bouncing off something. It either gets absorbed or it bounces off and propagates at the same speed, perhaps in a different direction.

Do all "unconsummed" beams of light end up being sucked up by a black hole ?

No. Light which falls into a black hole cannot escape. Light passing by a black hole may get pulled in by the gravitational field or it might just get bent around the black hole (like light would be bent by a focussing lens. However, light aimed directly at the black hole will disappear into the black hole.

Is it just me or the more I learn, the less I seem to understand.

Unfortunately, relativity and black holes are always described by the media in a way that tries to appeal to what people are familiar with and what they gain with that initial simplicity, they lose in the ability to explain the weirder things in a way that makes sense. Understanding the basic features of black holes is not really that difficult and it's actually pretty intuitive for the most part, but the price you have to pay on the front end is understanding a little more geometry and getting comfortable thinking about time as just another dimension instead of something intrinsically different from space. However, it does not require a lot of mathematics. Just good pictures with decent explanations.
 R_O_U_S
Joined: 3/20/2011
Msg: 213
Black holes...help!
Posted: 8/10/2011 7:39:21 PM
a black holes gensis is based on density and what some belive to be relativity, but i beleve to be dark matter collected on density causing enuogh bridge for the large density to brace from 3rd to higher dimensions to time collapse. i opine paul sayers sighning off.
 abelian
Joined: 1/12/2008
Msg: 214
Black holes...help!
Posted: 8/11/2011 5:01:27 AM

a black holes gensis is based on density and what some belive to be relativity,

A black hole is a consequence of general relativity. Without general relativity, you have no theory to tell you what a black hole is supposed to be or how to identify one. Without general relativity, you might be able to define something like a black hole in general relativity, but first you need a theory to tell what it is.
 PragmaticDoc
Joined: 8/4/2009
Msg: 215
Black holes...help!
Posted: 8/11/2011 1:32:24 PM
Ok I just finished "The Universe in a Nutshell" and have a question pertaining to black holes and the law of conservation of energy. A black hole is pulling eveything into itself, Light, mass, energy, everything. Since the total amount of energy always remains the same, as per the law states, does this mean all energy, as well as the light and mass are being moved to another dimension or simply being stored awaiting that last blast?
 swingarm1966
Joined: 3/27/2011
Msg: 216
Black holes...help!
Posted: 8/11/2011 5:46:18 PM
dosnt a black hole punch a hole through the space time fabric? If this is true there is something else going on other than just a "dark sphere" no? Sorry have not read the hole thread.
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