Yes indeed, corpuscular was intended to illustrate a 19th century mentality of the concept of black holes (which originated in the 19th century). The concept was similar...that all 'corpuscles' of light escaping from said massive star strove against gravity so difficult that it turned aside and was rent back into its origin. Thereby, no light could escape such a massive star.
Ok, thanks, makes sense now:-)
And you did explain the red shifting more than enough for me to figure out what you're talking about. (and I knew who schwarzchild was too,;-) )
Basically, what I was talking about doesn't have that much to do with the temperature of black holes or the evaporation of black holes.
What you want to know about is Hawking Radiation, as this is actually related to both of your questions. I suggest you grab a copy of Stephen Hawking's A Brief History of Time and read on hawking radiation. If you could get a copy of the illustrated brief history of time, even better, as I've found that book easier to wade through. I'm not going to try to explain hawking radiation, as a physicist friend of mine (not from caltech) yelled at me that what I was saying about hawking radiation would confuse people. Besides, Professor Hawking is far more elegant than I am.
I'd love to read some stuff on that if you have any links. I haven't seen any of that stuff and I have a slightly-more-than-amateur interest in astrophysics.
that's a very good question. And I can't explain it to you in a way that will satisfy you, all I can say it that it stems from special relativity, time dilation and length contraction.
I can tell you that time does not dilate for the astronaut, time flows smoothly for him as he passes the event horizon and flies down to his doom.
Any explanation I give trying to explain the paradox would involve lots of hand-waving on my part, so let's hope someone else can explain it better.
light does, in effect, "spiral down" into the singularity because of the curvature of space-time around the singularity. This is an approximation, since it requires us veiwing 4-dimensional space-time as a 2-dimensional surface.
Now, this is mainly just from my understanding of black holes having read Hawking's Brief History of Time and taken one astronomy course. But I don't remember ever reading about the light redshifting to infinite (if you could explain that in more detail for me, I'd be grateful).
And I'm not sure how you're using "corpuscular," I've never heard it used that way.;-)
Black holes can be detected (in theory of course) by looking for the emissions they give off. The theory goes (extremely roughly) that as individual particles reach the "edge" (event horizon?) of the black hole (crossing this line means you never come back), some of them are torn apart, half of the particle going in, half going out, and some energy is released during this fission. It is these fissions at the edge that make a black hole appear to give off energy, and make it detectable.
That type of radiation is called Hawking Radiation (after Stephen Hawking, naturally). However, this isn't what lets us detect black holes, as Hawking Radiation is ridiculously faint. Black holes can be detected by the X-Rays that they "inadvertantly" produce. When matter is falling into a black hole it is accelerated, heated, and compressed to such a degree that it gives off large amounts of X-Rays. I believe the first black hole we detected (again, assuming black holes exist), was Cygnus X-1 (or cygnus something), and we detected it by the x-rays it gave off.
Another method of detecting black holes is to look for graviational lensing effects. Because black holes are so massive, they bend the fabric of space time. (Imagine a sheet suspended in the air. Place marbles on the sheet. The marbles make depressions on the sheet, like stars make "depressions" in space-time. A black hole is so heavy, it's like dropping something that is the size of a marble but with the weight of a bowling ball onto the sheet. The sheet bends A LOT, and it actually will have a hole where the singularity is.) Light travels in a straight line, so if space-time curves, light also curves with space-time. Gravitational lensing was proved during a solar eclipse. Astronomers observing the eclipse noted that they were able to see stars that should have been blocked by the eclipsed sun. The sun's gravitational field caused enough "lensing" so that stars directly behind the star could be seen to either side of the star. So, if we find something out in space that is causing a LARGE amount of gravitational lensing, but we can't see anything, there's a chance it's a black hole. At that point we normally observe it more to determine if it is or isn't a black hole.
because as far as you are concerned, whatever you are watching falling into the black hole never actually falls into the black hole. Because of the time dilation that an object experiences as it falls into a black hole, we never see it actually fall into the black hole.
To use an example from Stephen Hawking's A Brief History of Time:
Suppose that you are watching an astronaut fall into a black hole. Suppose that you can see the watch on the astronaut's wrist. As the astronaut approaches the event horizon, the seconds will start ticking off slower and slower. Actually, each second will take twice as long as the one before, until finally, before the astronaut passes the even horizon, the last second on his watch will take an infinite amount of time to elapse (from your viewpoint). Of course, the astronaut notices none of this, and time passes normally for him as he flies through the event horizon to his death.
This is a consequence of special relativity. In your reference frame (the observer's frame), the astronaut will never actually pass the event horizon. But, since the speed of light is equal in all reference frames, you can still see him because light is still reflecting off of him as far as your concerned.
And the light doesn't grow "Dimmer" as you get closer to the event horizon. The light still has the same intensity, it isn't like the black hole is sucking photons off of their course out of light rays passing by, the event horizon is more like a "curtain", on one side light is passing normally (normally enough, it isn't slowing down, just "curving" because of the warping of space-time around the black hole), and on the other side of the event horizon, light spirals into the singularity, never to escape.
I don't think we can say that the black hole is rotating. The singularity is a point with (effectively) zero volume, and I would say that this precludes it's ability to rotate.
Since the singularity has zero volume, it must exert its gravitational force equally in all directions. Perturbations in a gravitational field would arise from unevenly distributed mass within a given volume. Since we have no volume, we can't have an uneven distribution of mass.
It's generally accepted that carbon based life-forms require water and oxygen. There has been a fair amount of scientific research done on this. Basically, because of the nature of any life form that is carbon based, it is going to need water and oxygen in some form. This is a simple fact of the chemistry that a life-form ends up having if it is carbon based.
Likewise, if an organism is silicon based, it would have a different set of requirements for life. There are actually papers that have been written discussing the chemistry and environment that would be required to produce and sustain silicon based life forms.
at night when they don't get sunlight for photosynthesis they have to perform respiration just like everyone else. That's why algae can take over a pond and kill fish, at night it eats up all the oxygen and the fish die.
Oxygen and Water are required for carbon based life. Those phototropic plants have simply figured out how to get oxygen in a different way, haven't they?
with the obvious additions of the metroid games, the obligatory pokemon games, and whatever games rare pumps out (usually the donkey kong games).
Maybe it's just me, but I personally have absolutely no taste for all of the fighting, sports and racing games that seem so prevalent on all of the consoles. I would say now that nintendo has a good media for their games (read: lots of memory) they can finally start making good rpg's. That's the only thing the N64 lacked, and I would say that the rpg's on the SNES were far better than any other console rpg's.
Too bad they won't get square back and enix abandoned the US. oh well, I didn't like FF7 and FF8 anyways, give me my bioware games.
making an analogy between a phone conversation and e-mail. I would guess that the main problem is that there is not any current legislation dealing specifically with e-mail, just a vague feeling some people have that e-mail privacy is protected under the 4th amendment.
e-mail and mail delivered by the US Postal Service are two very different things. There are no federal laws protecting e-mail in the same way that snail mail is protected. All of the complaints people lodge against Carnivore are based on the assumption that we have a "right to privacy," which stems from an interpretation of the 4th amendment's protection against unlawful search and seizure. (at least I think it's the 4th amendment.)
In any case, you can't compare e-mail to USPS mail. they are two completely different things, you shouldn't even think of them the same way.
I'm not terribly enthused about eventually working in Silicon Valley. I probably won't end up working for the government either. I just know one of my friends mother just started working for the government again as a coder, and since she had worked for them before they simply acted like she had never left in terms of the salary and benefits that she was receiving, so since she had worked for them for like, 8 years previously , they just pretended she was still an 8th year employee. I thought that was pretty cool.
Me? Well, I may earn half as much at home as I do in Silicon valley...but the cost of living is at least half as inexpensive, if not less.:-) Thankfully I don't have to make these decisions for a few years yet.
Moller
a quote for a recruiter at the caltech job fair
on
Nvidia Apologizes
·
· Score: 1
"We "tier" the GPA's we expect from schools. We expect the highest GPA's from state schools, slightly lower from many of the Ivy League schools, and even lower schools from Harvard and MIT. We expect the lowest GPA's from Caltech, they have their own tier for grades."
attack the MP3 format itself? I mean honestly now, why don't they just go ahead and sue the person who came up with the MP3 file format, and then sue Winamp, Real, Microsoft, and everyone else who publishes a player that is capable of using mp3's.
The RIAA has a problem with MP3's. It's not just they don't want people trading copyrighted material, they don't want them doing anything with a format they don't have any control over. I want to see the RIAA sue Microsoft to attempt to force Microsoft to remove support for MP3's from Windows Mediplayer. Obviously all MP3's contain illegally acquired copyrighted material (never mind all the songs I download because it's easire for me to download songs I have the CD for than for me to rip them myself), so of course an MP3 player should be illegal as well! Please. This is ludicrous to say it's the deathknell of whatever it is the RIAA thinks they're fighting.
as some karma whore said in another story, the record industry doesn't care about metallica, or most of the other bands that are traded on napster. The record industry makes most of their money on top ten hits, which mostly include such mindless drivel (although popular drivel) as britney, christina, and the boy bands (tm). How many people who are using napster are downloading these songs? What portion of the people who listen to top 10 music are using napster?
Never mind that this ruling makes no difference. There are so many alternatives to Napster, no one could stop this, even if they wanted to. Those poor fools...
Slashdot Mirror
hell no college?
Are you saying that a real sysadmin is someone who is:
not certified
not MSCE
and didn't attend college?
I can see how the first two may apply, but the third?
Yes indeed, corpuscular was intended to illustrate a 19th century mentality of the concept of black holes (which originated in the 19th century). The concept was similar...that all 'corpuscles' of light escaping from said massive star strove against gravity so difficult that it turned aside and was rent back into its origin. Thereby, no light could escape such a massive star.
:-)
;-) )
Ok, thanks, makes sense now
And you did explain the red shifting more than enough for me to figure out what you're talking about. (and I knew who schwarzchild was too,
again, thanks.
Moller
Basically, what I was talking about doesn't have that much to do with the temperature of black holes or the evaporation of black holes.
What you want to know about is Hawking Radiation, as this is actually related to both of your questions. I suggest you grab a copy of Stephen Hawking's A Brief History of Time and read on hawking radiation. If you could get a copy of the illustrated brief history of time, even better, as I've found that book easier to wade through. I'm not going to try to explain hawking radiation, as a physicist friend of mine (not from caltech) yelled at me that what I was saying about hawking radiation would confuse people. Besides, Professor Hawking is far more elegant than I am.
Moller
I'd love to read some stuff on that if you have any links. I haven't seen any of that stuff and I have a slightly-more-than-amateur interest in astrophysics.
that's a very good question. And I can't explain it to you in a way that will satisfy you, all I can say it that it stems from special relativity, time dilation and length contraction.
I can tell you that time does not dilate for the astronaut, time flows smoothly for him as he passes the event horizon and flies down to his doom.
Any explanation I give trying to explain the paradox would involve lots of hand-waving on my part, so let's hope someone else can explain it better.
Moller
light does, in effect, "spiral down" into the singularity because of the curvature of space-time around the singularity. This is an approximation, since it requires us veiwing 4-dimensional space-time as a 2-dimensional surface.
;-)
Now, this is mainly just from my understanding of black holes having read Hawking's Brief History of Time and taken one astronomy course. But I don't remember ever reading about the light redshifting to infinite (if you could explain that in more detail for me, I'd be grateful).
And I'm not sure how you're using "corpuscular," I've never heard it used that way.
Moller
A previous poster noted that if the earth collapsed into a black hole then it would be about 1mm across - which is clearly not zero.
No. The Event Horizon would be about 1 mm across. The singularity has a finite mass with zero volume. That is the definition of a singularity.
Moller
Black holes can be detected (in theory of course) by looking for the emissions they give off. The theory goes (extremely roughly) that as individual particles reach the "edge" (event horizon?) of the black hole (crossing this line means you never come back), some of them are torn apart, half of the particle going in, half going out, and some energy is released during this fission. It is these fissions at the edge that make a black hole appear to give off energy, and make it detectable.
That type of radiation is called Hawking Radiation (after Stephen Hawking, naturally). However, this isn't what lets us detect black holes, as Hawking Radiation is ridiculously faint. Black holes can be detected by the X-Rays that they "inadvertantly" produce. When matter is falling into a black hole it is accelerated, heated, and compressed to such a degree that it gives off large amounts of X-Rays. I believe the first black hole we detected (again, assuming black holes exist), was Cygnus X-1 (or cygnus something), and we detected it by the x-rays it gave off.
Another method of detecting black holes is to look for graviational lensing effects. Because black holes are so massive, they bend the fabric of space time. (Imagine a sheet suspended in the air. Place marbles on the sheet. The marbles make depressions on the sheet, like stars make "depressions" in space-time. A black hole is so heavy, it's like dropping something that is the size of a marble but with the weight of a bowling ball onto the sheet. The sheet bends A LOT, and it actually will have a hole where the singularity is.) Light travels in a straight line, so if space-time curves, light also curves with space-time. Gravitational lensing was proved during a solar eclipse. Astronomers observing the eclipse noted that they were able to see stars that should have been blocked by the eclipsed sun. The sun's gravitational field caused enough "lensing" so that stars directly behind the star could be seen to either side of the star. So, if we find something out in space that is causing a LARGE amount of gravitational lensing, but we can't see anything, there's a chance it's a black hole. At that point we normally observe it more to determine if it is or isn't a black hole.
Moller
because as far as you are concerned, whatever you are watching falling into the black hole never actually falls into the black hole. Because of the time dilation that an object experiences as it falls into a black hole, we never see it actually fall into the black hole.
To use an example from Stephen Hawking's A Brief History of Time:
Suppose that you are watching an astronaut fall into a black hole. Suppose that you can see the watch on the astronaut's wrist. As the astronaut approaches the event horizon, the seconds will start ticking off slower and slower. Actually, each second will take twice as long as the one before, until finally, before the astronaut passes the even horizon, the last second on his watch will take an infinite amount of time to elapse (from your viewpoint). Of course, the astronaut notices none of this, and time passes normally for him as he flies through the event horizon to his death.
This is a consequence of special relativity. In your reference frame (the observer's frame), the astronaut will never actually pass the event horizon. But, since the speed of light is equal in all reference frames, you can still see him because light is still reflecting off of him as far as your concerned.
And the light doesn't grow "Dimmer" as you get closer to the event horizon. The light still has the same intensity, it isn't like the black hole is sucking photons off of their course out of light rays passing by, the event horizon is more like a "curtain", on one side light is passing normally (normally enough, it isn't slowing down, just "curving" because of the warping of space-time around the black hole), and on the other side of the event horizon, light spirals into the singularity, never to escape.
Hope that elucidates things.
Moller
I don't think we can say that the black hole is rotating. The singularity is a point with (effectively) zero volume, and I would say that this precludes it's ability to rotate.
Since the singularity has zero volume, it must exert its gravitational force equally in all directions. Perturbations in a gravitational field would arise from unevenly distributed mass within a given volume. Since we have no volume, we can't have an uneven distribution of mass.
Moller
they could be silicon based.
It's generally accepted that carbon based life-forms require water and oxygen. There has been a fair amount of scientific research done on this. Basically, because of the nature of any life form that is carbon based, it is going to need water and oxygen in some form. This is a simple fact of the chemistry that a life-form ends up having if it is carbon based.
Likewise, if an organism is silicon based, it would have a different set of requirements for life. There are actually papers that have been written discussing the chemistry and environment that would be required to produce and sustain silicon based life forms.
Moller
they don't need it, they just take advantage of it? Plants take what they need. There isn't a "take advantage of" action that plants do.
at night when they don't get sunlight for photosynthesis they have to perform respiration just like everyone else. That's why algae can take over a pond and kill fish, at night it eats up all the oxygen and the fish die.
Oxygen and Water are required for carbon based life. Those phototropic plants have simply figured out how to get oxygen in a different way, haven't they?
Moller
with the obvious additions of the metroid games, the obligatory pokemon games, and whatever games rare pumps out (usually the donkey kong games).
Maybe it's just me, but I personally have absolutely no taste for all of the fighting, sports and racing games that seem so prevalent on all of the consoles. I would say now that nintendo has a good media for their games (read: lots of memory) they can finally start making good rpg's. That's the only thing the N64 lacked, and I would say that the rpg's on the SNES were far better than any other console rpg's.
Too bad they won't get square back and enix abandoned the US. oh well, I didn't like FF7 and FF8 anyways, give me my bioware games.
Moller
you mean people actually follow the link to my page? cool...:-)
now i guess that means I should put more pictures up!
Moller
making an analogy between a phone conversation and e-mail. I would guess that the main problem is that there is not any current legislation dealing specifically with e-mail, just a vague feeling some people have that e-mail privacy is protected under the 4th amendment.
Moller
no text
e-mail and mail delivered by the US Postal Service are two very different things. There are no federal laws protecting e-mail in the same way that snail mail is protected. All of the complaints people lodge against Carnivore are based on the assumption that we have a "right to privacy," which stems from an interpretation of the 4th amendment's protection against unlawful search and seizure. (at least I think it's the 4th amendment.)
In any case, you can't compare e-mail to USPS mail. they are two completely different things, you shouldn't even think of them the same way.
Moller
I'm not terribly enthused about eventually working in Silicon Valley. I probably won't end up working for the government either. I just know one of my friends mother just started working for the government again as a coder, and since she had worked for them before they simply acted like she had never left in terms of the salary and benefits that she was receiving, so since she had worked for them for like, 8 years previously , they just pretended she was still an 8th year employee. I thought that was pretty cool.
:-) Thankfully I don't have to make these decisions for a few years yet.
Me? Well, I may earn half as much at home as I do in Silicon valley...but the cost of living is at least half as inexpensive, if not less.
Moller
"We "tier" the GPA's we expect from schools. We expect the highest GPA's from state schools, slightly lower from many of the Ivy League schools, and even lower schools from Harvard and MIT. We expect the lowest GPA's from Caltech, they have their own tier for grades."
nt
I guess I just have to lie and say that I did rip all those mp3's myself when I actually downloaded them.
:-(
I might rip them myself...but my cd rom is of such low quality it takes 5 tries to rip a 3 minute song
attack the MP3 format itself? I mean honestly now, why don't they just go ahead and sue the person who came up with the MP3 file format, and then sue Winamp, Real, Microsoft, and everyone else who publishes a player that is capable of using mp3's.
The RIAA has a problem with MP3's. It's not just they don't want people trading copyrighted material, they don't want them doing anything with a format they don't have any control over. I want to see the RIAA sue Microsoft to attempt to force Microsoft to remove support for MP3's from Windows Mediplayer. Obviously all MP3's contain illegally acquired copyrighted material (never mind all the songs I download because it's easire for me to download songs I have the CD for than for me to rip them myself), so of course an MP3 player should be illegal as well! Please. This is ludicrous to say it's the deathknell of whatever it is the RIAA thinks they're fighting.
Moller
as some karma whore said in another story, the record industry doesn't care about metallica, or most of the other bands that are traded on napster. The record industry makes most of their money on top ten hits, which mostly include such mindless drivel (although popular drivel) as britney, christina, and the boy bands (tm). How many people who are using napster are downloading these songs? What portion of the people who listen to top 10 music are using napster?
Never mind that this ruling makes no difference. There are so many alternatives to Napster, no one could stop this, even if they wanted to. Those poor fools...
then understand where I go to school. Then talk about my GPA. Anyone here could be going to any other school in the nation and have a 4.0.