The efficiency of internal stellar processes indicate that stellar
evolution may exist as a two step process - http://www.hubblespacephotos.com/pics/sn1987a.jpg
In other words,the abundance of heavier elements that make existence
possible on Earth may have come from our own central star http://science.nasa.gov/newhome/headlines/ast08oct99_1.htm
This concept based on stellar evolution as a two step process leaves
no room for the non-geometric 'black' entity ,the outlines of a new
approach are so general that it can only be presented as a means to
redirect attention away from a contemporary view of stellar evolution
as a one step process .It does however provide a guide to where the
heavier elements on Earth originated as a consequence of the
efficiency of stellar processes but what these processes are is too
early to say.
Martin Brown wrote:
Sitav wrote:
OK. AGNs are hard enough to understand but just the basic idea of a
black hole is so confusing.
It shouldn't be all that confusing. The demented cosmic vacuum cleaner black hole of science fiction and edutainment programmes is
fundamentally wrong and very confusing though. It usually fails to obey
the laws of physics thanks to Hollywood special effects.
Gravity determines the escape velocity from the surface of a planet (or
any other body). In the case of the Earth around 7 miles a second.
Laplace first wondered classically about what would happen if you had
the entire mass of the sun squashed into a diameter of just 3km. At
that point the escape velocity at the surface becomes equal to the
speed of light.
If the sun was spontaneously turned into a black hole of the same mass, nothing much would change in our solar system. The planets would still orbit it in pretty much the same way as before (obviously we would no longer have any sunlight).
A black hole is formed when a star falls in
on itself. What does that mean?
Whilst a star is burning it is held up by thermal pressure - inflated a
bit like a hot air balloon. When the star runs out of fuel there is
nothing left to provide heat to keep it from falling in on itself under
the effect of gravity and the whole thing implodes as a supernova.
And even on my previous article about
AGN the answers i got were completely incomprehensible for me (i am
only 12! give me a break!).
Whatever happened to those child friendly astrophysics collecting
cards?
As that star "falls" does it rip a hole in
space and time forming the "hole"?
No. Most stars are nowhere near heavy enough to form a black hole. They
end up as white dwarfs or neutron stars which are much more compact
than ordinary stars. But still not as a black hole. If the dead star is sufficiently massive then there is no force of nature we know of that
can prevent total gravitational collapse to a point singularity.
A neutron star is only about 5x bigger in diameter than a black hole of
the same mass. But neutrons can still provide a strong enough force to prevent total collapse.
Even when a black hole is formed there is no hole in our spacetime - at least not one that you can ever report on. To see the central
singularity you have to be inside the event horizon and from there you cannot communicate with the universe outside.
And after all that what is a white
hole?
A hypothetical conjecture that may or may not exist (and probably
doesn't).
You are probably better off finding a local library with some popular astronomy and science books in it that are at about the right level.
Usenet is not always a reliable source of info.
And many of your questions are offtopic in the amateur astronomy groups
- not even the professionals have telescopes that can see black holes directly. Unfortunately you will get mostly gibberish answers from
cranks if you post in sci.astro.
BTW Take a look at the Chandra Crab nebula movie to see what an
accretion disk looks like.
Good luck.
Regards,
Martin Brown
OK. AGNs are hard enough to understand but just the basic idea of a
black hole is so confusing. A black hole is formed when a star falls in
on itself. What does that mean?And even on my previous article about
AGN the answers i got were completely incomprehensible for me (i am
only 12! give me a break!). As that star "falls" does it rip a hole in
space and time forming the "hole"? And after all that what is a white
hole?
On Friday, January 12, 2007 at 11:32:33 AM UTC, oriel36 wrote:when it is just as productive to consider it the birth of a solar system.
The efficiency of internal stellar processes indicate that stellar evolution may exist as a two step process - http://www.hubblespacephotos.com/pics/sn1987a.jpg
In other words,the abundance of heavier elements that make existence possible on Earth may have come from our own central star http://science.nasa.gov/newhome/headlines/ast08oct99_1.htm
This concept based on stellar evolution as a two step process leaves
no room for the non-geometric 'black' entity ,the outlines of a new approach are so general that it can only be presented as a means to redirect attention away from a contemporary view of stellar evolution
as a one step process .It does however provide a guide to where the heavier elements on Earth originated as a consequence of the
efficiency of stellar processes but what these processes are is too
early to say.
Martin Brown wrote:
Sitav wrote:
OK. AGNs are hard enough to understand but just the basic idea of a black hole is so confusing.
It shouldn't be all that confusing. The demented cosmic vacuum cleaner black hole of science fiction and edutainment programmes is fundamentally wrong and very confusing though. It usually fails to obey the laws of physics thanks to Hollywood special effects.
Gravity determines the escape velocity from the surface of a planet (or any other body). In the case of the Earth around 7 miles a second. Laplace first wondered classically about what would happen if you had the entire mass of the sun squashed into a diameter of just 3km. At
that point the escape velocity at the surface becomes equal to the
speed of light.
If the sun was spontaneously turned into a black hole of the same mass, nothing much would change in our solar system. The planets would still orbit it in pretty much the same way as before (obviously we would no longer have any sunlight).
A black hole is formed when a star falls in
on itself. What does that mean?
Whilst a star is burning it is held up by thermal pressure - inflated a bit like a hot air balloon. When the star runs out of fuel there is nothing left to provide heat to keep it from falling in on itself under the effect of gravity and the whole thing implodes as a supernova.
And even on my previous article about
AGN the answers i got were completely incomprehensible for me (i am only 12! give me a break!).
Whatever happened to those child friendly astrophysics collecting
cards?
As that star "falls" does it rip a hole in
space and time forming the "hole"?
No. Most stars are nowhere near heavy enough to form a black hole. They end up as white dwarfs or neutron stars which are much more compact
than ordinary stars. But still not as a black hole. If the dead star is sufficiently massive then there is no force of nature we know of that can prevent total gravitational collapse to a point singularity.
A neutron star is only about 5x bigger in diameter than a black hole of the same mass. But neutrons can still provide a strong enough force to prevent total collapse.
Even when a black hole is formed there is no hole in our spacetime - at least not one that you can ever report on. To see the central singularity you have to be inside the event horizon and from there you cannot communicate with the universe outside.
And after all that what is a white
hole?
A hypothetical conjecture that may or may not exist (and probably doesn't).
You are probably better off finding a local library with some popular astronomy and science books in it that are at about the right level. Usenet is not always a reliable source of info.
And many of your questions are offtopic in the amateur astronomy groups - not even the professionals have telescopes that can see black holes directly. Unfortunately you will get mostly gibberish answers from cranks if you post in sci.astro.
BTW Take a look at the Chandra Crab nebula movie to see what an accretion disk looks like.
Good luck.
Like most things, research has been far too slow in these matters.Regards,
Martin Brown
https://www.youtube.com/watch?v=5aPj--bedew
The images from Webb of SN1987a basically draw closer to not just stellar evolution but also solar system evolution as a two-stage process.
https://www.flickr.com/photos/nasawebbtelescope/53154921769/in/album-72177720305127361/
There is always that element that would cut off its nose to spite its face, however, the geometry of stellar evolution and certain supernovae follow distinct patterns. Current researchers announce the supernova event as the death of a star far too soon
Sitav, Be impatient!
I asked the same questions 2/3 of a century ago, of my father, a librarian with an inquiring mind.
Never the less, it has taken almost that long for me to approach a moderately satisfying understanding of my own, and a probable solution to the "apparent singularity problem".
Gravity... makes things fall down.
And gravitational attraction comes from all objects that have
mass - while only some objects are permanent magnets, for
example.
So, just as the Earth has gravity, so do stars. And, as we
know, the Sun is much bigger than the Earth, even if it is
only made of gases instead of solid rock.
Just as the Earth's gravity keeps the Earth's atmosphere from
escaping into space, the Sun's gravity is the reason that the Sun
has a generally spherical shape.
The pressure that a gas exerts increases if the gas is hotter.
A star has a lifetime; the hydrogen that stars are made of can
all fuse to helium, and then that helium can all fuse to carbon.
Carbon can fuse to, to silicon. But once you get to iron, fusion is
no longer a way to gain energy.
So really big stars, when they burn up the gases of which they're
made, changing them into substances that won't produce energy
from fusion, end up cooling off... and when they're cool, their
gravity will cause them to shrink.
Shrinking will take place even when stars change what fuel they
burn; once the hydrogen is used up, the star cools off, but it has
to get hotter to start burning helium - and shrinking due to gravity
will produce heat that will eventually be enough to do this.
But when a star runs out of fuel, shrinking won't ignite a new
fusion process. Instead, one of the possible results is that a star
will become a neutron star - gravity becomes so strong that the
electrostatic forces that keep matter organized into atoms and
molecules are overcome, and the star becomes like one giant
atomic nucleus.
The strong nuclear force, which is what defines the size of an
atomic nucleus, allowing individual protons and neutrons to both
take up space and stay connected to each other in a nucleus,
is only so strong.
If a star is big enough, its gravity can crush the star further, so that >instead of staying a neutron star, gravity overcomes "neutron
degeneracy pressure" - the strong nuclear force is attractive, what
keeps atomic particles apart in the nucleus is really that they're >Fermi-Dirac particles with spin 1/2, and so quantum mechanics
says they can't have the same state in the same space... but give
them more energy, and they can be in higher states.
As a star collapses under its own weight to approach the size of
a proton... it gets to the point where even light itself can't escape the >star. That's what's called a black hole. The interaction between gravity
and light involves relativity theory, particularly the general theory of >relativity.
Gravity curves space, and at the point where a star becomes a black
hole, that curvature is extreme.
This is brief, and got technical in spots, but I hope it helps a little.
John Savard
Sitav, Be impatient!
I asked the same questions 2/3 of a century ago, of my father, a librarian with an inquiring mind.
Never the less, it has taken almost that long for me to approach a moderately satisfying understanding of my own, and a probable solution to the "apparent singularity problem".
Much of the conflict/confusion is based on most discussions (as helpful as they might be) trying to simplify things by ignoring, or failing to include, the effects of mass on the rate of time (which causes gravity), and which varies at every point inthe universe, mostly dependent on time slowing (sometimes to a stop!) because of proximity to enough matter.
Later you should also consider the effects of speed, the other important influence on the rate of time, and why photons don't age.
I hope you enjoy your journey as much as I have.
JB
On Thursday, January 11, 2007 at 4:07:34 PM UTC-5, Sitav wrote:
OK. AGNs are hard enough to understand but just the basic idea of a
black hole is so confusing. A black hole is formed when a star falls in
on itself. What does that mean?And even on my previous article about
AGN the answers i got were completely incomprehensible for me (i am
only 12! give me a break!). As that star "falls" does it rip a hole in
space and time forming the "hole"? And after all that what is a white
hole?
On 16/09/2023 00:11, J Birch wrote:
Sitav, Be impatient!Have you seen the date on the post that Sitav made? He was 12 back in
I asked the same questions 2/3 of a century ago, of my father, a librarian with an inquiring mind.
Never the less, it has taken almost that long for me to approach a moderately satisfying understanding of my own, and a probable solution to the "apparent singularity problem".
2007 so by now he is about 28 which means if his interest lasted and he
was any good at mathematics he will be a tenure track professor by now!
This thread was built on from a discussion 16 years ago in order to demonstrate that there is nothing new to counter the view that certain supernova stars represent the emergence of a solar system rather than the demise of a star.
On Saturday, September 16, 2023 at 4:18:26 PM UTC+1, Martin Brown
wrote:
On 16/09/2023 00:11, J Birch wrote:
Sitav, Be impatient! I asked the same questions 2/3 of a century
ago, of my father, a librarian with an inquiring mind. Never the
less, it has taken almost that long for me to approach a
moderately satisfying understanding of my own, and a probable
solution to the "apparent singularity problem".
Have you seen the date on the post that Sitav made? He was 12 back
in 2007 so by now he is about 28 which means if his interest lasted
and he was any good at mathematics he will be a tenure track
professor by now!
Mathematicians, as the mathematician Pascal once noted, are hopeless
in perceptive matters and that forms a large part of astronomical observations, interpretations and conclusions-
" These principles are so fine and so numerous that a very delicate
and very clear sense is needed to perceive them, and to judge rightly
and justly when they are perceived, without for the most part being
able to demonstrate them in order as in mathematics, because the
principles are not known to us in the same way, and because it would
be an endless matter to undertake it. We must see the matter at once,
at one glance, and not by a process of reasoning, at least to a
certain degree. Thus it is rare that mathematicians are perceptive
and that men of perception are mathematicians, because mathematicians
wish to treat matters of perception mathematically and make
themselves ridiculous, wishing to begin with definitions and then
with axioms, which is not the way to proceed in this kind of
reasoning. Not that the mind does not do so, but it does it tacitly, naturally, and without technical rules; for the expression of it is
beyond all men, and only a few can feel it." Pascal, Pensees
When Pascal uses the term " only a few can feel it", he means it as
the balance between geometry and perception of motions is central to conclusions of any structure or series of events.
With 21st-century imaging, genuine observers would begin to find the
wordplay and voodoo to be uninteresting and those who practice the
bluffing are best left to themselves and those who know no better.
The balance between pentagonal and hexagonal geometry is not quite the same thing as a soccer ball which uses a combination of both-
https://media.geeksforgeeks.org/wp-content/uploads/football-157930_960_720.png
| Sysop: | Keyop |
|---|---|
| Location: | Huddersfield, West Yorkshire, UK |
| Users: | 493 |
| Nodes: | 16 (2 / 14) |
| Uptime: | 29:44:02 |
| Calls: | 9,739 |
| Calls today: | 29 |
| Files: | 13,741 |
| Messages: | 6,183,038 |
| Posted today: | 2 |
