Παρουσίαση
του άρθρου****Αμφισβητούμενο
μαύρο τρύπα
Γαλλική μετάφραση :
Αμφιβολίες
για την ύπαρξη των μαύρων τρυπών.
Συγγραφείς :
Jean-Pierre
Petit, Αστεροσκοπείο Μασσαλίας
| επιστήμες | jp-petit.com |
Pierre Midy,
CRI Orsay.
Για
να μεταβείτε απευθείας στο επιστημονικό άρθρο.
Αυτό
το έργο αποτελεί τα αποτελέσματα δέκα ετών προσπάθειας. Για τα τελευταία 30 χρόνια, οι αστροφυσικοί έχουν μόνο έναν όρο στα χείλη τους «μαύρες τρύπες». Το θέμα fascinate το κοινό και several books have already been devoted to it. Ωστόσο, η observational confirmation is still lacking : οι μαύρες τρύπες «λάμπουν με την απουσία τους».
Και όμως το σύμπαν είναι ευρύ. Μόνο ο γαλαξίας μας περιέχει τουλάχιστον 100 έως 200 δισεκατομμύρια αστέρια.
Η
ύπαρξη certain objects has been shown by observation, quasars for example. Γνωρίζουμε πλέον περισσότερα από τέσσερα χιλιάδες από αυτά. Αυτό δεν σημαίνει ότι κατανοούμε
αυτά τα αντικείμενα completely, πώς σχηματίζονται, πώς εξελίσσονται και η διάρκεια ζωής τους. Στην πραγματικότητα δεν γνωρίζουμε τίποτα για αυτά. Είναι απλώς catalogued in the
same way as were «nebulae» στην εποχή του αστρονόμου Messier.
Φαίνεται ότι certain quasars live in the centre of formations of the type galaxy. Αυτοί οι γαλαξίες έχουν ένα «active core», που θα μπορούσε να σημαίνει οτιδήποτε και τίποτα ταυτόχρονα· δεν γνωρίζουμε τίποτα για τη φύση της δραστηριότητας, ποια είναι η πηγή ενέργειας, για παράδειγμα.
Η σύγχρονη αστροφυσική φαίνεται να ικανοποιείται με little. Στην ερώτηση :
- Τι
είναι ένα quasar ;
Ο
αστροφυσικός απαντά :
- Είναι
ο πυρήνας ενός active galaxy.
Και
στην ερώτηση :
- Τι
είναι ένας active galaxy ;
Θα
απαντήσει :
- Είναι
ένας γαλαξίας με ένα quasar στο κέντρο του...
Recently,
a few years ago, discovered «gamma flashes», ένα την ημέρα. Το εξώφυλλο του γαλλικού περιοδικού Ciel et Espace (Sky and Space) once had the
headline «gamma flashes : a mystery solved at last». Απάντηση, στις στήλες του περιοδικού : ένα μικρό, brilliant spot has just been observed at the position of a detected gamma flash. Meaning : solving a mystery means knowing that areas of the sky that emit flashes also emit light....
Δεν είναι αυτό λίγο .. poor ?
Αντίθετα,
other objects exist whose existence was surmised, often with good precision,
before their observation. Το typικό παράδειγμα είναι η supernova, described in
1931 by the American astrophysician (of Swiss origin) Fritz Zwicky during a
famous conference at Caltech, USA. Ο Zwicky εξήγησε τότε ότι sufficiently
massive stars, say with masses above twenty solar masses, should come to a paroxystic
end with an increase in power in the space of a few days, το whole phenomenon
taking place over twenty days or so. Ήταν μια remarkable prediction, though
it wasn't taken seriously at the time. Ωστόσο ο Zwicky, tenacious, discovered
the first supernovae. Σήμερα γνωρίζουμε several hundred. Το ίδιο ισχύει για
neutron stars, identified subsequently with pulsars (rotating neutron stars)
and white dwarves. Αυτή η species too has several hundred identified individuals.
Η
black hole was proposed as an answer to a problem : what becomes of a neutron
star that exceeds a certain «critical mass». Αυτά τα neutron stars,
clearly identified, resemble enormous nuclei of atoms, without protons. Why
are these objects composed exclusively of neutrons?
Θεωρούμε
τα neutron stars ως όσα απομένουν από τον iron core of a massive star after it
has exploded. Ένα massive star είναι ένα αστέρι στο οποίο several types of fusion take place during its lifetime. Τελειώνει παράγοντας iron which cannot take part
in any further exo-energetic fusion reaction. Αυτός ο iron, heavy, falls to the
centre of the star therefore, like ash in a fireplace. When the star suddenly
runs out of fuel (as Zwicky understood) it collapses on itself – 80,000 kilometres
per second (give or take a kilometre per second of course). When falling onto
the iron nucleus this gaz is strongly compressed. Not only does it bounce off,
but several fusion reactions are produced and which no longer need to be exo-energetic
as energy comes from the brutal contraction of the star on itself. All sorts
of nuclear species are created, including many radioactive atoms of extremely
variable lifetimes. Το 1987 η explosion of the star Sanduleak, in the Magellan
cloud, gave definite confirmation of the existence of such phenomena (only 150,000
light years away).
Το
phenomenon crushes the iron core completely by dislocating its atoms. Γίνεται
so compressed on itself that electrons no longer have sufficient space to move
between nucleons. Trapped, they therefore combine with protons to give neutrons
and neutrinos.
Normally, when we compress a gas, the phenomenon known as pressure counteracts
the compression. Αυτό ισχύει επίσης για ένα liquid ή ένα solid (everything is compressible).
Αυτό συμβαίνει όταν γεννιέται ένα young star. Το proto-star είναι μια mass of
gas which settles on itself. Αλλά doing so it heats up and the force of pressure
limits contraction. Είναι ένα poor radiator αλλά πρέπει να lose energy by radiation
(infrared) before it can contract enough to become a real star. Ωστόσο, if its
mass is insufficient it will become a «big Jupiter» (this giant planet
continues to radiate more energy than it receives from the Sun but will never
become a star).
When the explosion of a supernova compresses the iron nucleus, the latter evacuates
its energy by emitting a fantastic quantity of...neutrinos. Εδώ το scenario
changes completely : radiative cooling is instantaneous because the neutrinos
can escape without difficulty. No counter-pressure therefore. The lump of iron
is crushed lamentably. Just a pile of neutrons remains, pressed up against each
other like Japanese in the subway during rush-hour.
Why a critical mass? Because the neutrons cannot take a pressure greater than
a maximum value. Like electric lightbulbs piled up in a mineshaft. After a certain
level of bulbs the glass will break and a pile of broken glass will fall to the
bottom of the shaft.
When a neutron star has a mass a little greater than twice the mass of the Sun,
pressure in its core becomes too great. The neutrons can no longer support it.
It is then supposed to collapse on itself and no known physical phenomenon is
able to go against this «gravitational collapse». A distressing perspective
for an astrophysician.
Even before it explodes a neutron star is a «relativist», as opposed
to a «newtonian» object. Αυτό φαίνεται από το aspect of the trajectories
of the «reference-particles» near a mass m (an atom, for example).
Γνωρίζουμε ότι το phenomenon of space-time curve brings about a precession of the
elliptical orbit of Mercury. Αλλά η precession είναι minute. Ωστόσο, το following
figure, developed from computer calculations, shows the important precession
of a quasi-elliptic trajectory around a neutron star.
Άρα,
δεν τίθεται θέμα να περιγράψουμε ένα neutron star με «newtonian material».
Το
calculation programme είναι relatively simple και one day, when I have the time,
I'll put it on the site so that you can play with it, and show the gravitational
lens phenomenon (very exaggerated in the following) :
Άρα,
καθώς τίθεται θέμα να περιγράψουμε το destiny of a neutron star reaching criticity,
a «field equation» needs to be used, that of Einstein.
S
= c
T
T
είναι ένα «tensor» που describes the local content in «matter energy».
Το tensor είναι nil on the exterior and non nil on the interior. Η geometric
solution must therefore be deduced from two equations.
Για το interior :
S
= c
T
για το interior
S
= 0
Solutions
for this type of equation are called «metrics». Ωστόσο δεν matters
what form the objects take. As well as that they are «tensors»,
και για να κατανοήσουμε what a tensor is, good luck ... It took me quite a while.
The
Sun is associated with a local «geometry», which is the solution for the
two equations. Η πρώτη describes the interior of the Sun and the second
the void around it. Ωστόσο, μπορούμε να describe only a sort of «ideal sun»
which consists of a sphere filled with matter of constant density. Αλλά αυτό
είναι better than nothing. Αυτές οι solutions have mathematical expressions which we
won't go into here. They will not mean anything to you. Each has its own «personal
pathology». Ας ονομάσουμε rn the star's radius, of constant density r. From
this density r, and the value c of the speed of light, we can calculate a first
characteristic radius, «R circumflex» :
Η
interior geometric solution είναι «non-pathological» if, and only if,
the value of radius rn είναι inferior to this critical value.
Με
τα same data μπορούμε να calculate the second characteristic radius :
που ονομάζουμε «Schwarzschild
radius» Rs. Η exterior solution, που makes reference to the «void»
surrounding our star of constant density r and constant radius, θα είναι non-pathological
if, and only if, the value of the star's radius rn είναι superior to this characteristic
length. When grouping both, είναι necessary that :
Η
quantity to the right depends on the star's density (between
1015 and 1016 grammes
per cubic centimetre). At constant density, η quantity to the left increases
as the cube of the radius Rn of
the star.
Αυτό
είναι valid for the sun, considered to be a star of constant density at first approximation.
Τι εννοούμε με «pathologies»? Όλα : quantities below radicals
that become negative, denominators that become nil. Βλέπουμε therefore that
a star of constant density cannot be described by the following type of stationary
solution :
Το «Schwarzschild radius» του ήλιου είναι 3,7 km : well inside (rn
). Μπορείτε να enjoy yourselves calculating it, given that its radius is 695,000
km, η value of the second critical radius «R circumflex» είναι higher.
Αν
ήταν θέμα του ήλιου, on the scale of the figure, το Schwarzschild radius
(3,7 km) θα ήταν just a point και το radius «R circumflex» θα went
way off the sheet. Η above figure refers more to a «subcritical neutron
star».
Πώς
take place η «climb to criticity»? It suffices to add layers of neutrons,
increasing in constant density (we liken the neutron star to, if not a solid,
at least a drop of practically incompressible fluid).
Obtained
the above curves simply by using the formula shown. The star's radius increases
but the «Schwarzschild radius» catches it up. And the two meet when
rn
reaches the value «R circumflex». Then, on the star's surface, the
quantity of sub-radicals becomes negative, denominators become nil etc. This
if the mathematical, geometrical translation of criticity. Which simply means
that it is impossible to describe the star using either or both the combined
geometrical solutions obtained from the Einstein equation with the second member
non nil (interior) or nil (exterior). The characteristic maximum value of this
radius is about 20 kilometres. The neutron star's density can be calculated
from this.
But
there is something that is little known, including among «cosmic men»,
even though it comes from work done during the 40's : there is another criticity,
of physical nature this time, which appears just before the star's radius reaches
this value. It is an extremely close value being inferior by just 5%. But when
the star's radius reaches it or, which comes down to the same thing, the mass
reaches a value double that of the sun's mass, pressure at the centre of
the star becomes infinite , by virtue of a «TOV»model developed
in the 40's by Tolman, Oppenheimer et Volkov (the Oppenheimer of the bomb).
Pressure
inside a neutron star according to the distance from the centre for different
values of object mass.
Αυτό
είναι fundamental piece of data for us.
Hereafter
η evolution of the presure, inside the neutron stard, versus the distanceto
its center, for different masses :
...Maybe
scientists, like others, do not ask themselves questions to which they think
they cannot give a reply. Πώς one reply to the question :
- What
happens in a milieu where, at a certain point, pressure suddenly becomes infinite?
But
nobody asked the question, at least not in that way. Apparently it caught nobody's
eye. Many cosmology specialists with whom I have spoken were unaware of this
aspect.
Ας
return to «the story of the black hole». Could say : The implosion
phenomenon of a destabilised neutron star είναι an unstationary phenomenon. Ας
build therefore an unstationary solution for the ensemble of the two equations
above. Ωστόσο, δεν γνωρίζουμε πώς να, in a credible manner. So theoreticians
turned towards the «exterior solution» (that which describes, for
example, the geometry at the exterior of the sun and which becomes «pathological»
at the Schwarzschild radius of 3.7 km).
- In
other words «take away the sun» και let us explore the properties
of this geometry. Like that...
- But
it's a solution that refers to an empty universe ?!
-
Take no notice, let's see what we get ...
Study
began on the radial trajectories of objects in free fall towards what would
be, under these conditions, «a black hole of solar mass» of 3.7 km
diameter. The variable t was retained, it was meant to refer to the time experienced
by an «exterior observer», a good earthling looking at the sun they
had just conjured away. It was discovered that the time of freefall of each
test particle, measured according to this time, became infinite. Ωστόσο, if
we attached a clock to the said particle, it would arrive at the geometric centre
of the object in a finite time period.Theoreticians
therefore proposed the following vision : -
This stationary, exterior
solution finds a new, providential employment. In effect, gravitational collapse
does take place in a very brief period (about one ten thousandth of a second
for a destabilised neutron star). Ωστόσο, as the phenomenon seems to last for
an infinite time to an «exterior observer», a stationary solution
can be used to describe an eminently unstationary phenomenon.If there
are no Thrushes, we'll eat Blackbirds....Starting
from this idea, theoreticians began to ask themselves what would happen to matter
when it crossed the Schwarzschild surface. And there they found all the horrors
mentioned earlier. The particle's time became... pure imagination. The particle's
speed exceeded the speed of light. It becomes a tachyon, whose mass is ... imaginary
etc., etc.Some
even suggested (and you can find it in many books) that on the interior of the
sphere, the variable r transformed itself into time and the variable t into...
radial distance.
As Jean Heidmann, cosmologist
at Meudon, now retired, used to say :
- *When
the talk turns to black holes, you have to leave your common sense in the cloakroom...*
Under
these conditions, if we decide to forget common sense, where is the limit to
unreasonableness? Πώς decide to build a «physics of the unobservable».
Αυτό είναι η περίπτωση για «dark matter» about which anything and everything
is said and written, often at the rate of several dozen papers a day. Nobody
seems to have looked into the gemellary model, abundantly developed on my site.
Ωστόσο, some foreign researchers (China, Japan) seem to have picked up on it
well.
There
is news in this area. In 88-89 I published three articles in Modern Physics
Letters A (reproduced on the site) which launched the idea, unprecedented, of
a cosmology in which physical constants could vary, including the sacrosanct
speed of light c. Η idea «rediscovered» in 1993. Numerous papers
have been published since in very selective reviews such as Physical Review,
Classical and Quantum Gravity. There is already quite a large group of «constant
variers». Some of them have discovered my work on the Internet site. Many
of them were stupefied, even more so by the fact that the work emanated from
France, a country which has never got itself noticed through an important innovation
in cosmology, or even in astrophysics (fields that are typically German, Russian,
American or British). Contact was established in a very cordial manner. The
Chinese, not without humour, said that he had to get down his atlas to find
the whereabouts of Marseille and had «the impression of discovering an
unknown region of the globe».
Why
this digression ? Because, in our opinion, the vertiginous pressure increase
in the neutron star's core should alter the constants of physics and create a «hypertoric bridge»
between the universe and its twin. It is an idea that needs further study. This being said, if help is required in this
entreprise, it will most likely come from the «constant variers» who
have already crossed the line. For the time being we are the only «gemellarists»
but things might not always remain that way.
In our
opinion therefore, the gemellary context should completely change the scenario
for a destabilised neutron star. Ωστόσο, before we are able to propose a challenger
model, we must study the classic model of the black hole. That is what is being
done in this long paper. Things are not treated «in order». In one
section we carefully looked at Kruskal's work, showing the faults in his approach.
Everything
is motivated. In 1960 Kruskal had noticed that in the initial model (the «Schwarzschild
metric») the speed of light was nil on the sphere in question, the «horizon
sphere», alias the Schwarzschild Sphere, and set about curing this «illness».
But
how do you work on geometric solutions ? Can others be invented ? The answer
is no. I believe that the article shows clearly the arbitrary character of the
choice of coordinates. By its essence, a geometric solution is of «invariant
coordinates», it does not depend on the coordinates chosen. Imagine a soap
bubble. It is a surface. In one sense it is a solution to a field equation which
corresponds to the fact that the energy used in tension, to counterbalance a
constant pressure inside the bubble, is constant on all its surface. Στην ερώτηση :
- What
is the surface that reacts mechanically in way that can support internal overpressure
?
Η
reply is :
- It's
a sphere.
Αλλά
αυτή η sphere, a geometric object, exists independantly of the coordinate
system used to identify its points. Τώρα γνωρίζουμε ότι when using a system of
meridians and parallels we create polar singularities, apparently singular
points whereas in fact they are not. They are singularities induced by the choice
of coordinates. In the case of the sphere, by the way, these singularities are
inevitable. Η figure below shows a sphere and its marking system of latitude
and longitude coordinates.
Remark
: We can map a sphere, give it a marking system with two parameters using just
one pole. See the following figures :
First
mark, first family of curves to a parameter a obtained by cutting the
sphere in planes through a straight line tangent to one of its points.
This
is combined with the second family of curves obtained by****cutting
the same sphere along another straight line tangent to the sphere at the same
point, for example, orthagonal to the first.
The sphere,
thus mapped, seen from another angle which hides its unique singularity.
