Naked Science Forum
Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: dagonweb on 03/04/2009 14:31:52
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I cannot my original post for some reason. Testing If I can post something else.
(later) No I still cant. I can modify, but I cannot place the original text.
Can a moderator please email me? Dagonweb at gmail dot com.
(later) Aha! *at* is disallowed!
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I have a LOAD of bizarre questions. Bear in mind when answering I am all but BLIND on mathematics,
despite my best efforts. It is neurological and I don't really like formulas. I am however a
slight bit better than average on plastic visualisation, so bear with me. When I have a question,
I will use this ♥ icon so if you see it, and have a clue,
I am curious what your take on this is. [p]
Imagine 2 neutron stars, both about 95% of mass required to collapse to a black hole, both rotating
very fast (probably both having exploded as supernovae) and spiraling together. Their rotational speed
is maximum naturally occuring, i.e. well in the hundreds of rotations per second. They swirl around
each other, and then finally start touching. [p]
♥1 How fast does this happen, second, weeks, days? i.e. assuming these
objects are at some point a million kilometers apart, how fast to their orbits decay due to tidal heating,
how would that manifest in visible phenomenon, etc. ? [p]
♥2 are there other effects causing their orbits to rotate (gravity
ripples?) and how can you sense these "from a safe distance" ? Is this emanation of rotational energy
visible? Would it heat nearby interstellar gas in some way? [p]
Ok, the pulsars (or quark stars, probably) start intersecting and merge. I suppose that'll be very
violent in nature. In the densest regions between them a schwarzschild radius starts forming, and eating
up all stuff around. The remaining neutronium (quarkium?) globs tumble or slosh like a wave around the
singularitous core region and after some time gulp inside. [p]
♥3 What would you see? A hypernova like flare event? Or the
neutronium material just cascades in... silently? Can neutronium be flattened out into a literal
accretion disk? (!!!) (wouldn't that be an attrition disk???) [p]
♥4 Where does all that rotational energy go? Common sense suggests
that at some time these objects would have motion energies bigger than the speed of light. That
cannot be clearly... That would suggest the schwarzschild radius to become in fact a flattened out
disk instead of a globule. [p]
♥5 How far can this ratio between polar diameter and equatorial
diameter escalate? I don't see these objects tear apart but I can see ... Can I expect pancake
black holes? Or rings? [p]
♥6 ... a violent sloshing around of material very close to the
event horizon... or an amount of material never actually falling in, staying in the stable rotational
zone. I that possible? Can you have a trail of free neutronium globules being sloshed outward from
such an event, rotating the black hole at greater (safe) distances? [p]
♥7 What happens when neutronium 'escapes' to a region of relatively
low gravity, such as less than 1% of the original gravity of the pulsars? [p]
(https://www.thenakedscientists.com/forum/proxy.php?request=http%3A%2F%2Fwww2.hku.nl%2F%7Eruud7%2FColliding%2520neutron%2520stars.jpg&hash=561b7a48bb15356fa5282e5a6f1252fe) [p]
♥8 would (theoretical!?) compositional sections of a black hole
have "virtual" rotation speeds inside a black hole. If not, where does the movement energy go? If yes,
can we assert that sections of a black hole are moving "inside" the black hole at speeds very close
to the speed of light? Or precisely "at" the speed of light, relativisticly speaking? Can these regions
inside a black hole have compositions, physiologies, structures? Can these regions inside a black hole
remain in a lasting (though not eternal) motion of they are about as heavy as an equal part, even
though these motions would be regarded as frozen in time as seen from outside the black hole? [p]
♥9 ...could a super advanced civilization speed up a black hole
"virtual rotation" faster than the speed of light? What would that do? Would it open up a black hole
to become 'visible' again in a narrow equatorial band?? I can imagine this would be counterproductive
if you'd do this by throwing in objects with a high speed (it would make it more and more different)
but what if super-advanced civilizations could use gravity waves to make [discrete portions of] a black
hole thats already very close to a rotational speed of 1c to move fast enough to achieve escape
velocity? [p]
♥10 what if I were able to adjust the speed of light in a region of
space, at will, and increase the speed of light in and around a region of black hole matter to
a high enough level as to make the black hole visible again, what would become observable from
the outside - would the black hole just explode, or has the escape velocity literally become
infinite? ... or didn't the object inside the black hole get enough time to literally collapse into
a form of matter that is stable (sub-quarkium?) at gravities higher than the one required to form a
black hole - would it instantaneously evaporate into gamma rays when such a thing happens? [p]
♥11 What happens with particles in an entangled state whose
one half falls in a black hole? What happens to the entanglement state of the other? [p]
♥12 ...could we engage in "gravity" astronomy when looking
at differing densities inside a black hole, just as we do when measuring densities in a satellite
which orbits the earth? [p]
♥13 A friend told me the mass of X-ray light leaving a black hole
at 45 degrees to a accretion disk is literally "heavier" than most types of matter we know - not
particles - photons. Is this true? [p]
♥14 I heard about planets having formed (or wandered) within less
than an AE of black holes and neutron stars. If those planets formed of post-supernova debris, what
kind of features, composition would they have ... Would these postnova debris planets be composed of
very high portions of partilarly heavy material, such as transuranids? [p]
♥15 Would that cause these planets to act as nuclear decay
reactors (as some say the earths core does) thereby emitting energy, their surfaces composed of
molted iron? ... Or heavier surfaces matters? [p]
♥16 ... and what kind of radiations do these planets around a pulsar
get from the main star? ... at 1AE? [p]
♥17 ...and what kind of radiation to these planets around a stellar
black hole do these planets receive? ... at 1AE? [p]
♥18 Do these planets literally glow in X-ray cooking? [p]
♥19 Would planets around a pulsar have an "aurora globalis", literally
a particle aurora covering the planet in the same way a coal glows in an open fire? [p]
♥20 what kind of visible aurora would be visible around a pulsar/
neutron star/black hole from a distance of 1 AE? Would an observatory be able to discern field lines,
glows, radiant plasma, pr anything of that nature? [p]
♥21 Can a black hole already be asserted to be in a state of
inflation (EXPLOSION!), however - it takes an eternity for us to notice, or we notice it if in
kosmological terms the speed of light were ever to climb up? Say what if the speed of light
be ten or hundred times what it is today, would meta- black holes be stable, extremely dense,
still collapsing, or can at a certain density these thing turn into very dense bright objects,
or would they go WHOOSH very hard and very loud? [p]
If anyone wants to ask clarifications on these scandalous questions, feel free to email me at
dagonweb at gmail dot com. [p]
I know I have committed at least several acts of heresy (and I like doing that)
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No one?
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Try to take the ones you first would like to be discussed, and please keep it to no more than three at a time, it's rather difficult to answer your ideas as they are in such a 'jumble', no disrespect meant by that. And be sure to explain the steps leading you to such a question in a simple manner. If you find that impossible you might need to reconsider your question :)
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I'd suggest posting the Qs one at a time, separately, and title the thread with the question you want us to look at - this is forum policy anyway, and we know that approach translates into far more answers far more quickly.
Chris
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Ok...! question number one:
I understand that neutron stars swirl around each other at breakneck speeds. Let's assume I would be on a spaceship one AE away from two pretty big neutron stars (or pulsars) that would be very close (say, 90%) of the mass required to make black holes - both of them. Let's assume they orbited each other at about a distance of 10 million kilometers. Now my first question is - would I see a decay in orbit due to tidal effects? Where does this energy go, and how fast would I see this orbit decay? Would energy "be radiated away" in some other way? Would I 'notice' gravity waves of some sort?
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A black hole is defined as an object whose escape velocity exceeds the speed of light. the mass of a black hole can vary "The supermassive black hole at the centre of NGC 4649 is a monster. It is about 3.4 billion times the mass of the Sun and a thousand times bigger than the black hole at the centre of the Milky Way." http://www.universetoday.com/2008/07/18/how-do-you-weigh-a-supermassive-black-hole-take-its-temperature/
So to answer that question I think you first need to define their masses, not only how near they might come in weight to a BH in percent. also you need to define if they are spinning or not and their angular velocity's. One might expect that the angular velocity will be a result of their respective mass, but I'm nor sure that this is a rule without exceptions.
As I understands it they are creating a 'slope' circling each other, and that will naturally draw them together around some common 'center'. And the tidal effects, which consist of the effect that gravity's pull is the strongest on the side they have turned against each other at any given moment, I don't see as that important.
I might be wrong, but that it has a stronger effect on Earth I believe is due to the 'dragging effect/inertia' of our oceans that in their turn slowly retards Earth's rotation around its axis. It's effect on two massive body's orbiting each other seems harder to see?
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Lets stay with spinning neutron stars (as they all do) and lets assume they both went supernova in very rapid succession, some 100K years ago.
My question is largely focussed on something I read somewhere - I understand that neutron stars "fall to one another very fast". Very fast relative to other stars? I don't know. What I understand is is that there is "a gravity wave mechanism", which I am trying to have someone explain to me here, that makes these objects lose angular momentum when in respective orbit. A moving neutron star is very heavy. So to somehow have kinetic energy being canceled out is a very important feature. So I am dying to know what you would SEE if I were an observer, looking from 1AE to these two neutron stars whirling together faster and faster and faster.
"A black hole is defined as an object whose escape velocity exceeds the speed of light"
Huh? Black hole. No....... two neutron stars very close in mass (lets say - 90% either of them) to the point where they'd collapse into a black hole. They aren't black holes. But make either of them just a tiiiiiny bit heavier and they'd collapse.
"As I understands it they are creating a 'slope' circling each other, and that will naturally draw them together around some common 'center'. And the tidal effects, which consist of the effect that gravity's pull is the strongest on the side they have turned against each other at any given moment, I don't see as that important. "
Slope? What do you mean 'slope'. What exactly 'slopes' ??
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Sorry, been up to late lately :) Never the less there are black holes rotating ech other. And massiveness do matter, neutron stars and Black holes alike.
We'll see if someone can address your question of tidal forces, the 'slope' I'm referring too is the natural result of gravity, when not treated as a 'force' but as a property of spacetime. To treat it as something 'carried' you will need 'gravitons' they are only defined as a 'must'¨as I understands it in String theory, even though our standard model seems to imply them. And they are as yet unproved.
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As for stars collapsing into black holes there are two sides. One that believe that black holes are constantly created. The other one states that the only time they could come to be was at the Big Bang.
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sorry, I am really tired, I answer without thinking here. A neutron star won't ever become a black hole, that is due to the the Pauli exclusion principle (no two fermions, (neutrons) can exist in the same state) To break that rule you need a Black hole as this is what defines a 'singularity', that place from where nothing really can be known. and where matter 'disappears'.
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If I were to observe a heavy neutron star, is it just a pinprick of light - something like the sun, just
small, very round and featureless? ...
... or would I see something happening around it. Fieldlines? Distortion? An accretion disk? Polar jets?
How bright would all respective elements be? How close can a shielded spaceship get to a neutron star,
approaching it from the equator. How stable and how solid can an accretion desk be, especially when watched
from the outside (edge on). Saturn's rings are fairly stable, right? Is an accretion desk pushed outward
by a neutron star (or black hole) because of radiation emerging from the object? How much would an accretion
disk be heated?
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Q 11. we seem to be discussing at another thread here dagonweb. Missed that you had that idea. What you would see should be a naked object where from light can reflect, however red shifted that light might be walking up the grawity well. Then there should be other effects too if it's spinning naturally, maybe you would be able to see 'around' the planet depending on the framedragging involved, in fact hiding it presenting a distorted image of the stars behind it instead? So you seem to have two 'forces' acting on it. One is the Neutron star's mass in itself, the other is its spinning 'angular motion' which adds to its 'relative mass' and creates framedragging.