black holes

How dense can we humans make an object? I mean, if we put an object in a diamond vise or
something and squeeze it really tight and give it nowhere to go but 'in,' can we start to make
objects with extremely high densities? Are those object stable, or upon release, do those objects
expand to less dense structures?

On a similar note, how much mass would a black hole the size of a marble have? What would
the radius of its light-absorbing capacity be?

Nemesio

Originally posted by Nemesio
How dense can we humans make an object? I mean, if we put an object in a diamond vise or
something and squeeze it really tight and give it nowhere to go but 'in,' can we start to make
objects with extremely high densities? Are those object stable, or upon release, do those objects
expand to less dense structures?

On a similar note, how much mass woul ...[text shortened]... size of a marble have? What would
the radius of its light-absorbing capacity be?

Nemesio

How dense can we humans make an object? I mean, if we put an object in a diamond vise or
something and squeeze it really tight and give it nowhere to go but 'in,' can we start to make
objects with extremely high densities?

I don't know the answer to the first question but to the last one I have a good idea. I think that process can't be done because materials have natural limits to how much they can be squeezed, stretched and whatnots. So if you pass the squeezing limit of the given material the material will break down. What happens to stars for them to break down is that the squeezing process isn't mechanical but gravitational. SO matter doesn't have a chance to break.So if you could get a way for things to be squeezed in a non mechanical way, in principle you could squeeze them into the point of becoming a black hole.


On a similar note, how much mass would a black hole the size of a marble have? What would
the radius of its light-absorbing capacity be?

Just solve the formula for the radius for the mass and you'll get an answer. m=rc^2/(2G). Estimating a 1cm radius for a marble (or 0.01m) we get the answer m=6.74*10^24Kg... Gulp
As for the radius of the light-absorbing capacity I think you mean what is normally called the event horizon. This is the region in space-time surrounding a black hole that marks the absolutely no turning back point. If cross it you'll end up on the black hole's singularity. Now this depend on the fact if the black hole has angular momentum or not. The no angular momentum case has both radius equal, but the rotating black hole case have different values for the two radii. Both are computable and have well known formulas (but I don't remember the formula for the rotating black hole) and if you do a google search using these terms I'm sure you'll find some good explanations. 😉

Consider joining Club 39

Originally posted by adam warlock
Estimating a 1cm radius for a marble (or 0.01m) we get the answer m=6.74*10^24Kg...

If you did the math correctly, that's just amazing. According to wikipedia, the mass of the earth
is 5.9736×10^24 kg, which means a marble-sized black hole has more mass than the earth by
about 13%. That's breathtaking.

Nemesio

Originally posted by Nemesio
If you did the math correctly, that's just amazing. According to wikipedia, the mass of the earth
is 5.9736×10^24 kg, which means a marble-sized black hole has more mass than the earth by
about 13%. That's breathtaking.

Nemesio

The only math I had to was algebra. Then Mathematica did the calculation.
But black holes truly are dense. Not as dense as Bush, of course, but they are dense.

Originally posted by adam warlock
Not as dense as Bush, of course, but they are dense.

On that subject, why do we simultaneously call some people 'air head' and 'dense'?

Originally posted by Nemesio
How dense can we humans make an object? I mean, if we put an object in a diamond vise or
something and squeeze it really tight and give it nowhere to go but 'in,' can we start to make
objects with extremely high densities? Are those object stable, or upon release, do those objects
expand to less dense structures?

Solids maintain their structure via the forces between the atoms involved. There are various different ways to fit atoms together (molecules) and each way has a particular energy. The atoms tend to look for the lowest energy format.
Some types of molecule have more space than others. A few have more than their liquid form (like ice). If you compress ice, it melts.
However, most atoms cannot get closer than a given distance without overcoming the repulsion of the nucleus'.
If you compress two atoms much further than that, the nucleus' must combine creating a nuclear reaction. I do not know if that can be done but slow compression. The usual method is to create 'compression' by accelerating the particles to high speeds then smashing them into each other. But since the compression is not maintained they usually decay quite quickly.
I believe that a Neutron star is a star in which the the atoms nuclei are all squashed together to form one massive atom with an unimaginable atomic number. It still does not necessarily form a black hole.

On that subject, a black hole smaller than the earth would probably need to have a higher density than an atomic nucleus.

Originally posted by twhitehead
Solids maintain their structure via the forces between the atoms involved. There are various different ways to fit atoms together (molecules) and each way has a particular energy. The atoms tend to look for the lowest energy format.
Some types of molecule have more space than others. A few have more than their liquid form (like ice). If you compress ice, ...[text shortened]... smaller than the earth would probably need to have a higher density than an atomic nucleus.

Hmm. I only took physics through calculus-based classical mechanics, and those maths I've long
since forgotten (about half my life-span ago). Maybe, then, you can walk me and anyone else
reading along how black holes form. I'm guessing from what you said, that the nuclear forces
involved in repelling atoms away from each other make it impossible for something with as little
mass as the earth to form a black hole. That is, a neutron star, while dense, lacks the sufficient
mass to create the gravitational forces required to overcome the nuclear forces and achieve
the density of a black hole.

Or did I not follow?

Nemesio

Originally posted by twhitehead
On that subject, why do we simultaneously call some people 'air head' and 'dense'?

Language idiosyncrasies. 😕

Originally posted by Nemesio
Hmm. I only took physics through calculus-based classical mechanics, and those maths I've long
since forgotten (about half my life-span ago). Maybe, then, you can walk me and anyone else
reading along how black holes form. I'm guessing from what you said, that the nuclear forces
involved in repelling atoms away from each other make it impossible for so ...[text shortened]... he nuclear forces and achieve
the density of a black hole.

Or did I not follow?

Nemesio

I too only took those physics courses that were part of my maths degree, but I have had an interest in cosmology and read a little about it since then.
As far as I know, black holes only form in two scenarios.
1. When a very large star collapses. (or two stars combine etc).
2. When high energy particles strike each other (as in the LHC or the atmosphere) but these only last for very brief moments.
Black holes slowly decay if they do not have a source of matter feeding into them so it is possible for black holes the mass of the earth to exist - thought they would have been much bigger when they formed.

I believe that stars go through various stages using various types of fuel - for example when all the suns hydrogen is converted to helium, it will enter a different stage in its life.
At present, the heat generated by the nuclear reaction is actually a large part of what stops it from collapsing to a smaller size.
The stages a star goes through depend a lot on its mass and whether or not that mass can overcome the various nuclear forces involved.

Originally posted by twhitehead

I believe that stars go through various stages using various types of fuel - for example when all the suns hydrogen is converted to helium, it will enter a different stage in its life.

Fascinating. Got a link for that?

Originally posted by Bosse de Nage
Fascinating. Got a link for that?

http://en.wikipedia.org/wiki/Stellar_Evolution
http://www.astronomytoday.com/cosmology/evol.html

And a little more technical: http://www.astro.umd.edu/~miller/teaching/astr606/

Originally posted by Bosse de Nage
Fascinating. Got a link for that?

Try this
http://en.wikipedia.org/wiki/Formation_and_evolution_of_the_Solar_System
go down to the heading "The Sun and planetary environments"

Or for general information about the life cycle of stars.
http://en.wikipedia.org/wiki/Stellar_evolution

According to the last link, it is estimated that when a star reaches the neutron star stage and at that point is greater than between 2 and 3 solar masses then it will form a black hole.
It must be noted that stars loose a lot of thier mass during thier life time so it would have to start out a lot bigger than our sun.

I saw a big hole and I had to paint it black.
It was a damn big hole and now its painted black.
I wana see you paint it paint it paint it black as cole.........
Roling Stones 1966.

Now has anyone found proof that there is water on Uranus?
That is something I'd realy like to know.

Originally posted by bluzdog
I saw a big hole and I had to paint it black.
It was a damn big hole and now its painted black.
I wana see you paint it paint it paint it black as cole.........
Roling Stones 1966.

Now has anyone found proof that there is water on Uranus?
That is something I'd realy like to know.

Well, he did just have an enema.....

Originally posted by Nemesio
How dense can we humans make an object? I mean, if we put an object in a diamond vise or
something and squeeze it really tight and give it nowhere to go but 'in,' can we start to make
objects with extremely high densities? Are those object stable, or upon release, do those objects
expand to less dense structures?

On a similar note, how much mass woul ...[text shortened]... size of a marble have? What would
the radius of its light-absorbing capacity be?

Nemesio

I'll try to answer parts of the "How dense can we humans make an object? I mean, if we put an object in a diamond vise or something and squeeze it really tight and give it nowhere to go but 'in,' can we start to make objects with extremely high densities? Are those object stable, or upon release, do those objects expand to less dense structures?" paragraph...

If you press a big chunk of coal to more and more extreem pressure you get a diamond, alright. We all agree to this. (My question is, what will happen with the equipment, part of this has to experience pressure as big as the diamod too, wouldn't it?) When we release the pressure, the diamond will stay stable. We know that, it has been done.

What happen if we go further: We give the chunk of fomer coal a bit more preassure. (We don't have the technology, but we, for the sake of discussion, pretend we have.) The atoms will go tighter and tighter. If the atom structure doesn't find a way to restructure itself (*), then we have an atomic counterforce. When we release the pressure, the chunk of matter will return to its previous stabel form, it will not continue in it's pressured state (if it's not stable as (*)).

Suppose you press it hard enough to form a bit of a neutron star matter, neutronium. Neutronium is a kind of matter where the atoms is so close to eachother so they are infact touching eachother. When an electron touches a proton, they combine into a neutron. So infact the whole chunk becomes neutrons and only neutrons. I guess is that neutronium is not stable under atmospheric preasure and normal temperature.

If we now press further, then the neutrons glides into eachother, and after certain limit, the quarks will blend into eachother so the neutron loses its individuality. Now we have a soup of quarks. My guess this is not stable either.

If we press further everything will be like a black hole. Not even this is stable. Release the preassure and everything will explode in order to be normal matter again. In this case a BigBang-like decompression that forms now Hydrogen atoms.

So, my guess is that man-pressured matter will not be stable, but in space neutronstars and black holes are stabel. Why?

The answer is gravitation. In the gravitational field from the object itself, its preassure will retain. But what will happen if gravitation suddenly stops? Then neutron stars will explode, black holes will explode, stars will explode and die, what about solid big things, like solid planets? (I don't know.) (Btw: The earth is not solid, so it will certanly fly away in parts due to centrifugal forces.)

But of course, gravitation is stable, will not stop, therefore neutron stars, and black holes, etc, are stable.

What about the black holes they are pruducing in CERN? They are not stable, because there are not gravitation enough to hold it together.

Now, much of the above is guessings of me. I might be wrong here and there. So you are allowed to give alternate explanations if you like.