APOD and General Astronomy Discussion Forum
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I'm afraid it's not possible to have the mass of the sun compressed into an object 300mm in diameter and have it remain stable. Once the total mass of the Sun gets compacted within it's own Schwartzchild radius (which is 3km), you have a black hole; nothing can prevent its further collapse.
Maybe be so, but! what is the steps from a neutron core to a blackhole.Even if it were somehow stable, it would still be inside an event horizon, and would technically be a black hole; it would behave exactly the same.
Well... that outcome is predicted by General Relativity, and I haven't seen anyone be able to poke holes in its predictions yet, not at the macroscopic scale. The problem is, once an object's mass falls within its own Schwartzchild radius, the escape velocity exceeds the speed of light. No force can hold up under that kind of gravitational field, as everything in the universe is governed by the light-speed limit (that we know of)... including all of the fundamental forces, which are what give structure and stability to matter.harry wrote:Hello All
qev said
I'm afraid it's not possible to have the mass of the sun compressed into an object 300mm in diameter and have it remain stable. Once the total mass of the Sun gets compacted within it's own Schwartzchild radius (which is 3km), you have a black hole; nothing can prevent its further collapse.
In this day an age i would not limit my thinking.
Well, if you're looking for density, it's total mass divided by volume. For the object you're proposing, it would be on the order of 1.4x10^32 kg/m^3, which is an utterly insanely high density, far beyond anything that could be stable under its own self-gravity. Remember that a neutron star of much lower density than this will collapse into a black hole.Let us think outside the circle and look for the answer. I need someone to look at the possiblities. This 300 mm ball is theoretical and would probably require a density of about 10^18 to 10^30
compared to a neutron star density of about 10^18 or there abouts.
So if we multiply 10^30 by 300mm we get some mad number which is greter than the width of our sun.
Well, there may be the 'quark star' stage, which has an estimated core density around 3x10^18 kg/m^3, which is roughly ten times more dense than the average neutron star's core density. But this is nowhere near the sorts of densities you're proposing.Maybe be so, but! what is the steps from a neutron core to a blackhole.Even if it were somehow stable, it would still be inside an event horizon, and would technically be a black hole; it would behave exactly the same.
Actually, that's the problem: we just don't know what the inside of a black hole looks like, or what happens to the matter that falls into it. Under General Relativity one gets a singularity, a point of infinite density and gravity, which physicists would like to avoid somehow, if they could. Until we have a decent working theory of quantum gravity, we'll never really be able to answer that question. It could very well be that all of the mass gets compressed down into a single 'super particle' or something equally bizarre. Who knows?A black hole is a state of matter that has the basic degenerated particals that make up all matter.
Its not a hole as so to speak of. But! just a massive compacted degereated particals.
I would not classify it as a singularity where all particals take up one point in space and time. I would assume that no two particals can ocupy the same space at the same time.
Preon stars are estimated to have densities exceeding 10^23kg/m^3. They're also much lighter than neutron stars, being generally thought to mass up to 100 times the mass of the Earth. From what I've read, if these things can exist, they would do so at the very edge of collapsing into a black hole, since at those densities the radius of the object is almost equal to its own Schwartzchild radius. I imagine these things don't hang around very long, if they even exist at all. Preons, as a theory, aren't terribly widely supported.Sorry my computer has not been fixed yet, and cannot search for preon stars and so on. Can someone do that and look at the possible size of a preon star in theory.
A preon star is generally thought to be much lighter than neutron stars, but the material that makes them up would be much denser. Very much like a one kilogram block of lead is much more dense than a thousand kilograms of water, but is smaller in mass.harry wrote:Hello All
Qev you are quite right in what you say and with bosons being able to occupy the same space.
A theoretical preon star would be denser than a neutron star and would not be lighter. This part of your writing I do not understand.
True enough! All we currently have to go on is General Relativity, and it tells us that things collapse to an infinity. Needless to say, nobody really likes that result very much.As for a black hole we can only assume what is happening inside from the progressive compaction of subatomic particals. I cannot see and infinite point in space. Maybe its just me until I have more info.
Thank you!Other than that your writing is great, I take my hut off.
Since the 1970's astronomers have known that Circinus X-1 produces radio waves as well as X-rays. A large 'nebula' of radio emission lies around the X-ray source. Within the nebula lies the new-found jet of radio-emitting material thought to be associated with an accretion disk of material falling in towards the neutron star. In Circinus X-1 its likely that the accretion disk varies with the 17-day cycle, being at its most intense when the stars are almost touching at the closest point in the orbit. It is then that the jets of matter appear to be ejected from the system.
Jets with speeds of ~ 99% (see note *) of the speed of light have been observed being emitted from the the regions around black holes in our own galaxy and have occasionally been seen emanating from neutron stars, but never before has an ultra-relativistic jet been seen that did not originate from a black hole region. The team has shown that the jets in Circinus X-1 are travelling at 99.8% of the speed of light. This is the fastest outflow seen from any object in our Galaxy, and matches the fastest jets powered by supermassive black holes at the heart of distant galaxies. Whatever process accelerates the jets to near the speed of light, it cannot therefore rely on the special properties of a black hole. "The key process must be one common to both black holes and neutron stars" said Kinwah Wu, formerly of the University of Sydney, now at University College London in the UK.
The Gamma-ray Large Area Space Telescope (GLAST) will open this high-energy world to exploration and help us to answer these questions. With GLAST, astronomers will at long last have a superior tool to study how black holes, notorious for pulling matter in, can accelerate jets of gas outward at fantastic speeds. Physicists will be able to study subatomic particles at energies far greater than those seen in ground-based particle accelerators. And cosmologists will gain valuable information about the birth and early evolution of the Universe.
For this unique endeavor, one that brings together the astrophysics and particle physics communities, NASA is teaming up with the U.S. Department of Energy and institutions in France, Germany, Japan, Italy and Sweden. General Dynamics C4 Systems has been chosen to build the spacecraft. The launch is scheduled for August of 2007.