Out of idle curiousity what would happen if say… a cubic meter of neutron star material suddenly materialized right on the surface of the earth.
Would it fall into the earth until it got to the center and then oscillate? Because of it’s density would it be super tough and able to withstand an atomic blast if at ground zero? Would bad and strange things happen to anyone in the vicinity of this object because of gravity waves? Is a meter of this stuff heavy enough to effect the earth’s orbital path if it did hang around at the center of the earth?
What would the properties of this exotic beast be if surrounded by the ordinary non-collapsed matter of the earth?
Actually, neutron star material are stable only because the tremendous pressure is balanced by the tremendous gravitational force of the neutron star. It’s the same with Earth’s atmosphere, actually - it’s dense enough to breathe only because it is pulled by Earth’s gravity and compressed against the surface.
So what happens if you take a cubic meter of 1-atmosphere air to the Moon and release it? It would instantly disperse, because there is not enough gravity to keep it compressed. So I expec the same thing would happen if you brought a cubic meter of neutron star material to the earth - it would instantly expand and disperse. Expand and disperse very, very fast.
By the way, a cubic meter of that stuff would weigh a hudnred trillion tons - roughly the weight of the Mediterranean Sea.
I respectfully disagree. Neuron stars are not my primany area of expertise, but I was married twice and I understand ‘dense’. I don’t understand the analogy between a neuron star and the earth’s atmosphere. A cubic meter of the earth’s atmosphere will expand and dissipate if released on the moon. A cubic meter of neuron star material will not dissipate at all. You only THINK depleted uranium is heavy. It doesn’t dissipate. A chunk of neuron star material, impacting at earth-crosser speed might well go right through and out the other side. If it suddenly appeared at the surface, it would likely go through several yo-yo evolutions and end up in the core.
It WOULD withstand an atomic blast at ground zero with little or no damage. An extra hundred trillion tons would likely not affect the earth’s orbit, and the material would sit at the earth’s core like last yesterday’s dumplings that never digest.
The effect on the earth’s magnetic field is beyond me, but gravity waves are not going to be a factor.
“These answers were believed buy the author to be good guesses at the time they were written”.
But a chunk of uranium is not held together by gravity. It’s held together by covalent bonds which are very short-distance forces, acting only on adjacent atoms. A chunk of uranium can be a few atoms large and the attractive forces will still hold it together. On the other hand, in a neutron star the only force holding the neutron star together is gravity. Much like with earth’s atmosphere, gravity is balanced with the repulsive forces between the particles. (Collision in case of the atmosphere, degenerecy pressure - i.e. neutrons “touching” each other - in case of the neutron star). Gravity is a much longer range force. If you cut a neutron star in half, gravity will be cut in half. If you cut a chunk of neutron star small enough, there will not be enough gravity to hold it together - the repulsive forces will win, and it will disperse. This limit is rather large - 1.4 times the mass of the sun, if I remember correctly.
I think scr4 is correct. Individual neutrons are not stable. They decay with a half-life of 15 minutes, giving off an electron and a neutrino, and turning into a protron. The gravitational pressure prevents this in a neutron star, but not in this cubic meter at the Earth’s surface. So all your neutrons turn into hydrogen atoms, essentially. The chunk would blow apart, but might not get a good “boom” going until it was inside the earth a ways.
scr4 has the right of it. Neutron star material would blow itself apart.
My question is would it blow ‘apart’ or re-inflate to some massive size but otherwise hold together as a great big new hunk of material sitting on (or in) the earth?
As for a cubic meter of the stuff that is a LOT of material. I like the Med comparison but here’s another one I heard.
A teaspoon full of Neutron Star material on earth would weigh as much as Mt. Everest.
Tiny correction to ZenBeam’s post: A neutron decays to a proton, an electron, and an antineutrino. Admittedly, it’s not like that makes much difference.
Jeff_42: What you’d end up with is the rlease of a bunch of energy, and the production of a bunch of hydrogen. I’m not sure of the exact amount of energy; take the rest mass of the neutrino, subrtact off the sum of the masses of the proton and the electron, and convert for an approximation. (It’s only an approximation because of the various binding energies of a clump of neutronium.) The amount of hydrogen would be essentially the same as the original amount of neutronium. Basically, once it cooled off, you’d just have a bunch more hydrogen in the atmosphere, until it escaped or bonded.
So the synoposis is that there would be a big, big boom. I wonder if there is a way to calculate the theoretical amount of energy that would be released from a cubic meter of this stuff “expanding” in a sub-critical gravity environment like the earth’s surface.
What specific mechanism would the energy come from? Is the compressed state simply a potential energy situation waiting to become kinetic in the expanded state like a spring? Yeah I know it’s a dumb ass analogy but this stuff is the deep end of the pool for me.
Big boom? I’ll say! To give you some idea, the half-life of neutron decay is approx. 15 minutes. And you have 100 trillion tons of the stuff. So in other words, you have 100 trillion tons of radioactive material with a 15 minute half life. You might end up vaporizing the Earth.
Your analogy sounds right on to me. The “stored” energy would be the repulsive forces that would tend to keep the neutrons from touching. These forces have been overcome by gravity. Remove the gravity, and they would spring into action.
I think it’s worse than that. While a neutron star is held together by gravity, the particles are in fact interacting strongly. What you have in effect is a very large atomic nucleus which would start to fission in a gazillion different places at once. Since the half-life of a neutron really is irrelevant inside a nucleus (or you wouldn’t have stable elements with neutrons, but there are such things), you don’t really know what each neutron is going to do. I can pretty much assure you that they won’t just sit there until their time to decay by beta emission rolls around.
Think about fissionable atoms - you’ve got 250 or so protons and neutrons, and if you add a neutron the nucleus becomes so unstable it splits into two chunks and emits other stuff (gammas, more neutrons, etc.) What you have is an atom with an atomic weight somewhere around 100 quadrillion times avogadro’s number. Say it takes 10 kilograms of plutonium to make a nuclear device - we’ve now got 100 trillion tons of something most likely fissionable. All kinds of things would start happening at once, and you’d end up with not only hydrogen, but a ton of other elements as well, probably even some very very heavy ones never before seen by humans (and not seen this time either, as the earth evaporates under the withering radiation and heat released.)
OK, so maybe the earth wouldn’t be completely destroyed, but I’d bet there wouldn’t be a cell left metabolizing on it.
Nah, if you were standing exactly antipodal of the neutron star matter when it went off you might survive. Not to say you’d be in good shape and it would be a huge “WTF was that?” to no one in particular.