Sounds like my spicy bolognese.
Coincidentally, this also causes the shedding of gaseous layers.
Good luck sinking your teeth into nuclear pasta. For one it’ll be tricky to get a hold of since it’s the stuff lodged inside neutron stars. Additionally, it may also be the universe’s strongest material. Neutron stars are the cores leftover from dead stars that have already shed their gaseous layers in a supernova explosion. …
OF course this is utterly bogus. A gram of iron, say made into a sheet, in space has strengh x per gram.
A gram of neutron star material out in space would more or less instantly be a cloud of expanding and beta-decaying neutrons with zero strength. Ending up as a puff of mostly ionized hydrogen and a few low energy gamma photons.
Doh, it's well known and studied in labs that things under crazy high pressures act differently while under those pressures. Not that it has any use other than study of matter *under those conditions*.
For example, we can make some things superconductive under high pressures at higher than the normal transition temperatures. But they don't stay that way with the pressure off.
So the above is yet another science press release exercise in click bait. Real scientists are getting tired of this, as it tends to devalue and discredit the few real things we mange to accomplish.
Pulsars fit the bill of observed neutron stars: objects of over 1.5 solar masses, no larger than a 20-30 km. The best explanation that fits the laws of physics is that they are spinning neutron stars. Therefore I wouldn't say that neutron stars are purely theoretical.
Sure, pulsars fit the bill of neutron stars. They also fit the bill of quark stars. How do we tell them apart? I mean, basically a quark star would be a somewhat more massive neutron star that gets crunched a bit smaller, and therefore spins a bit faster...
"A much more believable finger in the air number."
It's not a finger in the air number, it's derived from the physics of degenerate matter (very dense matter that no longer consists of atoms, but of free protons, electrons and neutrons.)
A white dwarf will only form a neutron star if its core has a mass greater than approximately 1.4 solar masses, as gravitational forces can then overcome the electron degeneracy pressure* that prevents protons and electrons from combining to form neutrons.
Also, a neutron star cannot have a mass greater than approximately 2.2 solar masses, otherwise gravitational forces will be strong enough to overcome the neutron degeneracy pressure and cause neutrons to collapse into quark degenerate matter (theoretically) or a black hole.
Neutrons are relatively massive particles, so are packed very closely together once they collapse into degenerate matter. Given we know the approximate upper and lower limits of a neutron star's mass, as well as a good idea of its density, we can state with some degree of confidence that its radius will be in the order of 10km.
*Degeneracy pressure is nothing to do with troublesome yoofs hanging around at the bus stop, it's pressure that stops particles getting closer together, due to the exclusion principle.
> Science doesn't acknowledge "forbidden".
Perhaps not, but nuclear physicists are wont to call some atomic actions "forbidden" from time to time anyway.
> "Someone please explain to me what those "competing forces" actually are?"
There aren't any of the type described. From Wikipedia:
"Most of the basic models for these objects imply that neutron stars are composed almost entirely of neutrons (subatomic particles with no net electrical charge and with slightly larger mass than protons); the electrons and protons present in normal matter combine to produce neutrons at the conditions in a neutron star."
So neutron stars are made of, well.. neutrons. Go figure.
On 'why are there protons at all'? I think that is a good question given the usual description of a neutron star as a thing that is made of neutrons. However, having taken a quick look at the paper, I learn the following cool (theorised) stuff:
"The crust comprises the outermost kilometer of the NS [...] The outer crust is a bcc lattice of nuclei embedded in a gas of degenerate electrons, which becomes increasingly neutron rich with depth. At the base of the inner crust the separation between nuclei becomes comparable to nuclei radii and nucleons rearrange themselves into complex shapes known as nuclear pasta."
So, in the crusty bit, there are still thought to be things resembling what we would recognise as nuclei, and so there will be protons around.
On 'what are the forces'? That is also a good question since at least in the non-crust neutron only part of a neutron star you'd expect there to be just attractive nuclear forces – and so why wouldn't the thing just keep on collapsing. The received wisdom is that although the nuclear forces make the neutrons really really really want to stick together as closely as possible this attraction is resisted by what is called degeneracy pressure – this is a quantum mechanical (QM) effect and is a consequence of what is often called the exclusion principle. The exclusion principle is everywhere in Nature – so as well as holding up neutron stars it is also what stops all the electrons in an atom collapsing to the same (lowest) energy level and forces them instead to occupy higher and higher energies – and thus gives us all of chemistry, and all of life etc.
All that off the back of one (comparatively) simple QM rule that has absolutely no underlying explanation whatsoever but if you assume it is true then everything fits wonderfully.
Got to love QM. It's the law (since, currently, there is no alternative).
"Why, I thought those two got along quite well (neutrons being neutral and all), even snuggling together inside most nuclei. Someone please explain to me what those "competing forces" actually are?"
There are several of them. Firstly, protons and neutrons aren't fundamental particles, they're composites made up of quarks. Neutrons have zero total charge, but if you try to jam two of them inside each other you start having to worry about how the internal charged parts react to each other (and there are no neutral quarks). It's essentially the same as how neutral molecules can become polarised and attract or repel each other.
Secondly, as far as we're aware gravity is the only force that is always attractive. The strong force is attractive only above a certain distance, once you get too close it actually becomes repulsive instead. This is why atomic nuclei don't simply collapse into black holes - the protons and neutrons can only get so close before they start being pushed apart again.
Finally, degeneracy pressure, as mentioned already, is caused by fermions being unable to occupy identical quantum states - essentially meaning you can't have two neutrons in exactly the same place with the same energy at the same time. This can be viewed as similar to electron shells in atoms - once you've filled the inner shell, any extra electrons will have to go in a shell further out; the outer shells have higher energy, so some input is required to actually get them there and that appears the same as pressure forcing them out. The same thing happens in pretty much anything involving quantum states - some of those states have lower energy than others and tend to fill up first; once they're full the exclusion principle stops anything else getting in there as well and forces them to occupy higher energy states instead.
String theory in particular seems to be a case of "throw it at the wall and see what sticks". (same for dark matter, but I'm not going to root out the wine-dark honeyed centres here—it's a load of Bologne)
(oh, and yea, it was prophesied and so his noodly appendages came to manifest and such)
Where's my hat?
> "One famous example are biological membranes in living cells. We've actually studied how the nuclear pasta lasagna exhibits the same structure and structural defects as the endoplasmic reticulum.
Maybe the premise of Robert L. Forward's "Dragon's Egg" is not so fanciful after all. It involves life on a neutron star, based on nucleonic processes, which are way faster than chemical ones. So entire civilizations rise and fall during the few days humans observe the star from orbit.
Given that the neutron star's surface has a variance of just a few micrometers, and that if you drop something from just 1m high it will hit the surface at 1,400 km/s, I think you'll find that you're never getting to build a mountain on a neutron star.
Bullet proof? Oh Yes, and at any visible thickness a pasta vest would probably weigh more than this planet given the densities involved.
The question should be 'Could a similar structure (even a billion times poorer) be manufactured and stable at Earths comparatively feeble gravity?
"the pasta's shear modulus is about 10^30 ergs per cm^3"
Argh..... What is so wrong with using normal units (GPa) as the unit for the shear modulus? Is it because 10^20 GPa sounds less impressive, or is it just to make the comparison with normal engineering materials a bit harder?
For the record, the shear modulus of most steel types is in the region of 77 GPa to 79 GPa, so you're going to have trouble eating corn on the cob after trying to bite through this pasta.
In fact, you could easily build a pasta based space elevator in the style of one of those "how tall can you build a tower out of dried spaghetti" competitions. That is, of course if the compressive and shear *strengths* are any good. I think the compressive strength is a given though...
Can you say Ringworld? Ringworld Engineers?
I get that while Larry Niven’s stories had discussed this material, these guys actually simulated it. BTW, good luck in trying to mine it... ;-)
But I have to ask... the simulation is based on the material as it is within a Neutron Star, or assuming that they could actually manufacture or mine it... would it react the same outside of the effects of a Neutron Star? Would it lose its liquidity?
Alien because of the Pak Protector reference.
Yes. Were he to enter in to the US illegally, I'd call him an illegal alien.
Extraterrestrial ? Yes to that too.
IIRC other species could become Pak due to the bacteria found in the root. I'll have to re-read Ringworld Engineers some time when I get the chance. FFS I think its been over 15 years since I read that.
BTW, Larry Niven is on LinkedIn. ;-)
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Best novel about life on a Neutron Star ever, "Dragon's Egg" by Robert L Forward (Physicist):
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