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In multiple sci-fi, Degenerate Matter is often used for a myriad of applications. Degenerate Matter consists of Neutronium, Quarkonium and other matter coming from dense stars. They have high strength, and are very, very dense.

As one said, a teaspoonful of Neutronium could be millions to billions of tonnes.

However, a small problem that reduces its usefulness is its insane instability in regular pressure. It is said that Degenerate Matter in general can only be stable in their own home stars, and in Earth, they will immediately explode into energy, such that nukes look small in comparison.

And in Earth, they say that to keep it stable, ridiculous amounts of pressure is required, far beyond labatory pressures currently possible. Also, extremely low temperatures are necessary.

The latter is easy, but the former is obviously a nearly impossible challenge.

Thus, I ask if there is any alternate way to store Degenerate Matter that needs not such ridiculous pressures, or a machine that could theoretically generate such pressures.

- One might point out that such high pressures are also what creates Degenerate Matter in the first place. Assume that the Degenerate Matter can be made with means other than super-high pressure, like Femtotechnology or being collected from stars.

- If you propose a machine that can provide such pressures to store the Degenerate Matter, than it can also create it, so good.

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  • $\begingroup$ Degenerate matter is what it is because of enormous pressure. Currently science knows no way around it. $\endgroup$
    – Alexander
    Commented Jan 2, 2020 at 7:36
  • $\begingroup$ Electron degeneracy pressure prevents matter be composed of only neutrons, neutron degeneracy pressure prevents formation of blackhole, these are states of matter given right conditions according to textbooks. Having that said maybe neutronium could be a form of exotic matter but hopefully time will tell... $\endgroup$
    – user6760
    Commented Jan 2, 2020 at 11:58
  • $\begingroup$ There is the hypothesis in nuclear physics that there could exist a type of "strange matter" that would have a similar density to degenerate matter in a neutron star but would be stable without external pressure, see my answer here along with the second part of my answer here. $\endgroup$
    – Hypnosifl
    Commented Feb 19, 2020 at 21:01

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If you have the means to harvest neutronium from a neutron star (or indeed any sort of degenerate matter from a natural source), then storing the stuff afterwards seems like it should be childs play because the original task is so unfeasible that you will have already achieved weakly godlike status is order to achieve it.

Similarly, whatever mechanism you used to overcome eg. electron degeneracy pressure (or to magically induce electron capture) to create the stuff yourself can simply be continuously applied to the resultant neutronium (or whatever) to prevent it going foom (or possibly "skoom" depending). It will be basically magic, so for your setting you can feel free to handwave some highly efficient gravity generator.

Other forms of potentially stable nuclear density matter have been hypothesised to exist, including strange matter. There's plenty of scope for interesting scifi things that aren't just "strangelets fall, everyone dies".


Lets end with a couple of nitpicks.

They have high strength

Probably not. Neutronium is probably a fluid.

Also, extremely low temperatures are necessary.

White dwarf and neutron stars have temperatures of hundreds of thousands of kelvin.

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The thing that prevents degenerate matter from forming in normal circumstances is the electric charge repulsion between electrons and protons. If a way could be found to neutralise the electromagnetic force in a small localised area then it would be easy to create degenerate matter. Simply feed matter into this area and it would degenerate into a soup of neutrons. If the area was also exceptionally cold the neutrons would not have a lot of thermal energy so would not stray too far.

Once created it would be dangerous to turn the device off as the degenerate matter would immediately “regenerate” and the regenerate matter would take up a much greater volume probably and explosion depending on how profligate you had been in feeding matter in in the first place.

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    $\begingroup$ It wouldn't be degenerate matter in that particular case; just neutron soup. If the density of your stuff isn't limited by some kind of degeneracy pressure, you probably can't call it degenerate. Just mildly debauched. $\endgroup$ Commented Jan 2, 2020 at 12:06
  • $\begingroup$ lol - not sure I fancy finding out though... $\endgroup$
    – Slarty
    Commented Jan 2, 2020 at 13:47
  • $\begingroup$ Electrons and protons attract (opposite charge), not repel. Electrons repelling each other is what keeps matter mostly empty space. $\endgroup$
    – Zeiss Ikon
    Commented Feb 19, 2020 at 20:17
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What is Degenerate Matter like neutronium?

Per definition, neutronium is a whole bunch of neutrons clustered together without any protons or electrons in the mix.

How is neutronium created in nature? By huge amounts of gravity. Gravity is so strong that first it overwhelms the electric force (that keeps atoms atoms with a nucleus and electrons) - the star becomes a soup of plasma where nuclei and electrons are separate from each other, and so can be forced closer together than a normal atomic radius. According to Wikipedia, that is what happens in a white dwarf.

Now, if you crank up gravity even further, that plasma soup becomes denser still until the nuclei break up into alpha particles (2 neutrons + 2 protons). The protons (positive charge) react with the electrons (negative charge) to form neutrons, slowly converting the entire mass to neutrons.

Artificial Gravity

That is the only solution I can think of. Artificial gravity, and gravitational shielding (= neutralizing gravity).

First off, to get the matter, you either need to create it yourself (= cranking up the gravity and weathering all the horrendous radiation the thing emits until you've got it condensed down to the neutron soup), or harvest it from an existing neutron star. To harvest, you need to come close enough to the neutron star to apply your own gravity fields (no dipping a bucket into the neutron sea - the bucket would just be consumed and join all the neutrons...). This probably requires coming close enough to the star that the star ship would be crushed by the gravitational pressure if you couldn't neutralize it with your artificial gravity.

So, since you presumably have strong enough artificial gravity + shielding to either create the matter yourself, or drag it away from a neutron star, you are all set for storing the matter. Just keep it in such a gravity field and you're golden...


Nice side Sci-Fi effects of artificial gravity to such a degree:

  • huge acceleration / deceleration for sublight space travel: get faster from A to B (if you can neutralize neutron star level gravity, neutralizing a couple hundred G of acceleration is nothing)

  • Maybe you can even create gravitational drives. If you are capable of inducing negative gravity (= being repulsed by matter instead of attracted), you can use that for lift-off and steer by attracting yourself to whichever object is in the direction you want to go. (Just take care that the object isn't lighter than you and instead crashes into you...)

  • Super weapon. If you can form gravity strong enough to harvest from a neutron star, destabilizing something as 'weak' as a simple sun should be child's play. Just induce a super-strong solar flare, and good-bye life on earth...

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  • $\begingroup$ Why do you need negative gravity? Just create a gravity well that is constantly in front of your ship. $\endgroup$
    – Matthew
    Commented Jan 2, 2020 at 18:05
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I'm not sure anyone has formulated an equation for the decay rate of material from a neutron star.

However, there is an equation for the decay rate of a black hole. I've used this equation in the past for a lower bound (completely an assumption on my part) for how quickly the material will decay. The results are a little surprising, so I'll share :

The evaporation equation for a black hole is : $ t = M^3 * {((5120 * \pi * G) \over (h * c^4)} $, where $M$ is the mass of the black hole, $G$ is the gravitational constant ($6.67 \times 10^{-11}$), and $h$ is Plank's Constant ($6.60 \times 10^{-34}$)

Simplifying the constant part of the equation, ${((5120 * \pi * G) \over (h * c^4)}$ calculates to $t = M^3 * 2.01 \times 10^{-7}$

Without doing the math, the time for a single neutron of this material to evaporate is virtually instantaneous, which is disappointing. But do you see how the decay time increases with the cube of mass?

So, taking a 100 kilogram "speck" of this matter, which would be something like a micrometer radius, the minimum evaporation time is : $ t = 100^3 * 2.01 \times 10^{-7} = $ 0.2 seconds, during which you'd be exposed to $ P = {E \over t} = {{mc^2} \over t} = {{mc^2} \over 0.2} = 1 \times 10^{19} $ Watts of power.

But, I hope you can see this scales with mass : 10 metric tons would decay in 5.5 hours, 100 tons would last for about 6 years and emit an almost-manageable 40 TeraWatts of power.

For the purposes of my story, I needed something much more stable and compact, and not nearly so hot, so I added a tweaking term :

I looked at the decay rate for 1 neutron's mass $1 \times 10^{-27}$ black hole = $ 2.01 \times 10^{-88} $ seconds and compared it to the halflife of a neutron (600 seconds) to determine that neutrons live $3.0 \times 10^{90}$ times longer than an equivalent mass black hole.

This changes the equation to : $t = M^3 * (2.01 \times 10^{-7}) * (3.0 \times 10^{90})$

Using this equation, the same 100 kilogram "speck" takes $1.9 \times 10^{82}$ years to decay completely (more than the lifetime of the universe), and generates a tiny $1.5 \times 10^{-71}$ Watts while doing so.

How Strong is This Stuff?

You imagined using the stuff of neutron stars as construction material. I'm not sure how viable that is. The only thing holding this stuff together is gravity. We can calculate how strong that force is : $ F = {{GM} \over r} = 3.1 \times 10^{-16}$ Newtons. There is also the weak force attempting to tear this stuff apart.

I would think of this stuff as super-fine, super-dense ash. I imagine you'd need to alloy this with something else that holds it together, and the neutron star stuff provides heat and weight to it.

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    $\begingroup$ Neutron stars don't decay (unless proton decay turns out to be real...), but once you've taken the neutronium out of that gravity well it'll have the same half life as any other free neutron, about 30 seconds or so. Black hole decay is totally unrelated. After 5 minutes, there will be less than 100 grams left of your 100kg initial block, and the highly energetic decay of all those neutrons will cause it to go foom so you won't have a block for very long. $\endgroup$ Commented Jan 2, 2020 at 11:55
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    $\begingroup$ Black hole evaporation happens because one of the particles in a virtual pair is getting captured by event horizon - and the other one is not. Since neutron stars do not have event horizon, this mechanism does not work. $\endgroup$
    – Alexander
    Commented Jan 2, 2020 at 17:55

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