# What element would make up a creature if it used the weak nuclear force during its metabolic processes?

I was doing some research on how to design a scientifically possible alien, when I came across an interesting section on metabolism. I found it very interesting and read about the weak force, as opposed to our electromagnetic radiation metabolism. I did more research on it, but all I found was a thought that creatures with that would manipulate their surroundings and absorb the difference. Additionally, they would be made of radioactive particles, but only become radioactive when they die.

So my question is, what element or elements would such a creature likely be based on (Pb, Uuq, etc.), and what environment would support such a creature?

This link will sum up what most of the websites I visited said, basically the same thing:
http://www.xenology.info/Papers/Xenobiology.htm

• Elements themselves are very much electromagnetic based. All chemistry pretty much is. Thus, asking about elements they would use is kinda moot. Also, one question per question, please. – Mołot Dec 24 '17 at 0:40
• Could you provide links to the things you've researched so far? – Lio Elbammalf Dec 24 '17 at 0:41
• en.m.wikipedia.org/wiki/Weakly_interacting_massive_particles – Spencer Dec 24 '17 at 1:43
• @Spencer Of course! I'd forgotten about WIMPs. Thanks for the reminder. Now I'll need to think if they can figure as possible candidates. – a4android Dec 24 '17 at 4:36

It is doubtful your weak force xenobionts could be composed of any elements or atomic matter.

Weak force lifeforms would be creatures unlike anything we can readily imagine. Weak forces are believed to operate only at subnuclear ranges, less than 10^-17 meter. They are so weak that unlike other forces, they don't seem to play a role in actually holding anything together. They appear in certain kinds of nuclear collisions or decay processes which, for whatever reason, cannot be mediated by the strong, electromagnetic or gravitational interactions. These processes, such as radioactive beta decay and the decay of the free neutron, all involve neutrinos.

Source: General Xenobiology

The fact alone that the range of the weak force is limited to 10^-17 metres and they don't bind anything together in the material sense suggests weak force organisms would have to be extremely small, of sizes far less than 10^-17 metres, probably several orders of magnitude less, in fact, and they would need some other force to hold them together.

In summary, this answer agrees with the proposition that: "Weak force lifeforms would be creatures unlike anything we can readily imagine."

Sometimes the obvious can easily escape one's attention. What environment could sustain such weak force organisms especially since the range of the weak force is so extremely short. There is only environment where matter could be readily accessible to organisms with such a short range. Namely, the interior of a neutron star.

Inside a neutron star matter will be within range of the weak force. However, what kind of nuclear chemistry would be necessary to sustain weak force creatures is effectively beyond current knowledge. Although there could be experts who have considered the interactions inside neutron stars to be able to have a good idea of what they are. This, if it exists, will be buried deep in the technical literature.

One possibility is that weak force lifeforms will be unable to exist outside of a neutron star. If they can exist outside neutron stars, it will require super-scientific technology on a mind-boggling scale.

• So could they exist as larger beings if made if and exotic form of matter – Amoeba Dec 24 '17 at 1:17
• @user45751 Now that's an interesting proposition! It would have to be a form of exotic matter of kind we haven't thought about previously (to my certain knowledge). Maybe the reverse makes more sense. Creatures made of "exotic matter" that can "metabolically" induce radioactivity via the controlled use of the weak force. This stands your question on its head, but might be more feasible -- at a very long stretch. This is in the realm of speculation. – a4android Dec 24 '17 at 1:45
• What do u mean it stands my question on it's head and of they exist as intelligent life and can interact with other intelligent life like human and eat by manipulating quarks to make radioactive decay what would the reaction from humans and other intelligent life that isn't weak force based likely be? – Amoeba Dec 24 '17 at 1:58
• @user45751 Sorry if that was confusing. Instead of being made from or with the weak force. They are made of exotic matter & are able to use the weak force as part of their organic make-up. Their encounters with humans & other sapient life will depend on the physical interactions they can exchange with each other. Size differences may be enormous. Normal biological organisms won't be safe near beings producing radioactivity. Both parties may need to keep a safe distance apart, say, using radio to communicate. Just off the cuff ideas. – a4android Dec 24 '17 at 2:15
• Thx for all the answers if u don't mind I have some more – Amoeba Dec 24 '17 at 2:26

# TL;DR

I'd propose that weak force life has a tiny change of existing in environments where particles travel at high speeds. A possible example is the jets produced by an active galactic nucleus. At the high energies (and high speeds) particles reach in these jets, the range of the weak force could be sizably extended to the point where it is less negligible than for a low-energy environment, because at high speeds, the $$W$$ and $$Z$$ bosons' lifetimes can be dramatically extended. While it's difficult to speculate as to what structures and processes - let alone life - could coherently arrive, I would bet that proton-antiproton collisions and the decay of charged leptons (muons and tau particles) might be potential sources of the $$W$$ and $$Z$$ bosons.

# The decay problem

The weak force is mediated by three particles: The charged $$W^{\pm}$$ bosons and the neutral $$Z$$ boson. Unlike the photon, their cousin, these bosons have mass, approximately 80.4 GeV and 91.2 GeV, respectively. Also unlike the photon, the bosons decay. The $$W^+$$ boson has several decay paths, including hadronic paths (dominated by quark-antiquark pairs) and leptonic paths (a positively charged lepton and its associated neutrino); the $$W^-$$ decays involve the corresponding antiparticles. For the $$Z$$ bosons, hadronic decays to quarks are also the main contributors, although pairs of charged leptons and their antiparticles may also be produced.

Both particles have half-lives of $$\tau\sim10^{-25}$$ seconds, and so the range of the weak force is approximately $$r\approx\tau c\sim10^{-17}$$ meters, even in the case of relativistic particles. Another way of expressing this uses the derivation of the half-life from Heisenberg's uncertainty principle: $$r\approx\frac{\hbar}{2mc}\propto\frac{1}{m}$$ where $$m$$ is the mass of the boson. Therefore, by decreasing the mass of the $$W$$ and $$Z$$ bosons, you could of course extend the range of the weak force. That said, changing the mass would involve changing weak force coupling constant across the universe, which would cause serious issues.

# Time dilation

Changing our fundamental constants seems to be right out, then, so let's stay away from those. Instead, let's see what happens if we try to extend the lifetimes of these bosons through time dilation. Time dilation comes in two flavors: gravitational and special relativistic. It turns out that to dilate time enough to significantly extend $$r$$, you need to be in a steep gravitational field, quite close to a black hole; this seems an unlikely and unsafe (certainly short-lived) setup.

However, we could extend the range of the weak force by instead having these bosons travel quickly, as happens with muons in Earth's atmosphere. The boson's lifetime should be $$\tau=\gamma\tau_0$$, where $$\gamma$$ is the Lorentz factor and $$\tau_0\sim10^{-25}$$ seconds, from before. The highest Lorentz factors we've seen come from ultra-high energy cosmic rays; the Oh-My-God particle had a kinetic energy of $$3.2\times10^{20}$$ eV, and thus (as you can determine by calculating the relativistic kinetic energy, $$T\approx m\gamma c^2$$) a Lorentz factor of $$\sim10^{11}$$, corresponding to a speed that differs from $$c$$ by less than one part in $$10^{23}$$. The boson's lifetime is then $$\tau\sim10^{-14}$$ seconds, and the weak force's range is a surprising $$r\sim10^{-6}$$ meters.

There are some caveats:

• Propelling a particle to this energy requires an active galactic nucleus, and therefore, ambient $$W$$ and $$Z$$ bosons can only survive in the jets emitted from such an AGN.
• The jets should be dense with leptons and hadrons, an extreme environment that produces gamma rays and cosmic rays. Interactions should be frequent, and it seems that bosons could very quickly interact with these ambient particles, limiting their range. There could be a limit similar to the GZK limit for cosmic rays, albeit involving these ambient fermions.
• The bosons presumably can't be accelerated to these speeds in the same manner as normal cosmic rays, but they could be produced by high-energy particles in the jets. Proton-antiproton interactions can produce both $$W$$ and $$Z$$ bosons; if these interactions transferred the majority of the progenitor's energies to the bosons, we might well see the bosons reach the required energies. This is guesswork on my part, though.

While I would propose AGN jets as an alternative to a4android's neutron star suggestion, simply because they're the only energy sources that could create these Lorentz factors, it seems clear that only these extreme environments could host anything akin to life based on the weak force.

# What particle(s) would life be based on?

As you might have guessed, you likely won't see elements per se in these jets. Nuclei, yes, primarily protons. What you will see is, as I mentioned before, a messy soup of hadrons and leptons, producing synchrotron radiation and gamma rays. These particles will make up your building blocks of life.

How will these bosons be produced, then? There are two basic types of weak force interactions: charged current interactions (involving the $$W$$ bosons) and neutral current interactions (involving the $$Z$$ boson). Examples include:

• Quark-antiquark interactions from proton-antiproton collisions, as I mentioned above. We see these occur in colliders. Typical pathways involve up and down quarks ($$u$$ and $$d$$) and their antiparticles ($$\bar{u}$$ and $$\bar{d}$$): $$\bar{d}u\to W^+,\quad d\bar{u}\to W^-,\quad u\bar{u}\to Z,\quad d\bar{d}\to Z$$
• Lepton decay, e.g. a muon decaying to a muon neutrino and a $$W^-$$ boson, which then decays to an electron and an electron antineutrino: $$\mu\to\nu_{\mu}+W^-\to\nu_{\mu}+e^-+\bar{\nu}_e$$

There are other hadronic decay processes, of course (e.g. pion decay); I list the above just as examples. The dominant production processes depend on the ambient fermions and hadrons.

### A note on WIMPs

I'd like to second Spencer's suggestion of weakly interacting massive particles, or WIMPs, which remain prime dark matter candidates. They're high-mass particles that interact only via gravity and the weak nuclear force, and hence would be excellent candidates for a creature that primarily uses the weak force insofar as it really couldn't interact in any other way. It does seem unlikely that they would combine in high densities, as dark matter doesn't clump quite like normal matter does, but they remain an interesting possibility.