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The repulsive force acting at small scales is not linked to the cosmic expansion rate, as detailed in other replies. It is highly misleading to attribute it to the "expansion of space". It's just gravitational repulsion arising from the (stress-)energy density of dark energy.

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Yes, Po-218, Lead-214 and Bismuth-214 are electrically charged, as a result they tend to stick to dust particles and solid surfaces that are negatively charged, a phenomena called Radon Daughter Plate Out. Indoor air contains mostly (>90%) attached progeny, stuck to dust particles. Attached (Po-218, Lead-214 and Bismuth-214) progeny are responsible for most of the radiation dose from indoor radon.

Vogiannis, E.G. and Nikolopoulos, D., 2015. Radon sources and associated risk in terms of exposure and dose. Frontiers in public health, 2, p.207.

To add to the already-excellent analysis already posted, I have to quibble about:

>There’d be a gradient originating from the source...

Exactly what "source" are you envisioning here? We're talking about radon gas mixed freely in the atmosphere. Any decay products would be distributed randomly and diffusely, as there is no monolithic source from which to originate.

Which implies that your top-level comment is incorrect. There is a force acting at small scales, due to the cosmological constant, there is a tendency to expand that you need to counteract via gravity for things to become static.

Note that the Weinberg interview you quote is from 1993. This was years before the discovery of the accelerated expansion of the universe. At the time it was thought that the expansion of the universe was purely inertial, but we know better now, and you should stop spreading obsolete information.

Right.

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What I'm gathering is that in normal air it would mostly cling on to dust particles, in dust-free air it would be an extremely low-partial-pressure gaseous component, and in pure form (say, a container of pure radon that decays) nearly all of it would attach to container walls, leaving an extremely low-pressure lead gas behind.

How likely to hit those though? Really low, right?

If you regard "finding the lead atom" I might agree, but "ionized(?) lead atom finds oxygen in air" would be one in five collisions.

3 x 10^-14 3.67 x 10^-12 Pa, actually, but I take your point.

Are all zooids in an organism genetically identical (or close enough) like somatic cells in a body are? Is their reproduction more similar to independent animals, or to cells?

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Radon-222 decays via several steps, a decay chain leading to non-radioactive, Lead-210. A lot of the radon decay products, Lead-214 and Bismuth-214, ends up coating dust particles and sold surfaces, a phenomena called Radon Daughter Plate Out. So the daughter atoms aren't usually free floating in the air, but usually more than 90% ends up sticking to dust particles and solid surfaces.

>A small fraction of radon progeny, typically 0.1 or less, remains unattached and in dynamic equilibrium with attached particles. Generally, dustier atmospheres are associated with smaller values of unattached fraction and higher concentrations of radon due to additional radiation emission from dust.

This is the decay chain for Uranium-238, which includes Radon-222

Radon-222 initially decays to Polonium-218, via emitting a positively charged Alpha particle. The resulting Polonium-218 atom, with a half life of 3.1 minutes, is electrically charged and it is attracted to charged dust particles and sold surfaces where it quickly decays to Lead-214 and Bismuth-214, formimg a radioactive coating, a major source of radiation exposure from indoor Radon gas.

These two isotopes, in comparison to other isotopes of the randon decay chain, have relatively long combined half life of just over 20 minutes.

Radon Plate Out can be demonstrated using a balloon. If you have a building or better still, a basement with a slight radon problem, and leave an electrically charged balloon in the room for an hour or so, then measure it with a Geiger Counter, you'll often find the balloon becomes radioactive due a coating of Lead-214 and Bismuth-214, from attracting Polonium-218 directly and radioactive dust particles.

https://youtu.be/C_P-euxMGSA

The Plate Out on glass is very sticky, I keep a Radium dial WWII compass safely sealed in an air tight jar. The inside of the jar gets coated with radon plate out, rubbing the glass with a wet tissue removes some of the contamination, the tissue gets contaminated, but most of the activity is stays stubbornly stuck to the glass.

It's possible some of plate out might have formed some sort of electrostatic bond, perhaps Van Der Waals force.

I can also measure the decay of the contamination:

https://imgur.com/XpibmUV

The isotopes have an average half life of just over 20 minutes, so it's decay noticed quite quickly (using a Radiascan 701a connected to logging software on my PC).

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I see, so in nature, an unpolarized atom in an atomic gas may be absorbing and emitting resonant frequencies, emitting each individual photon "in one direction" but in a random direction. Given enough time, and enough absorption/emission cycles, the emission pattern would appear as a random, or "all- directional" distribution (isotropic distribution).

As a thought experiment, if the atom was contained in a chamber with 4 walls, each wall being a photon detector capable of detecting the x, y coordinate of any photon that impacts the wall, and a beam of photons resonant with the atom was directed at the atom, the walls would eventually look like equally distributed swiss cheese, and eventually being 100% covered, but only after a sufficient period of time. One wall would detect the first emission at a specific x,y coordinate on the wall, and then the next emission would be detected sequentially, randomly by either that or another wall, and the process would continue until the photon beam stops.

So the atom is not in fact acting as a point-source "isotropic radiator" during re-emission (as I understood it being described in the linked video), whereby if you impact the atom with a single photon, then all 4 walls of our detection chamber would simultaneously detect the re-emission.of energy.

I already mentioned that, too...

> With lead alone almost all atoms would hit the wall and freeze out in milliseconds, although theoretically the vapor pressure is not zero.

The vapor pressure of lead at room temperature is absurdly small. Something below 10^(-20) Pa extrapolating from this graph.

Which is what makes it so hazardous to our lungs. Essentially it becomes a tiny particulate, and is also an alpha-emitter, which means that most of the radioactive energy is deposited in the small air sacs of the lung - hence, cancer risk.

If the scenario only takes the presence of lead into account, there's still a decent probability of lead vapor existing. You figure the vapor pressure of mercury is so well documented by experiments where ullage develops in a container filled in such a manner where no material other than mercury could be present; the same should be true of all materials subject to vacuum.

Or, put another way, your suggestion that lead would "freeze out" as soon as it hits the wall of its container suggests you could hit absolute vacuum (and thus absolute zero temperature) by simply waiting.

"Even [diatomic radical reactions] must fulfil strict geometrical (sic) conditions in order to pair lone electrons" I don't agree with. There is genuinely only 1 geometric paramater, i.e. the distance between the two atoms, unless you are implying Born-Oppenheimer doesn't apply or relativistic effects are necessary (which, they are, but for which your bouncing ball model doesn't account). Even the angle between their velocities does not matter following from Newtonian relativity.

I also believe your "energy threshold" (Eyering transition state Gibbs free energy?) is being imagined as far too high. Ground state monoatomic oxygen and lead must overcome only Pauli repulsion in the formation of the transition state, which will be on the same order of magnitude as Coulombic benefit entering the transition state, so I posit ca. 10% of bond enthalpy as the maximum barrier? Which for even the strongest diatomic leaves us with 90 kJ/mol, which for an ordinary reaction proceeds unmonitorably quickly at room temperature, for a more reasonable guess of 20 kJ/mol we need an argon matrix to observe these using IR spectroscopy. Reaction with triplet and heaven forbid singlet dioxygen will likely have larger barriers. Do I think these barriers will be large enough to stop reaction with a radon daughter lead? No not at all. Even under your assumptions.

Saying it will only occur when it forms larger clusters is frankly laughable. The ionisation energy goes up, the Gibbs free enegy of the transition state goes up, and frankly the chance of interacting with oxygen goes down, not up when forming a cluster. The total reactive lead surface area goes down rapidly with cluster size as core atoms become inaccessible, and on forming a cluster the volume goes down from overlapping atomic radii. On small clusters the cluster radius is a similar fraction of the mean free path as the atomic radius of a lead atom is of the mean free path, so forming a Pb(0) tetramer roughly quarters your reaction time. Lead metal sheets oxidises slowly, and can readily be chemically forced back to metal, however fine lead powder can ignite simply by throwing it through air.

Your assumption that lead clusters are forming in preference to reaction with oxygen is only true if your amount of parent radon is decaying much faster than it is diffusing or you have far more radon than oxygen. This is not true, as isolable radon (222Rn) has a half life of almost 4 days. Under any reasonable conditions this is much slower than diffusion and all radon will be well mixed with the surrounding air.

I would be frankly shocked to see any metallic lead deposition at all. I tried to read about experimental evidence for this however daughter isotope measurement is only performed by radiation measurments rather than any chemical means so the identity of the material is never stated (comprehensive article by Yamamoto et al. in J. Environ. Radioactivity).

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