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bio website nathanielvirgo.com
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I'm a post-doctoral researcher with a wide range of interests. My career is in complex systems science (or maybe cybernetics) and the origins of life, but I also have research interests in

  • the foundations of statistical mechanics and its relationship to information theory
  • Earth systems science
  • non-equilibrium thermodynamics in general

I'm also generally interested in the foundations of quantum mechanics and in black holes, though I wouldn't say I'm an expert on those things.

It's probably worth noting that despite the fact that my research is in physics-related areas, all my degrees are in other subjects. If I occasionally seem to start talking in an alien language, this is probably why.


1d
comment Would this pump water up? and if so, how far?
@adrian a Stirling engine does not turn ambient heat into work, it extracts work from the temperature difference between two thermal reservoirs. It is impossible to do it with only one. That is exactly what "perpetual motion machine of the second kind" means.
2d
comment Is the MaxEnt “interpretation” of statistical mechanics the current mainstream approach?
I would advise leaving this question open for a while to get a few answers rather than accepting the first. The currently accepted answer is not wrong and is fairly balanced, but it is only one person's view, not an authoritative answer.
2d
comment Why Does The Moon Apear White/Grayish and The Sun Yellow?
To add to @MarcvanLeeuwen's point, the moon is often clearly visible in broad daylight, and as far as I've ever noticed, always appears pure white in such conditions.
Aug
26
comment Would this pump water up? and if so, how far?
If the energy is to come from thermal ambient energy then you are breaking the second law. This is called a "perpetual motion machine of the second kind," and it's just as fundamentally impossible as creating energy from nothing (which breaks the first law and is called a perpetual motion machine of the first kind).
Aug
23
comment Hysteresis and dissipation
Ok, but the hysteresis in that case most certainly does involve dissipation. Without it all collisions would be elastic and the inner piece would continue bouncing around inside the outer one for ever.
Aug
23
comment Hysteresis and dissipation
What is a "loose running mechanical fit"?
Aug
17
comment Will climate change cause the Moon to move away from the Earth at a faster rate?
This is an interesting question, but probably a difficult one to answer. It's been suggested in the past that the movement of the continents has affected the rate of recession of the moon, mostly because vertically-oriented continents block the water from flowing with the tide. But the fluid mechanics are fiendishly hard to model. I would guess the effect of raised sea level would be extremely small, but I don't know.
Aug
11
comment Quantum entanglement faster than speed of light?
When the entanglement collapses, the particles are no longer entangled, and measuring whether the collapse has happened would be the same as measuring whether they're still entangled. There is no measurable change of any kind when the other particle is measured, magnetic or otherwise. Entanglement, or the collapse thereof, cannot be detected or measured in any way, except by comparing the results of the two measurements - which you can't do without sending a signal between the two points.
Aug
11
comment Quantum entanglement faster than speed of light?
This will not work because "some apparatus that only reacts when the entanglement is collapsed" fundamentally cannot exist. There is no way to tell whether a particle is entangled with some other particle or not.
Aug
11
comment Does any particle ever reach any singularity inside the black hole?
@G.'tHooft I know this is an old post and you're not active here any more, but... when you said to John Rennie above that "you are right, but only in a formal sense...", it doesn't seem to quite answer the point. Even if the infalling observer becomes practically unobservable to the outside one, they are still technically outside the horizon, and remain so until after the hole has evaporated. (Right?) So, formally, there is no spacetime point at which the infalling observer passes the horizon, and the argument in your post seems on the face of it not to hold up.
Aug
7
comment Why does physics have so many symmetries?
Personally, I think "why are there so many symmetries in the physical world" is a really interesting question, and a very clear one. It's one of those questions where you think, "huh, I never even thought of asking that before, but I'd really like to know if anyone has attempted to answer it." So I'm voting to reopen.
Aug
6
comment What planets are visible to the naked eye from Mars?
Don't forget Earth's moon, too - that should be quite clearly visible.
Aug
2
comment Physics-based derivation of the formula for entropy
What you are looking for doesn't exist. The derivation of that formula has always involved information-based concepts. It's just that until they were put on a firm theoretical grounding starting with Shannon in the late 40s, the information-theoretic parts of the argument were given in an ad hoc way. Information theory itself contains no assumptions, only definitions, so an information-theoretic approach does after all "assume only the laws of physics."
Jul
29
comment Has New Horizons' visit to Pluto taught us anything deeper than mere… facts?
Yes. For a start, Pluto and Charon apparently have internal sources of heating. For the moons of the outer Solar system their internal heat source was assumed to be tidal heating, but this can't be the case here. Depending on what's causing it, it might mean that the outer moons' internal heat is not just tidal heating after all. (Disclaimer: I'm no expert and this is all heresay from the popular press.)
Jul
24
awarded  Popular Question
Jul
21
comment What is the entropy of a mixed state in classical physics?
I'm not really sure what you mean by talking about "pure states" and "mixed states" in a classical system, since that terminology is from quantum mechanics. Can you elaborate on what you mean?
Jul
10
awarded  Nice Question
Jul
5
comment Is particle number a problem for formulating statistical physics in a mathematically rigorous manner?
@joshphysics you're right, that statement is too strong, it's also meaningful in the thermodynamic limit for the microcanonical ensemble. (In the limit, both ensembles agree unless you're at a phase transition.) I'll correct my answer when I'm back at a computer, if I remember.
Jun
25
awarded  Good Answer
Jun
14
comment Is there any easy process that absorbs heat?
I take it you mean "absorb heat from the environment at room temperature"? Otherwise cooking an egg (or anything else) would be an example - the coking reactions absorb heat, resulting in the pan being very slightly cooler than it would be otherwise, but still quite hot. For an easy process that absorbs heat at room temperature, you might try evaporation of water. (Or of anything else - ethanol evaporates faster, producing a more dramatic cooling effect.)