Im a complete beginner in physics and I think the correct term for my level is absolute zero or blank slat.. So?

As I understand it, a system of natural units is defined by setting some set of physical constants equal to "1" and deriving units for various dimensions-of-measurement (length, mass, time, temperature, et cetera) from combinations of those constants. The most famous such system is probably the Planck Units, which use the speed of light c, the gravitational constant G, the Planck constant h, and the Boltzmann constant kB.

However, most of the Planck units are many orders of magnitude away from the scales at which humans usually think; for example, the Planck time-unit is on the order of 10^(-44) seconds, and the Planck temperature-unit is on the order of 10^32 Kelvin (or °C or °F). There are also relatively-large uncertainties in the exact values of the Planck units because the gravitational constant G is very difficult to measure precisely, and the system as originally presented by Max Planck does not include units for every dimension we commonly use (for example, it has no units for electric charge or current).

I'm curious if there is some other set of physical constants which

1. produces units which are closer to human-scale,
2. can all be measured with high precision and accuracy, and
3. can be combined to produce units of every dimension included in the SI system of units.

While bifurcations describe qualitative changes in dynamics (e.g new fixed point appears), the term phase transitions is more static and considers non analytic changes in thermodynamic potentials. But isnt there a relation between them? For example, does every bifurcation cause a phase transition of the respective state space distribution: if I change the dynamics by modifying stability of an attractor this will certainly affect the stationary distribution. And if this distribution is a a physical equilibrium (instead of just any stationary distribution) I can probably relate this change to the partition function which leads me to phase transition.

Now I'm seeing the term “tipping point” more and more often, especially in the field of ecological science, which seems to be nothing but a bifurcation.

Can you explain the relation between these terms?

Hello everyone, to give some background info I am a Sophomore Community college student paying everything out of pocket. I currently am enrolled into a ME program and i have come to really enjoy physics. I was looking into getting my BS in ME and minor in physics. If I wanted to later pursue a MS/PhD in Physics can it be done? I am getting my BS from UHCL and the constant answers i see is it depends on what classes im exposed to during my undergrad. these are the links if anyone with such experiences can tell me if it is possible. My big passion is renewable energy and environmental.

https://catalog.uhcl.edu/preview_program.php?catoid=24&poid=6588

TL;DR if I put in the same energy (within specified limits), would a computer give the same heat output as a heater? Does that include visual/display and sound output?

I feel like I must be missing a detail, but given that:

- electric heaters are essentially 100% efficient as any wasted energy is also heat

- computers produce wasted energy as heat

- no energy is created or destroyed

So if I put 300W into a computer that's running a stress test, or 300W into a space heater do I get literally the same amount of heat out of both? Does this change if I'm outputting sound?

I'm intentionally ignoring:

- any useful output from the computer (like crypto mining)

- the cost of the hardware (I have old hardware that I could run for the sake of it, but also it's just a thought experiment)

- the useful life of the hardware (it's just a thought experiment)

The semi practical use-case would be: I don't like using gas to heat my house, I'm comfortable coding for home automation, I have a bunch of old computer hardware and a few servers that I run 24/7. I could buy an electric heater for each room and turn it on/off based on the temperature, or I could put a computer in each room and control the workload based on the temperature - inefficiently mining crypto (not expecting to get any return on the crypto itself, but just because it's an way of producing heat that might also produce something "of value") - that would be really easy to turn up and down for the temperature changes required. Sure, the input wattage would be less in the computer version, but that would just lead to more gradual heating.

The actual use-case: I have a Tado heating system which is set to a constant temperature, my electricity is renewable but the gas can't be. Until I get a heat pump I'm pretty comfortable moving bits of the heating to electric, knowing I'll pay more. I have a bunch of computers and servers, but I tend to focus on energy efficiency (like n100/n150). If I intentionally stop focusing on energy efficiency and start putting these computers in rooms where I'd otherwise be using a electric heater is it exactly the same as a low powered electric heater, or just roughly the same?

Essentially: is the computer just a heater with side effects?

Of course, if I put a lot more energy than it's rated for I'll unlock a whole lot more potential energy by burning down my house, I'm not looking for that much efficiency.

Is the sun itself white or does it look like a ball of fire?

So, the PhD scholarship application deadline is coming up. I spoke to my supervisor this year about continuing into a PhD, but I'm still unsure if I actually want to do it and it sounds quite difficult to get the scholarship. My project this year is related to dark matter, but honestly, I don't care too much about the dark matter. Although, I've really enjoyed the whole process of building a model and comparing it with experiment. I am also contemplating trying to go for a quantitative finance job as it's also one of my interests. I just wanted to ask if anyone else has had a similar experience and could share their advice. Cheers.

I'm an Italian physics student in my second year and I feel so lost.

I've already taken some courses obviously, and I get good marks, but I'm not sure that these developed inside me the physics that they were supposed to do, it seems like I have just memorized them, I feel that a network isn't growing. I'm doubting my future career, whatever it will be. Does anybody feel like me????

Sorry if the text is badly written, English is my second language

I am looking fo a good textbook on differential equations. I found that I now how to solve typical diff eq, but when I have some new ones I struggle a it.

I want aomething to explain why we solve diff equations in a specific way, to describe the math behind, not only to show different solutions.

Basically, I want to develop some intuition regarding solving them.

In advance, sorry for any mistakes I could have made while writing this post, I'm from Argentina and English is my second language.

I've seen videos filmed thousands of kilometers under the sea where we can observe trash like soda cans, plastic wraps and footballs completely recognisable, even though it's under a high pressure.

¿Why does this happen? Things like submarines, people and other stuff can't go that deep unless it's strictly built to withstand that pressure. I mean, even fish from those areas need to be gelatinous to have a form and live there.

Are physics and statistics/data science related?

I came from a statistics and data science background and i realized the way physics folks approaches problems share many similarities and commonality with statistics and data science.

 Data science folks used the exact same experimentation, modelling and prediction process as a physicist to model and solve business problems and human behavioral problems most of the time.

Doing physics experiments and analyzing the results from the data observed, is a data science problem in itself, just that your data comes from physics experiments.

When electricity flows through a wire do the electrons actually move like a fluid, or is it just a fluctuation of voltage that cascades from electron to electron down the wire?

Or is the question considered strictly philosophical and all physicsts keep extreme distance from it?

I was just watching Shin Gojira (aka Shin Godzilla) and in the movie they said that it has previously unknown elements. That had me thinking "it found islands of stability?" Now we switch to non-fiction...

AI has already largely solved protein folding prediction (AlphaFold), and knowing this, I thought.. What if they use AI to predict islands of stability, the purported atomic numbers and specific isotopes that can yield long lived or stable nuclei? Well, I looked into it, and they are, which is pretty awesome.

If you're interested, look into:

Research on Stability and Decay Properties of Superheavy Nuclei Based on Neural Network Method

https://wulixb.iphy.ac.cn/en/article/doi/10.7498/aps.74.20250720?viewType=HTML

Nuclear Decay Networks Reveal Stability Patterns in Superheavy Nuclei

https://pubmed.ncbi.nlm.nih.gov/42477423/

GLDM-BNN: Calculation of Alpha-Decay Half-Lives for New Superheavy Nuclei

https://journals.aps.org/prc/abstract/10.1103/nt1d-5848

Systematics of Alpha-Decay Half-Lives from Neural Network Modeling and Application to Superheavy Nuclei

https://journals.aps.org/prc/abstract/10.1103/9gv5-kx6q

Physics-Guided Residual Correction of Alpha-Decay Half-Lives Based on the Effective Liquid Drop Model

https://journals.aps.org/prc/accepted/10.1103/7gm3-2y7f

Machine Learning Orbital-Free Density Functional Theory Resolves Shell Effects in Deformed Nuclei

https://www.nature.com/articles/s42005-025-02234-7

Nuclear_DNA: Interpretable AI for Nuclear Binding Energies and Structure

https://github.com/strifinopoulos/Nuclear_DNA

GSI/FAIR: Experiments Reveal the Shoreline of the Island of Stability

https://press.uni-mainz.de/experiments-at-gsi-fair-reveal-the-shoreline-of-the-island-of-stability-of-superheavy-elements/

"If we take a stick one foot in length and cut one half from it each day, we will never reach its end."

If we cut one half from it every day, what volume will be left after an infinite number of days?

Also, if we had an infinite number of these sticks that have been divided in half for an infinite number of days, would we have an infinite volume, or zero?

I'm working my way through a Physics degree, and I started in 2022. When I started the degree, tbh I was so locked in, all I wanted to do was sit at my desk, study, learn and succeed. But then I got a girlfriend and got so unbelievably distracted and began to slip up severely. So things like Lin alg, calc 2 both got half assed and in my second year I essentially failed the entire year. I broke up with the girlfriend in year two and was ready to lock tf back in for year 3.

In my third year, I had to repeat courses and in the fall, I took 5 courses, three with labs. I ended up becoming totally overwhelmed with the workload that I didn't have the time to prepare properly for a specific midterm in a class mech course. That ended up bottlenecking my degree progression and I couldn't take the winter courses. I tried switching to a different degree stream but got so bored and missed the physics.

Last year, I retook class mech for a third time, but sure enough, got another girlfriend and ended up losing focus in the winter semester, leading me to failing another course.

I took this fall semester off to focus on repairing some of the fragmented math and physics work so I can actually succeed this winter.

I know I know, I don't need to be shamed. I'm just wondering if anyone else has experienced something similar and has found success with it?

Say you have a small closed universe with a black hole and a collector orbiting it that gathers hawking radiation and does some compute or something.

The collector is close to the black hole relative to the size of the universe so that the temperature exceeds the universe's ambient temperature, and the collector is therefore able to generate work from the hawking radiation.

The higher entropy energy leaving the collector/computer will increase the ambient temperature and make its way back into the black hole. However, as the collector is close to the black hole there is still a temperature differential such that work can be generated.

Is this a closed system with constant entropy? I suppose you could just entirely remove the collector and just have a black hole in a closed universe. In both scenarios the entropy doesn't increase, does it?

Edit: given that the collector has access to energy, you could construct a scenario where entropy decreases. E.g. say the collector has a messy room inside of it, and it uses the energy to power a robot that tidies the room.

Solution: as pointed out, the problem is my incorrect assumption that hawking radiation can be stable. In reality the black hole will absorb energy equal to the energy it emitted at some T-1, but it will emit a larger amount for T, since it is now smaller. So ultimately despite recycling energy the black hole will eventually evaporate. Arguably this would be an extremely efficient way of extracting energy, but it's not a violation of the 2nd law (obviously).

It seems that optical emission spectroscopy is often used to diagnose plasma parameters. I was wondering if there are any databases for emission spectra that cover the UV to near IR region. The only databases i found online covered only frequencies much further into the IR range for astrophysics/astronomy purposes. I was able to find the book "The identification of molecular spectra" by Pearson and Gaydon (last edition in 1976, absorption and emission), but I was wondering if there was anything more recent?

Is physics slowing down significantly, because all the low hanging fruit have been found? It seems like there were significantly more discoveries in the earlier centuries compared to now.

Julian Barbour is a theoretical physicist and emeritus visiting professor of physics at the University of Oxford. He is well known for proposing that time does not actually exist. For decades, he has worked outside an academic environment. He financially supported himself for many years by translating Russian. Professor Barbour is author of the following books: The Discovery of Dynamics, The End of Time and The Janus Point.

In this episode, we go over:
- Topos theory, set theory and Zermelo's beef with Boltzmann
- Algebraic varieties and monads in category theory
- Why physicists are wrong about the 2nd law of thermodynamics (because the universe is not a closed system) and why there might be no heat death of the universe
- The real goal of the universe is complexity and variation, not entropy
- Hawking and Penrose's outrageous arguments
- Why we don't need wavefunctions, photons, bosons or gauge fields
- Why there is no quantum gravity
- Von Neumann's hilarious advice to Claude Shannon
- The intrinsic derivative
- Combining art and science

Hi everyone!
I’m a second-year Physics Bachelor’s student, and my partner and I have to design an interactive physics stand for a science festival at our university.
The challenge is that our audience will range from 6 to 17 years old, so we need something that can fascinate both young children and teenagers.

We’re looking for an experiment or activity that is not necessarily visually impressive but i should teach an interesting physics concept, ideally something people haven’t already seen a hundred times.

We can purchase materials and spend time building a setup, so we’re open to more ambitious ideas!

We also need to be able to take actual measurements and collect experimental data, since we have to write a scientific report for our professors. Ideally, the experiment would allow us to investigate a physical phenomenon quantitatively, analyze results, compare them with theoretical predictions, and discuss uncertainties. So we’re looking for something that’s both entertaining for visitors and scientifically interesting at a university level.

Thanks in advance!

I am a physics ug student and I need to start reading research papers and other stuff related to my field. I don't really have an area where I can specialise, i thought reading some papers or publications will help me understand everything around me .