Evolution Definition and 735 Threads

https://www.npr.org/2024/12/18/nx-s1-5227247/you-dont-look-a-day-over-4-35-billion-heres-the-moons-anti-aging-secret The paper on Nature - Tidally driven remelting around 4.35 billion years ago indicates the Moon is old https://www.nature.com/articles/s41586-024-08231-0 I have yet to read...

I have a question about the evolution of the universe in reverse. I understand that three things happen: 1- The real black holes of the universe in reverse do not accrete, they expel. 2-The universe contracts. 3-The universe reaches the hot and dense state. Is this correct? Points 2 and 3 are...

How exactly does a star become a red giant, i.e how does its radius expand so much? When a star runs out of hydrogen to fuse into helium the star's core is essentially all helium, but the core isn't hot enough to start the triple alpha process to start fusing helium yet. So gravity takes over...

I heard about a chart today which I knew I immediately had to check. It's called the Histomap (by Rand McNally) and cleverly shows the evolution of the powers of empires, nations and states throughout 4'000 years. Here is an article about it, including the "histomap": “The Histomap: 4000...

Covers: - An investigation of consciousness - Microbiomes evolve with us - How life keeps time

Once you have got over the 'cute' appearance of pandas the temptation to regard them as a shouldn't be allowed, nonsense species. However, their evolution can actually be seen as a an inovative step towards. They have, apparently, been around for three million years so they are successful. You...

Hi, I have a question regarding the evolution of idea in the field of thermodynamics. Boltzmann is genereally credited with the notion of stasticis and it's relation to entropy. However, Boltzmann was inspired by the work of Maxwell (who himself followed the conceptual models of Bernoullli for...

An idea I was thinking about for the last few days: You want to calculate the ground state of some system from the Schrödinger eqn ##\hat{H}\left|\psi\right.\rangle = E\left|\psi\right.\rangle##. One way is to choose a trial state ##\left|\psi (t_0 )\right.\rangle## and use the TDSE to...

By the statement of the question, a solution must take the form ##\begin{pmatrix} \Psi_1 \\ \Psi_2 \end{pmatrix}## and the energy operator will be as per usual ##\hat{E} = i\hbar \frac{\partial}{\partial t}##. I am confused by the fact that ##S_y = \frac{\hbar}{2} \begin{pmatrix} 0 & -i \\ i & 0...

Hi, I have an upcoming exam in astrophysics. We have been told to make sure we study all figures and tables, s.t. we are able to explain them. However, I ran into these figures below, in my lecturer's PowerPoint and I do not know where they originate and aren't presented in my book. I'm having...

https://theintercept.com/2023/01/19/covid-origin-nih-emails/

The usual justification for why the evolution of physical systems is unitary in quantum mechanics involves arguments like "probabilities must sum to 1" or similar arguments that apply equally to any CPTP map. I'm just curious what justifications people here would use for selecting out unitary...

Hi Pfs, consider a pair of maximally entangled photons where the total momentum is null and the same thing for the total angular momentum. I suppose that this pair is like an universe: nothing outside the pair acts on it except maybe a device for the measurement of these two properties (no local...

The Maxwell wavefunction of a photon is given in [here] as follows: Because the curl operation mixes 3 different components, this wavefunction only works for a minimum of 3 space dimensions, with each grid point having 6 component numbers ##{E^1, E^2, E^3, B^1, B^2, B^3}##, and with the...

If energy is "not conserved" in General Relativity (or at least, it is difficult to define it) in the context of an expanding accelerating spacetime (like it happens in our Universe), are there any observations of deviations from the strict conservation laws in the evolution and formation of...

[Mentor Note -- thread moved from the schoolwork forums to the technical forums] Homework Statement:: Tentative Note and summary on the origin and the evolution of information in the universe. Relevant Equations:: none As a teacher of physics I got many questions asked by my students when...

An article came up on Phys.org about a white dwarf drawing in material from the planetary system surrounding it. Is this the ultimate fate of our solar system? https://phys.org/news/2022-06-dead-star-cannibalism-planetary-far-reaching.html...

Why do scientists refer to evolution as a theory which leads to the argument that evolution is "just a theory"? Why don't they use a less confusing word?

The Gene's-Eye View of Evolution. New book by Arvid Ågren (2021), reviews the field of population genetics that is involved with selfish gene kind of thinking (The Selfish Gene, Dawkins, 1976). It breaks down the big arguments into smaller parts and analyses them. Lots of references, but not...

I was watching a program on the formation of the Great Lakes, and it is quite interesting and fascinating. The huge salt deposits under the Lakes Michigan, Huron and Erie and fossilized sea sponges provide evidence of a salt water sea in the past. Limestone formed from successive corral reefs...

One of my friends sent a link to this illustration which I found very, very fascinating: (Image by Matt Baker, UsefulChart.com, image source: link) If I decipher the chart correctly, e.g. the letter "O" developed from an image of an eye. According to the wiki page about "O" an eye indeed...

According to wiki "Neanderthals are an extinct species or subspecies of archaic humans who lived in Eurasia until about 40,000 years ago." But according to wiki again: "A species is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating...

I am considering writing a story that features aliens indigenous to a planet orbiting a red dwarf star. Even so, because of its proximity to the red dwarf, the planet's surface receives much more radiation than Earth's surface does. What is more, the planet has no moon to stabilize its...

Are there certain things that threaten human evolution or at least threaten to make us less functional as a species? If for example we started living twice as long due to medical intervention with better health and started having children at twice the average age? Would it hurt much to have...

I want to develop a 2D random field and its change with time with constant velocity. My process: 1. Define a 2D grid [x, y] with n \times n points 2. Define 1D time axis [t] with n_t elements 3. Find the lagrangian distance between the points in space with the velocity in x and y ...

I have a fidelity between the initial state and final state is 1 at t=0,1,2...etc. What does it mean physically? Does it mean that the quantum state is not evolved here. But In quantum dynamics every physical system evolves with time.

How did you find PF?: QuorA Can you please suggest me a book similar in content to evolution of physics or physics for the inquiring mind perhaps a book with more detail and scope but maintaining the clarity of content shown in the previous listed books above please reply if you know

I have attached my work here. I don't know how to proceed further?

Recently I saw a video from a Christian creationist who was trying to debunk evolution with an argument that if evolution gives us new species all the time why would we make an effort to preserve those that are going extinct. So I was thinking a little bit about it and these are my conclusions...

During time evolution of one photon with vacuum state with hamiltonian as a^†b+b^†a, the answer is cos(t/ℏ)|0,1⟩+isin(t/ℏ)|1,0⟩. But i don't know how to do calculation to get this answer. Can someone please help me? I tried to do this calculation: |0⟩|1⟩(t)=e−iHtℏ|0⟩|1⟩...

The number of visible galaxies is to vanish in the long-term future with the ##\Lambda##CDM model (book and papers of L. Krauss et al). I am interested in a quantitative study on how the population of galaxies decreases; I could not find one so I do it myself: The scale factor...

Since it asks for the time evolution of the wavefunction in the momentum space, I write : ##\tilde{\Psi}(k,t) = < p|U(t,t_{0})|\Psi> = < U^\dagger(t,t_{0})p|\Psi>## Since ##U(t,t_{0})^\dagger = e^{\frac{i}{\hbar}\frac{\hat{p^2}t}{2m}}##, the above equation becomes ##\tilde{\Psi}(k,t) =...

This might be a 'that's just how it is' sort of question, but are there any theories of how humans and higher apes have evolved so that they don't break down uric acid? All other animals break this down into allantoin, and fish go one further and break that down into ammonia. Did 'us apes' end...

I am studying two level atoms interacting with fields in order to study Dicke Superradiance. From Loudon's book, the Optical Bloch Equations for a two level atom interacting with a field say (with rotating wave approx): $$\frac{d\rho_{22}}{dt}=- \frac{d\rho_{11}}{dt} = -\frac{1}{2}...

If different eyes appeared let say to less sun or an accidental mutation, has it become subject to selection of individuals like eugenism or due to modern gene technology nowadays ?

In the first version of their arxiv preprint, Frauchiger and Renner argued that only the many word interpretation of QM was consistent. https://arxiv.org/abs/1604.07422v1 In the second version, the famous one published in Nature Communications, they radically changed their conclusions. They...

https://phys.org/news/2021-04-billion-year-old-fossil-reveals-link-evolution.html I used to have some literature on ancient single cell organisms, but I haven't seen it in decades. https://www.cell.com/current-biology/fulltext/S0960-9822(21)00424-3 Sediments of the Torridonian sequence of...

Hello! Assume I have a classical system at a fixed temperature, such that the energy can be described by a Boltzmann distribution at that temperature. If I have a huge number of such systems in that state, and I measure the energy of each one, independently, the probability of measuring a given...

Two studies on human brain evolution/development. FIRST A new study is the first to identify how human brains grow much larger, with three times as many neurons, compared with chimpanzee and gorilla brains. The study identified a key molecular switch that can make ape brain organoids grow more...

Given the hamiltonian: \hat{H} = \hbar \omega_{0} \hat{a}^{+}\hat{a} + \chi (\hat{a}^{+}\hat{a})^2, where ##\hat{a}^{+}##, ##\hat{a}## are creation and annihilation operators. Find evolution of the state ##|\psi(t) \rangle##, knowing that initial state ##|\psi(0)\rangle = |\alpha\rangle##...

Dear everybody, Let me ask a question regarding the unitary time evolution of a given Hamiltonian. Let's start by considering a Hamiltonian of the form ##H(t) = H_0 + V(t)##. Then, I move to the interaction picture where the Schrödinger equation is written as $$ i\hbar \frac{d}{dt}...

The Canadian physicist, Lee Smolin proposed in the 90's that laws of nature may evolve and change over time. He begun proposing that only the constants of nature would evolve, while the most fundamental laws would remain the same, but recently he has change a little bit his ideas and has...

I am a little confused about how to solve it, probably it is easy but i didn't get it. I thought that would be a good idea to work with ##\psi = \alpha |a_{0}\rangle + \beta |a_{1}\rangle## in the Schrodinger equation with time involved, so that we get a system of differential equations...

New dog genomes from a variety of current dogs as well as many ancient dog genomes have recently revealed a lot about dog evolution. Article in Science (possibly pay-walled). News article in Science. NY Times article. Dog origins: It was thought that there might have been two origins of dogs...

Question --- So I've done a calculation which seems to suggest if I combine the system of a measuring apparatus to say an experimenter who "reacts" to the outcome of the the measurement versus one who does not. Then the change in entropy in both these situations is bounded by: $$ \Delta S_R...

I want to do a project for my class on the obstetrical conundrum. Which is basically the antagonism of selective pressures on pelvic morphology. I need help to find literature. I want to know if over the course of history, if Human baby's fontanelles increased in size in order to compensate for...

Hello I have been reading about the s-process and r-process in star evolution. And one thing i briefly saw mentioned was that both processes generally create higher abundances of elements with even number of protons than odd. It however did not explain why there is a slight bias towards even...

The sudden appearance of SARS-COV-2 as a virulent pathogen in humans raises the question of how it gained the ability to attack human cells and why it is highly contagious. If I understand this right, an article in Virology Blog...

Not sure whether this is the right category but bear with me.I've seen graphics where the information increase with time of evolution is projected like the one in the link below from Carl Sagan's book https://www.researchgate.net/figure/Page-from-the-book-of-Carl-Sagan-21_fig2_322153131 Now I...