# Site ## Pages - [Page not found](https://comp4020-agentic-coding-studio.github.io/comp4020-ass2-Vivek-Suryawanshi/404/): That page doesn't exist, or it has moved since you last looked - [Assessment](https://comp4020-agentic-coding-studio.github.io/comp4020-ass2-Vivek-Suryawanshi/assessments/): Every piece of graded work in the course, what it is worth, and when it is due. - [Let the numbers decide](https://comp4020-agentic-coding-studio.github.io/comp4020-ass2-Vivek-Suryawanshi/assessments/let-the-numbers-decide/): Two explanations can both sound plausible. Only a calculation tells you which one the evidence actually supports. - [What the explanation leaves out](https://comp4020-agentic-coding-studio.github.io/comp4020-ass2-Vivek-Suryawanshi/assessments/what-the-explanation-leaves-out/): Pick one explanation everyone already believes, and find the exact edge where it stops being enough. - [Where explanation breaks](https://comp4020-agentic-coding-studio.github.io/comp4020-ass2-Vivek-Suryawanshi/assessments/where-explanation-breaks/): Locate an open question the course leads to, and map exactly where present physics stops being enough to answer it. - [Lectures](https://comp4020-agentic-coding-studio.github.io/comp4020-ass2-Vivek-Suryawanshi/lectures/): What is covered, week by week, and which topics each lecture draws on. - [Why is the night sky dark?](https://comp4020-agentic-coding-studio.github.io/comp4020-ass2-Vivek-Suryawanshi/lectures/week-01/): The darkness between the stars looks empty. It is not. A dark night sky already tells us that the universe has a history. - [What is the oldest light we can see?](https://comp4020-agentic-coding-studio.github.io/comp4020-ass2-Vivek-Suryawanshi/lectures/week-02/): The dark sky is not really dark. Point the right instrument upward and the whole sky glows in microwaves — with a spectrum that looks exactly like something at a temperature. - [What is a temperature?](https://comp4020-agentic-coding-studio.github.io/comp4020-ass2-Vivek-Suryawanshi/lectures/week-03/): One molecule in an empty box has a speed and an energy. It does not have a temperature. Add an enormous number of them and temperature becomes one of the most reliable things you can measure. - [How does a crowd have properties its members don't?](https://comp4020-agentic-coding-studio.github.io/comp4020-ass2-Vivek-Suryawanshi/lectures/week-04/): You cannot predict where one gas molecule will be a second from now. Give a physicist a litre of the gas and they will tell you its pressure to several decimal places. - [Why does time run one way?](https://comp4020-agentic-coding-studio.github.io/comp4020-ass2-Vivek-Suryawanshi/lectures/week-05/): Run the film of a gas filling a room backwards and it looks obviously wrong, even though every collision in it still obeys ordinary mechanics. The arrow of time is not written into the laws. It has to come from somewhere else. - [How do organised structures persist at all?](https://comp4020-agentic-coding-studio.github.io/comp4020-ass2-Vivek-Suryawanshi/lectures/week-06/): The second law says disorder tends to grow. A whirlpool, a flame, and a living body all keep their shape anyway. None of them are cheating. All of them are open. - [Why hasn't the Sun burned out?](https://comp4020-agentic-coding-studio.github.io/comp4020-ass2-Vivek-Suryawanshi/lectures/week-07/): Chemical burning gives the Sun a few thousand years. Gravity gives it tens of millions. The rocks say billions. This is the week where arguing stops working and you have to calculate. - [How do two nuclei that can't touch, touch?](https://comp4020-agentic-coding-studio.github.io/comp4020-ass2-Vivek-Suryawanshi/lectures/week-08/): The Sun's core is hot, but not remotely hot enough to force two protons past their mutual repulsion. Quantum mechanics does not get them there by giving them more energy. It gets them there by not requiring a sharp edge at the wall. - [What is a particle?](https://comp4020-agentic-coding-studio.github.io/comp4020-ass2-Vivek-Suryawanshi/lectures/week-09/): Fire particles through two slits one at a time, and each one lands as a single point. Do it enough times and the points draw stripes only a wave could make. No single old picture explains both facts. - [What happens when you look?](https://comp4020-agentic-coding-studio.github.io/comp4020-ass2-Vivek-Suryawanshi/lectures/week-10/): A measurement is not a human blinking at reality. It is a physical interaction that spreads a quantum system's alternatives across an enormous environment until they can no longer interfere. That explains a great deal. It does not explain everything. - [Why does matter behave like matter?](https://comp4020-agentic-coding-studio.github.io/comp4020-ass2-Vivek-Suryawanshi/lectures/week-11/): A table feels solid. Push on it and it pushes back. The honest explanation for that push is not one tidy principle — it is atomic structure, electric repulsion, and quantum exclusion, all doing work at once. - [Where does explanation break?](https://comp4020-agentic-coding-studio.github.io/comp4020-ass2-Vivek-Suryawanshi/lectures/week-12/): Push a dead star's mass past its limit and gravity wins outright — that part we understand. Push relativity and quantum mechanics into the same extreme regime and neither is enough alone. Zoom out and most of the universe's contents have never been identified. Those are three different kinds of not-knowing. - [People](https://comp4020-agentic-coding-studio.github.io/comp4020-ass2-Vivek-Suryawanshi/people/): Who teaches the course, and how to reach them. - [Idris Fenn](https://comp4020-agentic-coding-studio.github.io/comp4020-ass2-Vivek-Suryawanshi/people/idris-fenn/): A tutor working across the course's first reviews and the practical work that follows them. - [Marisol Quaye](https://comp4020-agentic-coding-studio.github.io/comp4020-ass2-Vivek-Suryawanshi/people/marisol-quaye/): The founding convenor, responsible for the course's shape and its weekly teaching programme. - [Policies and support](https://comp4020-agentic-coding-studio.github.io/comp4020-ass2-Vivek-Suryawanshi/policies/): How AI and sources are handled, what mathematics is assumed and when, a teaching-calendar change, and how to get help. - [The CMB spectrum, from real data](https://comp4020-agentic-coding-studio.github.io/comp4020-ass2-Vivek-Suryawanshi/sessions/01-cmb-data-lab/): Real COBE/FIRAS measurements, plotted against a blackbody curve you compute yourself, so "the early universe looks thermal" stops being something you were told. - [Counting microstates by hand](https://comp4020-agentic-coding-studio.github.io/comp4020-ass2-Vivek-Suryawanshi/sessions/02-counting-microstates/): A system small enough to list completely, until the statistical argument for entropy is something you counted rather than something you read. - [The Sun's lifetime, calculated](https://comp4020-agentic-coding-studio.github.io/comp4020-ass2-Vivek-Suryawanshi/sessions/03-sun-lifetime-calculation/): The estimates that rule out chemical burning and gravitational contraction, redone by hand instead of read off the lecture. - [What degeneracy pressure can and cannot hold up](https://comp4020-agentic-coding-studio.github.io/comp4020-ass2-Vivek-Suryawanshi/sessions/04-degeneracy-pressure-limits/): Reasoning quantitatively about why squeezed electrons push back harder, and why that pushback runs into a ceiling gravity does not share.