Hi, everyone, I had a great conversation with Geraint F. Lewis, a Welsh astrophysicist and Professor at the University of Sydney, about some of the biggest questions in cosmology, physics, and our understanding of the world.

We explore what the Big Bang theory tells us about the beginning of the universe, why our current understanding of physics reaches limits when we try to look further back in time, and how neutrinos could reveal secrets about the cosmos — including why matter exists at all. We also mention the 2026 Nobel Prize in Physics, awarded to Francis Halzen for his work on the IceCube Neutrino Observatory.

Professor Lewis also explores what sparked the Scientific Revolution, how modern science transformed our understanding of the world, and why Einstein challenged aspects of quantum mechanics.

Professor Lewis's latest book, The Shortest History of Reality: From Plato’s Cave to the Mind-Bending Discoveries of Modern Physics — The Human Quest to Explain the World, traces humanity’s changing understanding of reality, from everyday intuition and ancient philosophy to the discoveries of modern physics. It explores the ideas that reshaped our view of existence, from Newton’s universe to the strange probabilities of quantum physics and beyond.

If you're interested in these subjects, you can check out our conversation, hope you find it insightful: https://youtu.be/38rUHEeAVHw

As the title suggests, I am wondering where I should get started with learning more about astrophysics.

In college I took one mathematics course and it was, "Applied Mathematics for Astrophysics" and it was one of the few classes where I felt like I was actively engaged and enjoyed learning a bit more than usual.

Now that was a little over 10 years ago and recently I have begun to think of how can I learn more before potentially deciding to upend my life and apply to a Doctoral (PhD) program somewhere to get a PhD in Astrophysics.

What books and other materials would people recommend I get started with to really learn more and delve deeper into this field of study and science, and most importantly help me understand whether or not I should look into this more. Truly the broadstrokes until I learn more and figure out a niche to learn even more about/focus more on.

It has been a month since my last update here, and the Oct 10 storm was the first real test of a lot of it. So here is how the site did, then what's new.

How it did on Oct 10. The arrival window for the Oct 8 CME opened at 17:06 UT on the 10th. The shock reached L1 at 14:40 UT, about two and a half hours before that. The storm estimate had an upper range of G2. It reached G3. So the timing was close and the strength was under. Both go on the public scoreboard with every other forecast the site has issued. So far that is 8 scored: 7 arrived inside the window, 1 just outside, with a median miss of about 10 hours.

I also ran a stricter test of the storm strength estimate and it did not hold up. At launch time it does no better than guessing the same level every time. The science page says so. The direction of a CME's magnetic field decides the storm, and nobody can measure that until it reaches L1.

What's new since September

A redesign. The CME list is now a table: launch, speed, whether it is aimed at Earth, and when it should arrive. Click one and the answer comes first: arrival time, the 80% window as a bar, and the likely storm strength.

A record of each forecast. Every CME now shows how its arrival forecast has moved and why, for example when NASA revises the speed. Once the window closes it shows what actually arrived.

Magnetic wake. A new map layer that draws the magnetic field measured at L1 where that plasma is now. A ribbon trails out from Earth, red where the field pointed south and blue where it pointed north. Each storm leaves a striped fan. The May 2024 replay is the one to look at.

A rebuilt 3D view. CMEs are whole cones now, the Sun is the real SDO image for that hour, and you can put the camera on Earth and watch a CME aimed at us turn into a halo.

Two new charts. A time-distance chart with every CME as a line climbing from the Sun. And a storm anatomy chart that puts one eruption on a single time axis: flare, protons, transit, the wind at L1, then Kp and Dst.

Satellite drag. An Atmosphere view that shows how much a storm swells the upper air, with the measured altitude of the ISS, Tiangong and Hubble back to 2015.

Maps. The aurora oval as a map you can tap for your location, and a radio blackout map for flares.

A status page. NASA moved its CME catalogue to a new address on Sept 30 and the site stopped picking up new eruptions for four days before I noticed. That is fixed. Now every data feed is checked every 10 minutes on a public page.

It also installs as an app from Chrome, Edge or a phone's home screen.

Still free, no account needed.

https://www.cmetracker.ai/live?utm_source=astrophysics

What would you want to see next? And if you watched the Oct 10 storm on it, what did you check first?

This is a two part question and I am going to reveal myself to be an absolute novice, so if I’m in the wrong spot for these types of questions please just show me the door.

I was watching a video about MoM-z14 galaxy, which per the video is the farthest observable galaxy. The video talked about how the photons from the galaxy have become stretched as the universe has expanded and that the galaxy is 33.8 billion light years away, even though the big bang thought to be ~13 billion years ago.

So if the wavelength of a photon is being stretched, would that not affect the speed of light? And does this mean the universe is expanding faster than the speed of light?

See also: The publication in the Astrophysical Journal

Is there anyone who has been selected for the Max Planck Institute for Astronomy Internship or any other Internship of the same reputation? If so, could you please tell me what you have done or what experiences you have had? I have been applying to summer schools and Internships, but haven't been selected for any of them. Could someone help me with what to do?

Okay, so this is a little out there, don't know if this is the place for it. But here goes: upon my expiration, I would like to be cremated and compressed into a diamond. I would then like that diamond launched out into the Kuiper Belt to become a comet seed that hopefully, through cunning physics, could pass by earth epochs later as a proper comet (or possibly Deep Impact the earth, I'm cool with either). Is that possible?

Researched on directions of failure of SETI.

Published on Zenodo, however I need an endorsement of astroph.IM to post on arXiv
Has anyone of ya'll posted on arXiv on this subject before, who could endorse me ?

Basically, how big does a quasi star need to be for the core to collapse into a black hole? I would assume it'd have to be bigger than the biggest star we know of (stephenson 2-18 I think) or is there another way it forms?

My daughter is a junior in high school and a strong interest in astronomy and physics. For the last several years her answer to "what are going to be" has been an astrophysicst. Her goal is PhD and work in Space; more theoretical and less hardware.

How would you approach the undergraduate years? Her top schools are UT Austin and U Arizona. What elsse should be considered? Would you start with physics as the BS or do an astronomy focus?

For those who have done graduate degrees, what would you do differently? Anywhere else this could be posted?

Thank you

Hello everyone!!

I’m a recent high school graduate in my gap year… I was thinking of making an astrophysics project using Python (no modules, pure Vanilla Python)

I’m thinking of making a 2D Newtonian gravity simulator

Here’s what I’m aiming to build-
-Pure Vanilla Python (only basic modules like math and random; no NumPy, SciPy, etc.)
-Newtonian gravity, 2D only
-Max 2 stars, 5 planets, 3 moons per planet (22 bodies total)
-User inputs masses, physical radii, orbital radii and initial positions/velocities
-Fixed 1-hour timestep
-Simulation duration: 1,000 years
-Using high school math and physics only
-Detect collisions (when, where, and between which bodies)
-Detect ejections (which body and when)

Only issue is, I have the idea, but don’t know where or how to even start…

Those who’ve worked on similar projects, what should I do?

Thanks!!

Hello!
I'm preparing for the regional level of the astronomy olympiad in my country currently and I wanted to know how I could prepare the Astronomy parts specifically.

I only need to do elementary astronomy currently-- specifically stuff relating to constellations and asterisms.

These are some example questions from the olympiad.

Q. In which constellation would you find globular clusters?
A: Sagittarius

Q. Star A rises half an hour before star B and it sets half an hour after star B from a particular location. Which of the following statement(s) is/are correct?

(a) The location is on equator.
(b) The location is in southern hemisphere and star A is more south than star B.
(c) The location is in northern hemisphere and star A is more north than star B.
(d) Both stars have the same right ascension.

How can I prepare for this as I haven't found a good guide for things aimed specifically towards these subjects.

Just a random thought. If two black holes of some mass (M) collided with one another, especially if they both had some angular momentum, shouldn’t the resulting black hole have a mass greater than the sum of its constituents? Since the kinetic energy of the collision would be sucked into the singularity? Since in this case M=e/C2? And since we all know that not even light could escape C then the kinetic energy of the impact must be converted into mass?

Hey everyone,

I’m currently a Computer Engineering student (M1 level in Europe) and I realized I want to pivot into computational astrophysics/cosmology, but I don't have a Physics degree.

My background:

• Math: Standard engineering math (Calculus I-III, Linear Algebra, ODEs).
• Physics: Basic university sequence (Classical Mechanics, Electromagnetism), plus some basic knowledge of tensors and General Relativity.
• CS: Low-level programming (C, C++), architecture, memory management, and HPC (High-Performance Computing). I also have some knowledge of Machine Learning. And some superficial knowledge in numerical methods and GPU acceleration.

I know my best entry point is using my computing skills to solve software bottlenecks in astrophysics/cosmology labs (e.g., optimizing heavy numerical relativity simulations). However, my long-term goal is not to just be the "IT guy" of the research group. I want to gradually learn the theory, understand the physical models, and transition into actual science.

My questions:

1. Is this gradual transition realistic? Can I start by doing heavy infrastructure work and eventually become a researcher, or will I be stuck as software support forever?
2. What should I prioritize for self-studying right now? Knowing ODEs, Calculus, and the basics of tensors/GR, what is the exact roadmap to get to the required level for this field?
3. What kind of places and research jobs should I look for?

Any advice or harsh truths are welcome. Thanks!

Hello fellow astrophysicists! I am currently applying to Spain for an exchange semester, and I only have extracurriculars left to take.

I was browsing through classes and an Extragalactic Astrophysics class caught my attention; it’s always been a special interest of mine. The class recommends basic knowledge of astrophysics.

I’ve only taken physics, calculus, and chemistry courses… So I don’t know if it would be a mistake to take this course. Please be completely honest with me, will this class be terrible for my GPA or will I be able to handle it?

So I started uni course and it had a compulsory python module. I liked the idea and decided to expand further with python since it feels essential for any career in astro.

I saw this book by IOP and since they regulate my degree I thought its a good idea to start reading it.

I only found this review but I wanted more trusted opinion from anyone who tried it. It doesn't have ADQL which i get is essential for python and i am not sure it would be a good idea to use the book now.

Okay so I had a random shower thought the other day and wasn't really sure where to ask but what happens to a compass in space? Does it still point north or does it just keep spinning or does the earths magnetic field mess with it?