StartsWithABang

The Universe is expanding, cooling, and dark. It started with a bang, and I'm here to bring it all to you!

Last Notes

2025-05-20 17:04:33 UTC

- reply

Energy is conserved in all GR solutions that possess a time-like Killing vector. (I.e., in static, non-expanding, non-contracting spacetimes.)
Schwarzschild and Kerr metrics have these vectors, and therefore there is global energy conservation in those spacetimes.
Also, there are still energy conditions (e.g., the null energy condition) that ought to hold even in non-energy-conserving spacetimes, which is why we can't just keep pulling things out of the quantum vacuum for free.
But John will understand these issues more deeply than I do, if what I've posted here isn't enough (or isn't rigorously true).

2025-03-08 15:15:49 UTC

- reply

So, let's pretend we lived in a world where instead of me being an astrophysicist who became a science communicator, I (or someone like me) was a condensed matter physicist who became a science communicator.
How should I be communicating the notions of states of matter (and/or phases of matter) to the general public?
What don't they know; what should they know; how should they think about it?
How do you convey "there are X different phases of superfluidity in different isotopes of helium" or "Y different phases of water-ice in solid form" or "every phase transition yields a new state of matter" without rendering everyday concepts of what a "phase" or "state" of matter is untenable?
In biology, we have many different granularities of classification for organism, from superkingdom to subspecies. Do we need something like that for states of matter? And what would it look like?
I'm legitimately not enough of an expert to have a strong opinion. What's yours?

2025-03-07 18:15:26 UTC

- reply

If he had said "phase of matter" I wouldn't have objected.
It's sort of like when planetary geologists use the geophysical definition of a planet: sure, there's nothing wrong with it in their own field, but telling the general public that the moon is a planet, Jupiter's galilean moons are planets, Ceres is a planet, hundreds of Kuiper belt objects are planets, etc., really misleads the public in a way I don't support.
You're not talking solely to other condensed matter physicists here; you're talking to the world. What would you like them to understand, and how can you meet them where they are? (Remember, their starting point is likely to be: solid, liquid, and gas are the three states of matter.)

2025-03-06 16:08:03 UTC

There are 7 states of matter; “topoconductor” isn’t one of them
There truly are more states of matter than just solid, liquid, and gas: a total of 7 states, all told.
But no, Satya Nadella, "topoconductor" isn't one of them at all.
https://bigthink.com/starts-with-a-bang/7-states-of-matter/
https://media.astrodon.social/media_attachments/files/114/116/342/846/323/076/original/abd7071bc4476e2d.jpg

2025-01-20 16:28:56 UTC

The Ring Nebula’s true structure revealed at last
For nearly 250 years, astronomers have marveled at the Ring Nebula.
At long last, we know its true shape, and while it does possess a ring, it truly is so much more.
https://bigthink.com/starts-with-a-bang/ring-nebula-true-structure-revealed/
https://media.astrodon.social/media_attachments/files/113/861/621/868/073/726/original/212ba3c37ec8576f.jpg

2024-11-20 18:51:14 UTC

- reply

Lovely! I am a big fan of creative cooking and this is the opposite of the turducken I made 16 years ago: reducing the turkey to its constituent parts instead of adding additional birds inside of it!

2024-11-20 18:13:22 UTC

What happens if you deep fry a frozen turkey?
It's that time of year once again: where 46 million turkeys are about to be cooked, and 1000+ home fires are anticipated.
Don't be one of them, and especially don't deep fry a frozen turkey!
https://bigthink.com/starts-with-a-bang/what-happens-deep-fry-frozen-turkey/
https://media.astrodon.social/media_attachments/files/113/516/635/789/654/434/original/0df571a673c328f8.jpg