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

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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

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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?

2025-01-20 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

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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!