Oliver Hahn 🇪🇺
@cosmohahn.bsky.social
130 followers 100 following 48 posts
Computational Cosmologist, Simulator of Universes, Producer of NaNs, Prof @univie.ac.at, opinions solely my own, (he/him), 334ppm
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Reposted by Oliver Hahn 🇪🇺
drnereide.bsky.social
Remebering Hannah Arendt’s birthday yesterday, 14 Oct 1906.

"The moment we no longer have a free press, anything can happen. What makes it possible for a totalitarian or any other dictatorship to rule is that people are not informed; how can you have an opinion if you are not informed?"
1/
#History
The half-length photograph portrays a young Hannah Arendt in 1933. Hannah has her hair gathered with a center parting. She wears a dark dress with a fitted bodice and a vertical row of buttons. Her arms are crossed, and she holds a cigarette between the index and middle fingers of her right hand.
cosmohahn.bsky.social
Somewhat excited about teaching to our undergrad students today how the velocity field of a fluid can always be decomposed into a scalar (expansion/compression), a vector (rotation), and a tensor (shear) part. Simple and yet profound...
cosmohahn.bsky.social
I don't know what that is, "JWST"... "Just Write Something Tonight"?
Reposted by Oliver Hahn 🇪🇺
startswithabang.bsky.social
Cosmic inflation’s biggest criticisms can’t undermine its success

There are always lots of arguments to be made against a leading scientific theory.

But good ones?

Take a close look at the ones against inflation, & see how weak-sauce they are.

bigthink.com/starts-with-...
#space #physics #astro
Cosmic inflation's biggest criticisms can't undermine its success
Inflation's two main criticisms, that it can predict anything and that the "measure problem" remains unsolved, can't erase its successes.
bigthink.com
Reposted by Oliver Hahn 🇪🇺
johnholbein1.bsky.social
This is your periodic reminder that you can add coffee stains to your LaTeX documents.
cosmohahn.bsky.social
I am a professor for data science in astrophysics and a cosmologist, working mostly in numerical cosmology
Reposted by Oliver Hahn 🇪🇺
profannawatts.bsky.social
Lol the Nobels can't even acknowledge women's contribution to discovery. But sure let's acknowledge The Machines.
Headline from an article in Nature this week that states "Prizes must recognize machine contributions to discovery. The future of science will be written by humans and machines together. Awards should reflect that reality."
cosmohahn.bsky.social
Proud moment: very hard work by Florian List (also w/ L. Winkler and T. Floess): our super-fast differentiable N-body framework "DISCO-DJ" had a first release (github.com/cosmo-sims/D...) and a massive paper (arxiv.org/abs/2510.05206) - we'll use it to fit simulations to our Universe... #cosmology
Reposted by Oliver Hahn 🇪🇺
Reposted by Oliver Hahn 🇪🇺
cosmohahn.bsky.social
Everything has to end. Many exciting talks and discussions how to extract maximum information about #cosmology from #galaxy-surveys and realise the promise of full #field-level-inference during our workshop @esivienna.bsky.social .... videos here (more to come): www.youtube.com/playlist?lis...
Reposted by Oliver Hahn 🇪🇺
esivienna.bsky.social
The week is slowly coming to an end. 🌌 Missed a session? Rewatch talks from Zoltan Haiman, Chiara Moretti, David Alonso & many more here:
www.youtube.com/playlist?lis...
Reposted by Oliver Hahn 🇪🇺
astrobites.bsky.social
What is a CV? How is this different from a résumé? How do I start building a CV? All of these questions and more await within this guide written by many of our authors! 🔭✨☄️
astrobites.org/2025/09/23/g...
Guide to CVs
What is a CV? How is this different from a résumé? How do I start building a CV? All of these questions and more await within this guide!
astrobites.org
Reposted by Oliver Hahn 🇪🇺
Reposted by Oliver Hahn 🇪🇺
esivienna.bsky.social
We’ve just started the workshop Putting the Cosmic Large-scale Structure on the Map: Theory Meets Numerics, organised by @cosmohahn.bsky.social, Cornelius Rampf & Cora Uhlemann. A full week of exciting talks and discussions is ahead. 🌌
📎 Info: www.esi.ac.at/events/e576/
cosmohahn.bsky.social
Very excited to kick off our workshop at @esivienna.bsky.social on "Putting the cosmic large-scale structure on the map" today. Looking forward to a week of discussions around extracting the maximum of cosmological information from astronomical observations. Amazing support by the ESI team. Thanks!
Reposted by Oliver Hahn 🇪🇺
jowolff.bsky.social
I’m in Vienna right now. A city which went from being the intellectual and cultural capital of the world to a “provincial backwater” (to quote Brian Barry) in a couple of decades due to nationalism, anti-semitism and fascism which drove away the leading scholars and artists it didn’t murder.
Reposted by Oliver Hahn 🇪🇺
johncarlosbaez.bsky.social
The United Nations has now ratified the High Seas Treaty, setting the stage to create huge conservation zones in international waters, covering 30% of the world's oceans!

highseasalliance.org/2025/09/19/h...
A whale's tail poking up from the ocean on a cloudy day.

Robert F. Bukaty/Associated Press
Reposted by Oliver Hahn 🇪🇺
startswithabang.bsky.social
What is the true purpose of scientific peer review?

#AskEthan

Passing peer review isn't "crossing the finish line" where every claim inside has now been verified to be correct.

Instead, it's "crossing the start line" by science's high standards.

bigthink.com/starts-with-...
#science #space
Ask Ethan: What is the true purpose of scientific peer review?
Just because a paper passes peer review doesn't mean that what's written, or what the author asserts, is true. Here's why it still matters.
bigthink.com
Reposted by Oliver Hahn 🇪🇺
stellarorigins2025.bsky.social
150 top scientists from around the World came to Vienna to discuss about the state-of-the-art on star formation studies! 🔭
#stellarorigins2025
cosmohahn.bsky.social
Well, dark energy does have affect on wrinkles...
cosmohahn.bsky.social
hahaha. feel free to send your own any day though...
cosmohahn.bsky.social
Also so very tired of this... In the attention economy, random cheap attacks and borderline crackpottery increasingly outshine the hard work of actual scientific discovery...
Reposted by Oliver Hahn 🇪🇺
rahmstorf.bsky.social
Wow. The US Energy Department has withdrawn its scam climate report and disbanded its „Climate Working Group“ in order to dodge a law suit against the scam.
They must have realized that this scam report by a few „climate skeptics“ is indefensible nonsense.

subscriber.politicopro.com/article/2025...
POLITICO Pro: DOE says it dissolved research group that wrote its controversial climate report
The department said the end of the Climate Working Group means environmental groups' complaint over alleged Federal Advisory Committee Act violations is no longer valid.
subscriber.politicopro.com