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John F. Wu
@jwuphysics
Associate Astronomer and Applied AI @SpaceTelescope. Secondary appointments in @JohnsHopkins Astro + CS. Opinions my own. He/him. 🦋 @jwuphysics.bsky.social
Baltimore, MD, USA
jwuphysics.github.io
Joined June 2020
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    John F. Wu
    @jwuphysics
    Dec 5, 2025
    New blog post. In the era of LLMs, what does learning look like? What happens when are overconfident in our understanding due to AI sycophancy? Is it even useful to use LLMs for education without outsourcing our thinking? jwuphysics.github.io/blog/2025/12/l…
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    John F. Wu
    @jwuphysics
    Oct 28, 2020
    Replying to @lqfacts
    Whoa, careful there. You might accidentally teach Republicans the definition of marginal tax rates!
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    John F. Wu
    @jwuphysics
    Dec 16, 2021
    CNN is selling NFTs of Hubble Space Telescope images and thanks I hate Web3 more than ever
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    John F. Wu
    @jwuphysics
    Oct 5, 2021
    I don't think it's an exaggeration to say that some of the biggest astronomical discoveries in the 2020s are only going to be made possible through self-supervised learning (SSL). arxiv.org/abs/2110.00023
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    John F. Wu
    @jwuphysics
    Nov 2, 2025
    Super common pathway. Towards the end of my PhD in Physics/Astro, I trained my first deep neural net on a GeForce 780 after watching @jeremyphoward on the @fastdotai lectures. Now I'm tenure-track faculty in (astro)physics, but still maintain strong curiosity in AI/ML
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    Yuchen Jin
    @Yuchenj_UW
    Nov 2, 2025
    Met a Meta AI researcher. He studied Physics in China, came to the US for a PhD in Physics, and then fell in love with AI, despite never having studied computer science. He watched Andrej Karpathy and Andrew Ng, bought a GPU, read every arXiv paper title daily, and dived into
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    John F. Wu
    @jwuphysics
    Dec 17, 2021
    I am so freaking excited to share that I'll be joining @STScI as a tenure-track Assistant Astronomer next year!
  • Vision transformers (ViT) and MLP-Mixer models tend to produce sharp loss landscapes. Thus, they stand to benefit most from the recently proposed sharpness-aware minimization (SAM) optimizer! (see Foret et al. 2021, ICLR for more on SAM) arxiv.org/abs/2106.01548
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    John F. Wu
    @jwuphysics
    May 29, 2025
    Nice post on USAID spending by @slatestarcodex
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    Sorry, I Still Think MR Is Wrong About USAID
    From astralcodexten.com
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    John F. Wu
    @jwuphysics
    Jun 28, 2021
    Replying to @WhoIsNickCage
    Yes fellow patriots support Ben & Jerry's, champion of conservative values, instead. It's the only way to own the libs (and antifa)
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    John F. Wu
    @jwuphysics
    Aug 12, 2024
    My twitter feed became absolute garbage overnight... Did this happen to anyone else? It's full of nonsense about JD Vance, "the most beautiful Olympic athletes", and other crap I do not care about. Used to be exclusively astronomy, machine learning, and software engineering...
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    John F. Wu
    @jwuphysics
    Aug 23, 2021
    Replying to @astrobites
    Is this a power law?
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    John F. Wu
    @jwuphysics
    Aug 16, 2022
    🚨🚨 Astronomy job alert! 🚨🚨 STScI is hiring *several* Astronomer (tenure-track, 50% research) and Scientist (20-50% research) positions! Lots of priorities this cycle: Exoplanets, IR Imaging/Surveys, UV spectroscopy, and General Astronomy! Apply: recruiting2.ultipro.com/SPA1004AURA/Jo…
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    John F. Wu
    @jwuphysics
    Aug 28, 2020
    I'm excited to share Part 2 of my blog series on visualizing and interpreting trained CNNs using @PyTorch, @fastdotai, and @matplotlib! We train a CNN classifier and then implement the Grad-CAM algorithm for image attribution in this post: jwuphysics.github.io/blog/galaxies/…
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    John F. Wu
    @jwuphysics
    Apr 24, 2025
    Thanks (partly) to Gemini, I've migrated my Substack and even older blog back onto my website
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