Hanno Rein

#Astrophysics Professor at the University of #Toronto, Minor Planet 12249, #UTSC, #UofT, developer of the several #iOS apps, #pilot, #cycling, #climbing, #running, #Egyptology, #woodworking, #astrodon.

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npub1rqq5rv8tr2yu3cssea82js0mwrms5k3jm9h49d2k6tuhew8w9khsjr7gnu

NIP-05 Address

hannorein@mastodon-social.mostr.pub

Profile Code

nprofile1qqspsq2pkr434zwguggv7n4fg8ahpac2tgedjm6jk4td97tuhrhzmtcpzemhxue69uhhyetvv9ujumn0wd68ytnzv9hxgqvw3dr

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relay.nostr.band

Author Public Key

npub1rqq5rv8tr2yu3cssea82js0mwrms5k3jm9h49d2k6tuhew8w9khsjr7gnu

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Last Notes

2025-06-12 00:06:20

One thing I find very unfortunate about the current situation in the US is that everyone seems to be primarily fighting for themselves or their own bubble. Immigrants, scientists, fired government employees, etc. I agree with all the individual causes, but what is really needed in my opinion is a broad coalition of groups working together. The US needs a general strike.

2025-04-18 23:47:18

Testing
https://files.mastodon.social/media_attachments/files/114/361/631/830/847/904/original/e4a4532d78d63d9b.png

2025-03-27 14:10:18

A student told me they use AI to generate quizzes to practice for the Quantum Mechanics final exam. I've tried it out. It's all bullshit! The answers may sound plausible but are often just plain wrong. It just can't do math.

2025-03-24 00:53:45

Does anyone have any personal experience with mailbox.org?

2025-03-24 00:53:45

Does anyone have any personal experience with mailbox.org?

2025-03-14 02:25:42

Democrats voting for this ridiculous funding bill might benefit from reading more history book. Good chapters to start with: Ermächtigungsgesetz and Appeasement.

2025-02-22 23:19:18

I do not understand why the big website made their search functions so much worse in recent years.
Today, I was looking for a spare part for my car. I know the exact part number. But if I search for that I get completely random results that have absolutely nothing to do with the search term I have entered. It used to be that you could at least put the important terms in quote marks, but that doesn't seem to work anymore either on several sites. #enshittification

2025-01-17 23:28:56

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@nprofile…4y4j did it not occur to anyone to do these things before the election?

2025-01-16 00:20:52

The University of Toronto spam filter is 💩. I don’t have any control over it (can’t turn it off) and it consistently categorizes emails from within the university as spam. This includes error messages from the university’s own mail server and reference letter requests from the university’s own admissions system. Support requests to get this fixed end up in a black hole because the entire email system has been outsourced to Microsoft and nobody at UofT can do anything.

2025-01-15 22:11:33

My university (Toronto) is looking into an "opportunity for the university to engage with #OpenAI on a master agreement to acquire #ChatGPT Pro".
This company is literally steeling our content to train their models. And the university is stupid enough to buy it back? Ridiculous.

2025-01-03 17:00:01

All #sourdough #bread I made since 2020. #baking
https://files.mastodon.social/media_attachments/files/113/765/487/779/115/744/original/a0807a67d841e5a6.jpg

2025-01-01 16:45:09

I'd file "adoption of reduced-precision floating-point types" under #enshittification
https://arxiv.org/abs/2411.12090

2024-12-30 15:57:42

I made a couple of improvements to my AltWeatherCan #iOS app. You can now sort forecasts by distance to your location. If you're like me and miss the old WeatherCan app, give it a try! It's free, has no ads, no add-ons, and it's #opensource. https://apps.apple.com/ca/app/altweathercan/id6737521465?platform=iphone #onstorm #swiftui #weather
https://files.mastodon.social/media_attachments/files/113/742/592/715/578/128/original/ea6c181e04978a17.png
https://files.mastodon.social/media_attachments/files/113/742/592/704/448/256/original/37b5dc0250f19448.png

2024-12-22 18:27:22

Can someone help me understand what's going on with reference counts during a #python exception in a #jupyter notebook?
# Cell 1
import sys
class Test:
def exception(self):
raise ValueError("test")
t = Test()
print(sys.getrefcount(t)) # -> 2
t.exception()
# Cell 2
print(sys.getrefcount(t)) # -> 4
Why does the reference count remain increased after an exception? Is there a way to avoid this?

2024-12-22 16:04:35

This is pretty cool: Amateur astronomers* were able to receive the carrier signal of Voyager 1. https://www.camras.nl/en/blog/2024/dwingeloo-telescope-receives-signals-from-voyager-1/
* Amateur astronomers who have access to a 25m antenna.
https://files.mastodon.social/media_attachments/files/113/697/320/861/166/037/original/12892f899214f31e.png

2024-12-13 00:14:23

🚨 My group had a second paper out this week. Lead on this one: Michael Poon.
We speculate about whether exomoons could push planets in multi-planetary systems on a high obliquity state. The answer is yes! The exomoon helps tilting the planet because it acts like a lever, thus enhancing a spin-orbit resonance. The idea is quite general. But we apply it specifically to β Pictoris b where an upcoming JWST observations will constrain the planet's obliquity.
https://arxiv.org/abs/2412.05988
https://files.mastodon.social/media_attachments/files/113/642/593/242/152/173/original/62096727b0b1e4a3.png

2024-12-12 00:16:41

🚨 We have a new paper out! Lead: @nprofile…artu
We shoot random stars and free floating planets at the early Solar System and see what happens. It turns out, there is a surprisingly high (1%) chance that a small object coming very close to the Sun can shake up initially circular and co-planer orbits to values that are consistent with the present day Solar System to a high degree.
https://arxiv.org/abs/2412.04583
https://files.mastodon.social/media_attachments/files/113/636/964/523/010/207/original/932d419f7a84db33.png

2024-12-05 17:31:25

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@nprofile…ssyg Hm. I see they use code from github with the licenses listed as "various open source". I don't like the sentiment of "you can do whatever you want with open source code". But maybe they did something better?

2024-12-05 14:12:48

So sure, these probabilistic weather forecasts are getting better at whatever they have been trained on to do. But in contrast to a physics-based simulation, I suspect they will not be good at predicting what they have not been trained on. And with climate change, there will be a lot more previously unheard of weather events.
https://www.nature.com/articles/s41586-024-08252-9

2024-12-03 14:39:14

There used to be a time where you could fine tune how your e-mail server is categorizing spam mail. Now there are basically zero settings. People probably think it's better if an "AI" makes the decision for you. But as a consequence, my university e-mail server (Microsoft) consistently categorizes its own undeliverable error messages as spam. #enshittification

2024-11-19 19:57:51

I'm preparing this week's #WebGPU lecture. Let's see how much we can optimize the calculation of the total energy in an N-body simulation:
0.02634s
0.00119s
0.00019s
...

2024-11-18 02:07:17

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@nprofile…kyj5 same!!

2024-11-15 15:26:02

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@nprofile…kyj5 I did it a few days ago. It took about a day to get the archive. Then I used the archive to delete all my posts. I won't delete the account itself because I don't want anyone to impersonate me and I want to keep a redirect up to here.

2024-11-15 12:51:41

☄️+⭐️=💥 My student Dang Pham led a project about fast radio bursts (FRBs) and interstellar objects (ISOs). In short: ISOs colliding with neutron stars could actually explain the observed FRB rate, the observed energy distribution, and even even some of the sub-structure. The paper has been accepted and is now on the arXiv. Check it out!
https://arxiv.org/abs/2411.09135
#astrodon #astronomy #astrophysics