Hacker News: dsqrt

New comment by dsqrt in "The threat is comfortable drift toward not understanding what you're doing"

dsqrt — Sun, 05 Apr 2026 13:18:03 +0000

The goal of academic research is to create understanding, not papers. If we outsource all research to LLMs, then we are only producing the latter.

New comment by dsqrt in "What no one has seen before: gravitational waveforms from warp drive collapse"

dsqrt — Thu, 06 Jun 2024 04:06:05 +0000

The NRPy package and tutorials are a good place to start: https://nrpyplus.net/

New comment by dsqrt in "SymPy: Symbolic Mathematics in Python"

dsqrt — Wed, 28 Feb 2024 15:34:11 +0000

You should check out Sage Manifolds [1]. It's built on top of Sage Math, but I think it can also use SymPy as computational engine.

[1] https://sagemanifolds.obspm.fr/

New comment by dsqrt in "Encouraging students to understand the 1D wave equation"

dsqrt — Wed, 20 Dec 2023 11:50:26 +0000

The finite-differencing time-domain method [1] (sometimes also called leap-frog [2]) is easy to implement and robust for scalar and electromagnetic waves. This other book by LeVeque [3] is a great introduction on finite-differencing methods for linear equations.

[1] https://en.wikipedia.org/wiki/Finite-difference_time-domain_...

[2] https://math.mit.edu/classes/18.086/2006/am53.pdf

[3] https://epubs.siam.org/doi/book/10.1137/1.9780898717839

New comment by dsqrt in "Scientists discover the highest energy gamma-rays ever from a pulsar"

dsqrt — Fri, 06 Oct 2023 10:45:19 +0000

Matter in neutron stars is compressed together by the enormous gravity. Once set free on your floor, this material would no longer be held together and will start expanding at close to the speed of light. The resulting explosion will probably obliterate the entire continent. A crude way to estimate it is to take into account the fact that the gravitational binding energy of matter at the surface of a neutron star is about 10% of the rest mass energy of the material, so once that material is removed it will liberate as much energy (If I got the numbers right, you get an explosion energy of 0.1 m c^2 ~ 10^13 megatons).

New comment by dsqrt in "So you want to learn physics (2021)"

dsqrt — Mon, 21 Aug 2023 12:44:30 +0000

I think this is, at least in part, specific to the US/Western tradition. US physics curriculum is built to get people up to speed with quantum physics ASAP, because this is the core of most physics research in US physics departments. If you look at Landau-Lifshitz's Theoretical Physics curriculum, you will find plenty of classical physics: from fluid dynamics, to elasticity, and plasma physics. For example, Landau-Lifshitz Vol. 6 is an excellent introduction to Navier-Stokes equations and their applications.

New comment by dsqrt in "Royal Astronomical Society: all journals to publish as open access from 2024"

dsqrt — Thu, 02 Mar 2023 14:25:14 +0000

RAS used to have all articles available to everyone for free after 1 year (immediately if one wanted to pay for open access). I thought this was a reasonable compromise. The new policy will damage early career researchers and groups at less established institutions that will not be able to publish their own research. I have published a number of papers on MNRAS, but now I will move to other journals. In principle, I can charge the publication costs to my NSF grant, in practice that means I would not be able to send my students to conferences, because research support funding is very stretched (no more than few thousand dollars per year per student). This would damage their career prospects. Theory grants are already very small and adding several thousand dollars extra to the budget can make the difference between the grant being awarded or rejected (it should not be, but this is how it works). Moreover, even at R1 institutions, a lot of theory research is actually not funded by federal grants.

Journals were created to support the scientific community and provide a platform for scientists to discuss. Charging exorbitant publication fees damages the very mission of these journals.

New comment by dsqrt in "How to become a good theoretical physicist"

dsqrt — Wed, 26 Oct 2022 11:24:34 +0000

This is interesting, but all of the links I tried were broken or led to broken pages. Unfortunately, with the widespread use of LMSs a lot of useful material is now behind University firewalls.

New comment by dsqrt in "We don't know how to fix science (2021)"

dsqrt — Wed, 27 Jul 2022 12:27:26 +0000

DOE [1], NASA [2], NSF [3] already require most research papers to be made publicly available.

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[1] https://www.osti.gov/

[2] https://www.ncbi.nlm.nih.gov/pmc/funder/nasa/

[3] https://par.nsf.gov/

New comment by dsqrt in "What a $500k grant proposal looks like"

dsqrt — Thu, 24 Feb 2022 13:59:36 +0000

Most of the federal grants I am aware of have duration of 3+ year (the typical duration of a PhD after having completed the course work).

New comment by dsqrt in "If Not Overturned, Bad Copyright Decision Will Lead Many to Lose Internet Access"

dsqrt — Sat, 05 Jun 2021 15:59:26 +0000

Perhaps Jamendo https://www.jamendo.com/ ?

New comment by dsqrt in "Breaking the warp barrier for faster-than-light travel"

dsqrt — Wed, 10 Mar 2021 14:41:01 +0000

Coincidentally, Alcubierre recently posted a review article on warp drives: https://arxiv.org/pdf/2103.05610.pdf. It looks like a good introduction to this topic.

New comment by dsqrt in "Telescope Sees Star Dance Around Supermassive Black Hole, Proves Einstein Right"

dsqrt — Fri, 17 Apr 2020 20:58:10 +0000

I would also recommend "The Large Scale Structure of Space-Time" by Hawking and Ellis. It uses some advanced mathematics and some prior knowledge of GR, at least at the level of Schutz or Carroll, is needed, but it is a wonderful book to learn about the global structure of spacetimes with black holes, singularity theorems and so on.

New comment by dsqrt in "Open letter from Italy to the international scientific community"

dsqrt — Sun, 15 Mar 2020 00:53:52 +0000

For what it means, I know some of the people on that list and I can say that they are real scientists.

New comment by dsqrt in "Adobe Summit Cancelled"

dsqrt — Tue, 03 Mar 2020 00:38:06 +0000

It is in the first page, but the link points to the FAQ instead.

New comment by dsqrt in "Flang: The Fortran frontend of LLVM [video]"

dsqrt — Sun, 09 Feb 2020 14:19:13 +0000

C has the "restrict" keyword to indicate that no aliasing should occur.

New comment by dsqrt in "Web-assembly powered WYSIWYG LaTeX Editor, supporting nearly all LaTeX package"

dsqrt — Thu, 05 Dec 2019 15:01:04 +0000

Single academics will likely not bother with Office365/Google, but University administrators are the ones buying enterprise software. In the past few years the trend has been for the central administration to push departments to give up their self-hosted mail servers and switch to Office365 (I have witnessed this at three different Universities). My guess is that something like SwiftLatex could sweeten the deal and convince the faculty to support some of these changes.

New comment by dsqrt in "I wasn’t getting hired as a data scientist, so I sought data on who is"

dsqrt — Fri, 16 Aug 2019 01:28:36 +0000

Exactly. The data is about the backgrounds of data scientists, but is incorrectly interpreted as the probability of becoming a data scientist given a certain background. Obviously the two are related (Bayes' theorem), but to draw any conclusion one would need to know the number of PhDs, Masters, etc. that are applying to become data scientists. For example, the fact that a small fraction of data scientists has a MOOC degree does not imply that the probability of becoming a data scientist if having "only" a MOOC degree is low. For all that we know the few people in the market having this kind of non-traditional preparation could have 100% success rate in getting those jobs.

New comment by dsqrt in "How to build something that lasts 10k years"

dsqrt — Wed, 12 Jun 2019 20:57:17 +0000

I am just thinking that, if future archeologists discover these warnings / language in frequent association with art, then they will probably not think twice about excavating an actual nuclear disposal site that exhibits them. They will probably think that the warnings were placed there to scare away thieves.

New comment by dsqrt in "How to build something that lasts 10k years"

dsqrt — Wed, 12 Jun 2019 11:51:14 +0000

Doesn't embedding these messages into art defy their very purpose of being a warning?