I’m glad this kind of work is getting highlighted on HN, but this is an extremely misleading title, to the point of being outright false. As often happens, this appears to be due to PR titles being controlled by non-specialists, not the study authors.
While the work the authors do is important, in no sense does the tool they produced actually run a simulation.
A simulation implies a physical model and usually partial differential equations that are often solved on supercomputers, but here the neural network is rather interpolating some fixed simulation output in a purely data-driven way.
The simulations have not gotten faster due to neural networks, cosmologists have just gotten better at using them. Which is great!
Edit: see the sub-comment in the thread by crazygringo for the lead author’s take
The lead author explains the work in this comment: https://news.ycombinator.com/item?id=45381598
(It was a bit difficult to find by just scrolling)
The title and the article are both independently true, just not together :) As in, there are certainly cosmic simulations that once needed supercomputers which now run on a laptop, that's just the story of computational progress.
More seriously though, https://www.404media.co/a-vast-cosmic-web-connects-the-unive... is another nice article about this work. It has a bit less detail (i.e. less proper nouns in it), but is more readable for it IMO.
That said, I do think the work is still a big deal. Emulators like this are crucial for exploring parameter spaces and doing inference at scale