Hacker News: n4r9

New comment by n4r9 in "Most data centers refusing to say how much water, electricity they use"

n4r9 — Fri, 02 Oct 2026 10:46:51 +0000

I disagree. There is community opposition against individual data centers. There are calls for moratoriums until rules and regulations are improved. Calls for outright blocking data centers even with improved regulations are a small minority in my experience.

New comment by n4r9 in "Most data centers refusing to say how much water, electricity they use"

n4r9 — Thu, 01 Oct 2026 13:11:53 +0000

Fair point. If you divide the 163.7 billion gallons annually among the 5426 data centers, the figure does come out lower at ~30 million gallons or ~100 million liters annually. That's still far, far larger than the largest swimming pools.

New comment by n4r9 in "Most data centers refusing to say how much water, electricity they use"

n4r9 — Thu, 01 Oct 2026 13:06:47 +0000

The government obviously has the power to regulate data centers. That's why people are petitioning them to do so, and why the lack of data transparency is frustrating. I'm not sure what argument you're making.

New comment by n4r9 in "Most data centers refusing to say how much water, electricity they use"

n4r9 — Thu, 01 Oct 2026 10:02:15 +0000

I don't dispute your lived experience. But if you have evidence to cite in contrast to what I've cited, then please do so.

New comment by n4r9 in "Most data centers refusing to say how much water, electricity they use"

n4r9 — Thu, 01 Oct 2026 10:00:29 +0000

If the data center is built despite multiple demands to desist, then it may not be a surprise per se, but it can still be an unaccounted stress on local resources.

New comment by n4r9 in "Most data centers refusing to say how much water, electricity they use"

n4r9 — Thu, 01 Oct 2026 09:54:30 +0000

Firstly, who is deciding whether to "allow" open loop cooling? And secondly, from what I gather, closed-loop sites require an order of magnitude more power than open-loop to run. That's still going to have a large impact on local resources, especially as around 2/3 of power plants supplying data centers are also ocated in water-stressed regions [0].

[0] https://fieldreport.caes.uga.edu/publications/TP121/how-data...

New comment by n4r9 in "Most data centers refusing to say how much water, electricity they use"

n4r9 — Thu, 01 Oct 2026 09:01:34 +0000

This went into the weeds a little bit, but I've tried going over the figures again. I'm not sure if I'm missing something here or someone got some units wrong somewhere, but data centers seem to use far more water.

A medium size data center consumes 300k gallons of water per day [0]. That's over 400 million liters per year.

Even if we go with the highest estimate vidarh gave of 1.8 million liters per year for a full-size olympic size swimming pool, that's a tiny fraction of what a typical data center uses.

[0] https://www.eesi.org/articles/view/data-centers-and-water-co...

New comment by n4r9 in "Most data centers refusing to say how much water, electricity they use"

n4r9 — Wed, 30 Sep 2026 14:54:03 +0000

> A typical data center uses 300,000 gallons of water each day (equivalent to the demands of about 1,000 households), but large data centers can use an estimated 5 million gallons of water each day

https://www.brookings.edu/articles/ai-data-centers-and-water...

New comment by n4r9 in "Most data centers refusing to say how much water, electricity they use"

n4r9 — Wed, 30 Sep 2026 13:40:25 +0000

Well, OP said "small swimming pool". I guess it's ambiguous.

New comment by n4r9 in "Most data centers refusing to say how much water, electricity they use"

n4r9 — Wed, 30 Sep 2026 13:38:59 +0000

The point is that they create a heavy and volatile local water demand on those metropolitan areas.

New comment by n4r9 in "Most data centers refusing to say how much water, electricity they use"

n4r9 — Wed, 30 Sep 2026 13:32:35 +0000

I agree that utility planners have their work cut out to plan for data centers. It's a different paradigm than what they're used to. I think they are being caught off-guard, but it's a matter of process and infrastructure. They typically plan around averaged or linear trends, but data centers can have volatile usage spikes, and supply can depend on e.g. seasonal rainfall which is challenging to predict.

New comment by n4r9 in "Most data centers refusing to say how much water, electricity they use"

n4r9 — Wed, 30 Sep 2026 13:14:58 +0000

> we demonstrate that data centers are an overwhelmingly urban phenomenon, with 97.5% of facilities situated in metropolitan and micropolitan statistical areas

https://www.nature.com/articles/s44284-026-00487-z

New comment by n4r9 in "Most data centers refusing to say how much water, electricity they use"

n4r9 — Wed, 30 Sep 2026 13:06:13 +0000

Roughly 80% of the water evaporates into the atmosphere. The remaining 20% is flushed out of the system to remove mineral build-ups and sent to local treatment plants.

New comment by n4r9 in "Most data centers refusing to say how much water, electricity they use"

n4r9 — Wed, 30 Sep 2026 12:26:40 +0000

> the water usage is heavily overblown compared to the agriculture industry

Data centers tend to concentrate their water usage within urban areas, causing a strain on local resources. The value of their output is much less tangible. Their water consumption scales up around tenfold if you consider the indirect usage from generating the electricity.

But on the other hand; yes, it would also help enormously if people ate less meat.

New comment by n4r9 in "Most data centers refusing to say how much water, electricity they use"

n4r9 — Wed, 30 Sep 2026 12:25:01 +0000

A swimming pool requires maybe 60k liters a year...

New comment by n4r9 in "500k facial scans at UK stations yield no arrests, 1 false positive"

n4r9 — Tue, 29 Sep 2026 13:07:01 +0000

The other problem is that stereotyping an entire social group simply alienates the members of that group. They perceive that society doesn't trust or value them, so in response they don't trust or value society. See e.g. racial profiling in the London Met's use of stop-and-search powers.

If your ultimate goal is harm-reduction, then stereotyping is irrational.

New comment by n4r9 in "500k facial scans at UK stations yield no arrests, 1 false positive"

n4r9 — Tue, 29 Sep 2026 13:03:18 +0000

Don't you think that isolating people in poor conditions amongst hardened criminals might make them more likely to commit crime when they get released?

New comment by n4r9 in "I switched to Brave"

n4r9 — Mon, 28 Sep 2026 17:15:39 +0000

Tbf opposing gay marriage is quite an extreme opinion in much of the developed world. I suspect Eich's position on the matter is tied to his Roman Catholic faith, so although he showed a certain level of remorse in 2014, he never actually came out in support of gay marriage. He then later spread misinformation about mask-wearing during COVID, including suggestions that people could die from wearing a mask.

New comment by n4r9 in "Why do we need human mathematicians anymore?"

n4r9 — Mon, 28 Sep 2026 13:08:47 +0000

FWIW I think the concept of "interesting" is so subjective, time-dependent, and nebulous, that to say there's "only a finite number of interesting" mathematics problems feels absurd to me. What's interesting in ten years time will depend on what other interesting things have been discovered in the intervening time. But you're right, I shouldn't have responded with a cheap joke.

Godel's incompleteness theorem technically relates to individual axiomatic theories (i.e. the set of facts that logically derive from a given set of axioms). The numerical encoding you refer to applies to logical statements within that theory. Arguably, the kind of mathematics that humans do is not constrained to a single theory, but is a more general form of reasoning that is often flexible about which axioms may or may not be assumed.

New comment by n4r9 in "There is more to code review than (automatable) detection"

n4r9 — Sun, 27 Sep 2026 21:44:52 +0000

There's been a lot of talk about the purpose of code review recently. It makes sense in the face of AI. Heres a link that was submitted a little while ago: https://mathstodon.xyz/@mjd/115096720350507897

And in response I wrote a non-exhaustive checklist of things that a code review can look for:

- Does it functionally achieve what it sets out to (as per tacker issue or PR description)?

- Does it have extraneous code? Leftover debug prints, private API keys etc...

- Does it have any obvious defects? Memory leaks, un-handled edge cases, security flaws, obsolete API calls, etc...

- Could it be more understandable? Add/remove abstractions, better variable/method names, more/less functional etc...

- Is the style consistent with the codebase and/or style guidelines?

- Are there obvious performance improvements? Hashset instead of list, lazy evaluations, etc...

- Is it sufficiently well tested?

I think LLMs are okay at most of these, and worst at the first.