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Comment Source term for Einstein's field equation (Score 1) 42

in his actual papers on relativity mass does not "create gravitation." Energy, momentum and some off-diagonal terms like stress and pressure gravitate. There is no mass term in the stress-energy tensor

There most certainly is. Density-- mass per unit volume-- is the (0,0) term of the stress-energy tensor.

Comment Re:All for it, but would like to know the launch r (Score 1) 17

If the launch fails at a point where it is say 50 miles up, and the reactor has been turned on prior to launch.

The conops says that the reactor doesn't get turned on until after it's successfully placed in a high orbit.

A good feature of nuclear reactors is that they aren't dangerously radioactive until after you turn them on.

Comment Re:Bye bye Wikipedia (Score 2) 31

Here's a case of a very experienced journalist getting caught by including made-up quotes that had been hallucinated by the AI he'd used to summarize research information: https://www.theguardian.com/te...

Vandermeersch added: “It is particularly painful that I made precisely the mistake I have repeatedly warned colleagues about: these language models are so good that they produce irresistible quotes you are tempted to use as an author. Of course, I should have verified them. The necessary ‘human oversight’, which I consistently advocate, fell short.”

When even experienced journalists fail to find AI hallucinations, you really can't expect unpaid volunteers to do better.

Comment Re:Bye bye Wikipedia (Score 4, Insightful) 31

Wikipedia is choosing to die. There is a lot wrong with a lot of what people are doing with GenAI but it is also super useful.

Unfortunately, even the best LLMs sometimes make up information ("hallucinate"), and the stuff they make up is deliberately crafted to appear exactly like real information. This is simply unacceptable for an encyclopedia.

If Wikipedia were written by paid professionals, you could plausibly put in place protocols to check and verify, and fire the ones who fail to check properly, but even paid professionals have been seen to let hallucinations through. As it is, as an encyclopedia that it is put together by volunteers, forbidding AI is pretty much a forced choice.

https://www.evidentlyai.com/bl...
  https://arize.com/llm-hallucin...
  https://thisweekinsciencenews....

Comment Re:So this is about AI slop spam from clankers (Score 0) 75

You aren't that interesting either and yet you found a way to look interesting with sock puppet accounts, maybe they'll just do the same.

The problem is that a sock puppet uses an actual human to operate it, while bots run with little or no need for human effort. So a human can turn out a handful of posts with sock puppets, while bots can be churn out thousands and thousands of posts, swamping any system with slop.

Comment Re: Potential dangers (Score 1) 92

Firstly, I see you have this notion that martian rocks must all be igneous.

You're not talking about rock, you're talking about regolith.

Depending on where the regolith is sourced

Regolith is not "sourced", it's blown across the whole planet. It's not simply "whatever the underlying strata is made out of".

But, since we are playing 'name the ignorance' in this exchange, your attestation stat perchlorate is 0.5% liberatable oxygen says 'Say i'm ignorant of basic chemistry without saying i'm ignorant of basic chemistry, and am bad at reading too.' The 0.5% statistic comes from the publication at bottom, and is the proportion of the regolith that is perchlorates.

I am the one who mentioned that regolith is 0.5% perchlorates, not that "perchlorates are 0.5% oxygen". *facepalm*

"Saying we'll get oxygen from the 0,5-1% of a poison in martian regolith, rather than bulk ice or CO2, is..."

For God's sake, learn to fucking read.

Washing the regolith to remove the perchlorate is a requirement for *any* other use of that regolith

Which is why you shouldn't be celebrating its existence. It is a problematic contaminant, not a resource.

As you have rightly pointed out, the water ice on mars is more 'frozen mud'. Cleaning the melt is going to be a necessary first step to using it *regardless*. That means either vacuum distillation, thermal distillation, or reverse osmosis filtration. Again, NOT OPTIONAL. This is necessary equipment that you need to bring, regardless.

And this just to get water, the most basic of offworld resources. And all of that equipment (especially the mining hardware itself) requires maintenance and spare parts, which impose more dependencies. And the TRL for use on Mars is low regardless.

You've gone from talking up the ease of operating on Mars to talking it down, yet your self-righteousness hasn't shifted at all in the process.

RO filtration is the least energy intensive of these.

Except, it isn't. 0,5-1% perchlorates. RO typically removes 90-95% of perchlorates. So you're down to ~500ppm. Human safety levels** are in the low parts per billion. You're five orders of magnitude off. Yes, you can purify water that far - and the more perchlorates, the easier - but you're talking an over millionfold reduction. It is not at all trivial. You're talking first RO to get it down to levels where it won't hinder bacterial growth, then bioreactor bacterial remediation, then filtration, then RO, then ion exchange. This is not some little, simple system.

** Plants can tolerate much more perchlorates than humans, but they also bioaccumulate perchlorates of exposed to them, so you have to reduce the water to low ppb levels.

The end products are clean water and perchlorate contaminated mud, and clean mud, with contaminated water.

Viola! *eyeroll*

And your "plan" for dealing with waste perchlorate doesn't just magically produce pure O2 and NaCl in the real world. First off, molten sodium perchlorate, which is what it becomes before it decomposes, is an extremely corrosive oxidizer. Exactly what are you planning to make the furnace out of, platinum? Secondly, you never get perfect decomposition. Apart from residual perchlorates, you have residual sodium chlorate, which is also corrosive, and is a literal herbicide. And your gas stream will contain contaminant chloride and chlorine dioxide, which, news flash, you don't want to breathe.

There is no way on Earth anyone would ever prefer this to just conducting electrolysis on the water that you've already purified.

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