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Comment by Sharlin | Hacker News Reader

Well, dragsters are laughably slow to accelerate if we're just talking about "acceleration world record" without qualifiers. (Assuming that "acceleration" here means "acceleration of a ground vehicle with a human driver" is just as arbitrary as "…of an electric ground vehicle…", after all. Actual acceleration world records of macroscopic objects are in the 10,000s of gs…)

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i have an ultracentrifuge in lab that can do 100,000gs sustained for hours

What is it used for?

Centrifuges are used for separation. An ultra is usually used for separating nominally-stable colloids (such as fine nanoparticle colloids), and miscible liquids where such high centrifugal force causes them to density separate.

I was also curious and found this youtube [1]:

Summary (found in video at 10:48)

1) separation of subcellular organelle (DNA/RNA) 2) extract solutions in biological fluids from aqueous to organic solvents 3) seperate lipid components 4) pelleting of ribosomes 5) pelleting of macromolecules

[1] https://www.youtube.com/watch?v=lRT_8nFc2Tk

Ha. On a hunch I watched that video and hunch confirmed in the first second: I used to work for those guys, but not in the Centrifugation division :-)

How often do you just turn it on just to give it a spin? I'm not sure if be as productive in a lab with so much nice equipment, but I'm sure people get used to it.

Cnidocytes accelerate a microscopic needle at anywhere between 40,000 and 5,410,000 g.

https://en.wikipedia.org/wiki/Cnidocyte

I think it's very clear this post is about cars.

It’s clear the article is about electric cars, so the GP’s point about ICE dragsters is irrelevant. (Note also that the HN title has been edited; the original title was just "Students break acceleration world record". In any case, dragsters are irrelevant here.)

It's very clear this article is about student made electric cars. Nitpick much? In any case, dragsters are much more relevant to the topic than random projectiles without any wheels or resemblance to a car.

Military-funded experimental railguns are in the 10s of 1000s of gs. Are these the record-holders of whom you speak?

I'm thinking probably alpha-particle decay exceeds that by a lot.

I imagine that's why the other person qualified their remark as referring to "macroscopic" objects.

Hmm, good point. Maybe small objects not quite close enough to a hydrogen bomb to be vaporized by the flash, then?

Related: the "nuclear manhole cover" [1] (actually a 900 kg piece of armor plate) which may have accelerated to several times Earth's escape velocity over the course of a few meters (tens of millions of g's which is definitely impressive for such a heavy object). It was likely vaporized due to compressive heating before escaping Earth's atmosphere, however.

(I'm rather amused by the idea that some manager type evidently thought that a hunk of steel might contain a nuclear explosion in what was in essence a very large cannon!)

[1] https://en.wikipedia.org/wiki/Operation_Plumbbob#Missing_ste...

A big enough hunk of steel can certainly contain a nuclear explosion.

At 900 kg, we're talking about a fairly small hunk.

A big enough anything can certainly contain any explosion.

If were going off on a tangent to nuclear explosions why not supernova: XKCD What if: https://what-if.xkcd.com/73/

Quotable quote: "However big you think supernovae are, they're bigger than that."

The following paragraph to that quote is a great demonstration of that point.

Like the borehole cap on https://en.wikipedia.org/wiki/Operation_Plumbbob Pascal-B

If you can only accurately know the position OR the momentum, is acceleration well-defined?

Sure, ignore the position, just focus on the rate of change of momentum with respect to time.

Well, that doesn’t quite work either. Energy and time are also conjugate variables, so there exists an uncertainty relationship between them.

And since you can relate energy to momentum in a well defined way…

I think my "10,000s of gs" was maybe a slight underestimate. A light-gas gun [1] can accelerate a projectile to velocities of several km/s over a distance on the order of a meter, giving an acceleration on the order of 1,000,000 g by a quick calculation.

[1] https://en.wikipedia.org/wiki/Light-gas_gun

Don’t forget explosively formed penetrators!

Good point!

Oh man! Thanks for that, some time ago I meant to look up the test equipment for those high speed micrometeorite impact tests.

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