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Comment by ryanklee | Hacker News Reader

> will stand a hundred feet tall, and it will weigh twenty-three thousand tons—more than twice the weight of the Eiffel Tower.

This is a strange sentence.

  (1) Notice Height of object-A; 
  (2) Notice Weight of object-A; 
  (3) Compare Weight of object-A to Weight of object-B
      where object-B is known more for its property of  
      Height than of its Weight.

The sense here (I think) is that the Eiffel tower is significantly taller than than ITER, and therefore ought to be significantly heavier. But it's not! ITER is heavier, and heavier by a lot. Go figure!

But what a silly line of reasoning. Is it a common conclusion that taller things should also be heavier things?

Further, this seems to me to be of the same breed as "bigger than the state of Rhode Island"-type of arbitrary comparisons -- only in this instance more confusing!

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The article's full of fairly silly elaborate descriptions. My favourite so far (3 pages in):

> Some in the field believe that a working machine would be a monument to human achievement surpassing the pyramids of Giza.

Which suggests that the pyramids of Giza are a monument of human achievement that hasn't yet been surpassed. You only need to take a look at almost any 20th century bridge, skyscraper or even ship to know that that isn't really true. Certainly the pyramids of Giza are a monument of ancient Egyptian achievement, but the last few centuries have completely and utterly surpassed that.

> the pyramids of Giza are a monument of human achievement that hasn't yet been surpassed.

> [...] the last few centuries have completely and utterly surpassed that

In terms of what they were built for, that is travel through time mostly unharmed for several thousands of years, a literal vessel of eternity, this claim is undebatably false. Few things we have built in the last two centuries will survive more than a decade if left unattended, and even fewer more than a century. It takes but a trip to Normandy to see german bunkers getting swallowed by nature. The smarter we get, the less durable we build things: we split atoms, we flick electrons and we land proxy explorers on nearby celestial bodies but our grandeur is a delusion and nothing will remain should our kin be obliterated. The testament of mankind that are such incredible buildings can only be surpassed by moving our butt out of this rock and sustain a decent living on the next one, ensuring our species survival. Any technological achievement is but a bullet point towards that goal.

> It takes but a trip to Normandy to see german bunkers getting swallowed by nature.

Or, especially for the SF Bay Area crowd, you could go to the Marin headlands and see US bunkers from the same era -- intended to defend against Japanese attack -- doing the same thing. Shorter trip.

We didn't expect the Japanese to wage a centuries-long war with us. They were made with a shortish fixed lifespan in mind. This is why they appear in disrepair. I imagine the Germans had the same calculus when they built theirs. But, yes, a they're good examples of things reverting to nature, slowly.

Many, many things last more than a decade. A stone house (of which there are many abandoned in the UK) will stand visibly for centuries.

There are many differences between bunkers and the pyramids. The biggest one is that bunkers were designed to be as low profile as possible. They are nowhere near the scale of the pyramids. Probably the next most important difference is the location. The pyramids were built in a desert environment which is hostile to the biggest enemy of manmade buildings - vegetation.

I'm not arguing that the pyramids aren't an incredible feat, or a monument to the achievement of an otherwise very low-technology early society. What I'm arguing against is the idea that the building of a fusion reactor would somehow be the first human development which would surpass the pyramids of giza as a monument of human achievement. The fact we have spacecraft in distant orbits which will remain exactly as they are for centuries or millenia is surely a much greater monument (albeit one which is hard to find). Our major cities (which are so entrenched that even if they were abandoned today would exist in some form for centuries, and certainly be easily identified for millenia) are vast monuments of human achievement. Can you really argue that the entirety of London is less of a monument of human achievement than the pyramids of giza?

You went from "a monument to human achievement surpassing X" to "the first human achievement surpassing X". Fairly silly you said? ;)

Fun fact: if you were to construct a cylinder that perfectly fit the Eiffel tower, the air within that cylinder would weigh more than the tower.

I think you're overanalyzing it. 23,000 tons is hard to visualize. Eiffel Tower is easy to visualize.

I think it was an interesting analysis (sounds like something I would have done). The Eiffel Tower example is strange not because it is a concretion, but because it is an example that one would expect be used in the description of something tall, not something heavy.

Just imagine a steel cube 3.6 meters wide. That's about 23,000 tons.

Here are some things, ordered by weight:

https://en.wikipedia.org/wiki/Orders_of_magnitude_(mass)

Given a lot of the article is about how they're having to reinforce the floor and so on to bear the weight of the thing, I think it's emphasising how dense the core is going to be.

You are easily confused.

This is unfair - he (I assume ryanklee is a he) merely said it was confusing, not that he was confused, and spent the entirety of his comment explaining why it was so (and I agree, it is an odd comparison). If you disagree, rebut him instead of condescending.

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