4 ms·

I love how every Tom, Dick & Harry with a bit of math & engineering thinks he can "dispel the myth" of HN Idea X with two minutes of off-the-top-of-his-head equ

by jmadsen 12y ago

I love how every Tom, Dick & Harry with a bit of math & engineering thinks he can "dispel the myth" of HN Idea X with two minutes of off-the-top-of-his-head equations. Read about these two: http://www.gravitricity.com/#people http://www.gravitricity.com/#people Do they seem like complete morons? Do you think they haven't studied this just a little bit more than you have? It doesn't mean their idea is good or will work - just that you aren't going to rip it apart with two hastily written paragraphs. People who ask questions about the costs, process, etc. are in the right spirit. People who think they can show off how clever they are really make me /facepalm

bduerst 12y ago
You don't need to be a carpenter to tell if a house is built poorly.
- deleted 12y ago
  [deleted]
- jmadsen 12y ago
  You don't need to be a carpenter to tell if the doors are hung straight. You DO need to be one to actually assess the overall build and structure.
  - aaron695 12y ago
    I think you need to re-read the point. Anyone can tell if a really really shoddy building is NOT structurally sound. What is hard to tell is if a building IS structurally sound. That is why engineers exist. Not for the previous.
  - bduerst 12y ago
    The picture they're drawing isn't very straight, as many have demonstrated. Until these "experts" provide evidence otherwise, it's useless to berate readers for pointing out the obvious.
    - logicallee 12y ago
      Bduerst, I have almost never downvoted anyone over anything. But I must say you have no right to put "experts" in quotation marks. Given their bio, they are experts. Which makes your comment a troll comment. (Unheard-of on HN.) Really, what do you think the definition of an expert is? "Just because he teaches the stuff at the University of Edinburgh, has sold a company to Siemens that created the world's only installed MW-scaled marine turbines (with the sale described by Bloomberg as a 'blow to the UK'[1]), and received an MBE for his contributions, does not make him an energy expert." Of course they're experts, even if they're ones you disagree with. [1] http://www.bloomberg.com/news/2012-02-17/siemens-to-take-over-u-k-tidal-turbine-maker-in-next-few-weeks.html http://www.bloomberg.com/news/2012-02-17/siemens-to-take-ove...
      - bduerst 12y ago
        I should have been more specific because I don't think what I was trying to communicate came across. I did not mean to imply that these people are not experts at anything, just that they should publish findings, test results, or at least a white paper on proof of concept. As it is, this website reads like they did the napkin math for the idea and are using only their credentials to legitimize it. Its an appeal to authority.
        jmadsen 12y ago
        Those are valid points, but I think too many here are assuming they don't have anything more substantial & this website is their entire speil. I don't think people like these two would risk their considerable reputations publishing something that every one of their peers could take apart at a cocktail party. More likely, there's more behind this website. HN readers rarely give that obvious benefit of the doubt.
- notatoad 12y ago
  There's a lot of things more complicated than building a house.
Retric 12y ago
I saw a similar idea using weights suspended between two mountain peaks but it was to expencive without drilling a hole. Intelligent people often run the best scams. Pumped storage can vary cheaply move a lot of mass up and down significant heights and it's still to expencive without a natural aquifers. The problem is power is rediculusly cheap and lifting crap takes far less power than you might think. "The main problem with gravitational storage is that it is incredibly weak compared to chemical, compressed air, or flywheel techniques (see the post on home energy storage options). For example, to get the amount of energy stored in a single AA battery, we would have to lift 100 kg (220 lb) 10 m (33 ft) to match it. To match the energy contained in a gallon of gasoline, we would have to lift 13 tons of water (3500 gallons) one kilometer high (3,280 feet). It is clear that the energy density of gravitational storage is severely disadvantaged." http://physics.ucsd.edu/do-the-math/2011/11/pump-up-the-storage/ http://physics.ucsd.edu/do-the-math/2011/11/pump-up-the-stor... For useful amounts of grid storage you need to be lifting on the order of 100,000+ tons up 1 km which starts to get really expencive just for cables.
deleted 12y ago
[deleted]

by jmadsen 12y ago

bduerst 12y ago

You don't need to be a carpenter to tell if a house is built poorly.

deleted 12y ago
[deleted]
jmadsen 12y ago
You don't need to be a carpenter to tell if the doors are hung straight. You DO need to be one to actually assess the overall build and structure.
- aaron695 12y ago
  I think you need to re-read the point. Anyone can tell if a really really shoddy building is NOT structurally sound. What is hard to tell is if a building IS structurally sound. That is why engineers exist. Not for the previous.
- bduerst 12y ago
  The picture they're drawing isn't very straight, as many have demonstrated. Until these "experts" provide evidence otherwise, it's useless to berate readers for pointing out the obvious.
  - logicallee 12y ago
    Bduerst, I have almost never downvoted anyone over anything. But I must say you have no right to put "experts" in quotation marks. Given their bio, they are experts. Which makes your comment a troll comment. (Unheard-of on HN.) Really, what do you think the definition of an expert is? "Just because he teaches the stuff at the University of Edinburgh, has sold a company to Siemens that created the world's only installed MW-scaled marine turbines (with the sale described by Bloomberg as a 'blow to the UK'[1]), and received an MBE for his contributions, does not make him an energy expert." Of course they're experts, even if they're ones you disagree with. [1] http://www.bloomberg.com/news/2012-02-17/siemens-to-take-over-u-k-tidal-turbine-maker-in-next-few-weeks.html http://www.bloomberg.com/news/2012-02-17/siemens-to-take-ove...
    - bduerst 12y ago
      I should have been more specific because I don't think what I was trying to communicate came across. I did not mean to imply that these people are not experts at anything, just that they should publish findings, test results, or at least a white paper on proof of concept. As it is, this website reads like they did the napkin math for the idea and are using only their credentials to legitimize it. Its an appeal to authority.
      - jmadsen 12y ago
        Those are valid points, but I think too many here are assuming they don't have anything more substantial & this website is their entire speil. I don't think people like these two would risk their considerable reputations publishing something that every one of their peers could take apart at a cocktail party. More likely, there's more behind this website. HN readers rarely give that obvious benefit of the doubt.
notatoad 12y ago
There's a lot of things more complicated than building a house.

Retric 12y ago

I saw a similar idea using weights suspended between two mountain peaks but it was to expencive without drilling a hole. Intelligent people often run the best scams. Pumped storage can vary cheaply move a lot of mass up and down significant heights and it's still to expencive without a natural aquifers. The problem is power is rediculusly cheap and lifting crap takes far less power than you might think. "The main problem with gravitational storage is that it is incredibly weak compared to chemical, compressed air, or flywheel techniques (see the post on home energy storage options). For example, to get the amount of energy stored in a single AA battery, we would have to lift 100 kg (220 lb) 10 m (33 ft) to match it. To match the energy contained in a gallon of gasoline, we would have to lift 13 tons of water (3500 gallons) one kilometer high (3,280 feet). It is clear that the energy density of gravitational storage is severely disadvantaged." http://physics.ucsd.edu/do-the-math/2011/11/pump-up-the-storage/ http://physics.ucsd.edu/do-the-math/2011/11/pump-up-the-stor... For useful amounts of grid storage you need to be lifting on the order of 100,000+ tons up 1 km which starts to get really expencive just for cables.

deleted 12y ago

[deleted]