4 ms·

You're saying that achieving 2.7% of the theoretical efficiency is good? Many car engines have an efficiency of around 20% for example, as compared to the maxi

You're saying that achieving 2.7% of the theoretical efficiency is good? Many car engines have an efficiency of around 20% for example, as compared to the maximum theoretical efficiency of 67%. If car engines performed only well enough to meet your standard of amazingness, your gas costs would be 7 or 8 times higher. Or if you used a modern Toyota engine for comparison, something like 14 times higher. Obviously I took an example from a different sphere for comparison... if you really find this to be an astonishing result can you elaborate?

arethuza 9y ago
On the other hand how well are we doing when it comes to achieving the maximum theoretical speed for interstellar spacecraft? :-)
amadvance 9y ago
You car is million times slower than the speed of light :)
- greydius 9y ago
  10 million. Light: 300000 km/sec, car: 0.03 km/sec
  - amadvance 9y ago
    My car is a lot faster than 108 km/h (0.03 km/sec) :)
    - moemoeg 9y ago
      In the context of the speed of light, it really isn't.
      - amadvance 9y ago
        greydius corrected me asserting that the factor between ligth speed and car speed is 10 millions, and not one million as I said. But in true there are production cars that pass 430 km/h, resulting in a factor of about 2.5 millions. A lot less than 10 millions. https://en.wikipedia.org/wiki/Production_car_speed_record https://en.wikipedia.org/wiki/Production_car_speed_record
        pixl97 9y ago
        You should not compare the fastest car speed, but the average car speed, which for this argument would probably be closer to 200km/h. That puts it in a factor of 5 million, which is within one order of magnitude of the original guess.
the8472 9y ago
Your car is not operating at 20% efficiency of theoretical limits if you take the whole energy pipeline into account. You know... fusion, sunlight, plankton, oil, refining, combustion, mechanical energy. On the other hand speed-of-light to actual ping times is an end-to-end efficiency calculation. Plankton in particular is terrible at converting energy. sun -> mj-PV -> battery -> electric motors run circles around those.
- krallja 9y ago
  > Plankton in particular is terrible at converting energy. Says the person who can't even photosynthesize!
lucozade 9y ago
Not to belittle the internal combustion engine but that's just the theoretical efficiency of chemical combustion. It's a local maximum. That's tiny compared to the global maximum energy available from the same amount of fuel. As a trite comparison, it's a similar to arguing the theoretical maximum speed that a person can run. Interesting, but doesn't tell you anything about the maximum speed that a person can move. The speed of light in a vacuum, though, is qualitatively different. It's not a local maximum, it's the global maximum. Anyway, I reserve the right to be impressed. I spend enough of my life being jaded and cynical. Sometimes I see things like this and it makes me think about stuff that I take for granted.

arethuza 9y ago

On the other hand how well are we doing when it comes to achieving the maximum theoretical speed for interstellar spacecraft? :-)

amadvance 9y ago

You car is million times slower than the speed of light :)

greydius 9y ago
10 million. Light: 300000 km/sec, car: 0.03 km/sec
- amadvance 9y ago
  My car is a lot faster than 108 km/h (0.03 km/sec) :)
  - moemoeg 9y ago
    In the context of the speed of light, it really isn't.
    - amadvance 9y ago
      greydius corrected me asserting that the factor between ligth speed and car speed is 10 millions, and not one million as I said. But in true there are production cars that pass 430 km/h, resulting in a factor of about 2.5 millions. A lot less than 10 millions. https://en.wikipedia.org/wiki/Production_car_speed_record https://en.wikipedia.org/wiki/Production_car_speed_record
      - pixl97 9y ago
        You should not compare the fastest car speed, but the average car speed, which for this argument would probably be closer to 200km/h. That puts it in a factor of 5 million, which is within one order of magnitude of the original guess.

the8472 9y ago

Your car is not operating at 20% efficiency of theoretical limits if you take the whole energy pipeline into account. You know... fusion, sunlight, plankton, oil, refining, combustion, mechanical energy. On the other hand speed-of-light to actual ping times is an end-to-end efficiency calculation. Plankton in particular is terrible at converting energy. sun -> mj-PV -> battery -> electric motors run circles around those.

krallja 9y ago
> Plankton in particular is terrible at converting energy. Says the person who can't even photosynthesize!

lucozade 9y ago

Not to belittle the internal combustion engine but that's just the theoretical efficiency of chemical combustion. It's a local maximum. That's tiny compared to the global maximum energy available from the same amount of fuel. As a trite comparison, it's a similar to arguing the theoretical maximum speed that a person can run. Interesting, but doesn't tell you anything about the maximum speed that a person can move. The speed of light in a vacuum, though, is qualitatively different. It's not a local maximum, it's the global maximum. Anyway, I reserve the right to be impressed. I spend enough of my life being jaded and cynical. Sometimes I see things like this and it makes me think about stuff that I take for granted.