But no, the 5000 LY was just inferred as an approximation by the estimate that the Eta Carinae event would be about 7500 LY away (if I am not mistaken), and the astronomers seem to think (based on whatever reasoning) that Eta Carinae going Hypernova would have some impact on space installations, but not severely damage earth lifeforms. Given the inverse square law for energy and particle densities, reducing the distance to the event by 1/3rd would already dramatically increase the infall, and so increase the likelyhood of adverse effects on life on a planetary surface.
However, I'm not academic about this - 300, 3000, 5000, or 10000, does it really matter? Especially if our astronomers can't do much more than guess. If they think 7.500 LY is safe, but they misguess, we're dead anyway.
Also, if stars are less dense, catastrophic events are less likely to occur - but so is diminishing the probability of intelligent life within the same timeframe as ours.
Well... when you ever wanted the answer to Fermi's Paradox ("if they existed, they'd be here") - this may well be it.
More-or-less regular events like this, purging a sphere of maybe 5000 LY clean of any higher forms of life may explain why we never see any traces of other advanced lifeforms (no radio signals etc.), especially if we presume that there's no practical FTL drive even remotely possible.
Maybe there is simply not enough time for any possible civilization to be noticed within our timeframe before they get extinguished.
Also, it'd be easy to imagine the astronomers to be slightly wrong in their predictions about the deadliness of Eta Carinae - our own extinction might already be underway...
And, as I understand it, there may be events much much worse than that...
Regards,
scotchco
Most fictional works, especially in Science Fiction are either incompetent or irrelevant. They may still be entertaining, amusing, or moving or touching or inspiring.
But usually, if you are halfway decently skilled in your job, you'll know that much more about its intrinsics than any of the authors which usually are just that: authors, not specialists in your own fields of interest (rare examples might contradict this).
So far, I never found a work of fiction who got the intrinsics in my own line of work (communications) even halfway right. Even stories based on specific issues often get it plain wrong. Conceptual ideas or influences? None to speak of.
After a decade in a field you know so much more about it than any author who researched it for a few days that there can be very little input from that direction. In many cases, even a strong hobbyist interest in the details of a field shows that the author is less knowledgeable in that area.
Is there a SF author who can provide insight or guidance concerning hardware developing to a hardware developer?
Is there a SF author who can provide insight or guidance concerning programming to a software developer?
I doubt it, alot.
Sometimes, you'll find some pearls, usually from authors with past experience in the given field - but those are then usually marred by inconsistencies in the remaining content.
As to the gasoline issue, someone correct me if I'm wrong (and yes, I know, those are only very rough estimates, without taking capacity reduction, and average efficiency etc. in account).
I'd imagine the output of the motor to some 2kW. With 1 kg of fuel this is supposed to run for 20 miles, equating to about 1 hour.
Now, 6kg of lead acid battery (12V, 17Ah) would be about 12 V x 17 A x 3600 seconds = 734,400 Wattseconds = 734 kJ.
Thus, his quarter gallon of fuel equals roughly the energy contained in about 10 lead batteries at 12 lb each = 120 lbs., not 377. Using NiZn or NiCd or somesuch it would be maybe about 60 lbs., for Lithium even less.
In practical application, however, as with the forklift example, the ratio is - due to certain specific characteristics of electric drives - probably even better than that.
Probably, his efficiency is not very good, either. Multiple-stage worm gear reduction? We are then looking at maybe 50% efficiency in the gear, maybe less. I'd like to know how hot the gear is after 1 hour...
Why not simply use a cheap and simple 1hp (or some such number) PMDC motor such as the Bosch GPA750 (8 lbs.), two Evercel NiZn batteries (12 lbs.) and a self-made two-stage belt/chain reduction (2 lbs.) together with a basic 4QD controller (1 lb.). For a somewhat heavier, probably almost same range, standard power-assist bike concept... Much less noise and more environmentally friendly?
Commercial NiZn batteries are already available from http://www.evercel.com/
Currently, they are exploding into the EV application market, with very favourable reviews from those who have started to use them.
Regards,
scotchco
To inefficient. Imagine that the small IC motor has maybe 2 HP. That would equate to app. 1.5kW. Can you find any fuel cell (or even proposal for such) that puts out 1.5 to 2 kW and which could be mounted on a bike? Methinks not...
Wouldn't that be much much better spent in trying to actually develop a real energy source, such as (long shot example) http://torsatron.tripod.com/fusor/fusor.html instead of just looking for another form of energy storage? THAT would be more worthy of an apollo/manhattan style project than just to develop a new battery/energy storage/transport medium, methinks.
Furthermore: given certain developments in battery technologies (e.g. NiZn, NaS etc.) - why not simply move towards standard EVs with "conventional" batteries (as hydrogen use in the proposed form is nothing else but some form of battery)? Maybe less fancy than fuel cells, but much more readily available.
Is it just me who thinks it frustrating that the industry successfully tried to block such developments with stupid lead (or poisonous NiCd, or expensive Lithium etc.) battery EVs, and as soon as truly useful battery/technologies come up, change the strategy and now all of a sudden start to talk about hybrids, hydrogen, and elusive fuel cells? It is as if they waited decades for a useful EV battery concept to pop up simply to jump ship, to now sit out another one or two decades.
Hydrogen, being just a storage technology, does offer nothing to solve the fundamental problems. IMHO it's just another kind of battery...
Biodiesel for hundreds of millions of cars, worldwide? An illusion, methinks.
Say the US market for gasoline as auto fuel is approximately 125 billion US gallons per year. How much land would you need to use to produce that in biodiesel?
Roughly estimated maybe 500 million acres?
Less than 100 million acres overall are currently used in the US to produce corn...
Slashdot Mirror
Now, 10 times 30 to 100 would be 300 to 10.000...
But no, the 5000 LY was just inferred as an approximation by the estimate that the Eta Carinae event would be about 7500 LY away (if I am not mistaken), and the astronomers seem to think (based on whatever reasoning) that Eta Carinae going Hypernova would have some impact on space installations, but not severely damage earth lifeforms. Given the inverse square law for energy and particle densities, reducing the distance to the event by 1/3rd would already dramatically increase the infall, and so increase the likelyhood of adverse effects on life on a planetary surface.
However, I'm not academic about this - 300, 3000, 5000, or 10000, does it really matter? Especially if our astronomers can't do much more than guess. If they think 7.500 LY is safe, but they misguess, we're dead anyway.
Also, if stars are less dense, catastrophic events are less likely to occur - but so is diminishing the probability of intelligent life within the same timeframe as ours.
Regards,
scotchco
Well... when you ever wanted the answer to Fermi's Paradox ("if they existed, they'd be here") - this may well be it. More-or-less regular events like this, purging a sphere of maybe 5000 LY clean of any higher forms of life may explain why we never see any traces of other advanced lifeforms (no radio signals etc.), especially if we presume that there's no practical FTL drive even remotely possible. Maybe there is simply not enough time for any possible civilization to be noticed within our timeframe before they get extinguished. Also, it'd be easy to imagine the astronomers to be slightly wrong in their predictions about the deadliness of Eta Carinae - our own extinction might already be underway... And, as I understand it, there may be events much much worse than that... Regards, scotchco
No.
Most fictional works, especially in Science Fiction are either incompetent or irrelevant. They may still be entertaining, amusing, or moving or touching or inspiring.
But usually, if you are halfway decently skilled in your job, you'll know that much more about its intrinsics than any of the authors which usually are just that: authors, not specialists in your own fields of interest (rare examples might contradict this).
So far, I never found a work of fiction who got the intrinsics in my own line of work (communications) even halfway right. Even stories based on specific issues often get it plain wrong. Conceptual ideas or influences? None to speak of.
After a decade in a field you know so much more about it than any author who researched it for a few days that there can be very little input from that direction. In many cases, even a strong hobbyist interest in the details of a field shows that the author is less knowledgeable in that area.
Is there a SF author who can provide insight or guidance concerning hardware developing to a hardware developer?
Is there a SF author who can provide insight or guidance concerning programming to a software developer?
I doubt it, alot.
Sometimes, you'll find some pearls, usually from authors with past experience in the given field - but those are then usually marred by inconsistencies in the remaining content.
Regards,
scotchco
As to the gasoline issue, someone correct me if I'm wrong (and yes, I know, those are only very rough estimates, without taking capacity reduction, and average efficiency etc. in account).
I'd imagine the output of the motor to some 2kW. With 1 kg of fuel this is supposed to run for 20 miles, equating to about 1 hour.
2000 Watt x 3600 seconds = 7,200,000 Wattseconds = 7,200 kJ
Now, 6kg of lead acid battery (12V, 17Ah) would be about 12 V x 17 A x 3600 seconds = 734,400 Wattseconds = 734 kJ.
Thus, his quarter gallon of fuel equals roughly the energy contained in about 10 lead batteries at 12 lb each = 120 lbs., not 377. Using NiZn or NiCd or somesuch it would be maybe about 60 lbs., for Lithium even less.
In practical application, however, as with the forklift example, the ratio is - due to certain specific characteristics of electric drives - probably even better than that.
Probably, his efficiency is not very good, either. Multiple-stage worm gear reduction? We are then looking at maybe 50% efficiency in the gear, maybe less. I'd like to know how hot the gear is after 1 hour...
Why not simply use a cheap and simple 1hp (or some such number) PMDC motor such as the Bosch GPA750 (8 lbs.), two Evercel NiZn batteries (12 lbs.) and a self-made two-stage belt/chain reduction (2 lbs.) together with a basic 4QD controller (1 lb.). For a somewhat heavier, probably almost same range, standard power-assist bike concept... Much less noise and more environmentally friendly?
Regards,
scotchco
Commercial NiZn batteries are already available from http://www.evercel.com/ Currently, they are exploding into the EV application market, with very favourable reviews from those who have started to use them. Regards, scotchco
To inefficient. Imagine that the small IC motor has maybe 2 HP. That would equate to app. 1.5kW. Can you find any fuel cell (or even proposal for such) that puts out 1.5 to 2 kW and which could be mounted on a bike? Methinks not...
Regards,
scotchco
Wouldn't that be much much better spent in trying to actually develop a real energy source, such as (long shot example) http://torsatron.tripod.com/fusor/fusor.html instead of just looking for another form of energy storage? THAT would be more worthy of an apollo/manhattan style project than just to develop a new battery/energy storage/transport medium, methinks.
Furthermore: given certain developments in battery technologies (e.g. NiZn, NaS etc.) - why not simply move towards standard EVs with "conventional" batteries (as hydrogen use in the proposed form is nothing else but some form of battery)? Maybe less fancy than fuel cells, but much more readily available.
Is it just me who thinks it frustrating that the industry successfully tried to block such developments with stupid lead (or poisonous NiCd, or expensive Lithium etc.) battery EVs, and as soon as truly useful battery/technologies come up, change the strategy and now all of a sudden start to talk about hybrids, hydrogen, and elusive fuel cells? It is as if they waited decades for a useful EV battery concept to pop up simply to jump ship, to now sit out another one or two decades.
Hydrogen, being just a storage technology, does offer nothing to solve the fundamental problems. IMHO it's just another kind of battery...
Regards,
scotchco
Biodiesel for hundreds of millions of cars, worldwide? An illusion, methinks.
Say the US market for gasoline as auto fuel is approximately 125 billion US gallons per year. How much land would you need to use to produce that in biodiesel?
Roughly estimated maybe 500 million acres?
Less than 100 million acres overall are currently used in the US to produce corn...
Regards,
scotchco
I am not sure about that. The price of gasoline in Europe is already 3 to 4 times as high as in the US. Still no major switch to hybrid or electric...
Regards,
scotchco