Pardon me for posting, but I was wondering…If I was somehow able to build a machine tha could extract energy from Neutrinos streaming off the sun, how much power could I get from it? If any? Say for the sake of this argument the neutrinos were “absorbed” by a 100’ x 100’ panel pointed at the sun, that was, say 50% efficient.
Or did I just screw up the question so much as to make it unanswerable?
Well, thanks for your patience,
Ranchoth
Are you just trying some sort of thought experiment or do you really think that there can be something outside a bad science fiction tv show that can actually capture neturinos?
Neutrinos normally fly through the entire earth without noticing it in their path. Neutrino detectors are lucky if they can catch a few (single digit) neutrinos in a day. There’s no such thing as an efficient neutrino absorber.
You’d be much better off trying to build an efficient solar panel. Because those aren’t even 50% efficient.
First of all you have to detect the neutrinos. Thats really damn hard and we have detectors that go down for miles and I still don’t think we’ve caught one yet. The other thing is that they have no charge (hence the name neutrino). They have a very very tiny mass (some people still say zero), so there wouldn’t be much of anything you could get from matter to energy conversion. IANA physicist though, so maybe someone else could answer otherwise.
The total neutrino flux from the sun is about 5 times 10[sup]6[/sup] cm[sup]-2[/sup]s[sup]-2[/sup]. The energies of these neutrinos lie in the 10 MeV ballpark. Thus, your 50% efficient 10,000 sq. ft. panel would be producing…
40 watts.
Unfortunately, as has already been pointed out, neutrinos interact very weakly. Neutrino detectors use kilotons of material and yet see only tens of interactions per day.
That’s it, eh? Would boosting the efficiency of the panel do cause any signifigant boost, or is 50% already stretching the limits of credulity too much?
Actually, I’m experimenting in putting something that can capture neutrinos IN a bad science fiction TV show. (Well, hopefully not bad. At least, not on purpose)
Ranchoth
If a 50% efficient panel generates 40W, obviously a 100% efficient panel would generate 80W. As for gredulity, even 0.01% efficiency is stretching it pretty far.
Such a material was used in at least one good science fiction though, namely Ringworld.
No matter what, the limits of credulity will be stretched. If your absorber was of an earthly density and was 100 ft. thick, you’d only stop about one in 10[sup]17[/sup] neutrinos. Just to drive that point home, that means an efficiency of no more than 0.00000000000000001.
After all is said and done, you should probably add one or two more zeros for things like:
energy collection efficiency: When the neutrinos interact, you’ll need to stop all the outgoing particles produced. (Any that sneak out will take energy with them.) Interestingly, neutrino oscillations conspire to make this a bigger problem for you than it had to be…
efficiency in converting the collected energy into a useful form (steam turbine turning a generator?)
In the end, we’re talking attowatts.