4 ms·
Most of the time when people make comments like that, they don’t actually mean “impossible” — they mean within the realm of reality. No one is going to be fusin
by orev 7y ago
Most of the time when people make comments like that, they don’t actually mean “impossible” — they mean within the realm of reality. No one is going to be fusing helium in quantities high enough to run MRI machines. It would greatly add to the discussion if we didn’t have to address these red herrings.
- sandworm101 7y agoNot how we use it now, but the total amount of helium needed to run an MRI machine (with recapture) isn't all that much. Devices like acoustic cold fingers can use a very very small amount of helium to create a steady heat pump. Currently, such devices are not integrated into MRI machines because tubs of liquid helium are cheaper, but there is no reason why we couldn't build a closed-cycle MRI machine that didn't use any net helium. https://en.wikipedia.org/wiki/Thermoacoustic_heat_engine https://en.wikipedia.org/wiki/Thermoacoustic_heat_engine https://en.wikipedia.org/wiki/Pulse_tube_refrigerator https://en.wikipedia.org/wiki/Pulse_tube_refrigerator
- yostrovs 7y agoThere are MRI machines that use nearly zero helium: https://www.medgadget.com/2018/09/philips-helium-free-mri-system-combines-productivity-with-high-quality-imaging.html https://www.medgadget.com/2018/09/philips-helium-free-mri-sy...
- HarryHirsch 7y agoLarge NMR facilities have started recycling their helium: Yale, Harvard, Madison, UGA.
- orev 7y agoAgain, not the point of the discussion. MRI was a simple example of how we use helium today. I could have easily said party balloons. It would help any conversation you have in general to avoid nitpicking on insignificant items and keep the discussion on the main point (which, if I have to spell it out, is the quantity of helium required to do various things) I do understand that when helium is depleted we will probably find other ways to accomplish things, but it’s still silly to be venting a gas that we KNOW has a finite amount over the lifetime of the Earth or using it for party balloons.
- daodedickinson 7y agoIt wasn't a red herring - the post he replied to reads: "we can never make any more until we get to the outer planets."
- c3534l 7y agoOf course not, not when helium is relatively cheap and plentiful. But when we're nearly out of helium, you'd better bet we'll figure it out.