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Scientists Levitate Mice for NASA
sterlingda writes to tell us that scientists have built a mouse-levitating superconducting magnet, working on behalf of NASA to study variable levels of gravity. The group hopes to ascertain what physiological impacts prolonged exposure to microgravity might have. "Repeated levitation tests showed the mice, even when not sedated, could quickly acclimate to levitation inside the cage. After three or four hours, the mice acted normally, including eating and drinking. The strong magnetic fields did not seem to have any negative impacts on the mice in the short term, and past studies have shown that rats did not suffer from adverse effects after 10 weeks of strong, non-levitating magnetic fields."
Look for The Flying DutchFrog to see electromagnet experiments in levitation on other vertebrates.
Damn_registrars has no butt-hole. Damn_registrars has no use for a butt-hole.
No, it works on the water in the animal. Red blood cells aren't ferromagnetic; all the iron is in haemoglobin, not little metallic bits.
# cat
Damn, my RAM is full of llamas.
For that matter, why does anyone think it's normal for humans to eat cow secretions?
Ah; now that's a more interesting one. Once upon a time it wasn't normal however, (almost certainly, unless you are a freak or are Chinese) you and your genetically dominant have been taking advantage of a recent gene mutation to make that normal.
=~ s,(.*),<sarcasm>$1</sarcasm>,g if any_point_you_wish();
That's begging the question. By definition, whatever humans do as a species is ipso facto *normal*. What is considered normal will change over time though.
Wait? Wha? Highschool physics much? How was this post modded 5+ informative when it's so wrong?
With 16T, you can levitate an object of any size so long as it predominantly consists of water. It's not like a 1g frog will float, but a 2g frog will fall in the same magnetic field. The reason why the things floated are small is because its easier to make small magnetic fields. If you have a current going around a loop, and you double the radius of that loop, your peak magnetic field drops by a factor of 4. You do not need 150kT to levitate a human. You just need a magnet that is physically larger with the same field strength and geometry.
One more thing. It's not just the magnitude of the magnetic field that controls whether something will levitate or not. The key is that the magnetic field gets weaker as you move up. Wikipedia tells me that levitation power is proportional to B*dB/dZ. (the magnitude of the field times how quickly it diminishes as you move upward) That is to say, if you had a 150kT magnetic field, and it was constant everywhere, you wouldn't float in it.
Regarding gradients: The gradients used in MRI vary in *position*. Yes in time, as well, but only because they are pulsed. We can ignore ramping issues to first order. Since the field varies as a function of position, when you move around, indeed the flux is changing which can induce currents in looped conductors so as to oppose the change. This is called induction. Many people, my self included, notice a strange sensation when first entering an MRI magnet. This is because the field is only homogeneous over a relatively small volume, outside of which there are once again field gradients (these are different than the intentional field gradients used to obtain an MRI image). It is probably not axons but something in the ear that is picking this up, I am not sure. Also, field strength has *nothing* to do with this effect. It's how fast the field changes as a function of position, i.e. the gradient, combined with the velocity of the pickup object.
Regarding repulsion: Water is diamagnetic. That means that the little spins (i.e. electrons) orbiting the atoms of a water molecule tend to align *against* the applied field direction. These spins will experience a repulsive force, hence the levitation.