Scientists Levitate Mice • Hacker News Board

Re: Scientists Levitate Mice

#31

Post by pmichaud » Thu, Sep 10, 2009, 3:10 PM UTC

LargeWu wrote: post #29

This reminds me of a Mythbusters episode I saw where they tried numerous "antigravity" devices. A few of them did manage to levitate objects, but worked either on magnetic fields or thrust. There was no alteration of gravity. That said, I'm a bit confused as to how scientists want to apply this achievement to low-gravity environments. Since gravity is not actually being altered here, it doesn't seem relevant. Am i to…

Clearly there are differences, but many of the same conditions apply, such as low pressure on the bones, so that it can still be useful in /most/ studies related to microgravity. It's a little like using an animal to test medicine -- there are differences, but the initial work can often be completed because of the overwhelming similarities.

Re: Scientists Levitate Mice

#32

Post by ynniv » Thu, Sep 10, 2009, 3:29 PM UTC

LargeWu wrote: post #29

This reminds me of a Mythbusters episode I saw where they tried numerous "antigravity" devices. A few of them did manage to levitate objects, but worked either on magnetic fields or thrust. There was no alteration of gravity. That said, I'm a bit confused as to how scientists want to apply this achievement to low-gravity environments. Since gravity is not actually being altered here, it doesn't seem relevant. Am i to…

"Gravity" isn't being created, but a uniform force is being applied at the molecular level, which is effectively the same. It is currently being applied "up" at roughly the same force as gravity, causing levitation. Vectoring this force down instead of up will produce force indistinguishable from gravity.

Re: Scientists Levitate Mice

#33

Post by Confusion » Thu, Sep 10, 2009, 3:59 PM UTC

brandnewly wrote: post #26

Confusion wrote: post #12

The first living creature to be levitated was a frog, in 1997: http://www.hfml.ru.nl/froglev.html . This link is completely devoid of news.

"Other researchers have made live frogs and grasshoppers float in midair before, but such research with mice, being closer biologically to humans, could help in studies to counteract bone loss due to reduced gravity over long spans of time, as might be expected in deep space missions or on the surfaces of other planets."

If you can levitate a frog, then you can levitate a mouse. Nothing new in that. Research on mice yields better predictions as to what would happen to humans. Nothing new in that.

Re: Scientists Levitate Mice

#34

Post by spyrosk » Thu, Sep 10, 2009, 7:25 PM UTC

DannoHung wrote: post #2

I wonder how much money and power it would take to build a human sized magnetic levitation chamber...

Wouldn't this cause some trouble on humans? If I understand how this works correctly, unless they have a completely empty stomach or levitate in a horizontal position there could be some unwanted levitation of fluids taking place..

Re: Scientists Levitate Mice

#35

Post by jacquesm » Sat, Sep 12, 2009, 2:50 AM UTC

ars wrote: post #17

joeyo wrote: post #8

Earlier quoted context omitted.

According to the original paper, they needed a 17 Tesla magnet to lift a 10 g mouse. I'm not exactly sure how to extrapolate that, but if it's linear it seems like you would need on the order of 100 kiloTelsa to lift a 150 lb person.

I'm quite sure it's not linear by weight supported. The field exists in the entire area, each water molecule gets supported individually by the field. So the field needs to be strong enough to lift a single water molecule against earths gravity. (Plus some extra since water is also lifting misc other stuff in the body.) You don't need a stronger field, you need one that covers the entire area, at the original strengt…

Magnetic fields drop off as the cube of the distance, because the molecules further away will experience much less force you will need a much larger magnet anyway.

That's not 'somewhat' stronger, that's a lot stronger.

If a mouse is 25 mm high and you would want to levitate something the size of a human of say 1.75 m high with the same density as a mouse then the required magnet would have to be roughly (8^6)/2 times as strong for the same effect.

Then you still have to take into account the size difference at the base of the field, figure another factor of about 10 or so for that.

If you take the 'easier' approach and levitate a person while laying down (probably a wise thing) then the required magnet strength would be smaller, but still not that much smaller, you now have a vastly large surface area to work with ~40 times as large, (30,000 square cm opposed to 75 square cm), and the height is still 10 times as much so figure another 8^3 as much for that.