Ask a physicist anything. (6)

[mzungu]

Somehow I doubt this is anything dramatically different from the already reasonably well-established field of FPGA computing.

FPGA = field programmable gate array. FPGA's can be dynamically reconfigured on the fly.

And man said let there be cyborg: Rat Brain Robot - YouTube

Robot with a biological brain - YouTube

 

[Maxwell511]

Electric shock therapy? Well, yes, there is some benefit to this. But there is a big difference between using electromagnetic fields on the body and inducing a current through it.

There are only two possible effects of electromagnetic fields on biology:
1. Deposition of heat. Electromagnetic fields do carry energy, and can warm of cells. You have to use a huge amount of radiation to have any biological effect in a warm-blooded animal like ourselves, though, so that this is almost never a danger.
2. Chemical reactions. Chemical reactions can be caused when the energy per photon in the electromagnetic radiation is large enough to start kicking electrons out of their orbitals. This starts to happen in the ultraviolet range, which is why UV radiation from the Sun causes sunburns and can cause skin cancer. No radiation lower in frequency can do this, which means that any radiation in the visible, infrared, microwave, or radio range is perfectly safe, provided the total energy deposited isn't too high.

Magnets themselves fall under electromagnetic fields in terms of how they can impact biology. And in realistic situations, it is just not possible to use a magnet to produce anywhere near as strong of electromagnetic fields as we experience on a daily basis. So the use of magnets in therapy is pure woo.

There is still research into the use of electromagnetics for therapeutic uses for neurological disorders. I mention deep brain stimulation, no likes doing that because it is really invasive. I think it is just a technological hurdle we have to over come and not a scientific impossibility. Using permanent magnetics wouldn't do anything such as on your fridge because they are too weak and not really directed at doing anything specific.

Something fun I read to day that relates to this topic.

 

[mzungu]

There is still research into the use of electromagnetics for therapeutic uses for neurological disorders. I mention deep brain stimulation, no likes doing that because it is really invasive. I think it is just a technological hurdle we have to over come and not a scientific impossibility. Using permanent magnetics wouldn't do anything such as on your fridge because they are too weak and not really directed at doing anything specific.

Something fun I read to day that relates to this topic.

When I had an MRI My belt buckle was being pulled so hard by the magnetic field that it was like someone had grabbed it and was trying to drag me. MRI induce very powerful magnetic fields and these fields have no effect on the body. I can accept at the most that magnetic fields can cause disorientation in birds and the such but in all earnest using magnets to cure ailments is tantamount to this:

That Mitchell and Webb Look: Homeopathic A&E - YouTube

 

[roach]

There is still research into the use of electromagnetics for therapeutic uses for neurological disorders. I mention deep brain stimulation, no likes doing that because it is really invasive. I think it is just a technological hurdle we have to over come and not a scientific impossibility. Using permanent magnetics wouldn't do anything such as on your fridge because they are too weak and not really directed at doing anything specific.

Can't post but if you google "nova magnetic mind control" , there's a vid about this; EM treating depression and brain functions.

 

[Chalnoth]

Well, on using EM fields to modify the brain, that is a very special case, because those are extremely focused, specifically-directed EM fields. Basically no fields that we ever run into are so focused or directed, and so have basically no net effect. They may produce some small random currents, but in the end these just have the effect of heating you up, and not enough to overcome the fact that you are warm-blooded (so that your body easily copes with the small amount of additional heat).

 

[Naraoia]

Many countries have a national flag, and separate flags for their constituent sub-groups. The Union Jack is made up of the flags of England, Scotland, and Northern Ireland (though Wales is conspicuously missing ).

I did wonder why that was.

Perhaps sedative is a better word... I feel calm when drinking tea! I have african rooibos, ceylon gardens, orange jaipur and indian spice and all of them have a calming effect! (it is black tea)

I think the calming effect comes from drinking something nice and warm. Hot tea has the same effect on me. Caffeine is a stimulant, but if you get a lot of it, you can develop tolerance so it'll no longer affect you.

The USA is the "alternate universe" of the UK akin to "matter versus antimatter".

Watch for the massive explosions triggered by annihilating Englishmen in New York

Sting - Englishman In New York - YouTube

Nothing. The innermost electrons of an atom are routinely within the nucleus. Not that often, because the nucleus is very, very small. But it happens.

Isn't the nucleus the densest part of the electron cloud for s orbitals?

</random chemistry class memory fragment>

So what do we know about the evolution of dinosaurs? Quite a lot! We have, for instance, just discovered evidence that Plesiosaurs, a type of aquatic reptile, gave birth to live young.

No, no no, please don't confuse dinosaurs with every other extinct reptile! For my emotional health if nothing else

That said, yay for pregnant plesiosaurs! The things that happen while I'm on holiday...

 

[Chalnoth]

Isn't the nucleus the densest part of the electron cloud for s orbitals?

</random chemistry class memory fragment>

Yes, it is! Well, for the s1 orbital, anyway. If I remember correctly, it remains the highest-density location for all odd orbitals.

However, the nucleus is still incredibly small, so the total probability is also going to be very small.

 

[Steffenfield]

If an object were able to absorb all light and not produce any heat, would it be completely invisible?

Are there any elemental compounds that come close to achieving such an effect?

 

[Chalnoth]

If an object were able to absorb all light and not produce any heat, would it be completely invisible?

That would be a classical black hole, and yes, it would be invisible, except for the fact that it blocks out the light behind it and that we can see stuff falling into it.

Of course, in reality, black holes do radiate through Hawking radiation, but black holes formed from collapsing stars emit so little Hawking radiation that it is nearly impossible to detect.

Are there any elemental compounds that come close to achieving such an effect?

Nothing short of a black hole.

 

[Steffenfield]

So all objects, outside of black holes of course, must reflect light to some degree?

 

[Tuddrussell]

So all objects, outside of black holes of course, must reflect light to some degree?

Except dark matter.

 

[Steffenfield]

So if I designed a clothing line that used dark matter as a fabric, we all could be invisible?

 

[Chalnoth]

So all objects, outside of black holes of course, must reflect light to some degree?

Yes, basically. Just bear in mind that there's a lot more than reflection going on. You also get scattering of light in essentially random directions, you get absorption of light at certain wavelengths and emission at other wavelengths, and objects are transparent to certain wavelengths.

 

[chris4243]

So all objects, outside of black holes of course, must reflect light to some degree?

We've made some impressively black objects, by carefully digging holes in it so that any light would have to be reflected several times and so has more chance to get absorbed. However, such objects still will reflect a little, and will also heat up and give off blackbody radiation.

 

[chris4243]

So if I designed a clothing line that used dark matter as a fabric, we all could be invisible?

You could make a new type of clothing fit for an emperor!

 

[mzungu]

You could make a new type of clothing fit for an emperor!

Scientists hiding events by creating a hole in time , Top Story - ecPulse.com

http://www.dailymail.co.uk/sciencet...ntists-develop-light-distorting-material.html

Klingons eat your hearts out!!!

 

[mzungu]

Here's one for ya mate: TOP TEN UNSOLVED PROBLEMS IN PHYSICS

 

[Chalnoth]

So if I designed a clothing line that used dark matter as a fabric, we all could be invisible?

Haha, well, you can't make fabric out of dark matter (dark matter doesn't stick together, so it can't be used to make anything), but it'd just be invisible itself if you could. Wearing invisible clothing would just make you look naked

 

[Chalnoth]

Here's one for ya mate: TOP TEN UNSOLVED PROBLEMS IN PHYSICS

Let's see.

1) Obviously not all the dimensionless parameters are calculable. Some may be, we don't know how many. But certainly not all of them. The idea that this is possible was basically only ever a pipe dream, and the discovery of spontaneous symmetry breaking has basically put the nail in that coffin. The grand unified theory proposals that we have are also all moving further in the direction of more spontaneous symmetry breaking, not less.

2) Yeah, okay, this one is completely unknown. And, unfortunately, we don't have any clear prospects on learning the details of quantum gravity on the horizon, because experimentally it's such a difficult problem.

3) Also unknown, but clearly it takes a very, very long time for protons to decay.

4) Supersymmetry is a really interesting topic, and there is hope that if supersymmetry exists that the LHC will be able to find it, possibly very soon. So maybe we will have some solid knowledge on this front within just a couple of years.

5) As I understand it, you don't get a universe that permits observers unless you have 3 space and 1 time dimension. Fewer dimensions and reality is too simple, so that observers can't exist. More dimensions, or a different mix of them, and reality is unstable or inherently unpredictable. Because of this fact, it is unreasonable to expect any deeper reason for why there are three space and one time dimension.
This paper discusses this fact, among other things: http://arxiv.org/abs/gr-qc/9704009

6) This is another good one. And even just saying "there is no cosmological constant" doesn't solve the problem, because then you have to explain why it is zero.

7) Another interesting one.

8) I believe Hawking finally solved the black hole information paradox by proving that a black hole which forms and evaporates in finite time leaves the information content of the universe unchanged.

9) This, to me, is tied up with question 2) and isn't really distinct.

10) This one I have no idea about. Seems pretty interesting, though.

11) Why is it important? Because it's interesting!

 

[Eudaimonist]

1) Obviously not all the dimensionless parameters are calculable. Some may be, we don't know how many. But certainly not all of them. The idea that this is possible was basically only ever a pipe dream, and the discovery of spontaneous symmetry breaking has basically put the nail in that coffin.

Why is that? And does that mean that it is known with reasonable certainty that some physical constants are variable and accidental? And is the probability distribution of this variation known?


eudaimonia,

Mark