[TML] Don't try this at home (was New 3d computer simulation design)

[Timothy Little]

On Sun, Dec 02, 2007 at 10:19:22PM +1100, Tim Rattray wrote:
> Dr Tanya Hill, Astronomy Curator, Melbourne Planetarium, has told me that
> this is caused by extreme magnetism, which cooks up the ionised gasses to
> millions of degrees.  (See http://en.wikipedia.org/wiki/Sun#Atmosphere)

The magnetic field is actually pretty weak.  The typical field
strengths are on the order of 0.0001 Tesla, only about twice Earth's
average field.  It's also very steady on human distance and time
scales, though it is much more intense near sunspots (up to 0.1 Tesla).

The power of the field is due to the fact that it operates over *huge*
distances.  The energy density of a typical volume of field is only on
the order of 0.004 J/m^3 - but over the volume of the Sun that adds up
to more than 10^26 J.  It also changes rapidly - but again, only
compared with the distances across which it operates.


> So you can just forget about going anywhere near the sun in anything
> made of metal.  Maybe you could get close in a nice teacup, or
> similar ceramic.  Of course, the effects of such magnetism on a
> human brain would be interesting

MRI scanners operate with fields of up to 20 Tesla, without having
adverse effects on human brains.  TMS is based on rapidly pulsed
changes in magnetic field with very specific focussed fields.  The
Sun's field is far too weak, too slow changing, and too diffuse in
gradient to have any such effects.


- Tim