While magnets and their field are often pictured like this
<a href="http:&#x2F;&#x2F;helios.gsfc.nasa.gov&#x2F;barmag.jpg" rel="nofollow">http:&#x2F;&#x2F;helios.gsfc.nasa.gov&#x2F;barmag.jpg</a>
in reality the field is everywhere like this
<a href="https:&#x2F;&#x2F;upload.wikimedia.org&#x2F;wikipedia&#x2F;commons&#x2F;5&#x2F;57&#x2F;Magnet0873.png" rel="nofollow">https:&#x2F;&#x2F;upload.wikimedia.org&#x2F;wikipedia&#x2F;commons&#x2F;5&#x2F;57&#x2F;Magnet08...</a>
so what the &quot;wormhole&quot; does is, it shields the field from the bar magnet inside the sphere, so only the field from the ends of the bar is projected outside, like this
<a href="https:&#x2F;&#x2F;d1o50x50snmhul.cloudfront.net&#x2F;wp-content&#x2F;uploads&#x2F;2015&#x2F;08&#x2F;dn28071-3_800.jpg" rel="nofollow">https:&#x2F;&#x2F;d1o50x50snmhul.cloudfront.net&#x2F;wp-content&#x2F;uploads&#x2F;201...</a>