The nuke deployed to destroy the hive produces background counts. Do nukes, like, release magical energy or something? Backgound count can feed Strain III; it must be magical. And yet nukes seemed distinctly non-magical.

Background count doesn't have to be caused by magic (and, most of the time, it's not) -- it's caused by human emotions. WWII era death camps have background count. Prisons have background count. In a lot of cities, "the barrens" sort of neighborhood has a background count. Nagasaki and Hiroshima have background counts. A room where an axe murderer just offed someone's family can have a background count, for a while.

Nukes are kind of traumatic, I bet. There's your background count.

Seams like an interesting hypothesis to me, that nukes in the 6th world do have less physically destructive power, because the convert part of it into astral energy (BC). Think of it like a reverse combat spell, not creating an elemental effect with magical energy, but the other way round.

The traumatic and toxic effect would do it´s part of cause

Why aren't happy places foci of strong emotions? Why are they always sites of utter poverty and despair?

Strong, joyful emotions can also cause a background count.

IIRC, a few places of worship have it. Oftentimes drug dens or prostitute shops have it as well.

There are often temporary BCs at large emotional mass events, like music festivals ore something. The event would have to take place over and over fore a very long period for the BC to become permanent. 2.000 soldiers dying on a battlefield in a singel day does just provoke stronger emotions than a Shildwall concert does, so that BC will last for a hundred years or more, as oposed to the day after the gig.

BC in places of religious or pseudo-religious worship do often have a BC, but it´s allmost allways aspected to that worship and gives magical practitioners of faith a bonus instead of a malus. I´m sure the great shrine of the king in Las Vegas will have a BC that hinders most magicians, but Elvis-Shamans would get a bonus!

Prositution shops have BC's? Are they happy of horrifyingly sad emotions, and are they mostly the johns'?

I don't believe it's actually a linear scale like that,
and I doubt it would be polarized either, having the Woodsto 2073 festival on the fields of Ghettysburg would certainly not return the count to normal there. It would just be very confusing. I would have any mages feel EXTREMELY bipolar in such a situation.

yeah. just picture BC as smoke. bad emotions release one color of smoke, happy emotions release another color.

I think smell is an even better analogy. Like a Ghoul wearing Charnell #4

SO back to why Nukes leave a huge background count. It's not the massive release of energy, it's the massive load of psychological baggage that built up around Nuclear Weapons during the cold war. The image of the mushroom cloud produces such feelings of foreboding in the average person that a nuclear explosion taints the astral where it goes off.

Similarly intense emotional buildups occur and cause background counts in other places too. Imagine what the background count in th St. Peters must be, or the Tower of London, or for that matter Yankee Stadium or Fenway Park.

BC 0 are places where everything is fine and dandy, there is no imbalance in the manasphere. Imbalances cause BC, be it good imbalance or bad imbalance.

Ask yourself: Is there a place where there is be no life on earth(which would have its own BC as there is a absence of life)? Then ask yourself: Can even a nuclear test site kill nothing? Can life in the nuke site NOT affected adversely(mutations and radiation often bring pain and suffering)?

also remember that the void of space is an astral warp, effectively BC of 5+. Since a nuke wipes out life pretty thoroughly, and then 'corrupts' it (almost like the horrors whom also corrupt astral space), I can see nukes having an effect in that way as well.