It's The End of the World As We Know It...

I have a vague idea for a doomsday machine for the Harry Potter universe, based on the self-replicating bludgers I used in the last couple of chapters of my story.

I want to work out how long it takes for them to cover the earth given travel at around 60 mph, random paths, and doubling in numbers every few seconds. My feeling is that this ends up working like the destruction of Jupiter in 2010: Odyssey 2 - you get so many that the mass collapses as a black hole - but my maths really isn't good enough; do they spread out and blanket the world first, or does the implosion happen while they're still over the UK? Obviously it depends on things like their mass (20 to 150lb depending on your source), replication rate, etc., and how many times they double before replication errors creep in. Let's assume that it's Voldemort casting the spell and aiming to maximise muggle casualties, so spelled to target cars, trucks, trains, aircraft etc.

Any thoughts?

Problems with pictures

Several people seem to be having problems with pictures posted to Dreamwidth coming out too huge, wider than the screen.

My fix for this is to start off with small versions of the pictures, e.g. 800x600, which Flickr etc will readily do.

But if you insist on starting off with something huge the fix is to edit the HTML for the picture insertion and add width="95%". This makes the picture take up 95% of the width of the reader's blog page. It does NOT do anything about file size, loading speed or bandwidth, however, which is why using smaller pictures is a better fix. Or do both, of course!