Where are the aliens? Are wormholes possible, and how can they be done? WTF are gamma ray bursts about?
Advanced civilisations look at the maths and decide wormholes are possible. Naturally this takes huge quantities of energy to attempt to "bend" the universe, let alone make a big enough worm hole to be useful and for it to be stable. But being advanced they can harness the necessary power, they have Dyson Spheres or Flux Capacitors or other high-tech systems that we see in our scientific literature and documentary programming on the History Channel.
But perhaps wormholes are effectively impossible, and so every time an advanced civilisation has tried it they have concentrated loads of energy down to a region, things have gone wrong, and there has been an immense explosion, gravitational collapse, or some other fun based on ultra-physics.
We see this from a distance as a GRB, they see it as thermonuclear reaction in the eye, and it smarts so much it wipes out their whole civilisation, their star and solar system etc.. Because they wipe themselves out so completely there is no more radio or other possibly detectable EM from the civilisation, and so once we have missed their artificial EM there will be no more.
So that's wormholes, the Fermi Paradox, and some GRBs solved, without even having to reach for "numbers". I gladly accept the inevitable nomination for a Nobel prize, ta muchly.