Don't worry though, this collision won't occur for another 3 billion years or so, by which time we'll all be long dead, having killed ourselves by much more mundane methods such as biological weapons or global thermonuclear war.
So unless they start testing and I don't think they will, then we have to assume that they don't have the most sophisticated thermonuclear weapons.
Fortunately for civilization, none of these conflicts, with the possible exception of the Cuban missile crisis, pushed the world to the abyss of global thermonuclear war.
By 1960 it was clear that the advent of nuclear weapons, in particular thermonuclear weapons, and ballistic missiles to deliver them, created the potential for a completely new kind of warfare: push-button, nuclear-missile war.
The issue they discussed was whether intense, short bursts of high powered heavy ion beams could ignite thermonuclear fuel confined by its own inertia so as to produce a net gain of energy.
We freely describe the thermonuclear fusion of hydrogen in the centers of stars as burning.
From 1957 until his death in 1976, Heisenberg worked on problems in plasma physics and thermonuclear processes.
It represents a major step forward for the heavy-ion approach to inertial-confinement fusion, in which small pellets of thermonuclear fuel are compressed to the point of burning by beams of heavy ions.
Fusion creates the power of the thermonuclear or hydrogen bomb.
Since the thermonuclear fusion of hydrogen within stars gives you helium, some regions of the cosmos could easily accumulate more than their 8 percent share of helium, but, as expected, no one has ever found a galaxy with less.