colliding submarines

So what is the actual probability of any two objects colliding at random in the Atlantic? Well it was high enough for the Titanic to come a cropper on its maiden voyage of 1912, but then again there had been warnings of large numbers of icebergs and the Titanic was steaming right through their path as they drifted down from the coast of Greenland. And, needless to say, the Titanic and the icebergs were constrained to move around on the two dimensional surface of the sea.

Now of course neither of the two crew members posted to look out for icebergs had binoculars. Similarly, nuclear subs nowadays spend a lot of time in stealth mode, which means turning off their sonar in order to be more invisible. Blind but invisible. Now take two equally blind subs and let them prowl around the bottom of the Atlantic and see what happens. By choice, they constrain themselves to the lower depths of the ocean which increases the probability of a collision. Then they have their favourite trenches to hide in and apparently use temperature gradients to help evade detection - assuming another sub has actually turned its sonar on of course!

So earlier this month it really happened. A French and British sub - both nuclear powered and loaded with nuclear weapons - went bump in the night. Imagine how that must have freaked them out! The funniest part is that in a way - assuming the crews weren't all just fast asleep at the tillers - it shows how amazingly successful both subs were being at what they were supposed to be doing.

So this has been quite the month for spectacular collisions, what with the Iridium communications satellite smashing into a defunct Russian satellite at very high speed. These satellites were in low pole-to-pole orbits. Unlike the much higher geostationary orbits above the equator, the pole-to-pole orbits look like lines of longitude and in fact the satellites crossed paths almost at right angles to each other. They were travelling about 10000 times faster than the two subs so I guess it's a good thing that - unlike the subs - they weren't armed to the teeth.