Thursday night I watched The Science of Doctor Who on BBC2 with the (oh so trendy) Professor Brian Cox. As he frolicked around in an old fashioned lecture theatre I thought it must be one of those Reith Lectures and I paid keen attention.
They’d roped in a room full of TV celebrities which I thought odd. Inviting celebs to watch An Audience with Victoria Wood makes some kind of sense but The Science of Doctor Who portrayed itself as a serious lecture. Why should I give additional credence to a speaker merely because some soap actor is gawping at him?
I also wonder about the veracity of the science trotted out in this program. I’ve been into science since I was a kid. Planets, black holes and first contact were the stuff of my youth and I am always slightly peeved when programs such as these are made and I see that we do not seem to have moved on very much.
These programs rarely go deep enough! Two things in particular bugged me about Thursday’s program. While dripping out standard scientific dogma Professor Cox based his arguments on two claims but never backed them up with any discussion of the questions which necessarily arise.
Firstly, the idea that nothing can escape from a black hole because the escape velocity of a black hole exceeds the speed of light and nothing can travel faster than the speed of light. This is taken as gospel by legions of science groupies and I have argued in pubs about this before to no avail because once some famous figure, like Professor Cox, states this on TV everyone repeats it ad nauseam as if they too understand the principles on which it is based. Usually they are TALKING BOLLOCKS!
To explain: Matter has the property of attracting other matter to it and this is what we call gravity. A gravity well is the effect of gravity surrounding a body of matter. As gravity is a fairly weak force, the body has to be pretty massive before gravity is appreciable so we’re normally talking about planets, stars and whatnot. The escape velocity is the speed an object must travel to completely escape from the gravity influence of a body.
But why should one leave a planet or star at escape velocity? Why could one not simply decamp at a legal and pedestrian 4 miles per hour? Ask anyone who pretends to understand this and they will not be able to explain it but state emphatically that it’s impossible. They are TALKING BOLLOCKS! The Wikipedai entry on escape velocity clearly states “A rocket moving out of a gravity well does not actually need to attain escape velocity to do so, but could achieve the same result at any speed with a suitable mode of propulsion and sufficient fuel. Escape velocity only applies to ballistic trajectories”. By this they mean that if you lob something you must lob it at sufficient speed.
Given this then the fact that the escape velocity of a black hole is greater than the speed of light need not dictate that it is impossible for an anything to ever leave a black hole and if this is true then the notion that a black hole is a “singularity” evaporates.
Secondly Professor Cox considered how light bouncing between two mirrors appears to travel at one speed between the mirrors yet if the two mirrors are set in motion the light moving between them must travel further (as it also travels along with the mirrors) and therefore the speed must be greater yet this would not be apparent to an observer travelling with the mirrors. This was portrayed as proof of Einsteinian relativity weirdness.
Well, duh! Obviously the light would travel further. Good old Newtonian physics would see to that as the light traveling between the mirrors would move in conjunction with the mirrors themselves (assuming that the whole palaver was set in motion together).
“But the speed of light can’t change, it’s always constant” whine the relativity pedants – Maybe so but the scenario portrayed in Thursday night’s program contributed nothing to this argument for or against. In the TV program the strangeness of Einsteinium physics did come through and it obviously beguiled the room full of media luvies but if one replaces the idea of light bouncing between mirrors with ping pong balls bouncing between bats then one can see that the movement of the balls is obviously different according to the motion of the observer which is what a lot of this speed of light weirdness is about.
I suspect that there is more to all this than meets the eye. An interesting thought experiment is to start from the idea that both mirrors or bats are stationary. Then one has to ask: stationary in relation to what? And this is where the whole relativity thing kicks in because there can be no concept of stationary without reference to another object.
But this is never discussed! Nothing said by Professor Cox on Thursday night explained why light must have a fixed speed. Since the scientific world, including, Professor Cox, bang on about this so much and since they base much of their arguments upon these two principles I suspect that there is truth in their arguments but I suggest that they underestimate the intellect and interest of the viewing public.
I recall a Reith Lecture fairly recently where they went deep and explained the background behind Heisenberg Uncertainty Principle. It was fantastic! I understood and it opened doors for me to understand further. Sadly, programs such as these are rare and as my memory dims my ability to explain the mechanisms fades and I find myself shouting over the jukebox “Something to do with particles….” before putting my pint to my face.
The Science of Doctor Who was a let down. It set itself up to be a serious lecture but in the end it was no more than a bit of fluff to milk the celebrity of Professor Cox and make a lot of actors feel they understand science without doing any thinking.