Wednesday, April 12, 2006

science programs and science facts

i think it reasonable to assume, along with most people that have access to programming via cable, that a channel that is called the "science channel", or the much better "nova" series on pbs, ought to be factually correct in its presentation and narrative content.

this is not so. they include narratives that suggests what is said is true. i will give you a couple of recent examples that suggest otherwise.

in a program about stars and our sun, the science channel asserts that the same nuclear process that provides nuclear power and the atomic bomb is the same as that occurring in the interiors of stars. they also state that the sun is converting four million tons of hydrogen into helium each second. not true.

they might have said instead that the sun is taking 600 million tons of hydrogen and converting it into 596 million tons of helium each second. the four million tons is released as energy, not helium.

all nuclear power stations employ nuclear fission in the energy releasing process, as do small nuclear weapons. the larger, most destructive weapons employ both nuclear fission and fusion processes, whereas the sun, along with all other stars on the main sequence of their evolutionary lives are converting hydrogen to helium solely through nuclear fusion. simply put, fission is where a nucleus is forced to split and fusion is where, as the name suggests, a nucleus is made heavier by the addition of others. it is the energy released in both processes that we see as the end result.

in a nova program about albert einstein (einstein's big idea), john lithgow, the narrator does a very decent job in his story telling, but the production team manage to leave out any discussion of gravity, the work of ernest rutherford, and the team that actually did 'split' the atom - crockcroft and walton. they make no mention at all of neils bohr , or quantum mechanics - probably the most successful scientific theory in the history of man. instead they choose to focus on lise meitner and otto hahn, who together were the first to explain and interpret what had happened in experiments, coining the term nuclear fission. to say that lise meitner split the atom is just plain wrong, though.

while i'm all for highlighting the tremendous advances brought about by scientists that are not famous in the eyes of the media, i am dead against factual errors. john lithgow, who impressively talked us through the meaning of e=mc^2, then immediately contradicts himself and the equation by saying that today, we are bombarding particles at the speed of light in particle accelerators. we are not, nor can we ever. the best we can do is to approach the speed of light, (relativistic speeds) but as einstein himself stated, nothing with a mass can ever reach the speed of light. his equation means that as we add more energy into a particle in order to raise it to higher and higher relativistic speeds, that energy is converted to mass, adding weight (because of gravity) thereby slowing it down, thus requiring more energy, and so on. a particle travelling at 99.8% of the speed of light would still see a photon travelling at 670 million miles an hour away from it. just the same as if it were standing still.

one other thing: einstein never actually wrote the famous equation e=mc^2 in that form, contrary to what they showed him doing in the program. what he actually wrote was dm=L/c^2 (the L represents energy).

which brings us to perhaps the most starling prediction of the theory of special relativity. and it wasn't even mentioned in the program. that if it were possible for us to hitch a ride on a photon travelling at the speed of light, we would be quite unable to tell anyone what the event was like. physical events happen in a time frame. any event can only be described because of a passage of time, from one state to the next. for a photon, however, travelling at the speed of light, there is no such thing as time. the universe and the photon do exist, but it is for a moment of no duration...

that means that for the light of the sun that took 8 minutes for the photons to travel the 93 million miles across space to reach your eyes, there was no passage of time. it is an instant. amazingly, this is true of the light of all the stars you can see in the night sky, even the ones whose light it has taken millions and millions of years to cross space to reach your eyes.

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