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Bad Physics It is often amusing when people who are writing an article that has nothing to do with physics, tries to either justify, or make some similar comparison, to something in physics. The article titled “bad physics” was one such example. This is another one.

Physics talks about “parthenogenesis”, that deals with how species reproduce. I certainly am not an expert in it, but I find this paragraph to be rather amusing and a chance to illustrate this concept in physics clearly to people who do not understand it:

For explaining everyday life—babies, puppies, puberty—the mommy-daddy story of procreation works fine. But at life’s edges, conventional biology, like conventional physics, breaks down. As you approach the speed of light, time slows and distances shrink. And as you approach extinction, genes find new ways to pass themselves on. Scientists call it “reproductive plasticity.” A Komodo dragon manufactures a mate. A shark’s got to do what a shark’s got to do. I think of all the consequences of Special Relativity (SR), this part is one of the most misunderstood by the general public.

1. Conventional physics does not “break down” as one approaches the speed of light. this is because SR IS a part of “conventional physics”. Maybe this author meant “classical physics”. It is misleading and wrong to not include SR within conventional physics. Stating it as it is gives the impression that physics simply doesn’t work close to c. This is absolutely wrong.

2. Time doesn’t slow down when one approaches c. This is a very popular misconception. The principle of time dilation requires TWO OBSERVES IN DIFFERENT INERTIAL FRAMES. Let’s say B is moving with respect to A. If A looks at B’s clock, A will see that B’s clock is moving slower. However, B can also say the same thing, since we have no preferred frame. B will see A’s clock also moving slower. HOWEVER, neither A nor B will see THEIR OWN CLOCK as being slow. The time interval in their own frame doesn’t change! So even if B is moving close to c with respect to A, B will NOT see its time slowing down. It will see A’s time slowing down! So what is stated in the article is utterly wrong.

Again, I’m sure this is just nitpicking, but it is surprising how many people who don’t normally read actual physics texts would get a lot of their understanding of physics via articles like this. At the very least, someone using something in physics to illustrate their point should pay a bit more attention on the ACCURACY of what they are writing.