Scientific and mathematical inaccuracies, misconceptions and errors that get under your skin

[katsabas]

The fact that people actually promote the use of grapefruit juice in order to boost the effectiveness of medicine, including Viagra. What's even more disturbing is that shit like that gets published.

 

[Veylon]

Intergalactic, as it's used in fiction. It often gets dragged in when humanity's ten ships are shooting at ten ships from another species that lives a dozen light years down the road over the one system that's in between our homeworld and theirs. OMG! Intergalactic warfare!

This kind of exaggeration is like describing a schoolyard scuffle as a global crisis. Galaxies have billions of stars each. Inter- means there's more than one of these monstrosities involved. The scale of a conflict that could be accurately described as intergalactic would be so vast in time, scope, and resources that it's nigh impossible to imagine. Worlds would be seared or shattered, billions killed, fleets massacred, and that would just be the small moment-to-moment news.

 

[DJjaffacake]

The idea that all radiation will a)give you cancer, or b)turn you into some sort of mutant is pretty retarded. Ionising radiation, which is UV, X-rays, Gamma rays, Beta radiation and Alpha radiation can cause cancer (notice the emphasis on can). Of those, UV and X-rays are only likely to cause cancer if you're coming into contact with them a lot, and Alpha is only really an issue if you ingest it. Light is a form of radiation for fuck's sake, no one gets cancer from exposure to light.

 

[Maxy]

"Human beings only use 10% of their brains."

This one really bugs the crap out of me. I usually hear it said by 'experts' on late night tv who are trying to sell books to expand our memory or unlock our psychic potential or some such rubbish.

Human beings don't only use 10% of our brains, we only use 10% of our brains at any one time. The parts of our brains that are active while we are for instance, reading a book, are inactive or less active when we are listening to someone talk, singing a song, playing jump rope, etc.

The plus side to that one is that you can always look smugly at whoever says it to you and say, "Well, maybe you do."

On a slightly more serious note, I thought the truth behind that little factoid was that only 10% (or less) of our brain cells are neurons?

Neither are actually true. While our entire brain is never concurrently active we switch between modes while doing things so frequently that its hard to pin down a "%" active at any given moment, and as far as I know a maximum has not been determined. I'm know it is above 10% however. The myth started as most do with a off hand comment later taken out of context.

dunno about how much of your brain is active at any one time, but from vague recollections of what one of my neuro lectures was telling me they are beginning to think that it MAY be closer to 50/50? the other half being glial/support cells ie astrocytes, oligodendrocytes, microglia <- this ones technically not a glial cell. another fun (maybe...) fact, your cerebellum contains approximately the same number of neurons as the brain (this was also another little bomb our lecturer dropped)

 

[Rodrigo Girao]

When it comes to bad science, nothing infuriates me more than those ridiculous studies that try to pin health benefits to genital mutilation aka circumcision. Their methodology is always wrong, and they twist the numbers to get whatever result they want; they never mention its destructive side effects, well known since ancient times; and they never touch the ethical problem of performing an irreversible body modification on people who have not consented to it.