Intuitive armchair physicists

12:39 PM 9/9/2009

-I once thought (middle school / early high school) that since you can divide space infinitely you could never touch anything. I was told that was dumbest idea ever by my physics teacher so I abandoned it. Was I actually right? I must know....

-You were right, but for the wrong reasons. You can divide space infinitely, but you can also divide time infinitely, so the two effects cancel each other out. However, you can't touch things because the electrons on the molecules of your hands, feet, etc. repel the electrons in any object that you attempt to touch. The closer the electrons get, the stronger the repelling force (by orders of magnitude). The only common way to overcome this is by reacting with the object (so I guess, if you've ever burned yourself with a solid base like lye, you have touched something). Any other ways of touching would mostly have to deal with nuclear reactions.

Of course, it really depends on how you define touching. If you define "coming close enough that the electron fields of your molecules exert the dominant force on the combined electron fields of another enclosed system", then you've touched plenty of things.

-What the fuck are you talking about, this isn't even true. Planck length (1.6*10^-35 m) is the smallest distance between two points from which it is theoretically possible to distinguish the two. This is due to (the other qualm with your post) Planck time, the smallest unit of measurable time.


-I'm not a physicist, but according to the wikipedia, the planck length is the shortest length that we can know anything about, not the shortest that can exist.

-certain versions of quantum gravity suggest that it is not only the shortest distance we can get information from, but also the shortest distance that can exist.

--
a biologist, engineer and mathematician were having coffee on the patio

across the street they watch as two people walk into a house. a few minutes later, three people leave the house.

they start to discuss how that could happen

biologist: the two people copulated, reproduced and three people leave the house

engineer: that's wrong, our initial observation must have been erroneous

mathematician: you're both wrong. if another person enters the house it will be empty again