Recent content by pilpel

Fact: The ring of integers Z is totally ordered: for any distinct elements a and b in Z, either a>b or a<b. Fact: The ring of integers is discrete, in the sense that for any element a in Z, there exists an element b in Z such that there is no element c in Z with a<c<b, and the same argument...

Given a fixed perimeter, what is the geometric shape (non-self-intersecting closed curve) that would maximize the enclosed area? MathWorld (I'm not allowed to link) and a few other sites insist that the answer is a semi-circle, but simple math with perimeter=100 m would show that a circle would...

Thank you all, but it's none of those, although "bounding pulse" comes close. It is in fact a Latinized name, as Moonbear suggested. I stumbled upon it once while as I was perusing a medical dictionary, and it drew my attention because it described exactly what I once felt under extreme anxiety...

I used to know this, but then I forgot and I can't seem to Google it. What is the name of that condition, usually acute and brought about by extreme anxiety or fear, in which you feel your heart pounding so powerfully that it seems to pulsate your entire chest cavity, and you can even feel your...

juanrga, Good point, but the amount of energy in the universe is a practical consideration, not a theoretical one. My question may be restated as "given an arbitrarily large amount of energy, does density have an upper bound?" Naty1, I must admit that I could never understand the notion of...

Is there a theoretical upper bound for the density of matter? Given a proton (already almost as dense as a black hole, according to Wikipedia), can you theoretically compress it into any non-zero volume? Has any work been done that shows that matter can or cannot achieve certain levels of...