Recent content by Shellsunde

It's the magnitude of the objects and their masses that warrants treating a relative absence of mass as a contributing cause for a galaxy's acceleration, correct? However, it seems a fallacy to treat the absence of a thing as if it were an actual, positive, contributing cause. The low-mass...

Recently, I read a few popularized articles portraying a study and associated calculations using astronomical measurements that posits a characterization of the direction and acceleration (or velocity) of our galaxy. The researchers assert not only is our galaxy being attracted by massive...

OK, watch your language, sonny.

Back up to the definition... Would someone help with a proper definition of chirality? What I read on Wikipedia, in the dictionary and elsewhere online didn't sink in for me. What I understood these sources to say is chirality is such that a thing and its mirror image can't be superposed...

How do they manage to calculate that the plane took the southern path? A few hours ago, it was reported that further analysis of the satellite pings convinced them that the plane flew the southern corridor, not the northern. How did they manage to get that result, do you think? We have...

Sun now has only a south magnetic pole??! This article in the popular press ["Strange Doings on the Sun", Wall Street Journal] mentions that the sun's regular oscillation in the location of its magnetic poles is now not synchronized, as it's expected to be. The sun's north magnetic pole has...

I thought there was complete agreement that a set has to be constructable. Evidently not, OK. That a set's elements must be well-defined is an essential characteristic of a set, too. That's an important conition, too. To Office_Shredder, are you using 'will' in the sense of 'intend', so as...

I think there are two problems. One, as you said, is that it is not yet known or even knowable who will enter Chicago in 2050. The second is, what precisely constitutes the boundary of Chicago. I think the future problem is the one the author wished to emphasize. My problem with that is the...

naive (intuitive) definition of "set" I happened upon a book by a Joseph Landin, once head of the math department at University of Chicago and subsequently Ohio State University, in which he gives this as a definition of a set and states this property: Shortly thereafter, he writes...

Thanks so much for these. I spent an hour-and-half playing with only a handful on them, from you first list. Very educational and engrossing and fun.