352 reputation
18
bio website wildcatsformma.wordpress.com
location Somewhere over the rainbow
age
visits member for 3 years, 7 months
seen May 21 at 20:42

My scientific interests:

  • Mathematics: Category Theory, Algebra, Logic (Model-Theory, ATP), Control Systems
  • Physics: General Relativity, QFT
  • Amateur Astronomer and Astrophotographer
  • Mathematica programming

My Websites:

WildCats
Premiere Mathematica package for category theory

xPrint Premiere GUI for tensor input and manipulation

Visit Mathematica.SE!

My non-scientific interests:

  • Skiing, Sailing, Windsurfing
  • Argentine Tango dancer

More or less fluent in (random order):

Italian, English, German, French, Spanish, Dutch and struggling with Russian


May
10
comment Is there a quark conservation law?
@JohnDuffield your answer is just silly, as physicus pointed out. Charge (which - hopefully - you agree is conserved under all interactions) also annihilates (or simply neutralizes). You start with a positive and a negative charge (electron and positron for ex.). Bring them together and you get annihilation (gamma rays). Zero net charge at the end and zero net charge at the beginning. Charge conservation. Same thing with quarks...except when there are weak interactions involved.
May
9
comment Free-falling from rest into a Kerr black hole
John , why don't you simply show us the eqs you have made and we start talking from there? This is not a philosophy Q&A place.
May
9
comment One-body General Relativity
"so a universe with only one body cannot exist" Perhaps it does exist,but unless that body is YOU,you would never know. I think you are wasting your time in meaningless thoughts. Every physics theory starts by studying a single source in isolation.Obviously this is an idealized model of a real source sufficiently distant/isolated from anything else. Continues....
May
9
comment Questions about MTW's “thousand” tests of the Einstein principle
@user12262 Free fall is defined and explained in paragraph 1.3 pag. 13
May
3
answered In general relativity, how do we think of Newton's third law for gravity?
May
2
answered Any tips on evaluating Riemann tensor?
Mar
30
comment Is there a default notation for 4-vectors while handwriting?
As you proceed with MTW the "boldness" decreases. The large majority of eqs are written in index notation, for the simple reason that it is the most precise one. There is a paragraph somewhere explaining the advantages and pitfalls of different notations. For serious work the index notation is unavoidable, except when working with forms only. So just be patient and keep on reading.
Mar
27
comment Is a nuclear bomb in some sense a bullet travelling at the speed of light, but along time rather than along space?
nice picture. Self produced, or....?
Mar
11
comment Is the universe 5 dimensional space-time or 4?
thank you for accepting my answer. I have added 2 long paragraphs. If you like my answer, you may also upvote it.
Mar
11
revised Is the universe 5 dimensional space-time or 4?
added last 2 paragraphs
Mar
10
answered Determining whether a space is really three or two dimensional?
Mar
9
answered Is the universe 5 dimensional space-time or 4?
Mar
6
comment Effect of a rotating disk on a grandfather clock
The real question is: did you ask granpa for permission to use his clock in this kind of experiment? :-) Seriously: is the pendulum free to swing in 3D? If yes, then the rotating disk has no effect. In any case relativistic time dilation is negligible at these low speeds
Jan
21
comment How eliminates the general relativity the Newtonian action at a distance? By the mediation of which “carriers”?
"it's my understanding that all moving bodies in space will lose kinetic energy continuously over time": this is a mis-understanding. The (real) Isaac Newton had this very clear in mind when he wrote the first law of motion. If you "wannabee" Newton, you'd better read it
Jan
21
revised If the Einstein Field Equations are so hard to solve, how did Einstein know they were correct in the first place?
edited some text
Jan
21
answered If the Einstein Field Equations are so hard to solve, how did Einstein know they were correct in the first place?
Jan
18
revised Can gravitaitonal waves orbit each other to form a standing wave?
edited title
Jan
18
suggested approved edit on Can gravitaitonal waves orbit each other to form a standing wave?
Sep
24
awarded  Autobiographer
Jul
28
comment On the coordinate independence of general relativity
@BenCrowell Really??? That's curious because I am restating and expanding on the hole argument (a terminology not found in the standard textbooks mentioned in my answer) mentioned by benrg in his accepted answer and that the OP declared to be very happy with. It seems you either did not understand the question or benrg.s answer or mine or...neither of them. Indeed your own answer is merely a restatement of the second part of my answer.