Recent content by nicksauce

I'm reading through these notes on numerical hydrodynamics. On pg17, they introduce the monotonized central difference flux limiter, which looks something like \frac{\partial~a}{\partial~x}|_i =...

Imagine I have a set 1,2,3,4,5,6,... Then some later time that set has now 2,4,6,8,10,12,... Both sets are infinite, but in some sense that set has expanded.

Yeah that's about right. If I remember correctly, a is about 8kpc and b is about 1kpc. I'm sure you can find more accurate numbers in papers.

I think you can summarize the idea simply: No metals = Less cooling = Higher temperatures = Higher Jeans mass = Higher stellar mass This seems to be a good overview of the situation (pdf): http://arxiv.org/pdf/astro-ph/0102503v3.pdf

Hmmm... perhaps I had misunderstood the problem then.

I think people also think the inflaton mass in something like 10^11-10^13 GeV, so the Higgs is too light. I forget the exact reasoning here though.

Well for one thing, the Inflaton field needs to be turned off somehow (since inflation ended), but as far as I know there is no way to turn the Higgs field off.

GR has frame dragging. GR does not have torsion. Therefore frame dragging cannot be the same as torsion.

Carroll and Ostlie, "Introduction to Modern Astrophysics", tries to cover basically everything in astrophysics and does a pretty darn good job of it in my opinion.

Hello. FWIW I'm doing my PhD in Astrophysics at University of Toronto, so feel free to ask any specific question about the program here, and I'll be happy to answer. You don't have to learn C++ to be ready for university. You can learn it there. But if you want to do a career in...

Well when you pull the sum out to the front of the integral, you have x^3e^{-(1+n)x}. Then when you substitute y = (n+1)x, you have to use x^3 dx= y^3dy / (n+1)^4. The integral can then be evaluated, presumably by parts, to get 6. Evaluating the sum is a bit tricky. If I was working through the...

This is a very useful article, thanks for posting. I often argue with people who think that rotation curves are the sole evidence for DM, so it will be nice to have this list handy.

Yes of course there is no force. The real question is give that there is no force, what, semantically is a better description of that fact.

My real reason for posting this is that I got in an argument about it with someone today and we spent a while on it. So I am now curious what other people think.

For this case, you can assume "you" are a point particle :)