Recent content by Thomas Moore

For those that are interested, there are two papers I found also intrigued by this recent "controversy" that specifically show eternal inflation models have many issues: 1. https://arxiv.org/abs/1408.2249 - Published in CQG 2. https://arxiv.org/abs/1508.02670 - Published in PRD Thomas

This past semester, I just took an introductory course on G.R., which translates to a lot of differential geometry and then concluding with Schwarzschild's solution. We really didn't do any cosmology. However, one of the themes that kept creeping up again and again is that in 4-dimensions...

Hi. That link was quite helpful. Well, this is where I got stuck though. For the first example, I wrote: 1. $L = \frac{\partial}{\partial t} - \frac{\partial^2}{\partial x^2} + 1/x$, which seems to work if you do $L u$. But, I'm not sure if adding 1/x is right like that. 2. But for this one...

Hi. I'm a bit confused on determining whether a certain PDE is linear or non-linear. For example, for the wave equation, we have: u_{xx} + u_{yy} = 0, where a subscript denotes a partial derivative. So, my textbook says to write: $L = \frac{\partial^2}{\partial x^2} + \frac{\partial^2}{\partial...

Hi. Yes, I saw this Wikipedia article. I was curious where the 10^-35 s^-2 comes from. Thanks.

Hi. I was just curious about the current value of the cosmological constant. My astrophysics class lecture notes say on the order of 10^-122, but the Wikipedia article says 10^-35 s^-2. Could someone explain where the 10^-35 s^-2 value comes from? Thanks!

Well, no numerical algorithm actually produces "infinity" as an output, you see your numerical algorithms diverge to very large numbers, like Runge-Kutta, Euler-Maryama, etc... How would you even put infinity in your software package?

Hi.. The paper does show according to my reading that solutions to the field equations blow up /diverge to infinity. Solutions to the Einstein field equations are "universes" are they not? FLRW, Schwarzschild, etc...

Hi. I am a first-year physics undergraduate student, and really want to become a cosmologist eventually. I was looking into how eternal inflation can generate a multiverse and came across this paper on the arXiv: http://arxiv.org/abs/1408.2249 It claims to have shown that eternal inflation...

Hi. If you read the article by Kohli carefully, and actually see Krauss' book, he actually claims that "nothing" is no space and no time. So he even postulates beyond the quantum vacuum, as the quantum vacuum is certainly space and time.

Hello everyone. Thanks for your input. I am slightly confused... Above, PeterDonis said that the article I referred to : http://arxiv.org/abs/1405.6091 is not really disproving Krauss' claims. I don't really know how he can say that. Although at least to me, Kohli is going through Krauss'...

Hi I am new on here, so please forgive me if this is in the wrong place. I am currently an Undergraduate physics major at UCLA, and want to pursue cosmology as a career eventually. A few of my friends are big fans of Lawrence Krauss, and recommended his book, a Universe from Nothing. I...