Recent content by zthompson47

Thanks for the help - I took a little break and was able to find a solution. I set up equations for each "relativistic mass" and plugged them into 4.9 as you said, and it looks like it applies for any value of w < c. With $$m_w = \frac{m_0}{\sqrt{1 - w^2/c^2}}$$ and $$m_v = \frac{m_0}{\sqrt{1...

I'm hoping that someone can help me understand a topic on page 86 of Feynman's "Six Not-so-easy-pieces", in the "4-4 Relativistic mass" section. He says, "It is an interesting exercise to now check whether or not Eq.(4.9) is indeed true for arbitrary values of w, assuming that Eq.(4.10) is the...

Thanks for the comments. I'm still a bit curious about the theoretical possibilities, but have dropped plans to find a cosmic mirror. Let's say a single photon left our galaxy a long time ago, hit a dust particle at some point, and reflected back instead of being absorbed. By good luck, it...

I thought dust was a broad term that includes molucular clouds of hydrogen that would exist in the early universe. Either way, the result would be star formation.

Is it even possible to detect reflected radiation from our galaxy?

I think part of the theory is that a dust cloud would be compressed as it enters a dense region, causing lots of star formation. It seems like those big stars would contribute most of the light for the spiral pattern.

I was wondering if there are objects near our galaxy that can reflect light from the Milky Way back to us for observation. If so, maybe they can provide information about the shape of the galaxy, for example. I'm sure there would be other interesting applications. I was thinking about it...

Check out http://en.wikipedia.org/wiki/Density_wave_theory which explains the spiral structure as a result of standing density waves. I think the idea is that as an orbiting star approaches an over dense region, gravitational force will accelerate it towards the dense region. On the way out of...

I meant d for density, and probably should have mentioned it or at least used the conventional ρ. That equation is derived from the first two that TEFLing listed.

First get an expression for mass (from Newton's law) $$M = \frac{gr^2}{G}$$ and an expression for radius (from the density formula) $$r = \left(\frac{3M}{4{\pi}d}\right)^{1/3} .$$ Now either plug the equation for r into the equation for M or the equation for M into the equation for r. If you...

Thanks for the reply. At first I was thinking that the molecule which was already in the low energy alignment would not be affected in any way by the field, but I'm realizing that something actually does change. It might not be affected immediately, but the molecule in the field would require...

I'm watching a Leonard Susskind video about the Higgs Boson where he gives an example of how an electric field can change the mass of a water molecule. If you put a water molecule between two capacitor plates (so the electric field is uniform and the field lines are parallel), it will tend to...

Thanks for the responses - I appreciate the links, and the articles seem to have the answers I seek. I just need some time to digest the info. Goodbye, intuition. In general it seems that I was focused on the target in the experiment, only looking for quantum effects when the particle is...

Hello, I've been trying to learn physics recently with the long term goal of understanding GR and cosmology. As a result, I have many questions, so I'll just get started.. In the famous double slit experiment, there is a coherent light source aimed at a double slit which produces an...