Recent content by helenwang413

Hi, I am stuck in a differentiation problem. I need to find the derivative of an integration of an unknown function with respect to the function itself, and then set the derivative to zero in order to find the form of the funtion which gives the minimum of its integration. For example, find a...

Under what condition can we change the order of integration and differentiation? Thanks!

Yes, the velocity explanation is accepted by most of the researchers. What is the best evidence for that? Besides, it sounds like, to me, a bit circular argument. You define a CMB rest frame, and then calculate the velocity dipole according to the Doppler effect. What if there is something...

How to understand that the cosmic microwave background (CMB) can define a cosmological frame? Cheers!

Hello, everybody! I find it hard in understanding negative pressure. What is the physical description of a negative pressure? Thank you!