Can you explain me the BH->WH bounce? What happens with the BH horizon? Already at the horizon the time is inf. slowed down for an observer in inf. How can we see the time inverses solution couple of bi/millions later? Does it mean that the WH occurs a bit elsewhere, on the other side of the brane?

I am curious, how can JWST bring insight into the inflation?

I understand why LIGO cannot detect low frequency GW, the arms are not long enough to measure the change on the scale of the lengths of the arms. I understand why Pulsar Timing Array cannot measure high frequencies, the pulsar pulses shape and sampling is two broad. But why cannot (e)LISA measure together with the low frequencies also the high frequencies to cover the range of LIGO, too? What kind of noise is eLISA limited by in high frequencies?

I don’t understand why my answer in the previous exercise was wrong. Train is at rest, I am at the platform so at rest too, And the “correct” answer says there would be a time difference and the video claims that the train is moving with respect to me with -v? Why if we are both at rest??