The 45-degree limit makes perfect sense to me Penny. If we look at feet and nanoseconds as x and y axes, then the angle between 1 on the feet axis and 1 on the nanosecond axis is, in fact, 45 degrees.

My question is about what we each see on our respective Now slices assuming the alien and I are stationary with respect each other. A super-nova that I see as happening “now” might seem to be happening “sooner”—if that’s the appropriate word—to the alien if he is closer to the super-nova. When we look at things farther and farther away, we are looking into the past. An alien that is a billion light years away is/was existing/existed a billion years ago, so its Now is quite different from mine. If he/she/it/whatever were able to see me at my Now, he would be looking into the future.

James Hogan had an fascinating take on this in his novel “Thrice Upon a Time,” which postulates time travel of information. I highly recommend it for anyone interested in this sort of speculation.