Well, maybe I should hold off a few minutes on my dreams of a Physics PhD… hahaha

I will visit Dr. Green during his upcoming Office Hours, and realize that my earlier comments are false. Dr. Greene will help me understand that my motion won’t change what I see when I look up at a star.

Instead my motion will only make me (or my similarly moving descendants) seeing ONE supernova, carve up SPACETIME differently than if I (we) were motionless. My (our) motion versus my (our) lack of motion will simply change what I (we) perceive (post-process) as simultaneous events here on Earth and at the star.

Still fascinating!

My previous comment leaves me wondering, though. Can it possibly be that standing on a moving conveyor belt with your telescope would allow you to see a distant cosmological phenomena’s past. Then stopping and reversing the conveyor belt’s direction and waiting for the conveyor belt’s speed to become constant but in the opposite direction, you would see it’s future? So if moving toward a dying massive sun would allow you to see a supernova, but then reversing your conveyor belt, you could see the dying sun still intact?

I understand this is a conceptual question since the myriad motions of obits, galaxies etc, would skew everything and render this experiment logistically challenging…

Then one can imagine placing a telescope on a large, fast(ish) spinning merry-go-round and observing a supernova happening and unhappening over and over again. Yes this is accelerated motion but unlike twin paradox, the acceleration effects might be considered negligible since the speeds in this problem are very low?

Would love some feedback on this question. Thanks!

Rhetorical question: Is 46 years old too late for an engineer with a Master’s degree to embark upon a Physics PhD? This stuff is fascinating and I have become a YouTube—binging astrophysics videos junkie thanks in large part to Dr. Greene’s magnificent pedagogy.

In reply to Klaus’ comment, I would guess that a current application of these concepts, is that cosmic phenomena need to be translated from Hubble Telescope perspective to a sidereal perspective (relative to distant stars) in efforts to map out how something would look with no relative motion.

He put c^2 as a common denominator on the right hand side, then brought the 10^18 x v^2, with sign change to the left hand side =, factoring out V^2 from both terms now on the left hand side. What remains on the right hand side is (c^2)x10^18.

I love this course and I understand it, and see the logic, nonetheless I find it fascinating that if another ship travelling in the opposite direction at much slower speed, they will of course say the distance and travel time is different than their space-travelling counterparts, even when crossing one another in a very close fly-by. This seems to imply that space can be severely ‘distorted’, for the lack of a better word, in one very local space, dependent upon the traveller’s speed/perspective, which says something very interesting about space existing in multiple configurations simultaneously. I guess it is not distortion, but more perspective being in the eye of the beholder. Incredible.

What if we have free will but that distant relatively moving observers are merely witnesses playing back events in whatever time direction they so choose, in a universe that has instantly unfolded at its inception. That way we have our cake and eat it too: free will and coherent physics models of reality.

Love this course. I am just commenting playfully here, since the comments seem to have inspired a philosophical discussion.