Something would have to cause the big bang and therefore that’s not the beginning, but the genesis is outside of time because time is a construct existing as an artifact of space that was created at the big bang. We can’t have space without time nor time without space, but even within that construct, light observes neither time nor space and since every photon emission and reception were events that took no time, then the big bang isn’t anything that happened, except from our point of view. The construct must be finite because none of it took any time and it’s already done, but not from our point of view as beings constructed of spacetime itself.
physics.stackexchange.com/quest … a-receiver
[i]Richard Feynman’s PhD thesis was about just this topic, if I am understanding your question rightly. Here is an earlier question about Feynman’s thesis that addresses some of the fascinating issues involved with this.
At the suggestion of his thesis adviser John Wheeler, Feynman explained photon emission as a two-way interaction in which the regular photon is emitted and follows the “retarded” solutions to Maxwell’s equations. “Meanwhile” (in some rather abstract sense of the word indeed) a target atom or particle in the distant future emits its own photon, but a very special one that travels backwards in time – a type of solution to Maxwell’s equations that had been recognized since Maxwell’s time but had been ignored. These solutions were called the “advanced” solutions. This advanced photon travels back in time and “just happens” to arrive at the source at the exact instant when the regular photon is emitted, causing the emitting atom to be kicked backwards a tiny bit.
Amazingly, Wheeler and Feynman were able to write a series of papers showing that despite how mind-boggling this scenario sounded, it did not result in violations of causality, and it did provide a highly effective model of electron-photon interactions. From this start, and with some important changes, Feynman eventually produced his Feynman-diagram explanation of quantum electrodynamics, or QED. The curious time relationship continue in Feynman’s QED, where for example a positron or anti-electron simply become an ordinary electron traveling backwards in time.
Staying fully consistent with his own ideas, Feynman himself described photon interactions as always having an emission and a reception event, no matter how far apart those events occur in ordinary time. In his view, if you shone a flashlight into deep space, the photons could not even be emitted until they found their “partner” advanced photon emission events somewhere in the distant future. The proof of it is in the very slight push back on your hand that happens when you shine the light, that kick coming from the advanced photons arriving from that distant point in the future and nudging the electrons in your flashlight filament.[/i]
The universe is a closed loop where something is emitted and something is returned for energy conservation both in terms of space and in terms of time; therefore it’s not infinite. A photon can’t even be emitted until its partner is found in distant space and time.
I see what you’re saying, but I think that’s better described as a segment because all lines are infinite. Placing the origin at zero on Cartesian coordinates is really an arbitrary placement as we could have the x and y intercepts anywhere. We could start counting at zero: 0, 1, 2, 3… or we could start from -2: -2, -1, 0, 1, 2, 3… To say it has a beginning is an arbitrary segmentation because it really doesn’t have a true intrinsic beginning and neither does it have a true intrinsic ending (although the size of the universe should cap it off).