Thread by @Jsincla43477730

Dad joke on Father's Day: Why should you avoid a romantic relationship with a tennis player?

Because love means nothing to them.

Dad science joke on Father's Day: Why should you avoid putting a photon in charge of your schedule?

Because time means nothing to them.

Photons and their experience of time has become meaningful. I'm breaking some news. On William Lane Craig's recent trip to the UK, he was interviewed along with cosmologist Roger Penrose! They had a wonderful talk and WLC had a chance to confront Dr. Penrose . . .

. . . with some of the recent criticisms I put in print of his Conformal Cyclic Cosmology. One of those criticisms has to do with the way Dr. Penrose deals with the apparent temporal infinite future of our cosmos. He needs the future to end in a finite time so . . .

. . . the current eon can end and a new universe with a new Big Bang begin. Penrose appears to be arguing that time 'just is' the existence of clocks and, in fundamental terms, clocks just are fermions. So he needs particles like electrons to turn into massless particles . . .

. . . like the photon. And since the photon (in relativity) has no experience of temporal intervals . . . he says time stops. So what does this mean? If time literally ceased, then this break in the timeline seems to imply that you can't have a future. Time stopping . . .

. . . means that before-after or 'simultaneous' relationships can no longer connect one universe to another because the timeline 'breaks'. A similar problem affects the Hawking-Hartle cosmology. There, the problem is that there seem to be two timelines connected . . .

. . . 'normal' time (Lorenzian) and 'imaginary' time (Euclidean). But since the two timelines are incommensurate, there is no 'before-after' relationship to them. Similarly, if time 'stops' there doesn't appear to be a clean timeline between one cycle and the next.

Now, in the recent interview, Dr. Penrose invoked the experience of the photon as a way to avoid this problem. He said that, in the inertial reference frame of the photon, time intervals don't exist (yet temporal ordering still does?). So time isn't 'nuked'; . . .

. . . it is still there and there can be a meaningful temporal relationship between cycles. Is this true? My reaction is to have a problem with this on a few levels. First, no observer can 'sit' on a photon. Is it at all meaningful to invoke the photon as . . .

. . . an observer's reference frame. I don't think so. We usually invoke notional observers in physics when talking about the viability of various concepts.

Second, even if one allows the conception, I have a problem with Penrose's idea that temporal ordering exists . . .

. . . for such an observer even if time intervals do not. It is precisely because of temporal intervals that temporal ordering exists. If there were an observer who failed to see this, the conclusion should be that that observer is viewing a distorted version of reality . . .

; not setting conditions on reality. It sees an incomplete picture rather than setting new metaphysical conditions on the nature of time. After all, there are General Relativity models that are universes that only contain radiation (photons); and time flows just fine.

Dr. Penrose also had some interesting ideas on how electrons could lose their mass (and spin; anything that makes it a fermion) which has to do with dark energy. I believe this idea is far from mainstream ideas in particle physics. I'll get back to you on it.