Books: The Order of Time & Helgoland

Next up on the reading table, a pair of books by Carlo Rovelli on quantum physics for the layman that looked interesting.

The first (2018) looks at the arrow of time and why entropy always increases. Entropy is THE ONLY property of the physical world that has a difference between past state and future state. Why is that?

At the speed of light time stands still, so the light you see from a distant star is just leaving the star at the same moment you perceive it -- from the "point of view" of the photons. The vast universe spread out around us is therefore embedded in a "space-time continuum" measured in light years where simultaneity is all around us -- we are seeing the universe "as it is now" but those "nows" are accumulated for our eyes only. Another observer in another location will have another collection of "nows." It's the same universe, but each point in space is also a unique point in time, in the age of the universe.

The whole "space-time continuum" is a concept I've yet to wrap my head around.

I say "for the layman" but whether it's the translation from Italian or the depth of the concepts, as a layman, I'm not following a lot of this.

What I *can* follow seems a tad obvious. Rovelli notes that quantum theory requires a minimum unit of time, the Planck time (10 to -44 seconds). He then notes that the only reason times seems continuous is the "blurring" caused by being on such a different scale than quantum effects.

Yeah, no shit Sherlock.

He notes that driving along a road and entering a fog bank, there is no hard edge to the fog, even though it appeared solid from a distance. On the quantum scale, he continues, your marble countertops would be similarly "foggy" at the boundary.

Yeah, no shit Sherlock.

At the quantum level, there are no cats. Not even Schroedinger's.

In the last third of the book, Part III, the author goes off on a grade school philosophical tangent: what is the nature of the "I"? Is it the brain that thinks, the body that feels, the accumulation of feelings and memories that make us "us"?

Bah. Get back to quantum gravity.

"Helgoland" is so far a much better book. About the development of quantum physics and some of the implications and predictions of the theory.

Written "for the layman." We'll see if I can follow any of it.

Starting a new book (2023) by Rovelli called "White Holes" which describes what happens if you fly into a black hole.

Time slows as you approach the event horizon, but only from the perspective of an observer outside the black hole. From the spaceship entering the black hole, time chugs along at a steady normal rate. Once past the even horizon, you can still see the stars outside the black hole, but space around you is compressed.

We know from Einstein's thought experiment and Rovelli's previous book that time does not pass for a photon.  It, traveling at the speed of light, is simultaneously at all destinations along its path of travel, both at the star of origin and at your retina, and all points in between.

So at the event horizon of a black hole, where time slows to a stop, does that mean matter entering a black hole is accelerated to the speed of light?

My head hurts from thinking about it.  Hopefully Rovelli will address this issue and unconfuse me.

The author postulates (as far as I understand what he's writing) that inside a black hole a star collapses to a singularity.  On the other end of that singularity is a white hole, a big bang -- a new universe being created.

This comports with my own understanding of cosmology.

The universe appears to be expanding because every direction we look is red-shifted, as if matter were flying away from us.

But my thought is that the universe is not expanding.  It is simply speeding up.  That causes all light emitted a long time ago, at an earlier age of the universe, to be shifted toward the red.  Time is not constant.  In fact, if we reverse the apparent arrow of time, to try to return to the Big Bang, the origin of the universe, we would find time getting slower and slower the earlier we went.  Therefore there is no "beginning" because time itself did not exist before the universe.  Time and matter are inextricably linked, you cannot have one without the other.

So it is inside a black hole.  Matter is compressed to quantum elements and beyond; and time slows to a stop.  There is no "beyond" because the other side is a whole new universe -- a universe with no beginning or end.

This may or may not help. It is as confusing as fuck no matter how you describe it.

What is a white hole? – with Carlo Rovelli

Yes, yes indeed.  Same diagrams, same arguments as in the book.  The talk is basically the book explained in front of an audience.

I THINK perhaps Rovelli has 9./10 of the argument he's seeking, but hasn't quite put the pieces together correctly.  I have an idea of how it would look.

I'll finish the book, and then write him a letter.  His email is readily available online.  I shall have to think on this a bit, to avoid making a fool of myself, but I have an intuition that it might work.

There is a point in his presentation where he went off the rails and misspoke.  He said that big bangs were similar to white holes, but different.  This is his error I think.  

I think every black hole "pinches off" a piece of the universe, and every white hole (or big bang) starts a new universe, totally unconnected to the old universe.

His speculation that dark matter is actually a cloud of white holes.... hmm, I'll have to think on that.  Very interesting speculation, very important speculation. Puzzling it is, yes, puzzling.

Here's what I wrote:

NoCoPilot wrote:

Dear Professor Rovelli,

I just finished reading "White Holes," and watching your Royal Institution talk on the same. I have previously enjoyed "Helgoland," "The Order of Time" and "Reality is Not What It Seems." I have also attended lectures by Kip Thorne and Roger Penrose... though I am by no means qualified to evaluate them. I'm just an interested amateur, two years your senior.


My own understanding of black holes and white holes is pretty much aligned with your research, but I have a couple of different speculations I'd like to run past you. Feel free to ignore this e-mail completely; I'm writing primarily to get my own thoughts in order.


#1. Time is not a constant. We know from Einstein's thought experiment that if a person were riding a photon, time would not pass. The photon emitted from a distant star that you see in the night sky—from the photon's point of view—left the star at the exact same moment you perceived it. We can say therefore that time moves at the speed of light. FTL travel is not possible because it would require traveling backwards in time.


We also know that time slows down in the vicinity of a gravitational field, and in extreme cases like a black hole, time slows to a stop at the horizon.


From the outside perspective. Not, as you point out in your books, from the perspective of a spaceship traveling into the black hole. From that perspective, time chugs along without pause.


Relate this to the previous statement, "time moves at the speed of light." If time slows down at the event horizon, then the speed of light also slows down at the event horizon. The event horizon, from the perspective of an outside observer, is the cessation of local time. The black hole ceases to exist, as it is outside our experience of our time (and space). It is "black" because it is literally outside of our universe.


But from the spaceship's perspective, there is no cessation. The spaceship crosses into the black hole, and enters into a new arena, cut off from the old universe, but continuous from the point of view of the spaceship.


#2. The Big Bang. Your insight that white holes are the opposite of black holes I think is exactly right—white holes are the other side of a black hole. In your RI speech you said white holes are "like the Big Bang but different." Here I disagree: I think each white hole might be a big bang. Instead of matter being sucked into black holes, you have matter pouring out of white holes.


Like black holes, time dilation gives different perspectives between inside observers and outside observers. Something coming out of a white hole experiences normal time. But from an outsider's perspective, the matter exiting the white hole would seem to move immeasurably slowly just as it escapes the horizon, and then it would speed up.


#3. The Red Shift. As we look out into our universe, everything is red-shifted, in rough proportion to its distance from us. From this data scientists have concluded that the universe is expanding, and originated in a Big Bang.


Looked at from a perspective of variable time however, the red shift could just as easily be a speeding up of time since the light was emitted. From the photon's point of view, of course, it was emitted right now, but in a different, slower timeframe. To the photon, we are speeding up -- just as if we left a white hole. Cosmic acceleration might account for the red shift.


Back to "time moves at the speed of light" -- if each of us is speeding up, in proportion to our distance from each other, then the universe need not have a beginning, or an end. It is eternal... but different parts move at different rates of time, depending on whether you're leaving a white hole, or watching somebody else leaving a white hole.


#4. Continuous Creation. With white holes potentially everywhere, and black holes known to be everywhere, we are left with the idea that maybe matter is forever being created—in what are known as vacuum fluctuations—and at the same time maybe matter is also continuously being extracted from the universe, when black holes "pinch off" a piece of the universe forever. Our universe may be built like Swiss cheese, continuously exchanging energy from one place to another. You hint at this solution on page 88 of "White Holes."


Outside observers like us cannot see this happening, because time literally ceases to exist at the event horizons. However, from the point of view of energy (quantum energy?) the process is continuous and smooth. The universe moves energy around all the time, like the backstage crew at a play. This describes Hawking radiation, as you yourself described it on page 102.


#5. Dark Matter. It may be that this constant exchange of energy is what shows up in our cosmological calculations as dark matter. This stuff is literally invisible, because it is outside our universe, but it might have gravitational pull because it is concentrated energy and thus distorts space. The vacuum fluctuations —the clouds of white holes and black holes that are continuously breathing matter in and out —are the background "ether" in the universe.


In number 1 above, substitute "quantum energy" for "spaceship," and I believe you have a pretty good formula for how black holes and white holes interreact.


#6. Matter. Energy by itself has no time. It is only when energy condenses into matter that it creates time, and time begins to move at the speed of light in all directions away from the matter. This the fabric of our universe, our visible universe, our universe which is matter, having condensed out of the interstitial energy, the cloud of white and black holes.


Energy without matter, without time is free to enter black holes and exit white holes at will. In fact, it may be the event horizons where energy is converted into matter and vice versa. The very process of creating matter creates time, and creating time at the event horizon is what creates matter. Matter + time = a universe.


Pinching off one part of the universe, feeding another part. On and on, the Swiss cheese bubbles.

Alas, it doesn't make much sense. Even after I wrote it out.

Looking forward to your next book,

Well, I got a reply: "Thanks for your thoughts."

Ah well. I didn't expect even that much.