New Perspective on Gravity Might Brighten Up Our Dark Universe


(system) #1
There is room for dissent in the sciences, even when it threatens to overturn deeply cherished theories.
This is a companion discussion topic for the original entry at https://biologos.org/blogs/guest/new-perspective-on-gravity-might-brighten-up-our-dark-universe

(Chris Falter) #2

Hi Casper,

Thanks for your lucid, informative, and stimulating article. It was definitely not fried air!

Advent blessings,
Chris


(Casper Hesp) #3

Thank you Chris, glad you enjoyed it.

I’ll be available here for discussion in case anyone has further questions or thoughts related to this topic.


(Nick) #4

Hey Casper, I admire your attitude and am covetous of your intelligene.

I am no scientist nor do I care for the minutiae of it, but I do like to try to gain a cursory understanding of things.

So is the idea of the mass containing sphere saying that maybe the dark/matter energy is at the edges of the universe exerting its gravity from the frontier rather than from throughout?


(Chris Falter) #5

Hi nickster -

The way I read the article was that any mass, anywhere, would exhibit the properties that emerge from qubits. The gravity property emerges from qubits at the surface, and dark energy properties emerge from throughout (i.e., the volume).

This post of mine is mostly designed to see whether I understood the article or not. Hopefully, our friend @Casper_Hesp will come along shortly to clarify these issues, and my comprehension level will become evident.

Warm Advent wishes,
Chris


(Nick) #6

Yeah Chris don’t send any physics questions my way! I still can’t believe my radio works.


(Casper Hesp) #7

Hi Nick,
Thank you for reading along and for your generous compliments. The point of this article is to give the reader only a very cursory understanding of the ideas, so you’ve come to the right place.

In short, that’s not how it works but I appreciate your inquisitiveness. These ideas require some unusual brain gymnastics so I think my ultra-short teaser is actually too short. Allow me to elaborate a bit. The idea we touched upon with the image of the mass-containing sphere is called the “holographic principle”. In the article I simplified it to make it easier to understand. A more official way to state it is as follows:

The holographic principle states that the description of a volume of space can be thought of as encoded on a lower-dimensional boundary to the region.

Note that it focuses on a way of encoding the description of a volume of space. It does not speak directly of the actual location of mass, energy, or the exertion of forces within that volume. (In fact, gravity is not a force in itself but results from curved spacetime).

Information encoded on the surface:

  1. The first step is simply to imagine that the information that describes a mass-containing sphere is stored on its surface (in the qubits).
  2. The second step is to imagine small disturbances occurring in this information. Naturally, this causes the amount of disorder to increase (causing the information to be more evenly distributed across the qubits.
  3. The third step is to realize that “increasing disorder” on the surface is equivalent to movement towards the center of the sphere (this effectively makes the surface smaller, allowing for a more evenly distributed use of the qubits). Verlinde showed that this results in Newtonian gravity plus some extra effect. The by-product might be able to explain away dark matter. Verlinde has shown this for a few cases. In fact, he thinks that dark matter probably does not exist.

Information encoded in the volume elements:

  1. This time, the first step is to imagine that the description is encoded in the volume elements.
  2. The second step is again to assume an increase of disorder in this information over time.
  3. The third step is to realize that “increasing disorder” in the volume elements is equivalent to movement away from the center (in this case, spreading out in the volume leads to a more evenly distributed occupation of the qubits). This effect is weaker than the surface effect, but becomes stronger as the volume increases. This could explain why the expansion of the universe is currently accelerating, an effect that has been associated with dark energy. The dark energy properties indeed emerge from throughout, as @Chris_Falter said.

I hope this answers your question Nick. Feel free to ask more!

Thank you for the input Chris, I think you understood it well, as far as my own understanding reaches. I would phrase the first sentence somewhat differently though. I think a more accurate phrasing would be to say that any mass, anywhere, would be subjected to the properties of spacetime that emerge from qubits.

Finally, an important disclaimer: I am not a string theorist. I do my best to grasp and convey these ideas based on my own background in theoretical physics (which is more directed at astronomy). I never studied the nitty-gritty of quantum information theory or quantum entanglement. I am speaking here mainly in my capacity as a science journalist, not as an authority on the specialization of Verlinde :).

Greetings,
Casper


(Nick) #8

Man I am just not smart enough I guess Brother.

The way I understand it is that for some time now that science has been telling us that Relativity is true in a macro sense somewhat and that quantum is in micro/atomic sense, and I guess that this theory from the guy down the hall from you might be telling us that they are not really different and Newtonian, Einsteinian, and quantum are not mutually exclusive after all?

I think one time you answered a question for me about the uncertianty principle. I understand that we can’t measure/predict where the electron is at any certain time, but I never could understand if we were certain that we were uncertain or uncertain as to whether we could ever be certain. ie. that maybe some day we could measure or I guess at absolute zero the electron is static but I think that it no longer remains an atom if it is unmoving.

It seems like maybe what you are saying here with this new theory is that maybe we actually know more on this Einstein/quantum deal than we thought we did, and just have been looking at it from the wrong angle.

Oh well, keep trying to help us out my friend!
I guess I just don’t have the math to understand these things.


(Casper Hesp) #9

Hi Nick,
I think the most important thing you need for understanding these things is a curious, imaginative mind. And it seems to me you’re right on the money with that!

It’s true that General Relativity has been successful on the macro-scales and Quantum Mechanics on the micro-scales. Scientists have had the intuition for a long time that these two frameworks should be unifiable into a single picture somehow. But the “how” has remained a big question mark (with String theory being the most notable contender). Approaches like the one of Verlinde are attempts at unification. His framework is largely derived from String theory.

In addition, Verlinde’s theory claims that General Relativity is partly inaccurate on the very largest scales. That’s exactly where we see most of the influences of “dark matter” occurring. Verlinde’s Emergent Gravity might explain those influences without introducing dark matter. Does that make sense?

This is a bit off-topic, but the answer to your question can be found in what is called the Copenhagen interpretation of Quantum Mechanics. Roughly, this view holds that the electron literally does not have a definitive position or velocity before it is disturbed by our measurement. Instead, the electron is completely described by its own “wave function”, smeared out across space. Compare this to a pattern of waves in the sea. Who can tell us precisely “where” the pattern is located on the surface of the water? Nobody, because it is smeared out across many kilometers.

At the moment of measurement, the electron interacts with the laboratory instrument (picture this as a collision between their wave functions). This forces the electron to a specified position (we call this the collapse of the wave function).

However, the measuring instrument is macroscopic, so its wave function is too complex for us to understand. This makes it impossible for us to be 100% sure of the outcome of that interaction. This is what introduces the apparent randomness into the measurements. As Einstein once said, “God does not gamble.” :slight_smile:

Hope that helps. Mathematics would be necessary to really get to the bottom of it, but most of these things require imagination rather than calculation!

Casper


(Ben McFarland) #10

@Casper_Hesp, Thanks for a great summary. This made several things clear to me that weren’t clear in other accounts. I’m most fascinated by how this theory appears to be based on emergence. You used the example of temperature, and emergence has been applied to other areas, even consciousness emerging from the firing of neurons. If this theory continues to work, does that support the importance of emergence in general, do you think? In other words, is there any reason to think that emergence is one of the fundamental characteristics of our universe, and that we should give more weight to explanations that involve emergence, or is that taking it too far? Yours, Ben


(Casper Hesp) #11

@benmc
Hi Ben, thanks for the interesting question!

As you probably already know, emergence is a central concept in our understanding of complex systems. It occurs whenever a system as a whole has properties that cannot be completely defined in terms of the individual components of the system. (For example, a gas has the property temperature which cannot be completely defined in terms of individual molecules).

Since pretty much all of science is dealing with complex systems, I think it is almost impossible to make this concept even more important. But if gravity itself could indeed be understood as an emergent phenomenon, this would certainly help to raise awareness of the importance of the concept of emergence in complex systems. Of course, this also extends to the study of the human brain. Our brain is the pinnacle of complexity!

In relation to consciousness, one connection that strongly intrigues me is that the theory of Verlinde is based on the concept of entropy (a measure of disorder). This concept has also gained traction in the context of the human brain and consciousness. The authors of this very influential paper published in 2014 put forward what is called the “entropic brain hypothesis”. In their vision, our brain’s capacity to suppress entropy to just the right sub-threshold levels (e.g., enough to be sensitive to changes, but not oversensitive) is part of what contributes to the unique properties of human consciousness (as compared to animal consciousness). They argue that psychedelic drugs act as a disruption of that balance which can produce conscious states much more similar to that of animals.

Anyway, don’t know if I’ve answered your question, but I’ll stop here for now :slight_smile: .

Casper