What is it with gravitons and black holes?

I occasionally wonder about what physicist really think regarding the hypothetical particles, gravitons, those carriers of the gravitational force mandated by the need* to quantize all the forces of nature.  Specifically, I wonder how they behave in and around black holes.

I know, from my understanding of General Relativity, that the influence of gravity travels at the speed of light, and the recent LIGO results, and all other experimental results of which I’ve heard, are consistent with that.  This must surely mean that the proposed gravitons travel at the speed of light, and are thus mass-less particles.  And if they are carrying a force, they must have some form of inherent energy, which means that, according to Einstein at least, their path would be affected by gravity.  This seems contradictory in some ways, but it’s my understanding that the electrical force produced by a moving electron also acts backward on itself, so I guess that’s not completely unreasonable…though here I’m veering further away from any deep knowledge, much to my sorrow.

My real question applies to the surface of an event horizon, that boundary in space-time within which all things are separated from the outside by the strength of the gravitational force – more particularly, according to Einstein, by the degree of curvature of space-time.  If gravitons are particles, carrying the gravitational force, are they constrained by the effects of the event horizon, or –  presumably because they wouldn’t be self-interacting – do they simply pass through it, it being irrelevant to their motion, unlike all other things with finite speeds…which means everything.  That sometimes seems contradictory to me, though by no means am I certain that I’m thinking correctly about this.  Could it be that the gravitons within and outside of an event horizon are two separate populations of gravitons, with the external ones somehow being generated at the horizon?  If not, then how can a particle ignore the degree of gravity, unless, of course, as a mentioned above, they are not self-interacting – which wouldn’t be unusual, since, if I understand correctly, photons also don’t interact with other photons.  But photons would, obviously, interact with gravitons, of course, otherwise they wouldn’t be effected by gravity, as we know they are…the most extreme example of this being at a black hole.

I know that a possible explanation for this might be found in M theory, in which we exist in a 3-brane that floats in a larger, higher-dimensional “bulk,” and that gravitons, unlike all the more “ordinary” particles are not constrained to remain within that brane, but can go above and below it, so to speak, thus bypassing any barrier that is exclusive to the brane.  But I don’t know if this really deals with the issue.

And, of course, how can the idea of gravity as a force, mediated by a quantum particle, be reconciled with the convincing and highly fruitful model of gravity as the consequence of the curvature of space-time?  Obviously, I don’t expect anyone to know the deep answer to this question, since it’s the biggest, most fundamental problem in modern physics:  our two best, most powerful theories of the world don’t work when brought together.  But if anyone out there has any idea of at least the form of such a possible reconciliation – i.e. do proponents of quantum gravity think that it will eliminate the notion of curved space-time, or do they think, somehow, that it will be an expression thereof – I would be delighted to hear from you.  My best reading to date on things like string theory hasn’t given me any real insight into the possible shape of such a unification.

Anyway, these are some of the thoughts that are troubling me this Monday morning.  I’d love to know any of your thoughts in response, or if you have any recommendations on further study materials, I would welcome those as well.


* due to the Uncertainty Principle, among other things.

One little old mayor

There’s an interesting scene in the movie The Dark Knight in which the Joker confronts Harvey Dent in the hospital, and conveys to him what he sees as the misplaced and irrational prioritization of alarm among human populations.  The scene is wonderful for many reasons—it’s well-written, well-directed, and brilliantly acted—but I think it is also conveys an important point about which many of us don’t think carefully enough.

In the scene, the Joker says that he’s noticed that “nobody panics when things go ‘according to plan’.  Even if the plan is horrifying.”  He then adds, “If tomorrow I tell the press that, like, a gang-banger will get shot, or a truckload of soldiers will be blowing up, nobody panics, because it’s all ‘part of the plan’.  But when I say that one little old mayor will die, well then everyone loses their minds!”

This is a deeply important point, because it highlights a profound illogic in our moral prioritization of who is important, who is to be protected, who is an “acceptable loss”, and who is “hands off.”  We become more outraged—or at least more exercised—when one of our “leaders” is threatened or even killed than when soldiers, or even ordinary citizens, are put in jeopardy.  This is not morally defensible. Continue reading “One little old mayor”

In defense of scientism

[Originally posted on robertelessar.com on July 20th, 2017]

On this 48th anniversary of the Apollo 11 moon landing, I want to talk a little bit about science, and how it, in principle, can apply to nearly every subject in life.

The word science is derived from Latin scientia, and earlier scire, which means “to know.”  I am, as you might have guessed, a huge fan of science, and have in the past even been a practitioner of it.  But science is not just a collection of facts, as many have said before me.  Science is an approach to information, and more generally to reality itself, a blend of rationalism and empiricism that calls on us to apply reason to the phenomena which we find in our world and to understand, with increasing completeness, the rules by which our world operates.  Personally, I think there are few—and possibly no—areas into which the scientific method cannot be applied to give us a greater understanding of, insight into, and control of, our world and our experience. Continue reading “In defense of scientism”

The problem of attribution

The era of Facebook memes bearing quotes, to say nothing of the siloing and compartmentalization of views experienced in online life, has led me into a minor quandary, and I want to get my thoughts out on the matter, for your consideration and potential feedback.

I am a great fan of the idea of intellectual property, being, as I am, a writer of both fiction and nonfiction.  The writer has the right to what he or she writes, just as any artist has for his her or works of art, and musicians have to their music.  I think most people agree that it’s unethical—and certainly it is illegal—to use another person’s created work against his or her wishes, especially if one is making money by doing so.  Even works in the public domain—including those that were written so long ago as to be considered ancient, such as the works of Homer, Plato, and Sophocles—shouldn’t be reproduced in whole without giving credit to the author.  We should remind ourselves of the source of such works, and give credit to the memory of those who have written words that we found moving; certainly, we must give credit to the creators who are still living, especially if we are going to make money in the process.  We should also, in the latter case, get permission, and usually we should pay them. Continue reading “The problem of attribution”