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Physics/Gravity and Dimensions


QUESTION: There is a concept of gravity being the inertia to the accelerating expansion of the universe in a fourth dimensional hyperspace.  Has this perspective officially been found to be invalid?

There is another perspective that the universe is holographic based upon the two dimensional nature of information from black holes.  If the perspective of a holographic universe in which the third dimension of volume is illusionary should turn out to be valid, would it imply that the 11 dimensions of M-theory should be seen as being 10?

ANSWER: Your first question really doesn't make any sense.  No perspective is "officially" found valid or invalid.  And the question itself mixes terms that are not directly related in a way that makes no sense.  M-theory currently seeks to mate many theories together.  The holographic theories of time may be related, but really they've worked hard to minimize the number of dimensions necessary from that perspective to explain the universe.  I have yet to hear a theoretical physicist state anything about being able to use a holographic paradigm to reduce the number of dimensions in M theory.  Until then, I would have to say that no, we're stuck with 11 dimensions for such a theoretical framework.

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QUESTION: Pertaining to the first question, let's replace "officially been found to be invalid" with "not commonly accepted as being valid by academia".  

If the concept of gravity or the warping of spacetime being caused by the inertia experienced by mass in relation to the cosmic acceleration makes no sense, wouldn't that in itself make the concept not commonly accepted as being valid by academia?

ANSWER: Your first question still makes absolutely no sense as phrased.  Please rephrase the question itself and not the peripheral parts.

Warping of spacetime is caused by mass, not by the inertia experienced by particles with mass.  And no...because the question you posed makes no sense does not affect the observations of people who (not all of whom are in academia, don't single them out) take such data.  Their observations are what they are and don't reflect how you ask questions.  Please re-ask in a way that makes some kind of sense and I'll try to answer it.

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QUESTION: Upon what grounds has an answer been provided if the question makes no sense as phrased?  The statement "Warping of spacetime is caused by mass, not by the inertia experienced by particles with mass." provides the answer to the question (unless the key part of the question pertaining to "in relation to the cosmic acceleration" was intentionally excluded).

Although I accept the statement that has been provided as the answer to the question, perhaps it can be specifically pointed out in what way the question makes no sense as phrased.  Better yet, it would probably be simpler for me to just rephrase the question as a statement that can be critiqued thereby revealing all of its conceptual errors.  Here goes...

Gravity is the fourth dimensional inertia experienced by mass undergoing the acceleration of the expanding universe.

(Small grammatical thing, the most common usage for "gravity" is for gravitation here on Earth, whereas gravitation is the general physical term for the phenomenon.)

OK,  Inertia is a resistance to change. Gravitation causes change in matter's state of motion.  So you called gravitation "the fourth dimensional inertia."  The rest of the sentence is not to be ignored, I'm just isolating the first part...and not unfairly, it's a good conceptual breaking point because the sentence stopped making sentence there.  The fourth dimension is time, so while you can play with motion through and inertia in the dimension of time, that implies a fifth dimension or an absolute time on top of what we perceive as time.  This is not an idea that hasn't been played with (I'm sure by many people), but has nothing to do currently with the acceleation of the expanding universe.  That's...there's just no relation there at all.  So the question still makes no sense.  


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Dr. Stephen O. Nelson


I can answer most basic physics questions, physics questions about science fiction and everyday observations of physics, etc. I'm also usually good for science fair advice (I'm the regional science fair director). I do not answer homework problems. I will occasionally point out where a homework solution went wrong, though. I'm usually good at explaining odd observations that seem counterintuitive, energy science, nuclear physics, nuclear astrophysics, and alternative theories of physics are my specialties.


I was a physics professor at the University of Texas of the Permian Basin, research in nuclear technology and nuclear astrophysics. My travelling science show saw over 20,000 students of all ages. I taught physics, nuclear chemistry, radiation safety, vacuum technology, and answer tons of questions as I tour schools encouraging students to consider careers in science. I moved on to a non-academic job with more research just recently.

Ph. D. from Duke University in physics, research in nuclear astrophysics reactions, gamma-ray astronomy technology, and advanced nuclear reactors.

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