Did Einstein Claim 4D Space-Time?

[Eclipse Now]

Hi all,

following on from my last science questions (and thanks to all those who helped out there, some of the Youtube videos were amazing!) I just needed to add another question. This is the recent claim I'm dealing with — help please? (Thanks in advance! Reminder: I'm NOT a Creationist — so please don't lecture me. I just want to understand this 4D thing!)

 

The 4D thing isn’t something Dr Humphrey’s made up. It is one of three possible shapes the universe can have according to Einstein’s general relativity. Big Bang theory calculations are all based on the Einstein variable that supposes curved 4-D space. The balloon illustrates this, although the astronomer in the film did not go into that kind of detail. You can read it yourself in Einstein’s Annus Mirabilis which includes his entire set of papers (from 1905 and later additions including his cosmological constant work of 1917). If I recall correctly, it was the paper on the cosmological constant where you’ll find this information.

[CraigD]

(title) Did Einstein Claim 4D Space-Time?

That question’s a little like asking “Did Leibniz claim calculus?” Like Leibniz with the ideas of and earlier mathematicians (and possibly, though controversially, contemporary ones like Newton), Einstein didn’t originate the idea of that combining 1 timelike dimension and 3 spacelike ones into a single geometric space, but did such really cool things with it that you might without too much argument deed its ownership to him.

 

If you’ve not had much classroom or self-taught formal education in modern physics in general, and spacetime in particular, the first thing I’d recommend you endeavor to grasp is the importance of 4 dimension spacetime consisting of 3 spacelike (AKA spatial) and 1 timelike (AKA temporal) dimensions. This will steer you clear of confusion 4D spacetime with the idea of “the 4th dimension” and “4 dimensional space” as it was usually used prior to the “miracle year” of 1905.

 

The 19th century witnessed a revolution of ordinary geometry in more than 3 dimensions – “hyperspace”. Surprisingly to me these ideas, which seem natural, intuitive, and mathematically easy to me (“so easy a computer can do them accidentally”, to coin a phrase) compared to the sophisticated work of mathematicians 100+ years earlier, simply don’t appear in any literature, or appear to have been much thought of, prior to around 1825. By the late 19th century, practically anybody deserving of the claim a decent math education thought about it, so much so that it had a pseudoscientific fringe, involving such embarrassments as eventually criminally convicted “spiritualist” Henry Slade convincing the respected astrophysicist Johann Zöllner that he was able to tie a knot in a unbroken band by somehow moving it in an occult 4th spatial dimension.

 

Though the evolution of ideas in science and general human culture is hard to precisely trace or predict, it seems to me this set us up for the formalism of Einstein and Minkowski, where a 4th temporal dimension was added to the usual 3 spatial ones, related by Minkowski’s elegantly simple metric,

[math]L^2 = (x_2-x_1)^2 +(y_2-y_1)^2 +(z_2-z_1)^2 -c^2(t_2-t_1)^2[/math].

 

In short, this metric keeps the length of lines representing the paths of points moving through space to be unchanged as they’re transformed by being observed by observers with different relative velocities, in nearly the same way that the length of a line in 2 or 3 dimensional space is preserved by the ancient Pythagorian/Euclidean metric,

[math]L^2 = (x_2-x_1)^2 +(y_2-y_1)^2 +(z_2-z_1)^2[/math],

as the line is transformed by being observed by observers with different positions and orientations.

 

There’s nothing mystical about this – no 19th century parlor magic tricks – just a different, neater way of formally representing how physical reality works. Just look – in awe, I hope – at the beautiful, simple similarity between the above 2000+ year old and barely 100 year old formulae!

[Eclipse Now]

So, in English, you're discussing the history of mathematical thought as it starts to trace not just the 3 physical dimensions of width, breadth, and height, but the '4th dimension' of time as it is influenced by relativity? And there's no '4th dimension' in space as posited by Creationists, but a misunderstanding of time and how it interacts with speed and mass? Cool.

[JMJones0424]

Eclipse Now, I offer the following in the hopes of clearing up your misconceptions, though I am likely the wrong person to do this. As was discussed previously, your friend is again either mistaken or lying. If you want to learn about cosmology, I don't think you can find a better starting point online than Ned Wright's Cosmology Tutorial. I think you would be far better served to at least go through the FAQs there, if not the whole site, rather than mucking about with this creationist cosmology pseudo-science crap.

 

"The 4D thing isn’t something Dr Humphrey’s made up."

I was unaware of who Dr. Humphreys was, but after a google search, I feel safe in ignoring anything he has to say on cosmology.

 

"It is one of three possible shapes the universe can have according to Einstein’s general relativity."

The fact that spacetime is composed of three spatial dimensions and one temporal dimension says nothing at all about the shape of the universe.

 

"Big Bang theory calculations are all based on the Einstein variable that supposes curved 4-D space."

I don't know what variable of Einstein's he is referring to. It seems to me that he is referring to Omega, the ratio of the density of the Universe to the critical density just sufficient to prevent recollapse of the Universe. The subject is covered here by Ned Wright. There are in fact three different geometries that satisfy general relativity, flat (Euclidean), positively curved, or negatively curved. If the universe is curved, then the radius is so large that it appears flat to us. Again, the fact that spacetime is composed of three spatial and one temporal dimensions has nothing at all to do with this.

 

"The balloon illustrates this, although the astronomer in the film did not go into that kind of detail."

The astronomer doesn't go into that kind of detail because it is false. The balloon analogy is only meant to illustrate how an expanding universe gives the illusion that all observers appear to be at the center of expansion. All evidence points to either a flat universe or a curved universe with a radius so large that the portion of the universe we can observe appears flat.

 

"You can read it yourself in Einstein’s Annus Mirabilis which includes his entire set of papers (from 1905 and later additions including his cosmological constant work of 1917). If I recall correctly, it was the paper on the cosmological constant where you’ll find this information."

Your friend is the one making claims which are demonstrably false, it is he/she who should be providing support for his claims.

 

Seriously dude, if you want to learn about cosmology without going through years of university level courses, it is possible. There are lots of quality resources on the internet and at public libraries specifically geared towards the layman. Trying to learn about cosmology from a creationist is a waste of your time. Read Ned Wright's site. If there's anything that isn't covered, or isn't clear, then please ask for clarification. However, everything your friend has said so far has been wrong, and I see no reason to expect anything of any value to come from him. Every time he talks cosmology, imagine that you are being given a lesson in climate science by Lord Monckton.

[earthist]

Hello, Eclipse. I'm new here, so I've only read a few of your posts, and I'm also not a scientist, but rather a "duffer," not unlike yourself, trying to learn things and understand the universe. In other words, take everything I say with some seasoning, and wait to see if the real science folks here criticize it before taking it too far.

 

 

On the other hand, as I do read your posts, I feel pangs of sympathy with your predicament as I perceive it. In some cases, I can say, "I've been there." In that light, I hope perhaps that I can help a bit.

 

 

Here is my personal, non-scientific interpretation/understanding of space-time.

 

 

Time is the way we distinguish between what's us and what's other. We perceive things that are not us after the fact. This is easy to see when we view something light-years away as in stars and galaxies. What we see in the present actually happened a long time ago. It's a bit harder to see that the same holds true for literally everything that isn't us. Even scrutinizing a bug from a distance of a foot or so, the light we see takes a tiny bit of time to reach us, and the bug we perceive is not the bug that is there now. Thus, the only present is the self. I would propose that awareness of self, consciousness, is dependent on this mechanism. With no separation between self and other, there is no awareness of self by definition.

 

 

A byproduct of time, then, is an awareness of who's me and who's "other." The more I become aware of time, the more I become aware that there are others in the universe, and the larger the universe becomes. The awareness of time grounds me in the sense that I gain perspective as to who/what is me, and who/what is others.

 

 

This is the meaning behind space and time being inseparable: "space-time". It locates me. It grounds me. And understanding it, I can more easily imagine how things look from other viewing points. In other words, I can better understand, and tolerate, differences and similarities among people (and all life forms).

 

 

Time as a measure of change is then added to that view. Sequencing allows us to make sense of things, and helps to keep us "sane," but it is not an illusion. Change does occur. Recalling the definition above of time as space, I can see that you might become aware of a change either before or after I do. In other words, your measure of time, your clock, if you will, "ticks" differently than mine. Again, I gain perspective and tolerance -- and understanding by "seeing" time as a dimension.

 

 

I hope that's useful, and I hope I'm not hopelessly off-base with it.

[Little Bang]

An interesting idea about space/time. http://universe1.freeforums.org/what-is-your-definition-of-time-t21.html

[newdealtn]

Hi all,

following on from my last science questions (and thanks to all those who helped out there, some of the Youtube videos were amazing!) I just needed to add another question. This is the recent claim I'm dealing with — help please? (Thanks in advance! Reminder: I'm NOT a Creationist — so please don't lecture me. I just want to understand this 4D thing!)

I read some of Einstein's work, and he did talk about four dimensions of space-time, three dimensional space and one dimension of time. There was little or no discussion of eleven dimensions in his time. His point was that, while the single dimension of time is very different in nature from the three dimensions of space, the fabric of space and time are interwoven in the ways illustrated by relativity. If he meant more than that by his assertions, it certainly was not evident to me in my reading.

 

You know, the three dimensions of space are extremely interwoven. We can see indefinitely in all directions. We can move through them. We do not move through time; rather we fall through it, unable to stop our fall, unable to see ahead or behind (but only to anticipate what may be and remember what has been). Perhaps time is not a dimension, or if it is, it is only a collapsed dimension having only quantum measure. Any way, it certainly is not what we mean when we speak of spatial dimensions.

 

Samm

[maddog]

Eclipse,

 

Like JMJones, I googled this Dr Russ Humphreys to get a little of his background. Though I see his credentials are legit, I am not sure I can follow some of the statements he has made. I doubt that I would read his book either. So first to answer the original question [reworded].

 

"Did Einstein [consider] Space-Time as a 4D [Manifold] ?"

Answer: Yes, he did. By the time of the thirties, Dr. Einstein was somewhat of a celebrity while at Princeton. It was during an interview he was asked a question about why he considers Space-Time as 4 dimensional. His answer was "time is added to prevent everything from happening all at once!"

His flippancy was his hallmark.

 

Reading his book "The Meaning of Relativity" (I have my own copy), he defines the notion of Space-Time in 4-dimensions (I add the mathematical term "manifold" so a to generalize by not requiring a "Euclidean" geometry). As mentioned earlier Einstein was really only think of 4-dimensions. Though he did chair a paper in 1915 by Kaluza that he recommended for publication on unifying EM with Gravity that did so by adding a "roll-up" dimension - making 5-dimensions. This was latter generalize by Felix Klein in abt 1926 (Kaluza-Klein theory. I think this is where adding dimensions comes from. Einstein did not actually participate).

 

The bigger problem: You are listening to someone who is spewing constructs of statements that are not logically formulated nor thought out nor any credence to credibility. So a "rule of thumb" I follow in this case which is: "do not rigorously discuss <argue> a topic with someone who can claim a statement as valid either - because of stated in the bible or because of their belief". Instead, I recommend, "Have a nice day!" :blink:

 

maddog