An electron the size of our Universe!

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Jstanley01
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Re: An electron the size of our Universe!

Post by Jstanley01 » Mon Mar 20, 2017 10:55 pm

guitarrista wrote:Check this out!! : http://htwins.net/scale/ (use the slide)

Planck's length is 10^-35 m. Size of universe is around 9* 10^26 m. Earth's diameter is 1.3 * 10^7 m. An electron is 10^-18 m.

So the ratio of sizes between the universe and an electron is almost 45 orders of magnitude: 9*10^44. If you shrink the universe down to an electron, you have only 17 orders of magnitude left for smaller things. The Earth is 20 orders of magnitude smaller than the universe, so the largest object in the new universe would be ten times larger than the size of the Sun.

Hopefully I did not mess up the math :lol:
I love that site! Interestingly, the smallest object visible to the naked eye is the human egg cell, which is mathematically in the middle between the span of the universe and that of a Planck Length. So we are in the center of the universe, size-wise, as zygotes... Significant?...
Attitude is more important than the past, than education, than money, than circumstances, than what people do or say. It is more important than appearance, giftedness, or skill. -W.C. Fields

PeteJ
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Re: An electron the size of our Universe!

Post by PeteJ » Tue Mar 21, 2017 12:23 pm

Very significant I'd say.

Pat Dodson
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Re: An electron the size of our Universe!

Post by Pat Dodson » Tue Mar 21, 2017 2:01 pm

Jstanley01 wrote:...Interestingly, the smallest object visible to the naked eye is the human egg cell, which is mathematically in the middle between the span of the universe and that of a Planck Length. So we are in the center of the universe, size-wise, as zygotes......
Thankfully as we grow and mature most of us recognise we are not the centre of the universe. :wink:

PeteJ
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Re: An electron the size of our Universe!

Post by PeteJ » Wed Mar 22, 2017 11:38 am

Um. We are at the centre of the universe. Afaik this is the view of science. Everything is at the centre. The centre goes everywhere with you.

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Andrew Fryer
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Re: An electron the size of our Universe!

Post by Andrew Fryer » Wed Mar 22, 2017 11:58 am

Yes, in the same way that we are all at the centre of the surface of the sphere that is the Earth.
1975 Calatayud y Gisbert, Yamaha CG131S.

gitgeezer
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Re: An electron the size of our Universe!

Post by gitgeezer » Wed Mar 22, 2017 12:15 pm

Yes, I agree, I am the center of the universe. Everything that happens in the universe is, one way or another, about me.

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Andrew Fryer
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Re: An electron the size of our Universe!

Post by Andrew Fryer » Wed Mar 22, 2017 12:28 pm

It's an interesting thing to think about. I posted because I was glibly repeating something I had seen before, that (superficially) everywhere is the centre, but isn't it truer to say that there's no centre (because no circumference?)? I think we can see that the surface of a sphere has no centre (is it similar to wondering if a neutral equilibrium is a real equilibrium?), but it's harder to see that the 3-D surface of a 4D universe also has no centre. If we think we're at the centre where there isn't one, have we really progressed from thinking that the Earth is the centre of the solar system? (I never studied topology) It's humanising the inhuman by letting psychology creep in unawares. Which is almost what this thread is about.
1975 Calatayud y Gisbert, Yamaha CG131S.

Pat Dodson
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Re: An electron the size of our Universe!

Post by Pat Dodson » Wed Mar 22, 2017 1:15 pm

gitgeezer wrote:Yes, I agree, I am the center of the universe. Everything that happens in the universe is, one way or another, about me.
Um yes. But aside from ourselves aren't those who go about acting that out such a pain? :wink:

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Andrew Fryer
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Re: An electron the size of our Universe!

Post by Andrew Fryer » Wed Mar 22, 2017 7:58 pm

I'm watching a programme on the size of the universe, and a few things are puzzling me. Firstly, someone is adamant that the expansion of the universe is NOT about galaxies moving apart, it's about space-time expanding. That's not a problem - the problem is, if space-time is expanding, then aren't the laws of physics altering with it, and isn't the speed of light being affected, so that maybe the red-shift is a bigger mystery than we thought? Also they are telling us that not only is the universe expanding, but that it is being held together by more gravity than should be there. Isn't that self-contradictory? Or do they mean it is holding together on the expanding fabric of space-time, in which case, they are denying that gravity is a part of that fabric? This is more closely linked to my first question than I thought. It's almost as though all the laws of physics are both part of the fabric of space-time and also external to that fabric.

I need to hold fire: now 10 minutes on and it's a runaway universe! Err, all that dark matter disappeared?
But in the initial stages of a big-bang, there will be a runaway scenario. Perhaps we are still only in the comparatively initial stages of the big-bang? Turns out the universe is infinite and space-time isn't curved - someone has done a massive triangulation exercise and found the angles add up to 180 degrees to 3 decimal places. But is that sufficiently accurate? And if the universe is infinite, then perhaps our local, accelerating expansion is caused because we are locally less massy than the invisible universe outside us?

I think the moral of the story is probably that TV programmes never tell you everything you need to know.
1975 Calatayud y Gisbert, Yamaha CG131S.

gitgeezer
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Re: An electron the size of our Universe!

Post by gitgeezer » Wed Mar 22, 2017 10:08 pm

Galaxies are moving apart, but not because they're moving through space. They're simply being carried along with the expansion of space, under the influence of dark energy. But this moving apart applies to galaxies that are already a considerable distance away. At relatively close distances, the gravitational attraction between galaxies may be stronger than the influence of dark energy and so they may actually be getting closer together. Thus the Andromeda Galaxy and the Milky Way Galaxy are moving together, on a collision course.

Think of a loaf of raisin bread. As it rises, each raisin moves farther from every other raisin. An observer on one of the raisins would see every other raisin moving away, and the farther away a raisin was, the faster it would move away. The nearest raisin might appear to move hardly at all, while the farthest raisin might move several inches in the same amount of time. And yet the raisins (galaxies) do not move through the dough (space), they are simply being carried along with it.

The speed of light of a galaxy moving away from us does not change. Rather it is stretched out, so that its frequency decreases and moves toward the red end of the spectrum. This effect is called a "red shift" and is evidence, discovered by Edwin Hubble, that red-shifted galaxies are moving away from us and the farther away a galaxy is, the more it is red-shifted and thus the faster it is moving away.

Einstein's speed limit of the speed of light applies to objects, including galaxies, moving through space. It does not apply to the expansion of space itself, which may expand at any speed. Thus the galaxies at the edge of the visible universe are being carried away from us at faster than the speed of light. Once they exceed the speed of light, the light they afterwards emit will never reach us. Thus more and more galaxies will disappear from view. In effect, they cross the boundary between the visible universe and the universe beyond, which some say is infinite.

Dark matter was proposed as a way of explaining the behavior of stars within galaxies and of nearby galaxies to each other. The amount of gravity required for that behavior was far more than could be accounted for by ordinary (visible) matter. While the gravity of ordinary matter and dark matter together is enough to hold groups of galaxies together, it is still less than the force of dark energy. If dark matter were evenly scattered through the universe, dark energy could perhaps be overcome. But dark matter is evidently clumped here and there along vast filaments, along with the clumping of galaxies.

Of the total energy of the universe, ordinary matter contributes about 5 percent, dark matter about 27 percent, and dark energy about 68 percent. Dark energy wins.

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Re: An electron the size of our Universe!

Post by Jeffrey Armbruster » Thu Mar 23, 2017 1:22 am

Does gravity influence the expanding (or not) "fabric" of spacetime? And what exactly is this fabric? A metaphor to be sure, but does it just project something comprehensible into what would otherwise be a big 'who knows?'. I'm thinking that this fabric isn't a metaphor for the materiality of all existence, since it includes time--but rather is the 'fabric' of space-time where (in which?) all material phenomenon appear. So, would gravity affect that? And is it itself material? Or, just to reduce everything to cliche, is it metaphorically not the mateiral notes, but the silence between the notes within which the notes appear?

I may well not understand this aright.

And why am I here instead of somebody else?
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gitgeezer
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Re: An electron the size of our Universe!

Post by gitgeezer » Thu Mar 23, 2017 2:36 am

To make sense of physical phenomena, and convey that sense to others, physicists sometimes "reify" the phenomena. To "reify" means to treat what may be nothing more than an abstraction as though it actually existed. To do this they must use words from the real world that most approximate what they are trying to understand and convey. The "fabric of spacetime" is one of these.

One of the handouts I received during a course on Cosmology was titled "What's bad about this habit," written by N. David Mermin, a retired professor of physics. Here's what he had to say about spacetime, after first discussing the "quantum state" and quantum fields:

"What about spacetime itself? Is that real? Spacetime is a (3+1)-dimensional mathematical continuum. Even if you are a mathematical Platonist, I would urge you to consider that this continuum is nothing more than an extremely effective way to represent relationships between distant events. And what is an event?

An event is a phenomenon that can usefully be represented as a mathematical point in spacetime. … So spacetime is an abstract four-dimensional mathematical continuum of points that approximately represent phenomena whose spatial and temporal extension we find it useful or necessary to ignore. The device of spacetime has been so powerful that we often reify that abstract bookkeeping structure, saying that we inhabit a world that is such a four- (or for some of us, ten-) dimensional continuum. The reification of time and space is built into the very language we speak [such as "fabric of spacetime"] making it easy to miss the intellectual slight of hand.

So when I read that spacetime becomes a foam at the Planck scale, I don't reach for my gun. (I haven't any.) But I do wonder what that foam has to do with the macroscopic events that spacetime was constructed to represent and the macroscopic means we use to locate events."

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Re: An electron the size of our Universe!

Post by Jeffrey Armbruster » Thu Mar 23, 2017 2:52 am

thanks, gitgeezer! Amazing how you can pull this up just like that. You obviously are far better able to understand this than me; I've read a few popular science books and nothing more. But it's put to us that galaxies are moving apart because spacetime is expanding--here, the 'fabric' doesn't seem to be a convenient representation, but a foundational reality. No spacetime...no nothing. Or again, we hear that gravity can slow or accelerate spacetime. I guess that I'm curious about how gravity works on time. But I can see how I'm falling into the very habit that he warns against.

I love that he talks about 'mathematical Platonists"! I think Brian Greene is exactly that, and I said as much in a post a few years ago.
Paul Weaver spruce 2014
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PeteJ
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Re: An electron the size of our Universe!

Post by PeteJ » Thu Mar 23, 2017 12:03 pm

The problem seems to be that all the metaphors break down in the end. Andrew worries about letting psychology into cosmology, but if space and time are psychological phenomena as per Kant and the rest then we have no other option.

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Re: An electron the size of our Universe!

Post by Jeffrey Armbruster » Thu Mar 23, 2017 3:41 pm

Peter, Aquinas called this 'reversion to the phantasm'. It may be that if you stay strictly with the math, you can avoid this. But as soon as you attempt to say what the math is 'about'...you end up with the "fabric" of spacetime.

I'm not sure that Kant says space and time are psychological realities so much as he says that our understanding of them is necessarily bound by finite categories of space and time that structure our consciousness.

As always I may have this wrong. I've not even had coffee yet.
Last edited by Jeffrey Armbruster on Thu Mar 23, 2017 7:47 pm, edited 1 time in total.
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