Expanding Universe

[sanctus]

Well it seems that back then there were now atoms, and then consider the most famous physics equation E=mc^2 therefore you can imagine that the mass was in another form than the matter we know now...

[lemit]

The concept that is difficult for me, and seemingly impossible for others--given the power pseudoscience has over people--is the failure of science to explain everything. It is very unnatural to think that the object being measured doesn't disappear; our ability to measure it fails. Beyond that, we all turn into five-year-olds, asking endlessly what's outside the boundaries of boundless time and/or space, and why we aren't being given better answers.

 

I'm beginning to think it might be reasonable to suggest we know one thing from before the Big Bang: there were arguments about the dimensions of the known universe. Any idea what language those arguments might have used?

 

Thanks.

 

--lemit

[sanctus]

Lemit, one of those arguments comes in brane-theories others in string-theory, so the former has some kind of Group-theory-language (or math if you want) and the latter as well (Kalabbi-Yau spaces?)

[Time_Travel]

Well it seems that back then there were now atoms, and then consider the most famous physics equation E=mc^2 therefore you can imagine that the mass was in another form than the matter we know now...

 

 

 

Mass was in another form?

 

when the mass was created initially at some point after BB, from that time to present did the mass expand?

[Southtown]

If space expands, wouldn't matter 'feel' it?

[Theory5]

The concept that is difficult for me, and seemingly impossible for others--given the power pseudoscience has over people--is the failure of science to explain everything. It is very unnatural to think that the object being measured doesn't disappear; our ability to measure it fails.

I dont think its the failure of science, we have 'experts' on subject matter no human has ever witnessed, no human mind could ever fully comprehend. These laws of time and space are not as simple as we claim them to be. I think its the limits of our mind that limit our advances in science and understanding.

 

 

If space expands, wouldn't matter 'feel' it?

only if the matter was expanding with space. The way I understand this as a small box with a finite but huge amount of tiny balls that can be crammed together. The box is the universe and as it expands it allows for more room of the balls. Is this an accurate model?

[lemit]

If space expands, wouldn't matter 'feel' it?

 

If I remember right, that's one of the quirky little things General Relativity addresses.

 

It's kind of like having to hold on because the earth is spinning so fast.

 

--lemit

[freeztar]

The way I understand this as a small box with a finite but huge amount of tiny balls that can be crammed together. The box is the universe and as it expands it allows for more room of the balls. Is this an accurate model?

 

Yes, that is accurate. Although I think the "balls" in the beginning were not recognizeable as balls or any form of matter we can think of. Pure, unbridled energy might be better.

 

In physical cosmology, assuming that nature is described by a Grand unification theory, the grand unification epoch was the period in the evolution of the early universe following the Planck epoch, in which the temperature of the universe was comparable to the characteristic temperatures of grand unified theories. If the grand unification energy is taken to be 1015 GeV, this corresponds to temperatures higher than 1027 K. During this period, three of the four fundamental interactions—electromagnetism, the strong interaction, and the weak interaction—were unified as the electronuclear force. Gravity had separated from the electronuclear force at the end of the Planck era. During the Grand Unification Epoch, physical characteristics such as mass, charge, flavour and colour charge were meaningless.

Grand unification epoch - Wikipedia, the free encyclopedia

[Southtown]

If I remember right, that's one of the quirky little things General Relativity addresses.

 

It's kind of like having to hold on because the earth is spinning so fast.

 

--lemit

Extra inertia? lol

[Time_Travel]

I think i understand this about the Matter now::

 

I still was searching on this topic. Then i stumbled upon this website which said

" if all the matter of the humanity is compressed by removing space within the atom then the matter would fit in an area smaller than a marble".

 

Then i came to know there is a HUGE space between the electron and the nucleus. Its something like this if i understand correctly " if the nucleus is the size of a marble, then the electron (pin head size) would be rotating 2 miles away from the marble."

Thats a huge huge space between nucleus and electron of atom. its almost like at subatomic levels there exists nothing.

 

So to my question of whether matter is expanding along with space then the answer has to be NO. only the space is expanding . when initially when all the matter was created it must have had fit in very small area, and because of the expansion of Space atoms formed and the rest is history and present.

 

If there wouldn't have been expansion of Space then there wouldn't have been life or planets or galaxies etc etc.

 

Am i correctly interpreting the expansion of space correctly??

[modest]

Mass was in another form?

 

Yes.

 

I still was searching on this topic. Then i stumbled upon this website which said

" if all the matter of the humanity is compressed by removing space within the atom then the matter would fit in an area smaller than a marble".

 

Then i came to know there is a HUGE space between the electron and the nucleus. Its something like this if i understand correctly " if the nucleus is the size of a marble, then the electron (pin head size) would be rotating 2 miles away from the marble."

Thats a huge huge space between nucleus and electron of atom. its almost like at subatomic levels there exists nothing.

 

So to my question of whether matter is expanding along with space then the answer has to be NO. only the space is expanding . when initially when all the matter was created it must have had fit in very small area, and because of the expansion of Space atoms formed and the rest is history and present.

 

If there wouldn't have been expansion of Space then there wouldn't have been life or planets or galaxies etc etc.

 

Am i correctly interpreting the expansion of space correctly??

 

You are very much on the right track.

 

Atoms have a nucleus (which have some subatomic particle in it) and electrons. For as long as atoms have existed in the universe it would be best to think of them as not really changing in size in a significant way. Atoms, in other words, do not expand with space.

 

If you look far enough back in the history of the universe when everything starts to look like a dense soup—there aren't galaxies, planets, stars and that kind of thing, as you say. Everything is compressed together so tightly that it is a homogeneous mix of radiation and matter and the further back in time you look the more dense and the hotter it is.

 

When you look back beyond 13 billion years ago when the universe was only 70,000 years old you reach a point where the density is too high and temp too high for electrons to bind to the nucleus of atoms. Before that point there were no atoms, there were only atomic nuclei, electrons, and radiation. This is the radiation-dominated era.

 

Atomic nuclei are made of protons and neutrons and they bind together making the core of an atom. If you look back further to when the universe was only about 3 minutes old you reach a temp and pressure where neutrons and protons will no longer be bound. You have free protons, free neutrons, free electrons, and radiation.

 

Further back when the universe was unimaginably small and only a fraction of a second old was the quark epoch when not even protons and neutrons could exist. What we now consider "matter" was then a hot dense quark-gluon plasma. At this point everything exists in its elementary form as point particles. Nothing that exists can be said to have any size as we think of 'size' today.

 

There are a lot of subtle issues and it is hard to summarize your question into a simple answer. The history of matter in the universe is quite complicated and it is inexorably tied to the expansion of space. Nucleosynthesis itself happened because of the expansion of space. But, the simplest answer is that the size of an atom is not directly expanded by the expansion of space.

 

~modest

[Time_Travel]

If there is space between nucleus of atom and electron, wouldn't that expand too??

Since the Space no matter where it is will have the same properties.

[lemit]

[W]hen the universe was unimaginably small and only a fraction of a second old was the quark epoch when not even protons and neutrons could exist. What we now consider "matter" was then a hot dense quark-gluon plasma. At this point everything exists in its elementary form as point particles. Nothing that exists can be said to have any size as we think of 'size' today.

 

Is that different from a Black Hole?

 

Thanks.

 

--lemit

 

p.s. There's a chance I might have a follow-up question.

[Time_Travel]

Is that different from a Black Hole?

 

Thanks.

 

--lemit

 

p.s. There's a chance I might have a follow-up question.

 

 

 

Good Question.

 

If yes then we may be living(Our Universe) in one of the black hole now.

[modest]

If there is space between nucleus of atom and electron, wouldn't that expand too??

Since the Space no matter where it is will have the same properties.

 

No. Electrons are attracted to the nucleus of an atom by an electrostatic force and they keep their distance from the nucleus by the kinetic energy (or angular momentum) of the electron. Those factors are quantized so that an electron will not get closer or further (on average) from a nucleus unless it changes its quantum numbers and jumps energy levels and takes up a different orbital.

 

The 'force' responsible for the expansion of space is gravity. Objects like galaxies, stars, and atoms follow paths dictated by general relativity—the collective effect is that everything on very large scales is moving away from everything else. Gravity, including any repulsive contribution from the cosmological constant, is far, far, far too weak to change the energy level of an electron and therefore change the size of an atom. The electron and nucleus have the same gravitational potential and no gravity-induced force exists between them. The distance is too short.

 

~modest

[Time_Travel]

OK now everything is falling in place( for my curious mind). Wish i could have shown the same curiosity and interest in my school and would have got an A+++ :)

 

Now if gravity doesn't affect the electron to fall into nucleus( hope using i am the right words)

then at what scale does the gravity affect matter?

[modest]

Now if gravity doesn't affect the electron to fall into nucleus( hope using i am the right words)

then at what scale does the gravity affect matter?

 

Wikipedia's Metric Expansion of Space article explains well,

 

Local perturbations

 

The expansion of space is sometimes described as a force which acts to push objects apart. Though this is an accurate description of the effect of the cosmological constant, it is not an accurate picture of the phenomenon of expansion in general. For much of the universe's history the expansion has been due mainly to inertia. The matter in the very early universe was flying apart for unknown reasons (most likely as a result of cosmic inflation) and has simply continued to do so, though at an ever-decreasing rate due to the attractive effect of gravity. In addition to slowing the overall expansion, gravity causes local clumping of matter into stars and galaxies. These stars and galaxies do not subsequently expand, there being no force compelling them to do so. There is no essential difference between the inertial expansion of the universe and the inertial separation of nearby objects in a vacuum; the former is simply a large-scale extrapolation of the latter. A uniform local "explosion" of matter can be locally described by the FLRW geometry, the same geometry which describes the expansion of the universe as a whole. In particular, general relativity predicts that light will move at the speed c with respect to the local motion of the exploding matter, a phenomenon analogous to frame dragging.

 

This situation changes somewhat with the introduction of a cosmological constant. A cosmological constant has the effect of a repulsive force between objects which is proportional (not inversely proportional) to distance. Unlike inertia it actively "pulls" on objects which have clumped together under the influence of gravity, and even on individual atoms. However this does not cause the objects to grow steadily or to disintegrate; unless they are very weakly bound, they will simply settle into an equilibrium state which is slightly (undetectably) larger than it would otherwise have been. As the universe expands and the matter in it thins, the gravitational attraction decreases (since it is proportional to the density), while the cosmological repulsion increases; thus the ultimate fate of the ΛCDM universe is a near vacuum expanding at an ever increasing rate under the influence of the cosmological constant. However the only locally visible effect of the accelerating expansion is the disappearance (by runaway redshift) of distant galaxies; gravitationally bound objects like the Milky Way do not expand.

 

If the universe were perfectly homogeneous and there were no local perturbations in density (like stars and planets) then the rate of expansion between two things at small scales (rather than just large, intergalactic scales) would be given by Hubble's constant which is about 75 (km/s)/Mpc or 2.43 x 10^-18 s^-1.

 

This means that something at distance [math]r[/math] would have a velocity of,

[math]v=r \times 2.43 \times 10^{-18}[/math]

due to expansion. For example, the width of the Milky Way, 100,000 lightyears (9.5 x 10¹⁷ km), would expand at,

[math]v=(9.5 \times 10^{17} \ km) \times (2.43 \times 10^{-18} \ s^{-1}) = 2.31 \ km/s[/math]

which is about a third of the velocity of the space shuttle. So, the effect of expansion over the distance of a galaxy's diameter would be relatively insignificant. Over the width of a solar system it would be about .03 millimeters per second. You could convert those to kinetic energy via e=1/2mv².

 

But, these numbers assume that the universe has a uniform distribution of matter at small scales which is not the case. In reality the expansion only shows up over intergalactic distances where homogeneity is a good approximation.

 

~modest