If the space between stars expands,why would the space between molecules not expand?

Question

Is it proposed that local electromagnetic and strong nuclear forces negate universal expansion?

If not, then the Hubble constant continues to apply clear down to Planck length. We would then need to say that given a simple example, the Earth has increased in diameter by 10mm in 5,000,000,000 years; as we apply a value of 72 km/sec/Mparsec as the Hubble Constant.

Answer 1

The simple way to understand the reason you're not expanding is that you are held together by electromagnetic forces. These electromagnetic forces are strong enough to overpower the expansion of the Universe. So you do not expand.

Similarly, the Earth is held together by a combination of electromagnetic and gravitational forces, which again are strong enough to overpower the Universe's expansion.

On even larger scales---those of the Solar System, the Milky Way, even the Local Supercluster of galaxies (also known as the Virgo Supercluster)---gravity alone is still strong enough hold these objects together and prevent the expansion. Only on the very largest scales does gravity become weak enough that the expansion can win

A second way to understand this is to appreciate the assumption of homogeneity. A key assumption of the Big Bang is that the Universe is homogeneous or relatively uniform. Only on large enough scales will the Universe be sufficiently uniform that the expansion occurs. You are clearly not uniform---inside your body the density is about that of water, outside is air. Similarly, the Earth and its surroundings are not of uniform density, nor for the Solar System or the Milky Way

Also note that the definitions of length and time are not changing in the standard model. The second is still 9192631770 cycles of a Cesium atomic clock and the meter is still the distance light travels in 9192631770/299792458 cycles of a Cesium atomic clock.

Answer 2

Molecules do not expand. However, you would have to replace the static electrostatic potential in the Schroedinger equation that describes atoms and molecules with an effective time dependent potential which included the expansion of the underlying metric. The resulting equation would describe atoms/molecules which would experience an excitation from an external field. If this expansion field has Fourier components which can excite transitions between quantum states, you got yourself a transition probability from the ground state to an excited state. Since the expansion would be isotropic, I would expect to see a new transition rule which goes from s -> s' states! This is very different from an electromagnetic excitation which transfers a spin 1 and therefor can only go from an s to a p state. In other words: the Hubble expansion leads to transition probabilities which can be uniquely distinguished from any electromagnetic interaction.

I bet there is a paper out there which does all the required calculations about what to expect in atomic physics near the end of the world.

:-)

Answer 3

we find the wavefunctuion of the electron in the atom by either splving the schrodinger using an approximate hamilton pr more accurately using the dirac electron equation in a central potential.
Solutions in the case of the hamilton method (i personally have not solved the dirac equation in acentral potential) are independant of time so the wavrfunction of the electron in an atom does not change over time.
So our wavefunction, which is the best way of describing an electron, basically gives us a set enrgy, eigenvalue, for each eignrnfunction or wavefunction which does not depend on anything but the elctron and the nucleus.
Due to this fact as the univeres expands the atom will stay the same; so as the universe increses insize if we believe its energy is finite then matter will become more sparse.
Also it is important to note that all current forms of quantum mecanics, field or otherwise, cannot br formed on curved space. This means when we usually use general relativity to explain the expansion of the universe it is very difficult or imposssible to use any form of QM to predict the atom. A better theory is needed,

Answer 4

heheh I am pleased by 3 of the answers here so far my hat is off to the 3 guys that posted.

OK sounds like the 'big rip' redux to me.
This has to do with hubble constant meets with relativity.
in a nutshell when the expansion speeds start to approach light speed expect weird things.. even maybe atomic level changes. but no worries we have about 14 trillion years or so till this happens.. in the meantime i suggest beer marriage then kids.
or maybe just beer...

Answer 5

Currently, other forces such as gravity predominate at scales up to galaxy clusters. There is a hypothesis called the Big Rip that says eventually the expansion could become so strong that galaxies, and eventually even atoms, would be ripped apart by expanding space.

Answer 6

To the bare eye its basically area or vacuum. although there is darkish be counted in that area, wich is invisible to the interest. a user-friendly mistake is to imagine that there is not any longer some thing there, even as truly there is skill modern-day. also time is a measurement wich envelops the completed universe. although the user-friendly you spot from theese parts are previous and so we we see this area relative to the earth. in case you've been in yet another galaxy and appeared on earth, you would possibly want to work out the earth 11.7 million years in the past (nearest galaxy) and also you would possibly want to work out the earth relative to the galaxy.