Ask Me Anything Ask Dr. Joe - Now WEEKLY!

[DrJoePesce]

Thank you Dr Joe! Of course, it always helps having an informed source, apart from that it is a pleasure to discuss these questions without aggressive or intimidating influences. I hope you will admit that it is peculiar, especially if we take the Socratic route:
Q) Are stars different from Galaxies?
Ans) Yes of course they are, a star is an individual entity while a galaxy is made up of billions and billions of stars.
Q) That being so and taking our own Galaxy as an example we find that the stars are separated by distances of light years (1 light year is 10,000,000,000,000 km approx.) This being the case isn't it strange that the stars within these gigantic galaxies are not expanding away from each other? ?? The present wisdom states that :

"Space is expanding from the Big Bang and the acceleration of dark energy. But the objects embedded in space, like planets, stars, and galaxies stay exactly the same size. As space expands, it carries galaxies away from each other. From our perspective, we see galaxies moving away in every direction. "

Quote from Universe today.

It must indeed be a peculiar form of expansion especially since it is based on these assumptions that the theory that the Universe is expanding away at several times the speed of light is based.

Thanks for the great questions, Jzz!

The short answer is: They are all moving away from each other, because the universe is expanding everywhere. Even you and I are moving away from each other!

BUT: Currently universal expansion is most noticeable only on the largest scales. Hubble's law says v = H x D

v = velocity (always of recession) in kilometers per second
H = Hubble's constant, about 70 in kilometers per second per megaparsec (3.3 million light years)
D = distance in megaparsecs

H is the rate of expansion, and notice it is "only" 70 km/sec over a megaparsec!

If we want to know what the expansion is on our scale (or even those of stars) - the local scale - we need to keep in mind that 1 cm is about 3 x 10-25 megaparsec! Expansion on these scales is happening, but at a rate far smaller than the nucleus of an atom! And so local gravitational effects are far more important (that's why the most local of galaxies are affected more by interaction with the Milky Way than with the universal expansion).

In the far distant future, however, even on these local scales universal expansion will take over such that even atoms and their consituents will be pulled apart.

Dr. Joe

 

[Helio]

Hi Dr. Joe,

Im still puzzled as to how extensive this view of expansion goes. For instance, I would think that the distance between an electron and the hydrogen nuclei would not vary over time. Hence, the wavelength of the CMBR would not have had a much shorter wavelength in the much smaller universe of 13.8 Gyrs ago; the wavelength then and now for emission should be the same, though traveling to us will redshift it. Is this not the case?

My impression is that there’s a balances of the forces, where, say, a galaxy’s gravity counters the DE force so that the galaxy’s size remains unchanged, though a little stretched more than it would be without DE. A summation of the forces viewpoint. Is this correct?

 

[DrJoePesce]

Hi Dr. Joe,

Im still puzzled as to how extensive this view of expansion goes. For instance, I would think that the distance between an electron and the hydrogen nuclei would not vary over time. Hence, the wavelength of the CMBR would not have had a much shorter wavelength in the much smaller universe of 13.8 Gyrs ago; the wavelength then and now for emission should be the same, though traveling to us will redshift it. Is this not the case?

My impression is that there’s a balances of the forces, where, say, a galaxy’s gravity counters the DE force so that the galaxy’s size remains unchanged, though a little stretched more than it would be without DE. A summation of the forces viewpoint. Is this correct?

Currently you are correct because on the smallest scales expansion is miniscule. But it's happening continuously and the universe is ever stretching and getting bigger.

In the far distant future even the electrons in atoms will be pulled apart, and even further in the future the sub-atomic components of protons, neutrons, etc will be pulled apart.

 

[DrJoePesce]

By the way, the CMB photons are a fossil from a period when the universe started to become transparent (~300,000 years after the big bang). At that point, the photon field was at 3,000 - 5,000 degrees (like the surface of a star), so the photons' wavelengths would have been in the visible part of the electromagnetic spectrum. They've now been redshifted down to 2.74 degrees and are in the microwave portion of the spectrum.

 

[Helio]

By the way, the CMB photons are a fossil from a period when the universe started to become transparent (~300,000 years after the big bang). At that point, the photon field was at 3,000 - 5,000 degrees (like the surface of a star), so the photons' wavelengths would have been in the visible part of the electromagnetic spectrum. They've now been redshifted down to 2.74 degrees and are in the microwave portion of the spectrum.

But at the time of their emission, space was 1100x smaller, so I’ve assumed the proton-electron distances, which determines photon wavelengths, were not 1100x closer to one another, else the wavelengths would have been far different than what we see, after redshift due to distance during the expansion to us.

But perhaps a super tiny distance did exist between them due to DE as a force.

I tend to see expansion like a rubber band, not dissimilar to the balloon analogy. Put two separated rocks on a large rubber band, then stretch the rubber band and they will separate farther with time. Connect the two rocks with a bungee chord, however, and they will only separate farther based on the rate the rubber band stretches. The rocks represent not only the proton-electron distances, but also the radial star distances from their galactic center, or even galaxies in a cluster.

IOW, can we model DE as a force vector in a simple FBD (Free Body Diagram), so that the expansion movement stretches things but the greater force, say gravity, limits the distance they can be separated?This implies that the galaxies would not change in size over time, assuming they quit eating dwarfs.

But, as you note, this won’t be true in the long term since the relative strength of DE is growing, hence the observed acceleration rate of the expansion. Eventually, it will over-power all things, including atoms, though we are extrapolating with something we don’t really understand.

Thanks for your patience!

iPad

 

[rod]

But at the time of their emission, space was 1100x smaller, so I’ve assumed the proton-electron distances, which determines photon wavelengths, were not 1100x closer to one another, else the wavelengths would have been far different than what we see, after redshift due to distance during the expansion to us.

But perhaps a super tiny distance did exist between them due to DE as a force.

I tend to see expansion like a rubber band, not dissimilar to the balloon analogy. Put two separated rocks on a large rubber band, then stretch the rubber band and they will separate farther with time. Connect the two rocks with a bungee chord, however, and they will only separate farther based on the rate the rubber band stretches. The rocks represent not only the proton-electron distances, but also the radial star distances from their galactic center, or even galaxies in a cluster.

IOW, can we model DE as a force vector in a simple FBD (Free Body Diagram), so that the expansion movement stretches things but the greater force, say gravity, limits the distance they can be separated?This implies that the galaxies would not change in size over time, assuming they quit eating dwarfs.

But, as you note, this won’t be true in the long term since the relative strength of DE is growing, hence the observed acceleration rate of the expansion. Eventually, it will over-power all things, including atoms, though we are extrapolating with something we don’t really understand.

Thanks for your patience!

iPad

"But at the time of their emission, space was 1100x smaller..."

Helio, what you said here about the size of the Universe when the CMBR first appears as light, is not well known I think and you are correct. Using the cosmology calculators, you can plainly see this coming at you

Cosmology Calculators

LAMBDA - Links to Calculators

LAMBDA - Calculators

lambda.gsfc.nasa.gov

Cosmology calculator | kempner.net

Depending upon the values for H0 and z = 1100 for the redshift of the CMBR today(something not measured via spectroscopy), you can see the angular size diameter that is the radius of the universe as if observed from Earth. So in 380,000 years, space expands some 39 to 41 million light year radius to explain the origin of the CMBR seen today near 2.7 or 3.0 K. Not only is the Universe much smaller in radius and diameter, space is expanding faster than 100 c velocity starting from a very tiny size after the Planck time in the Big Bang model until the CMBR appears. Small items like this in the BB model explaining the CMBR should be plainly shown to the public in my view. Using z=1100 for the CMBR redshift today, the cosmology calculators show the Universe radius as seen from Earth ~ 46E+9 light years, the comoving radial distance.

 

[Orion]

Hi Orion - I'm afraid I don't know the answer to that off the top of my head. Let me do some research. I believe there has been quite a bit of writing on this....

Dr. Joe

Thanks.

 

[Jzz]

Depending upon the values for H0 and z = 1100 for the redshift of the CMBR today(something not measured via spectroscopy), you can see the angular size diameter that is the radius of the universe as if observed from Earth. So in 380,000 years, space expands some 39 to 41 million light year radius to explain the origin of the CMBR seen today near 2.7 or 3.0 K. Not only is the Universe much smaller in radius and diameter, space is expanding faster than 100 c velocity starting from a very tiny size after the Planck time in the Big Bang model until the CMBR appears. Small items like this in the BB model explaining the CMBR should be plainly shown to the public in my view. Using z=1100 for the CMBR redshift today, the cosmology calculators show the Universe radius as seen from Earth ~ 46E+9 light years, the comoving radial distance.

What if.............................. the CMBR is not the relic radiation from the Big Bang it is made out to be? What if the CMBR is the present day signal from the massive hydrogen clouds that constitute most of the 5% of baryonic matter in the Universe? Certainly the signal from Hydrogen clouds and the so called CMBR are almost indistinguishable. Where does that leave the CMBR in real terms? Why is there no distinguishable and identifiable signal in the present day and time from the massive hydrogen clouds and other baryonic matter. Is the Universe really that quiet? The first signal, later identified as the CMBR, was widely present in all radio and televisions sets of the time. Where has that signal or noise disappeared to? Modern technology has succeeded in successfully filtering out all extraneous noise from our transmissions, that doesn't mean it (the CMBR) is not still there. It has just been filtered out.

 

[Catastrophe]

That is very interesting. I had not come across that idea before.

Does the CMBR really exist? | Naked Science Forum

       Atoms are made up of 99.99999999% empty space. How is it that we canât just walk straight through walls considering that we are made u...

www.thenakedscientists.com

"Further, one of the founding principles of science, is that light can never be at rest, it and all electromagnetic radiation are either moving at the speed of light or have been absorbed. This being so, how is it that we have this humungous dinosaur called CMBR which is apparently just hanging there, immobile fixed in one place in the Universe? Is it possible?

The answer is that it is not. THE CMBR is not the thermalised (static??) radiation that everyone seems to accept without question. Instead, it is a reflection of present events that are taking place in the Universe, it correctly reflects the distribution of matter in The Universe. Think of the huge, massive beyond belief, clouds of gas in which the CMBR has its origins. Is it possible to think that these massive clouds of gas are static, that no movement at all takes place. No. You can be sure that currents are generated that give rise to radiation and constant interactions with light and electromagnetic radiation coming in from stars and galaxies taking place."

BUT

How does this affect CMB as supporting evidence for BBT?

Cat

 

[DrJoePesce]

But at the time of their emission, space was 1100x smaller, so I’ve assumed the proton-electron distances, which determines photon wavelengths, were not 1100x closer to one another, else the wavelengths would have been far different than what we see, after redshift due to distance during the expansion to us.

But perhaps a super tiny distance did exist between them due to DE as a force.

I tend to see expansion like a rubber band, not dissimilar to the balloon analogy. Put two separated rocks on a large rubber band, then stretch the rubber band and they will separate farther with time. Connect the two rocks with a bungee chord, however, and they will only separate farther based on the rate the rubber band stretches. The rocks represent not only the proton-electron distances, but also the radial star distances from their galactic center, or even galaxies in a cluster.

IOW, can we model DE as a force vector in a simple FBD (Free Body Diagram), so that the expansion movement stretches things but the greater force, say gravity, limits the distance they can be separated?This implies that the galaxies would not change in size over time, assuming they quit eating dwarfs.

But, as you note, this won’t be true in the long term since the relative strength of DE is growing, hence the observed acceleration rate of the expansion. Eventually, it will over-power all things, including atoms, though we are extrapolating with something we don’t really understand.

Thanks for your patience!

iPad

Thanks Helio - remember, though, expansion isn't linear and it's not the same everwhere (that is, locally it is minuscule, but on large scales it's, well, large).

Think about the rubber band as you stretch it: Watch your hands as you pull them apart. They move a large distance from each other, but the rubber band in the very center is only stretching a small amount (much smaller than what your hands are doing). Of course, there is no "center" to the universe, but the center of the rubber band is like the local expansion.

Dr. Joe

 

[DrJoePesce]

What if.............................. the CMBR is not the relic radiation from the Big Bang it is made out to be? What if the CMBR is the present day signal from the massive hydrogen clouds that constitute most of the 5% of baryonic matter in the Universe? Certainly the signal from Hydrogen clouds and the so called CMBR are almost indistinguishable. Where does that leave the CMBR in real terms? Why is there no distinguishable and identifiable signal in the present day and time from the massive hydrogen clouds and other baryonic matter. Is the Universe really that quiet? The first signal, later identified as the CMBR, was widely present in all radio and televisions sets of the time. Where has that signal or noise disappeared to? Modern technology has succeeded in successfully filtering out all extraneous noise from our transmissions, that doesn't mean it (the CMBR) is not still there. It has just been filtered out.

Hi Cat - not quiet - but chaotic and "noisy": there's the CMB, there's infrared and x-ray background, etc. (these "backgrounds" by the way are caused by objects we can yet see clearly - to our instruments they are just a "haze" of photons. As technology improves we aer then able to resolve these individual objects).

But to your point about (cold mostly) hydrogen gas clouds - yes, there are a lot of them, everywhere. They do emit, but not at the same frequencies as the cosmic microwave background, so they are distinguishable from that. Hydrogen in these clouds mostly emits an emission line with a 21 centimeter wavelength.

And mapping such hydrogen gas gives us a great idea about astronomical objects (like star forming regions in our galaxy and others), the intergalactic medium (stuff between galaxies), and large-scale structure. And here is some mapping of our galaxies structure, from the Very Long Baseline Array, one of our (NSF's) observatories:

VLBA Measurement Promises Complete Picture of Milky Way - National Radio Astronomy Observatory

A new record for directly measuring distances within our home Galaxy gives astronomers the ability to finally produce an accurate map of the whole extent of the Milky Way.

public.nrao.edu

Dr. Joe

 

[DrJoePesce]

And, of course, I'm sure you all have seen the fantastic image of the region near our supermassive black hole, Sagittarius A* (Sgr A*)!

https://www.space.com/milky-way-monster-black-hole-first-image-eht

 

[Bruh_Moment]

hi dr. what would happen if Sagittarius A exploded. Would we be affected by the explosion?

 

[Jzz]

But to your point about (cold mostly) hydrogen gas clouds - yes, there are a lot of them, everywhere. They do emit, but not at the same frequencies as the cosmic microwave background, so they are distinguishable from that. Hydrogen in these clouds mostly emits an emission line with a 21 centimeter wavelength.

Dear Dr Joe,
What a wonderful interaction, this is! That being so, I hope you will not take it amiss if I humbly disagree. Consider that approximately 73% of the mass of the visible universe is in the form of hydrogen. Helium makes up about 25% of the mass, and everything else represents only 2%. Is it then fair to state that these massive, massive clouds of Hydrogen are absolutely quiescent? If one is fortunate enough to come across a valve radio, this will immediately become apparent from the huge amount of static noise picked up between stations! Surely that is not ALL in the 21 cm range? IF the CMBR was anything but in the hydrogen spectra of emissions, there would be room for doubt but as things stand I don't think it can be absolutely established. Am I to understand that the clouds of hydrogen are absolutely isolated from gamma rays, x-rays and cosmic rays? Given the prolific nature of these types of radiation that reach the earth I think it is doubtful. Wouldn't these gamma rays, x-rays and cosmic rays react with the hydrogen to some extent, what about plain light frequencies from the near infra red to the far ultraviolet? Surely these would also react and result in some kind of signal?
To merely state that the clouds of hydrogen are super cooled and therefore largely quiescent isn't really satisfactory given the amount of activity going on. 10,000,000,000 neutrinos pass through every square centimetre of our bodies every second! Therefore, unless there is something definite out there waving and saying I am the CMBR, I feel there is still considerable doubt about the matter.

 

[Helio]

Thanks Helio - remember, though, expansion isn't linear and it's not the same everwhere (that is, locally it is minuscule, but on large scales it's, well, large).

Think about the rubber band as you stretch it: Watch your hands as you pull them apart. They move a large distance from each other, but the rubber band in the very center is only stretching a small amount (much smaller than what your hands are doing). Of course, there is no "center" to the universe, but the center of the rubber band is like the local expansion.

Agreed, but in order for this rubber band to, say, double in length, then every incremental section must double, even the central regions. [We can arbitrarily pick a tiny point and agree there is no expansion but this is only a math point, not a tiny region.]

So, using our rubber band where we’re in the center, 1/2 way to either end will stretch by 1/2 the new distance to the end. It, like all other sections has doubled its distance from the center. Thus an expansion of 2x occurs throughout our perfect rubber band.

In the balloon analogy, all regions expand evenly, but I still think, perhaps in error, that those non-rubber dots (let’s used glued hard plastic ones) don’t stretch - their far greater tensile strength prevents any comparable expansion.

Am I missing something?

 

[Wolfshadw]

Hey Dr. Joe!

Thanks for staying with us and explaining the Universe as we see it.

With the total lunar eclipse occurring this week, could you explain the mechanics of what's happening, why it's happening and why only twice a year?

Thanks
-Wolf sends

 

[DrJoePesce]

Dear Dr Joe,
What a wonderful interaction, this is! That being so, I hope you will not take it amiss if I humbly disagree. Consider that approximately 73% of the mass of the visible universe is in the form of hydrogen. Helium makes up about 25% of the mass, and everything else represents only 2%. Is it then fair to state that these massive, massive clouds of Hydrogen are absolutely quiescent? If one is fortunate enough to come across a valve radio, this will immediately become apparent from the huge amount of static noise picked up between stations! Surely that is not ALL in the 21 cm range? IF the CMBR was anything but in the hydrogen spectra of emissions, there would be room for doubt but as things stand I don't think it can be absolutely established. Am I to understand that the clouds of hydrogen are absolutely isolated from gamma rays, x-rays and cosmic rays? Given the prolific nature of these types of radiation that reach the earth I think it is doubtful. Wouldn't these gamma rays, x-rays and cosmic rays react with the hydrogen to some extent, what about plain light frequencies from the near infra red to the far ultraviolet? Surely these would also react and result in some kind of signal?
To merely state that the clouds of hydrogen are super cooled and therefore largely quiescent isn't really satisfactory given the amount of activity going on. 10,000,000,000 neutrinos pass through every square centimetre of our bodies every second! Therefore, unless there is something definite out there waving and saying I am the CMBR, I feel there is still considerable doubt about the matter.

Hi Jzz - nothing amiss!

Actually, some of the hiss of radio/tv static is CMB!

Most electromagnetic radiation (of all wavelengths) is generated by so-called thermal sources: fusion or other forms of heating. (Some is "non-thermal", generated by, primarily magnetic fields and their interaction with electrons).

These thermal sources (stars, gas clouds, etc) radiate at all wavelengths (more or less) but the peak fo their emission varies with temperature, and the photons with wavelengths off the peak could be few and far between. For example, the Sun's surface is some 6,000 degrees. The peak of emission of the solar surface is in the middle of the visible part of the spectrum (of course), but there are also other photons, X-ray, gamma-ray, UV, radio, IR. But at lower numbers. A cold gas cloud (the state that most hydrogen is in for a galaxy like ours) emits most of its electromagnetic radiation in the radio. There are SOME photons at other wavelengths but relatively few. Certainly the gas clouds absorb photons, and the energy imparted lead to that 21cm wavelength emission line I mentioned originally.

Keep in mind that most hydrogen is locked up in stars (only about 10%, give or take, is in the form of interstellar gas clouds).

By the way, I'm not saying the universe is quiescent - far from it. But the preceeding gives a (very high level) picture of the electromagnetic radiation field. And you are correct about the neutrinos (but they are barely interacting with anything). By the way, there are far more photons zipping around than there are particles of matter, and they are mostly the microwave photons from the CMB.

Dr. Joe

 

[DrJoePesce]

Agreed, but in order for this rubber band to, say, double in length, then every incremental section must double, even the central regions. [We can arbitrarily pick a tiny point and agree there is no expansion but this is only a math point, not a tiny region.]

So, using our rubber band where we’re in the center, 1/2 way to either end will stretch by 1/2 the new distance to the end. It, like all other sections has doubled its distance from the center. Thus an expansion of 2x occurs throughout our perfect rubber band.

In the balloon analogy, all regions expand evenly, but I still think, perhaps in error, that those non-rubber dots (let’s used glued hard plastic ones) don’t stretch - their far greater tensile strength prevents any comparable expansion.

Am I missing something?

Hi Helio - it is great that you are thinking deeply about this! I think what is missing is that all regions are not expanding evenly (and/or linearly). Think about the rubber band. If you move your left and right hand (holding each end of the band) 1 cm, the ends of the band you are holding move 1 cm, but the rubber in the very center of the band does not move 1cm... Just like the universe between my fingers is expanding an a scale far smaller than the size of sub-atomic particles, yet 1 billion light years away it is expanding at 65 km/sec.

Dr. Joe

 

[DrJoePesce]

hi dr. what would happen if Sagittarius A exploded. Would we be affected by the explosion?

Hi Bruh_Moment, great question! So there is no practical way a supermassive black hole can explode (but see later). What could happen is that it starts to "feed" at a higher rate than it is now (that is, more matter can fall into it than is presently). In that case, it could become what we call "active" and a disc of material falling into the black hole would form (the accretion disc) and a jet of material could be generated, squiring off into interstellar space. These events would produce a lot of high energy photons, and it wouldn't be very good for anything in the region immediately near the black hole. There are some other things that might happen but all are unlikely to affect us, but we would certainly notice them!

Dr. Joe

 

[DrJoePesce]

Hey Dr. Joe!

Thanks for staying with us and explaining the Universe as we see it.

With the total lunar eclipse occurring this week, could you explain the mechanics of what's happening, why it's happening and why only twice a year?

Thanks
-Wolf sends

Hi Wolfshadw! A lunar eclipse happens when the Earth passes between the Sun and the Moon (and only when the Moon is full). The shadow of the Earth falls across the Moon and we experience a lunar eclipse. This sort of eclipse is visible anywhere on Earth the full Moon is visible.

Theoretically, we should get a lunar eclipse (and the other type, a solar eclipse, where the moon passes between the Earth and the Sun and the Moon's shadow falls on Earth) every month. But we don't, because the plane of the Moon's orbit is tlited by 5 degrees to the plane of the Earth's orbit. Thus, we can only get an eclipse when the three bodies (Sun, Earth, Moon) line up and that happens in frequently.

Does that make sense?

Dr. Joe

 

[Helio]

Hi Helio - it is great that you are thinking deeply about this! I think what is missing is that all regions are not expanding evenly (and/or linearly). Think about the rubber band. If you move your left and right hand (holding each end of the band) 1 cm, the ends of the band you are holding move 1 cm, but the rubber in the very center of the band does not move 1cm... Just like the universe between my fingers is expanding an a scale far smaller than the size of sub-atomic particles, yet 1 billion light years away it is expanding at 65 km/sec.

Dr. Joe

Agreed, I understand all that you’ve said, but my argument is more nuanced, perhaps.

Let’s make your rubber band 2 meters in length (1m L&R) so a 1cm stretch on both ends, keeping the middle point the same, becomes an expansion of 1%. But, and this is my question, any given segment will also stretch 1%. So the first mm in length from the center will stretch, in this case, 10 microns.

So, if our universe has expanded, say, 10% since its nascent days many billions of years ago, it’s hard to expect our galaxy to have expanded that same 10%, again ignoring dwarf consumptions.

Worse, since most atomic H is primordial, it seems likely that its electron’s orbit will not now be 1100x greater in radius from the proton due to expansion since Recombination.

Or am I still missing something?

Thanks for your patience!

Perhaps others can assist us .

iPhone

 

[DrJoePesce]

Agreed, I understand all that you’ve said, but my argument is more nuanced, perhaps.

Let’s make your rubber band 2 meters in length (1m L&R) so a 1cm stretch on both ends, keeping the middle point the same, becomes an expansion of 1%. But, and this is my question, any given segment will also stretch 1%. So the first mm in length from the center will stretch, in this case, 10 microns.

So, if our universe has expanded, say, 10% since its nascent days many billions of years ago, it’s hard to expect our galaxy to have expanded that same 10%, again ignoring dwarf consumptions.

Worse, since most atomic H is primordial, it seems likely that its electron’s orbit will not now be 1100x greater in radius from the proton due to expansion since Recombination.

Or am I still missing something?

Thanks for your patience!

Perhaps others can assist us .

iPhone

Locally it is still vanishingly small, so yes, it's increased by a large factor, but a large factor times a very small number is still a very small number. For the almost 14 billion years, the amount is so small the atom can adjust (and atomic forces are far stronger than exapansion). But, in the far distant future ,this will no longer the case and the inexorable expansion will eventually win out. Even sub-atomic particles and their forces will be overcome and they will be pulled apart.

 

[Wolfshadw]

But we don't, because the plane of the Moon's orbit is tlited by 5 degrees to the plane of the Earth's orbit.

Is that a consistent 5° or does that fluctuate? Again, not big on orbital mechanics.

-Wolf sends

P.S. Thanks again!

 

[Helio]

Locally it is still vanishingly small, so yes, it's increased by a large factor, but a large factor times a very small number is still a very small number. For the almost 14 billion years, the amount is so small the atom can adjust (and atomic forces are far stronger than exapansion). But, in the far distant future ,this will no longer the case and the inexorable expansion will eventually win out. Even sub-atomic particles and their forces will be overcome and they will be pulled apart.

Thanks. That’s the answer I was hoping to see.

 

[DrJoePesce]

Is that a consistent 5° or does that fluctuate? Again, not big on orbital mechanics.

-Wolf sends

P.S. Thanks again!

No, the tilt does not fluctuate.