Bjarne on: Dark Energy, only an illusion.

[wollery]

Wouldn't two planets with the same density have the same gravitational pull?

I'm interested in your opinion on the latter

No. Two planets with the same mass would have the same gravitational pull at the same distance from their centres, but if one was smaller (and therefore denser) then standing on the surface would be closer to the centre, and would result in a stronger pull.

 

[Bjarne]

If Earth was half the size but the same mass, gravity would be stronger.

Finnally....

Longer relative to what?

To what it was before..

And since the meter is the measure of length, something that was a meter in length, and is still a meter in length is, by definition, no longer than it was before.

Relative “longer”

You're real good at coming up with objections. Now tell me how you will measure (prove) this.

By measuring the EM spectre a certain (stable) place over time.
Whether this is possible depends on how accurate we can measure change in the EM spectre. I don’t know this right now.

These are the things I like to discuss. Flaws of the current and accepted theories. However, it seems to me this is discussed as Schwarzschild radius???

Proportionality between black holes and size of galaxies is not understood.
According to my theory it a pieces of cake.
http://www.youtube.com/watch?v=leZdJmUF4lM&feature=player_embedded

In which case we wouldn't notice the expansion of space, because everything would be expanding relative to everything else.

Right
And since we know that time and (according to my opinion) certainly also distances are relative, + the the fact we do not notice any changing’s to the law of nature over time even though space here also MUST expand (unnoticed), I think we can conclude that the law of nature always will be the same, doesn’t matter if matter and space expands.

 

[wollery]

Right
And since we know that time and (according to my opinion) certainly also distances are relative, + the the fact we do not notice any changing’s to the law of nature over time even though space here also MUST expand (unnoticed), I think we can conclude that the law of nature always will be the same, doesn’t matter if matter and space expands.

Except that we do notice the expansion of space, which kind of knocks a dent in your argument.

 

[Landrew]

Except that we do notice the expansion of space, which kind of knocks a dent in your argument.

Yes, if everything expanded together, space/time/matter, it would all look mostly normal, except for a few odd things:

• A probe that we sent out of the solar system a few decades ago would be farther away than it's supposed to be.
  
• The farther away the objects we observe, the more they seems to be accelerating away from us.
  
• Fossil evidence seems to suggest that the earth was smaller and had less gravity 100 million years ago.

Or it could be argumentum ad ignorantiam at work. A physicist may be better able to explain these things with dark matter or some such thing. I guess it wouldn't be much fun if we could only talk about things to which we were superbly qualified.

 

[Kwalish Kid]

Yes, if everything expanded together, space/time/matter, it would all look mostly normal, except for a few odd things:
A probe that we sent out of the solar system a few decades ago would be farther away than it's supposed to be.

There are always anolmalies where engineering is involved.

The farther away the objects we observe, the more they seems to be accelerating away from us.

As well explained by general relativity.

[*] Fossil evidence seems to suggest that the earth was smaller and had less gravity 100 million years ago.

Not even close to being correct.

 

[sol invictus]

Yes, if everything expanded together, space/time/matter, it would all look mostly normal, except for a few odd things:

No, it would be completely undetectable, because if everything expands uniformly (including "constants" of nature with units of length), no ratios of lengths change. But ratios of lengths are all one can ever measure - in other words, we can only measure the length of something in units of the length of something else. If both the length of the thing we're measuring and our unit of length stretch by the same amount, the result of our measurement is unaffected. If everything stretches by that same mount, the results of all measurements are unaffected.

Of course in an expanding universe that's not at all what happens. The earth is the same size now as it was 100 million years ago, in units of (for example) the radius of Mars. But over those 100 million years galaxy clusters moved apart; they are now farther away from each other (in units of, for example, the radius of Mars).

 

[MRC_Hans]

No, it would be completely undetectable, because if everything expands uniformly (including "constants" of nature with units of length), no ratios of lengths change. But ratios of lengths are all one can ever measure - in other words, we can only measure the length of something in units of the length of something else. If both the length of the thing we're measuring and our unit of length stretch by the same amount, the result of our measurement is unaffected. If everything stretches by that same mount, the results of all measurements are unaffected.

Excuse me, but let's get this straight, not so much for the sake of Bjarne, as he only listens to what he wants to hear anyway, but for all others.

Suppose the universe was somehow expanding, in the way Bjarne imagines. Then yes, all ratios and yardsticks would expand with it and visually, nothing would change. However, a lot of other things would:

- Density: Since the volume of all objects would increase with the third root of the expansion, then although we would still call one gallon one gallon, a doubled gallon would actually hold 8 'old gallons', but unless you want to add some way of producing more mass, it would still weigh the same as before. Which would mean that the weight/mass ratio of all objects would be constantly decrease.

- Speed: A speeding object would seem to slow down, as the lenght it had to traverse in a given time would constantly increase. So without some magical source of extra energy to accelerate it, it would be observed to slow down. (I know Bjarne will say that it does, but unfortunately for him, he needs his 'resistance to motion' to channel energy through his 'space wind' so that would make his ideas even more inconsistent. .... Not that I expect that to bother him).

- Frequency: Since lengths would change, all kinds of wave-forms would constantly change frequency. *)

- Orbits would be impossible: If distances kept expanding, unless there was some tremedous energy source to constantly lift orbiting objects ever farther away from their primaries, they would appear to be spiralling down. - And IF they were somehow lifted up, their orbital times would need to change.

*) It might be possible to claim that ALL expands, also speeds, masses, time, and the speed of light. However, since we only know these from their relationsthips to each other, we would be unable to know, and it would have no effect what so ever on the universe as we can observe it.

Hans

 

[CaveDave]

...
As for the 're-curving' of the crust, I believe Bjarne means that as the continents adjust to a larger radius of curvature (since expansion is supposedly expressed at the surface by creation of oceanic crust), compressional forces act at the continents' centres. Although it is wrong, this idea at least makes more sense than the explanation given in the video that Bjarne linked to, whereby continental mountain ranges apparently form by crustal thinning and subsidence at the centre.

On the one hand, he seems to claim that NO possible measuring device or instrument can detect the global expansion because the particles that make these objects are expanding at the same rate (possibly interesting from a purely philosophical perspective), and on the other, claims that creation of oceanic crust and "recurving" of continental plates must take place to compensate for the expansion.

Do you or anyone else not see an obvious flaw in that chain of reasoning?

I could be mistaken, but that seems to be an obvious disconnect.




Do I err?

Cheers,

Dave

 

[sol invictus]

Suppose the universe was somehow expanding, in the way Bjarne imagines. Then yes, all ratios and yardsticks would expand with it and visually, nothing would change. However, a lot of other things would:

- Density: Since the volume of all objects would increase with the third root of the expansion, then although we would still call one gallon one gallon, a doubled gallon would actually hold 8 'old gallons', but unless you want to add some way of producing more mass, it would still weigh the same as before. Which would mean that the weight/mass ratio of all objects would be constantly decrease.

- Speed: A speeding object would seem to slow down, as the lenght it had to traverse in a given time would constantly increase. So without some magical source of extra energy to accelerate it, it would be observed to slow down. (I know Bjarne will say that it does, but unfortunately for him, he needs his 'resistance to motion' to channel energy through his 'space wind' so that would make his ideas even more inconsistent. .... Not that I expect that to bother him).

- Frequency: Since lengths would change, all kinds of wave-forms would constantly change frequency. *)

- Orbits would be impossible: If distances kept expanding, unless there was some tremedous energy source to constantly lift orbiting objects ever farther away from their primaries, they would appear to be spiralling down. - And IF they were somehow lifted up, their orbital times would need to change.

*) It might be possible to claim that ALL expands, also speeds, masses, time, and the speed of light. However, since we only know these from their relationsthips to each other, we would be unable to know, and it would have no effect what so ever on the universe as we can observe it.

Hans

None of those things would change under the circumstances I described, for just the reason you give in your last paragraph. Perhaps the simplest way to see this is to realize that the only things that have any physical meaning are dimensionless quantities, because dimensionful quantities change when you change units. So if everything expands in such a way that all dimensionless ratios are fixed, then nothing has changed.

Another way to think about it is to imagine that for some reason we decide to use a system of units in which our unit of length - let's call it the tmeter - is changing with time. In a year, the tmeter will be half the length it is today. Of course we don't actually have any tmeter sticks that behave that way, but we can perfectly well define them mathematically and use them as a unit.

So after a year the lengths of everything - measured in tmeters, naturally - will have doubled. And not just lengths, speeds will change too, measured in tmeters/second, as will anything else with length appearing in its dimensions. In particular the universe will be expanding (very rapidly!). But obviously nothing other than those numbers will change, because the length or radius of something physical, like the earth, won't have changed in units of the length or radius of anything else physical, like Mars or a hydrogen atom. Someone not acquainted with the tmetric system can and will claim that no lengths have doubled, and that in fact that nothing has changed at all - and they'll be completely correct.

Point being, if all physical lengths are changing at the same rate and in the same way it's completely equivalent to nothing changing at all.

 

[wollery]

On the one hand, he seems to claim that NO possible measuring device or instrument can detect the global expansion because the particles that make these objects are expanding at the same rate (possibly interesting from a purely philosophical perspective), and on the other, claims that creation of oceanic crust and "recurving" of continental plates must take place to compensate for the expansion.

Do you or anyone else not see an obvious flaw in that chain of reasoning?

I could be mistaken, but that seems to be an obvious disconnect.




Do I err?

Cheers,

Dave

No, you do not err.

You do occasionally umm.

 

[Landrew]

On the one hand, he seems to claim that NO possible measuring device or instrument can detect the global expansion because the particles that make these objects are expanding at the same rate (possibly interesting from a purely philosophical perspective), and on the other, claims that creation of oceanic crust and "recurving" of continental plates must take place to compensate for the expansion.

Do you or anyone else not see an obvious flaw in that chain of reasoning?

I could be mistaken, but that seems to be an obvious disconnect.




Do I err?

Cheers,

Dave

There might be a few clues to a global expansion. Although your measuring sticks would all be growing along with everything they measure, the gravitational constant might actually be constant, therefore the pterosaurs may have had a much easier time taking off from a smaller planet than we have now.

Also, a space probe sent away from earth, at a constant speed, once it's fuel is spent, should be a given, calculated distance away from earth after a given time. If it happens to be farther away from earth than it should be, that sounds like evidence of a global expansion of space.

 

[wollery]

There might be a few clues to a global expansion. Although your measuring sticks would all be growing along with everything they measure, the gravitational constant might actually be constant, therefore the pterosaurs may have had a much easier time taking off from a smaller planet than we have now.

A smaller Earth would make the surface gravity higher, meaning that they'd have a harder time taking off.

Also, a space probe sent away from earth, at a constant speed, once it's fuel is spent, should be a given, calculated distance away from earth after a given time. If it happens to be farther away from earth than it should be, that sounds like evidence of a global expansion of space.

Except that if space is expanding at the same relative rate as the Earth and any yardstick we use, then the probe's extra distance will be cancelled out by the extra size of our measuring devices.

 

[Andrew Wiggin]

As a child I read about the expansion of the universe and wondered if gravity were real or just a result of the earth's expansion at the equivalent of 1G.

I came to the conclusion that such expansion would have made the solar system rather crowded and we would have bumped into the sun.

ETA: it was about the same time that I considered if drinking gasoline would let me run as fast as a car.

These are positively reasonable hypotheses compared with some I've heard here... At least they're testable in some sense, and you were not delusional enough to take them on face value without thinking about it, even as a child.

A

 

[Cosmic Roy]

On the one hand, he seems to claim that NO possible measuring device or instrument can detect the global expansion because the particles that make these objects are expanding at the same rate (possibly interesting from a purely philosophical perspective), and on the other, claims that creation of oceanic crust and "recurving" of continental plates must take place to compensate for the expansion.

Do you or anyone else not see an obvious flaw in that chain of reasoning?

I could be mistaken, but that seems to be an obvious disconnect.




Do I err?

Cheers,

Dave

I'm sure you're right, but I must admit that I haven't been following Bjarne's arguments about space, measurements, density, etc; there are many posters here who will subject them to a more thorough analysis than I could. I just pounced on Bjarne's claim that his theory is supported by Neal Adams's version of the expanding Earth hypothesis, since that particular claim requires such heroic ignorance that I couldn't let it pass.

 

[Toke]

These are positively reasonable hypotheses compared with some I've heard here... At least they're testable in some sense, and you were not delusional enough to take them on face value without thinking about it, even as a child.

A

As a kid I did at some point realise that things are often more complicated that they look, and that if my straightforward and logical theories clashed with the more commonly held opinion, it could be because I had overlooked something.

It appears that CT's does not reach that stage.

 

[MRC_Hans]

On the one hand, he seems to claim that NO possible measuring device or instrument can detect the global expansion because the particles that make these objects are expanding at the same rate (possibly interesting from a purely philosophical perspective), and on the other, claims that creation of oceanic crust and "recurving" of continental plates must take place to compensate for the expansion.

Do you or anyone else not see an obvious flaw in that chain of reasoning?

I could be mistaken, but that seems to be an obvious disconnect.




Do I err?

Cheers,

Dave

Only in trying to make sense of Bjarne's ramblings.

Hans

 

[MRC_Hans]

*snip*
Point being, if all physical lengths are changing at the same rate and in the same way it's completely equivalent to nothing changing at all.

On that I agree. However, that is obviously not Bjarne's ides since he wants to explain various observed phenomena this way. So obviously, the expansion scenario he imagines must be observable.

However, Bjarne has a rather consistent habit of explaining various phenomenon by claiming some exotic property of reality, and when people point out that reality does not appear to have that property, he tries to argue that it is not observable. But of course, he can't have both.

Hans

 

[Landrew]

A smaller Earth would make the surface gravity higher, meaning that they'd have a harder time taking off.

Did you see the astronauts bounding along on the moon, and hitting a golf ball out of sight? The moon is 1/6 the mass of the earth, and has 1/6 the gravity.

Except that if space is expanding at the same relative rate as the Earth and any yardstick we use, then the probe's extra distance will be cancelled out by the extra size of our measuring devices.

The Voyager probes have a 50-year battery and send to earth their position calculated by their relative position to the planets and stars. If they are farther away from earth than their speed should place them, you could either hypothesize that dark matter is pulling the probe away faster, or space itself has grown larger since it was launched in 1977. If there are other explanations, I'd like to read them.

 

[sol invictus]

Did you see the astronauts bounding along on the moon, and hitting a golf ball out of sight? The moon is 1/6 the mass of the earth, and has 1/6 the gravity.

Is the earth's mass supposed to be changing when it expands? If so, how, exactly? Proportionally to its volume - i.e. fixed density - or some other way?

If the earth had the same mass but a smaller radius, the surface gravity would be larger - that's what wollery was telling you. If instead you fix the density, so that the mass scales as radius cubed, then a smaller earth would have weaker gravity by a factor of the ratio of radii (i.e. if you decreased the radius by 2 - and hence the mass and volume by 8 - gravity would be 1/2 as strong at the surface). The moon actually is a little more than 1/4 of the earth's radius, but its gravity is only about 1/6th of the earth's - from which one can conclude that its average density is a little less than 2/3rds that of earth (presumably because it lacks a metal core).

The Voyager probes have a 50-year battery and send to earth their position calculated by their relative position to the planets and stars. If they are farther away from earth than their speed should place them, you could either hypothesize that dark matter is pulling the probe away faster, or space itself has grown larger since it was launched in 1977. If there are other explanations, I'd like to read them.

There is in fact a reported anomaly in the position of the Pioneer probes - but they are closer to the sun than expected.

 

[Landrew]

Is the earth's mass supposed to be changing when it expands? If so, how, exactly? Proportionally to its volume - i.e. fixed density - or some other way?

Yes, quite simply. That's what I meant by time/space/matter all expanding together. Gravity increasing with mass according to the gravitational constant.

There is in fact a reported anomaly in the position of the Pioneer probes - but they are closer to the sun than expected.

Right you are, and so are the Voyager probes. At the very least something is going on that we don't understand. If I were a betting man, I'd bet a dollar that the dark matter (sucking everything outwards) theory will look really silly in about 50 years.