Could the universe just be a piece of something bigger?

[marshallmeyer1]

Could the "universe" just be a piece of something bigger?

Okay, I say universe in quotations because it's supposed to refer to everything. But what if our current perception of the universe was just a small piece that, along with many other "universes" orbited some megaplanet?

Does this sound feasible? It may sound idiotic, but how would you go about disproving this theory if we can only see so far with the Hubble Telescope?

 

[Mordred]

There is no way to answer this question without speculation.
Their are multiverse theorem
such as bubble universe however they are models yet to be shown with any evidence.

 

[Chronos]

Theories like eternal inflation predict a virtually unlimited supply of other 'universes', as do some versions of string theory and any number of more ... exotic theories. There is, to date, virtually zero observational evidence supporting these theories. Furthermore, most such theories assert these regions are causally disconnected from our universe, which places them in the realm of speculation, not science.

 

[phinds]

Okay, I say universe in quotations because it's supposed to refer to everything. But what if our current perception of the universe was just a small piece that, along with many other "universes" orbited some megaplanet?

Does this sound feasible? It may sound idiotic, but how would you go about disproving this theory if we can only see so far with the Hubble Telescope?

"orbiting some megaplanet" is NOT the kind of thing that even the speculative theories that have been mentioned talk about. I'm not sure if you are just using loose terminology or what, but what you are specifically saying does not seem to fit anywhere in science.

 

[marshallmeyer1]

Of course I'm using loose terminology. I am just inquiring as to whether or not it would be feasible to refute a theory such as this. I am not stating that I have any observational evidence to ascertain or even contemplate it. It's more of a philosophical question on my part, and I wanted to know whether it would be possible to absolutely refute it.

Thanks for all the answers.

 

[phinds]

Of course I'm using loose terminology. I am just inquiring as to whether or not it would be feasible to refute a theory such as this. I am not stating that I have any observational evidence to ascertain or even contemplate it. It's more of a philosophical question on my part, and I wanted to know whether it would be possible to absolutely refute it.

Thanks for all the answers.

If it were refutable, then it would be scientific, not speculative. A key thing that separates speculation and religion from science is falsifiability. There are serious proponents of the many worlds theory and other theories but so far none of them are falsifiable, so remain speculative.

 

[Mordred]

If it were refutable, then it would be scientific, not speculative. A key thing that separates speculation and religion from science is falsifiability. There are serious proponents of the many worlds theory and other theories but so far none of them are falsifiable, so remain speculative.

That is a very nice descriptive I'll have remember that quote.

 

[Prima Terra]

Sometimes...as a consequence of naivety..or simply a disinterest in mathematical language in your youth..a 'philosophical/whimsical ' approach to pondering the structure of our visible universe can come upon us unexpectedly...most especial after viewing astro-photography. For instance...could you drop an equation for a moment...and agree that we must be the center of our universe...for every image ever recorded by us...had already reached us...long before we opened our eyes to view them. Moving on from that...when we speculate the dynamics of something which has no real dimension..despite not being able to accurately represent real time data of a planet within an of the Centaurii systems...how may we exploit this concept of...for example...the image of Andromeda having reached us long before glass was invented...for that is what I would term...faster than speed of light.

 

[Chronos]

Any theory that is unfalsifiable is, by definition, not scientific.

 

[ImaLooser]

Of course I'm using loose terminology. I am just inquiring as to whether or not it would be feasible to refute a theory such as this. I am not stating that I have any observational evidence to ascertain or even contemplate it. It's more of a philosophical question on my part, and I wanted to know whether it would be possible to absolutely refute it.

Thanks for all the answers.

OK, suppose there is a supermegagargantuan black hole that is not inside our visible universe, but it is close enough to have some effect. We would see galaxies accelerated toward that black hole, so the visible universe would not be homogenous. But it is.

Suppose that the entire visible universe is orbiting that supermegargantua. That would cause a slight curve in everything: nothing would move in a straight line. If it were very far away and the orbit very slow it would be a very slight effect and very difficult to detect. So we can never completely disprove that, we can only find upper bounds on the curvature. Such has been sought and it's as close to zero as we can measure. Another way to detect it would be that galaxies closer to Gargantua would be orbiting more rapidly. That might be detectable, since we can observe galaxies that are very far apart. Finally, Gargantua would have been much closer in the distant past so the effects would have been stronger in the past and should be detectable, I would guess. If Gargantua is so far away that no effects can be observed then maybe it is not worth worrying about.

 

[fzero]

If it were refutable, then it would be scientific, not speculative. A key thing that separates speculation and religion from science is falsifiability. There are serious proponents of the many worlds theory and other theories but so far none of them are falsifiable, so remain speculative.

Any theory that is unfalsifiable is, by definition, not scientific.

I would argue that certain questions about the universe are necessarily unfalsifiable, but not necessarily unscientific. Consider the question:

"Did stars form beyond our cosmic horizon?"

This is a question we cannot expect to resolve experimentally, but asking it does not constitute religion. It is merely speculative, without being unscientific.

Since this isn't a philosophy forum (and I don't have much taste for it anyway), it's best not to derail the discussion much more.

OK, suppose there is a supermegagargantuan black hole that is not inside our visible universe, but it is close enough to have some effect. We would see galaxies accelerated toward that black hole, so the visible universe would not be homogenous. But it is.
...

If Gargantua is so far away that no effects can be observed then maybe it is not worth worrying about.

"Not inside our visible universe" means outside the cosmic horizon, which means no signal from the object whatsoever could have reached us. So this object would also be too far away for its indirect effects to be observed, since gravitational effects are also bounded by light speed.

 

[ImaLooser]

I would argue that certain questions about the universe are necessarily unfalsifiable, but not necessarily unscientific.

"Not inside our visible universe" means outside the cosmic horizon, which means no signal from the object whatsoever could have reached us. So this object would also be too far away for its indirect effects to be observed, since gravitational effects are also bounded by light speed.

Falsifiability is desirable but not essential. It is possible to build up enough evidence in favor of a theory that one is convinced, even though no way to refute it presents itself.

I thought that objects not in our visible Universe today could have been in the visible Universe in the past, since it is believed that at times the Universe expanded at a speed greater than light, such as the inflationary era. But I am not certain about that.

 

[George Jones]

I thought that objects not in our visible Universe today could have been in the visible Universe in the past, since it is believed that at times the Universe expanded at a speed greater than light, such as the inflationary era. But I am not certain about that.

No. Although somewhat counter-intuitive, it is the other way around. Not al things viewable today were viewable in the past. Once an object is viewable, it is, in principle, viewable forever.

Related, but, perhaps, confusing:

I know this is very counter-intuitive, but I really did mean what I wrote in posts #52 and #55.


Thanks for pushing me for further explanation, as this has forced me to think more conceptually about what happens.

This can happen because the Hubble constant decreases with time (more on this near the end of this post) in the standard cosmological model for our universe. Consider the following diagram:

O                                B        A        C
*                                *        *        *


*                    *     *     *
O                    B     A     C

The bottom row of asterisks represents the positions in space (proper distances) of us (O) and galaxies B, A, and C, all at the same instant of cosmic time, t_e. The top row of asterisks represents the positions in space of us (O) and galaxies B, A, and C, all at some later instant of cosmic time, t. Notice that space has "expanded" between times t_e and t.

Suppose that at time t_e: 1) galaxy A has recession speed (from us) greater than c; 2) galaxy A fires a laser pulse directed at us. Also suppose that at time t, galaxy B receives this laser pulse. In other words, the pulse was emitted from A in the bottom row and received by B in the top row. Because A's recession speed at time t_e is greater than c, the pulse fired towards us has actually moved away from us between times t_e and t.

Now, suppose that the distance from us to galaxy B at time t is the same as the distance to galaxy C at time t_e. Even though the distances are the same, the recession speed of B at time t is less than than the recession speed of C at time t_e because:

1) recession speed equals the Hubble constant multiplied by distance;

2) the value of the Hubble constant decreases between times t_e and t.

Since A's recession speed at time t_e is greater than c, and galaxy C is farther than A, galaxy C's recession speed at time t_e also is greater than c. If, however, the Hubble constant decreases enough between times t_e and t, then B's recession speed at time t can be less than c. If this is the case, then at time t (and spatial position B), the pulse is moving towards us, i.e., the pulse "turned around" at some time between times t_e and t.

If the value of the Hubble constant changes with time, what does the "constant" part of "Hubble constant" mean? It means constant in space. At time t_e, galaxies O, B, A, and C all perceive the same value for the Hubble constant. At time t, galaxies O, B, A, and C all perceive the same value for the Hubble constant. But these two values are different.

Probably some of my explanation is unclear. If so, please ask more questions.

 

[ImaLooser]

No. Although somewhat counter-intuitive, it is the other way around. Not al things viewable today were viewable in the past. Once an object is viewable, it is, in principle, viewable forever.

Aha, I get it. Once full the pipe never runs dry, but it could be very red-shifted.