Debate How big do you think is the Universe?

[lexico]

Universe: How Big ?

Is the universe infinite or finite ?
In volume, density, and mass ?
Let's talk about it !
Please add relevant comments and links; what you have below is just what was readily available on the web.

Credit: Douglas Scott's FAQ page
Astronomy Group at University of British Columbia

According to the following passage, the dimensisions are;
RADIUS: ~10,000 Megaparsec or 3 ?~ 10^26 metres
DENSITY: ~ 10^-26kg/m3
TOTAL MASS: ~ 10^54 kilogrammes

Q: "Do you know where I can find an estimate of the total mass of the universe?"
Submitted by [email protected] 10/00

A: "From observations of the Universe it is possible to determine the average density. In other words the mass per unit volume (or the mass-energy equivalent per unit volume). Currently the mass-energy census of the Universe identifies at least 5 separate components: ordinary matter (baryons); massive neutrinos (a known, but ellusive particle, which may have a small mass); cold dark matter (some as yet unidentified particle); photons (mainly the CMB); and Dark Energy (which may dominate the census, even although it doesn't behave like matter at all!). It appears that the Universe has a "flat" geometry, so that =1, and estimates for the contributions from each of the 5 components are 5%, 0.3%, 30%, 0.01% and 65%, respectively.

Coverting into density requires having an estimate of how fast the Universe is expanding, i.e. the Hubble constant (since that goes into the definition of , as described in another answer). Using a typical value for H0 the overall density of the Universe turns out to be about 10-26kg/m3. This corresponds to about 1011 times the mass of the Sun in every cubic Megaparsec of volume. This value is uncertain both because the value of isn't precisely known, and also because the value of H0 isn't precisely known either. But it's certainly the correct order of magnitude. You'd also get a proportionately lower number if you wanted only the density in baryons, for example.

The total mass of the Universe, on the other hand, is not a very clear concept. The Universe is likely to be either infinite in volume, or so very large that it can be considered infinite for all practical purposes. That means that the total mass of the Universe is also infinite. The thing which can be well-defined though, is the mass within the observable part of the Universe. In other words we can ask: how much mass is contained within the volume that we can have observed since the Big Bang? The radius of the observable Universe is about 10,000 Megaparsec (or about 3 ?~ 1026 metres). Using the above estimate for the total density this gives a total mass in the observable Universe of about 1054 kilogrammes. That's the best answer I can give for the mass of the Universe!"

According to the following passage,
RADIUS: ~ 300 Yotta meters or 3 x 10^26 m
DENSITY: ~10^-26kg/m3
TOTAL MASS: ~ 6 x 10^53 kilogrammes.

Q: "Do you know where I can find an estimate of the total mass of the universe?"
Submitted by [email protected] 10/00

A: "If the Universe has "flat" or "open" geometry, then formally it has infinite volume, and therefore infinite mass. Something which is better defined is the mass within the "Observable Universe", which means the part of space from which we can have received light in the history of the Universe so far. This gets bigger every day!

The approximate answer is that the radius of the observable Universe is currently estimated to be about 300 Ym (that's "yotta-metres", or 10^24m, which is the largest SI prefix!). So you take that number, cube it, and multiply by 4/3, to get the volume of the whole sphere.

Then you have to decide what density you want to use. Are you only interested in luminous matter, or do you want to include all the baryons (regular stuff made of protons and neutrons)? Or do you want all the particle dark matter too? And what about the dark energy? If you include everything, then the average density in the Universe today is about 10-26kg/m3. And the mass in the observable Universe can be estimated accordingly.

There are several uncertainties and approximations here though - so don't expect your answer to be much better than an order of magnitude estimate!"

 

[Mycernius]

The universe is infinite. Try to get to the edge of it, you will not get there, as time and space are curved. The Universe is also expanding at relativistic speed, so must be able to travel faster than this to get there. The universe is also one of many. For every discission you have made, somewhere the opposite is made. If time travel is possible, in order to go back you must also move sideways into another universe. Where you originally came from you did not exist before you where born. In this alternate universe you do exist before you where born. Therefore infinite universes.
I love quantum physics, it's fun :wave:

 

[Brooker]

I think infinite, but the area holding the matter within it is finite. Once you get out of that area, it's just a vast plain of endless nothing.

 

[TwistedMac]

I'm going with "honestly can't say"... but in the words of James Hetfield I'll say it's "much too big to see".

 

[misa.j]

This thread makes me think of a quote of Einstein;
"There are only two things that are infinite, human stupidity and the universe, and I'm not sure about the universe."

I love thinking about space, but it often drives me crazy.
I have found a cool link.
http://hubblesite.org/discoveries/hstexhibit/index.html

 

[lexico]

Great links, agnostics of cosmology!

Time and space never ending
Disturbing thoughts, questions pending
Limitations of human understanding

Is never a name for what's bigger than we can see, or will we ask forever what is beyond, or will the questions stop one day? Misa.J quotes Einstein saying "human stupidity" is surely infinite, but the universe possibly not. (paraphrase) Yet questioning is one expression of the highest form of intelligence as we know it. So will the questioning stop, due to infinite stupidity, while the upper limits of the universe, both in mass and diameter, are answered, due to the tunnel-visioned and relentless progress of science ?

Light from the farthest regions of the universe takes billions of years to reach Hubble. Amazingly, when we look at these most distant of all views, we see events that occurred before Earth itself existed — when the universe was merely a fraction of its present age.

They seem to have some idea of the age of the universe. But light traveling for billions of years should have a place of origin. So could that mean the universe has a boundary ? Boundary in the sense of an upper limit whithin a closed system where nothing escapes but only recurs in an infinite loop ? Or is it just an expression to be easily thown out at some point ??

For an analogy, a satelite can orbit the earth ad infinitum, but that does not mean the eath, including its effective gravitational sphere, is infinite. Or the closed electric circuit planned for power transmission or magneto-levitational trains being planned; the electric current will in principle flow infinitely, but we know that the extent of it is within bounds of the circuit.

 

[Maciamo]

it can only be infinite, as there can't be a limit without something behind it. Even emptiness is part of the universe, and if everything were emptiness, it would still be infinite.

If your definition of universe is only what contains matter and energy, what do you call the rest (if there is such thing as "pure emptiness" anyway) ?

Likewise, some people think that a god or supreme being created the universe. But does that mean that this god is not part of the universe (inside t) ? If not where is it ? If it is "outside" or in a parallel dimension, why not say that this place is also the universe, as by definition the universe is everything that exists (if you have another definition, how do you call "everything that exists" ?). So forcedly, any thing that does not belong to the universe doesn't exist. As there can't be anything, the universe must be infinite and comprise all existence, including all dimensions and emptiness.

 

[TwistedMac]

it can only be infinite, as there can't be a limit without something behind it. Even emptiness is part of the universe, and if everything were emptiness, it would still be infinite.

If your definition of universe is only what contains matter and energy, what do you call the rest (if there is such thing as "pure emptiness" anyway) ?

Likewise, some people think that a god or supreme being created the universe. But does that mean that this god is not part of the universe (inside t) ? If not where is it ? If it is "outside" or in a parallel dimension, why not say that this place is also the universe, as by definition the universe is everything that exists (if you have another definition, how do you call "everything that exists" ?). So forcedly, any thing that does not belong to the universe doesn't exist. As there can't be anything, the universe must be infinite and comprise all existence, including all dimensions and emptiness.

that's all based on definitions of a word though.. what we need are more words to help us put thoughts into words

 

[Shooter452]

What is the shortest distance around the universe?

"Point in any direction. And you will be pointing at yourself."

Robert A. Heinlein,
Stranger in a Strange Land

 

[ashuri2]

wait...the question was about the actual mass and volume of the universe, right? so are we saying that the universe (the area to which it extends) itself is ifinite because it is closed, and that the mass, however, is finite because of the law of conservation?
*confused*

 

[lexico]

there can't be a limit without something behind it.

Under a different set of premises, the limits of a closed, finite, bound system cannot be observed by its residents from the inside, the outside (as there is none), or from the boundary itself (as it is not accessible or visible like the wall of Berlin). A 1-dimensional being within a closed loop is bound in a finite world, but does not and cannot perceive the boundary except by abstract reasoning and imagination. The same goes for 2-, 3-, 4-, or 5-dimensional beings whichever we happen to be.

Even emptiness is part of the universe, and if everything were emptiness, it would still be infinite.

Again you are reading into the text your preconceived idea; hence invalid as positive, objective argumentation, but valid only as a statement of your personal conviction.

If your definition of universe is only what contains matter and energy, what do you call the rest (if there is such thing as "pure emptiness" anyway) ?

In you thread of thought (under your assumptions) that part which contains matter and energy however low in density should all be considered part of the universe. The author (Douglas Scott) quoted seems to agree with you in the idea of an infinite universal space, but that's his personal conviction apart from his profession, not as a proven or proveable scientific idea in astrophysics. And that's exactly why he limits his calculation to the heavenly bodies and interstellar gas of generally low density.

As for the rest, it is non-existent. So how could you possibly expect me to name a non-entity, something that doesn't exist ? I do not wish to fall into the trap of language and promote misconception either in my head or others'.

Vacuum exists, and we can reproduce it to a degree, but never a perfect vacuum on a macroscopic scale. Hence I believe "pure emptiness" is only an abstraction of "near vacuum" that we can experience, but not a physical reality in any observable sphere that we know of, and a misleading term in the cosmological sense of the word.

Likewise, some people think that a god or supreme being created the universe. But does that mean that this god is not part of the universe (inside t) ? If not where is it ? If it is "outside" or in a parallel dimension, why not say that this place is also the universe, as by definition the universe is everything that exists (if you have another definition, how do you call "everything that exists" ?). So forcedly, any thing that does not belong to the universe doesn't exist. As there can't be anything, the universe must be infinite and comprise all existence, including all dimensions and emptiness.

I am just a little concerned that some people might be offended by discussing religion here although I personally have no problem with it. Your idea of Universe looks more resembling the neo-Platonian ideas of St. Augustine or Thomas Aquinas less the anthorpomorphic idea. As a critical thinker of science and religion, I can only say that faith is a highly personal experience, and so is science.

One thing about science; it has the potential of easily corrupting into a pseudo-faith assuming the air of authority by employing fashionable language, which only attempts to picture its unclear and inaccurate ideas very much like the old-world superstitions that the avant-guards of enlightenment sought to destroy. I therefore consider every person's idea of science differently, and the same goes for religion. There is no such sacred ground beyond doubt that one can be safely in the truth by claiming either denomination or a subdenomination; these are only names.

I would like to offer one question; can science as we know it ever answer the question of why? Why the four forces of nature ? Why the rules of electromagnetism exist as they are, and not otherwise ? When all the questions of chicken and egg are reduced to the first stages of chemical evolution in the primordial soup, the question yet remains unanswered; why ?

Finally we may arrive at a very clear and good explanation of how life on earth started 3,000,000,000 yrs ago, and the universe 300,000,000,000 yrs ago, but we can almost never answer the ultimate why ? Grammatically speaking the interrogative "why" only applies to beings of intelligence and having a personality whether human, beastly, or divine. I happen to find your ideas far more religious than my almost pagan Christian faith. You an anonymous believer, and me a fake ? Sorry for going off topic. :gomen:

 

[Mycernius]

The current thought is that the universe is about 15 billion years old. What started it and what will happen to it are are question that no-one can really answer. Is the universe itself a closed loop? Expands, contracts, explodes and starts again or the heat death of the universe. Entropy take more effect and the universe eventually becomes a cold dead place with only black holes moving around it.
Douglas Adams had a good take on the universe. Once someone explains the universe completely it ends and begins with something even more confusing than the last one. he also mentions Gods as beings that came into existance a second after the creation of the universe and not before it as they claim. As a result they have gone into hiding and refusing to answer that question.

 

[RockLee]

The universe is expanding, but at a point it will stop and the reverse process will happen.So it's not infinite...I don't think infinite exists in space :souka:

 

[Mycernius]

The universe is expanding, but at a point it will stop and the reverse process will happen.So it's not infinite...I don't think infinite exists in space :souka:

But what about the heat death. That states that the universe will not stop expanding. You seem to subscribe to the Big crunch theory.
I have seen a theory of the universe is infinite based on plasma physics saying that the universe is older because of the way string of galaxies exist. 15 billion years is not long enough for these strings to form, therefore it must be older and is in a constant state of renewal.

 

[Brooker]

I think "God/Supreme Being" (whatever you want to call it) and the universe are the same thing and both are infinite. So for me it's hard to discuss one without at least mentioning the other. The "mind" of the universe is the order that allows things to come together to form more complex things, like atoms, planets, people, stars, hamsters, etc. *Check out the quote in my sig*

 

[lexico]

"Given half a chance, order emerges from chaos, and given optimum conditions, matter keeps on self-organizing until it can get up, crawl around, and write poetry." -David Grinspoon

I could not have said it better. (Let me say that optimum probably meant "good enough" instead of "the best possible.")
This is probably true regardless of the magnitude of the universe or the existence of a divine being.

 

[Brooker]

This is probably true regardless of the magnitude of the universe or the existence of a divine being.

But I believe that such an order could not exist without a designer (or, as I see it, the "designer" IS the order). If you come across a building, you can pretty much assume someone designed it. It would be pretty silly to think that the building might have come to be through a series of strange coincidences or natural trial and error.

(Sorry for getting on a theology tangent but I can't help it. For me, the connection between space and theology is one of the things that makes it such an interesting subject.)

 

[lexico]

Sorry for getting on a theology tangent but I can't help it. For me, the connection between space and theology is one of the things that makes it such an interesting subject.

I believe that cosmological discussions are by nature ontological, and hence naturally related to theology. Besides that you or I are not bent on proselytizing, so I don't think anyone would object so long as we keep to objectivity for the sole purpose of explicating the possible meanings of our subject question. But if anyone does with good reason, and we can stop any time. We are civilized people, aren't we ?

"Given half a chance, order emerges from chaos, and given optimum conditions, matter keeps on self-organizing until it can get up, crawl around, and write poetry." -David Grinspoon

But I believe that such an order could not exist without a designer (or, as I see it, the "designer" IS the order). If you come across a building, you can pretty much assume someone designed it. It would be pretty silly to think that the building might have come to be through a series of strange coincidences or natural trial and error.

I interprete David Grinspoon's statement as order emerging out of chaos without a designer. As for the building, it is an artifact so the analogy seems to be skewed towards the supposition of a designer. Jaques Monod, in his Chance and Necessity discussed the difference between an artifact and a natural object. A chrystal shows astounding regularity, but we know that it is a natural object. I forgot his logic and conclusion, but I remember that it had something to do with intention or design; this is not easily detected from an observation of the surface. In Godel, Escher, Bach, the same question is raised. I remember it said something in the following.

"Naturally regular objects such as chrystals are predictable and have a low level of complexity, whereas objects produced by a living being (such as DNA, and protein) or artificial objects (for example a Godel mathematical treatise, a Bach musical piece, and Escher artwork, a Dunhuang manuscript, a natural speech act) show higher levels of complexity or playfulness neither absolutely predictable nor totally random."

It is my understanding that certain objects in nature of the second class (living beings) have emerged out of full chaos by going "through a series of natural trial and error." The idea of chemical evolution that culminated in the first DNA/RNA's capable of replicating themselves outside any membrane, just floating in the organic ocean some 3000,000,000 yrs ago, does not require a jump of logic or a leap of faith in my opinion.

Already quite early in the 1900's Russian scientists (of course with their ideological purpose, yet objective in their methods of experiments) succeeded in generating several kinds of amino acids from all inorganic substances such as water, oxygen, nitrogen, CO2, and methane when heat and electrical energy were applied for a certain duration. Similar reasonable models and experiments have been proposed and conducted, though I am not aware of any one particular ground breaking experiment because I did not look for them. I would think the theory of chemical evolution is pretty much established, unless otherwise proven.

From inorganic substances to glucose, fatty acids, amino acids, and nucleic acids would be the first step, and from there to proteins, DNA/RNA's, fats, and sugars would be the next step. From infertile DNA/RNA's to self-replicating DNA/RNA's would be the next step. From membraneless DNA/RNA's to procaryotes, then on to eukaroyotes, then to protoplants, then to protoanimals would be the ensuing stages in the evolution of early life forms.

No plan or design was necessary for all this to happen, but only simple, common elements in nature with enough time to permute them through the possible combinations was enough. In the case of eartly life forms, it took roughly 1,500,000,000 yrs for the first life to emerge out of randomness or chaos as David Grinspoon would have it.

 

[Maciamo]

Under a different set of premises, the limits of a closed, finite, bound system cannot be observed by its residents from the inside, the outside (as there is none), or from the boundary itself (as it is not accessible or visible like the wall of Berlin). A 1-dimensional being within a closed loop is bound in a finite world, but does not and cannot perceive the boundary except by abstract reasoning and imagination.

Now I think the problem is your definition of infinte. What you are describing is the same as the infinite to me. There are many kinds of infinite, among others:

- 2 or 3 dimensional (one line with no end vs 3D shape extending to the infinte)
- closed infinite (the infinite line is still part of something else bigger and 3D)
- open infinite (3D infinite extending in all directions)
- limited infinite (yes, there is such a thing, eg. a line with a definite start point, but continuing to the infinite)
- circular infinite (if a 2D line goes in circle, it is infinite because you can count an infinite number of 360 degree turns, although the shape is finite)
- unipolar infinite time (time only infinite from a starting point or to an ending point)
- bipolar infinite time (time unlimited in both past and future)

What you are describing is an 3D circular infinite. My conception of the universe is more of an open infinite.

Vacuum exists, and we can reproduce it to a degree, but never a perfect vacuum on a macroscopic scale. Hence I believe "pure emptiness" is
only an abstraction of "near vacuum" that we can experience

That's why I said if there is such thing as "pure emptiness" anyway

Your idea of Universe looks more resembling the neo-Platonian ideas of St. Augustine or Thomas Aquinas less the anthorpomorphic idea.

Certainly not. Of all the main Western philosophers, and I can tell you that those with whom I the most at odds are the Platonians, Neo-Platonians and Idealists (eg. Hegel). My conception of the universe is too materialist for that.

One thing about science; it has the potential of easily corrupting into a pseudo-faith assuming the air of authority by employing fashionable language, which only attempts to picture its unclear and inaccurate ideas very much like the old-world superstitions that the avant-guards of enlightenment struggled to destroy.

Funnily enough, that's what I was thinking to tell you, as you are the one to mix science and philosophy. Science is nothing without observations and experiments. Philosophy is based on logics and reasoning (taking what we know of sciences into account, of course). In other words, science is only the practical and experimentable branch of philosophy. With our primitive knowledge of the universe, how could we give so much credit to science ? There was a time when people thought that the Eart was the centre of the universe, then the sun, the sun our galaxy... Until a few years ago, most people still believed in the theory of the Big Bang.

I would like to offer one question; can science ever answer the question of why?

No. In a metaphysic level (god, the universe...), this is reserved to religion and philosophy. The difference is that religion makes up nice stories just based on imagination and spiritual belief, while philosophy mostly uses reason and logics (altough the Idealistic current of philosophy is more pantheistic- like, and thus more religious).

I happen to find your ideas far more religious than my almost pagan Christian faith.

What ? I don't believe in anything that cannot be demonstrated by logics. As explained just above, I am not religious but philosophical. Using science (which requires experiment) to explain metaphyical problems is futile.

The difference between you and me is that you attach too much importance of science and not enough to logics. But our scientifical knowledge evolves much faster than logics and must be updated all the time (eg. reading the news today we now suppose that the first bipeds or "humans" were not 3.2m years old but 4m years old thanks to a new discovery - where will we be in 10 or 100 years from now ?). It still cannot answer questions related to the unknown and unobserved such as emptiness or infinity (which can only be grasped by logics with the help of mathematics).

 

[Brooker]

I interprete David Grinspoon's statement as order emerging out of chaos without a designer. .

I think he intended it that way, but I interprete it differently.

A chrystal shows astounding regularity, but we know that it is a natural object.

But I would say a chrystal is "designed" too. What is the difference really between an "artifact" and a "natural object"? If humans are created by nature, and building are created by humans, how can buildings be unnatural? How can something natural create something unnatural? I think we only see it that way because WE created it. But if a beaver creates a dam, no one calls that unnatural. When we create a building, we're taking resources found in nature and forming them into something we find useful. The beaver does the same thing. And I don't think the fact that what we've created is more "advanced" than what the beaver has created makes any difference.

The idea of chemical evolution that culminated in the first DNA/RNA's capable of replicating themselves outside any membrane, just floating in the organic ocean some 300,000,000 yrs ago, does not require a jump of logic or a leap of faith in my opinion.

But without order, that could never happen. The only leap I'm making is attributing that order to "the force". Without that order (without "the force") I don't believe anything could ever form, just random stuff floating around, bouncing off each other, never forming into anything.

From inorganic substances to glucose, fatty acids, amino acids, and nucleic acids would be the first step, and from there to proteins, DNA/RNA's, fats, and sugars would be the next step. From infirtile DNA/RNA's to self-replicating DNA/RNA's would be the next step. From membraneless DNA/RNA's to procaryotes, then on to eukaroyotes, then to protoplants, then to protoanimals would be the ensuing stages in the evlution of early life forms.

Yes, but WHY? What makes that happen? Mother nature? Science? The force? I think they're all the same. My beliefs are all about the unification of everything.

No plan or design was necessary for all this to happen, but only simple, common elements in nature with enough time to permute them through the possible combinations was enough.

I think it takes a much bigger leap of faith to think that all of that would just happen on it's own. Without order and the universe's WILL (which I also attribute to "the force") to form into something more complex, that would never have happened.