Where is the center of the universe?

[Helio]

The difficultly in explaining implies incoherence.

Modern cosmology has established GR (General Relativity) as the framework for our understanding. As difficult as GR is, it is even more accurate in all objective tests.

Why must the universe include all?

Cat likes to note that stuff beyond the universe we can possibly ever observe should be included and be called the "Universe". There is no disagreement that there are region we can't observe due to the fact their light will never reach us in an expanding universe.

Why can't it have a boundary?

GR argues that you can't find a boundary, except the observational boundary due to expansion as noted above.

What if different speeds were being miscalculated as distance?

Yes. This was a big issue in the early 1920's. The highly respected GR model of de Sitter argued that the universe was static (not expanding) and those velocities found by Vesto Slipher represented motions through space, not motion of space.

How can we be sure of what other galaxies see?

This was a big question and it brought the "Great Debate" between two prominent astronomers (Curtis and Shapley). Hubble put the nail in the coffin when he found galaxies were more than about 1 million lightyears away. He used several techniques, especially the use of Cepheid Variables that have a set brightness for a set no. of days of variability. But he also used their relative size and brightness to improve his accuracy. Over time, astronomers have improved things a lot further.

Why have we found no other life like our own?

One light year distance is about 6 trillion miles. The nearest exoplanet is 4.3 times this distance. Only about 50 exoplanets out of 6,000 found are in their respective HZ (habitability zone) where the star's radiation is just right to allow water to remain in liquid form, where life has a chance, so it is assumed.

The existence of these questions allows participation by those who sing, "He got the whole world in His hands."

There is no evidence that He does or doesn't. But I have views on this and....... well, they're outside the purview of science.

Welcome aboard, TwoSocks.

 

[Catastrophe]

Being a pedant, might I suggest a slight re-phrase, from:

Cat likes to note that stuff beyond the universe we can possibly ever observe should be included and be called the "Universe".

to:

Cat likes to note that stuff beyond any observable universe should be included and called the "Universe".

The term "observable universe" should be more closely defined.
For example, in principle it should include all creatures and technology able to observe using whatever input, anywhere in the Universe. (That is, according to semantics). For example, if a movie camera is recording, is it observing, then or when later reviewed by a human.

Wiki offers a more parochial view, probably suitable for everyday use, relating to humans on or near planet Earth.

The observable universe is a ball-shaped region of the universe consisting of all matter that can be observed from Earth or its space-based telescopes and exploratory probes at the present time; the electromagnetic radiation from these objects has had time to reach the Solar System and Earth since the beginning of the cosmological expansion.

It is assumed, in my definition, that any emr has had time to reach the observer in question.

Cat

 

[Catastrophe]

TwoSocks, welcome.

Your first post is sufficient to keep several of us answering for a long time.

You might like to spend a little time browsing, as many have been discussed at length several times already. Then, perhaps post a single question (for a start), highlighting some particular aspect. There are always new angles.

Cat

 

[Helio]

Speaking of the "tension", I was off a little in my understanding of the conflict.

The value of the current expansion rate is 73.0 (+ or - 1)
The expansion rate needed to get to where we are today from the time of the CMBR is 67.4 (+ or - 0.5).

I had thought the latter was the rate found for the CMBR period, but it is the average rate from then till now, at least I think I have that right.

But the question is unaltered...."What good is acceleration if we never go faster?" IOW, if the universe has been accelerating during any part of the 13.8 Gyrs ago to today, then a faster expansion rate makes only good sense to me. So what am I missing?

To add some irony to all this... It was Adam Reiss that announced in 1995 that the universe was accelerating in its expansion. Yet here he is, below, explaining the different rates but, seemingly to me, ignoring the obvious. It's like he's sitting on the elephant in the room and asking "what elephant?". The tension for me is that I don't get the tension.

Here's his video, and it's nicely done...

Adam Reiss video

 

[TwoSocks]

Modern cosmology has established GR (General Relativity) as the framework for our understanding. As difficult as GR is, it is even more accurate in all objective tests.

Cat likes to note that stuff beyond the universe we can possibly ever observe should be included and be called the "Universe". There is no disagreement that there are region we can't observe due to the fact their light will never reach us in an expanding universe.

GR argues that you can't find a boundary, except the observational boundary due to expansion as noted above.

Yes. This was a big issue in the early 1920's. The highly respected GR model of de Sitter argued that the universe was static (not expanding) and those velocities found by Vesto Slipher represented motions through space, not motion of space.

This was a big question and it brought the "Great Debate" between two prominent astronomers (Curtis and Shapley). Hubble put the nail in the coffin when he found galaxies were more than about 1 million lightyears away. He used several techniques, especially the use of Cepheid Variables that have a set brightness for a set no. of days of variability. But he also used their relative size and brightness to improve his accuracy. Over time, astronomers have improved things a lot further.

One light year distance is about 6 trillion miles. The nearest exoplanet is 4.3 times this distance. Only about 50 exoplanets out of 6,000 found are in their respective HZ (habitability zone) where the star's radiation is just right to allow water to remain in liquid form, where life has a chance, so it is assumed.

There is no evidence that He does or doesn't. But I have views on this and....... well, they're outside the purview of science.

Welcome aboard, TwoSocks.

A boundary might not be currently measurable bit that doesn't mean one doesn't exist. Seems we're able to speculate on what is beyond the visible universe... except for its edge.

If a galaxy to the left is moving away at X speed and one to our right at 2X, then the center is towards the right. Of course, if you measure distance with red shift, and you measure speed with light color too, can't the red shift contaminate the other measurement?

Regarding what other galaxies see, I was just observing that there's no way to know because we aren't there.

And if we've been looking for other life for 50 years at 6 trillion miles a year, them we've taken in 300 trillion miles of planets, and found nothing.

Our time might have been better spent learning to divide by zero.

 

[Catastrophe]

TwoSocks,

And if we've been looking for other life for 50 years at 6 trillion miles a year, them we've taken in 300 trillion miles of planets, and found nothing.

Can you please suggest any scientific, or even half logical, basis for this?
What would you expect to find in 50 years?
Do you mean constant searching, by how many? In how many directions?
I think we need some parameters.

Cat

 

[TwoSocks]

TwoSocks,



Can you please suggest any scientific, or even half logical, basis for this?
What would you expect to find in 50 years?
Do you mean constant searching, by how many? In how many directions?
I think we need some parameters.

Cat

Well the explanation was that 50 life habitable planets were located in one light year, 6 trillion miles. So I was making the point that SETI, etc. have been listening for 50 years, a much larger sample. And the best signal ever received, the WOW! signal, occurred more than 40 years ago. If anyone else was listening and recorded it, they haven't admitted to it. But we do know that the frequency on which it was received was known as "the hotline" internationally. Governments all over the globe agreed to not use the hotline frequency in case aliens radioed us. So you can guess others were listening too, even in 1977.

 

[Catastrophe]

TwoSocks

Sorry. You have misunderstood this.

No life has been detected on any planet anywhere.

Wiki gives:

This is a list of exoplanets within the circumstellar habitable zone that are under 10 Earth masses and smaller than 2.5 Earth radii, and thus have a chance of being rocky.[3][1] Note that inclusion on this list does not guarantee habitability, and in particular the larger planets are unlikely to have a rocky composition.[4] Earth is included for comparison.

Cat

 

[TwoSocks]

TwoSocks

Sorry. You have misunderstood this.

No life has been detected on any planet anywhere.

Wiki gives:



Cat

I understood it to mean only 50 life-sustaining planets could be found in one light year's volume of space. I didn't make any assertion about life existing anywhere else, other than earth.

I did observe that it was odd that the whole world was staying off the alien hotline radio frequency, but only one receiver was listening when the WOW! signal came through. You might expect others would be monitoring the hotline too, but no one else has confirmed or refuted the mysterious signal.

 

[Catastrophe]

I understood it to mean only 50 life-sustaining planets could be found in one light year's volume of space. I didn't make any assertion about life existing anywhere else, other than earth.

I did observe that it was odd that the whole world was staying off the alien hotline radio frequency, but only one receiver was listening when the WOW! signal came through. You might expect others would be monitoring the hotline too, but no one else has confirmed or refuted the mysterious signal.

No. Not life sustaining.
"Note that inclusion on this list does not guarantee habitability,"

No. Not anywhere.
"in one light year's volume of space"

Cat

 

[Unclear Engineer]

Where did the idea come from the there would be 50 planets in one light year volume of space (cubic or spherical dimension?)?

And, where did the idea come from that those would have any form of life?

 

[Catastrophe]

Post

Where did the idea come from the there would be 50 planets in one light year volume of space (cubic or spherical dimension?)?

And, where did the idea come from that those would have any form of life?

#59.

I understood it to mean only 50 life-sustaining planets could be found in one light year's volume of space. I didn't make any assertion about life existing anywhere else, other than earth.

I did observe that it was odd that the whole world was staying off the alien hotline radio frequency, but only one receiver was listening when the WOW! signal came through. You might expect others would be monitoring the hotline too, but no one else has confirmed or refuted the mysterious signal.

Life-sustaining treatment is any treatment that serves to prolong life without reversing the underlying medical condition. Life-sustaining treatment may include, but is not limited to, mechanical ventilation, renal dialysis, chemotherapy, antibiotics, and artificial nutrition and hydration.

Life sustaining implies that the life already exists to sustain.


Cat

 

[ViciousVirgo]

I made an account (but I’ll stick around) to say I thought this was a *beautifully* written article. Thank you sir to the author. These are the types of questions I like to grapple with and you made it interesting and accessible for part time space enthusiast normie folk like me I got what you were puttin down. Fascinating stuff.

 

[Catastrophe]

Vicious Virgo, welcome to the Forum!

Are you referring to post #1? Why not stay around and tell us your thoughts?

Cat

 

[mokeshame]

I think there was no big bang but have my own prediction that there was a big impulse.
The universe began when two utrafast and dense particle escaped and was able to leave an group of entagled particles those origin was another universe. These particles got a new entagledment and trapped other particles in their wake giving origin to our universe. The big impulse was the slowest part of our universe and still is, so it is on the edge of our universe.

 

[Catastrophe]

mokeshame,

The universe began when two utrafast and dense particle escaped and was able to leave an group of entagled particles those origin was another universe.

And how did the "other universe" begin?

Cat

 

[mokeshame]

mokeshame,


And how did the "other universe" begin?

Cat

Also with big impulse(s). The big impuls started when the primal photon was able to divide. It reproduced itself and create energy(we can still see remnains of this in fission). Primal photons are here before the void and before anything. Its an almighty particle and always works into itself and can do everthing with itself until eternity in unlimited forms. Its has no beginning and no end. Its pure existence and existance cannot be started nor can it end. it caused itself.

A primal photon is the epoch of entaglement. More and more happend at once and then existence expanded..

 

[josefnspace]

what if the 'big bang' was not an explosion?

perhaps it was/is a collision/intersection of/between

'dark' matter and 'light' matter continuums (continua?)

resulting in our universe.

 

[Catastrophe]

And the "universe" before that?

Cat

 

[josefnspace]

And the "universe" before that?

Cat

didn't exist.

our "universe" is the result of the intersection.

have you ever observed two bubbles?

you may find this article interesting.

Multiverse - Wikipedia

en.wikipedia.org

 

[josefnspace]

TwoSocks

Sorry. You have misunderstood this.

No life has been detected on any planet anywhere.

Wiki gives:



Cat

"No life, as we know it, has been detected ..."

 

[Catastrophe]

josefnspace,

Are you suggesting that some other life has been detected?

Cat

 

[Atlan0001]

The simplest, oldest, diagramming illustration of an 'Infinite MULTIVERSE Universe (U)' is still this one, G=1!

Gravitational constant - Wikipedia

en.wikipedia.org

'There will never be the vectoring direction and magnitude of 'One World' without two . . . and/or "many" . . . worlds!
================
"I am 'matter' (+)! You are antimatter (-)!"
"No! I am matter (+)! You are antimatter (-)!"
"No way! I am matter (+/-)! You are antimatter (-/+)!"
"Get it through your own thick skull, I am matter (+/-)! You are antimatter (+/-)!"
"YOU get it through YOUR thick skull, I am matter (-/+)! You are antimatter (-/+)!"
Opposites attract? Likes repel? (G=1) (asymptote 0-g, and/or, 1-g (n-g)).
Then there is the Trojan, "Schrodinger's Cat" (asymptote: both entangling (unity (one)) and neither entangled (null unity (many)))!

 

[josefnspace]

josefnspace,

Are you suggesting that some other life has been detected?

Cat

not at all.

the parameters being used are for carbon based lifeforms.

anthropomorphic orientation

 

[ChrisA]

The universe is undeniably vast, and from our perspective, it may seem like Earth is in the middle of everything. But is there a center of the cosmos, and if so, where is it? If the Big Bang started the universe, then where did it all come from, and where is it going?

Where is the center of the universe? : Read more

Think of two ants standing on a balloon. They are on oposite sides. Now we slowly fill the balloon with more air. Ech ant sees the rubber onver its feet expanding equaly away on all direction and assumes it must be in the center of the expansion. But the ant would see the same excat thiong no matter where it stands.

The universe is like this, EVERY observers sees the universe expening away in all girections and it appers he is at the center

The ballon is a 2D curved surface, the universe seems to be a 3D curved surface but in each case there is no absolute "centrer" of the surface and an infinate number of "appearent" centers.