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Author Topic:   Cosmological Q&A
AshsZ
Member (Idle past 5400 days)
Posts: 35
From: Edgewater, FL USA
Joined: 05-17-2008


Message 1 of 11 (472449)
06-22-2008 1:36 PM


I've had a list of questions regarding this topic - more like a compilation of questionable ideas of which I would like to throw out there in hopes to find some answers on as well as open the door for others to do the same as I.
There are a lot of aspects of physics which seemingly become paradoxical and/or counterintuitive, concepts which appear to have two (or more) correct but diametrically opposed explanations, and so on and so forth. I'd like to throw some of these out to start a sort of Q and A post. And so, I'll divulge >>>>
The idea that the universe is expanding at an accelerating rate is a conclusion based on observation of objects in the cosmos - we find that the further out we look, the faster the objects are moving away from us. While it seems scientists are infatuated with trying to explain why objects are moving like this, I haven't heard a lot of questions about the implications of this observation.
Does this mean that at some point, waaaay out there, objects are actually moving away from us at the speed of light? If so, wouldn't this mean that these objects would virtually have infinite mass? And if this is so, would this mean that our universe is basically bordered by a black hole?
Also, the further away you look, the further back in time you are seeing. Since this is the case and we see objects moving away from us at greater rates of speed the further away we look, wouldn't this mean that the universe isn't actually expanding? i.e. if you look out at 7 billion light year miles and see objects moving away at 500,000 miles per hour and then look out at 14 billion light year miles and see objects moving away at 1,000,000 miles per hour, wouldn't this mean that the expansion rate is actually slowing? 14 billion years ago things were moving 2x the rate they were moving 7 billion years ago. If you continue to divide the distance you look out, things are moving even slower away from us. Taking this one step further, does this mean everything you see out at 14 billion light year miles was actually right where we are at this moment? Would space then be the shape of an infinite number of toroids with an itty-bitty "hole" at the very center where we exist - our observations are as if we are looking along the surface of a loop of time and space? Not saying this in any sort of "centric" way - us being at the very center is just a condition of observing the universe.
I am aware of the concept of "comoving distances", which basically states that what we observe out in the cosmos isn't actually as old as the light year miles would suggest. This is because when the whole thing went "boom", the light from distant objects was emitted across expanding space, which made it actually travel further distance to reach us. Because of this, the visible universe is 46 billion light years in any direction. This throws the 14 billion year metric I used above a bit off, so lets just entertain that previous paragraph as if you are looking out 46 billion light years. With this small correction, the question above still stands - wouldn't this mean you are actually looking right back to "here" and that the universe isn't really expanding at an accelerating rate?
Going back to the idea that the universe is essentially "encased" by a black hole, and tying this into the looped universe, that would imply that the universe actually started out as a black hole. Perhaps we are in some iteration of the "other side" of a great crunch event which created a black hole containing ALL of the universe. This idea is something that makes it difficult to imagine the big bang - if you had all of the universe in some really tiny volume, wouldn't that be a black hole? How could it go BANG and expand? Or perhaps the "big crunch" isn't everything gravitating back to one point, it is everything hurtling into the bordering "black hole" - being spit back to the beginning and cycling all over again? Out there at the "edge" there could be someone watching US cross that point and "poof" we're on the other side of the loop.
Also, a question on gravity... What would happen if you were to significantly slow or even stop the local time of the space of an object? i.e. time dialation.. Would gravity have a lesser to no effect on that object?
Many more Q's but enough for now.
Edited by Admin, : Change title from "Some Q's and hopefully A's on ASTROPHYSICS" to "Cosmological Q&A".

Replies to this message:
 Message 3 by onifre, posted 06-24-2008 1:50 PM AshsZ has replied

  
Admin
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Message 2 of 11 (472551)
06-23-2008 8:19 AM


Thread moved here from the Proposed New Topics forum.

  
onifre
Member (Idle past 2951 days)
Posts: 4854
From: Dark Side of the Moon
Joined: 02-20-2008


Message 3 of 11 (472720)
06-24-2008 1:50 PM
Reply to: Message 1 by AshsZ
06-22-2008 1:36 PM


Does this mean that at some point, waaaay out there, objects are actually moving away from us at the speed of light?
As I understand it the Universe is expanding at a rate faster than the SoL.
wouldn't this mean that these objects would virtually have infinite mass?
Not if whatever is causing the Universe to expand has no mass itself.
14 billion years ago things were moving 2x the rate they were moving 7 billion years ago.
Ok, when you look at something 14 billion light years away, you are NOT looking at something 14 billion years ago, the light years is referencing distance in relation to our position in the Universe.
I am aware of the concept of "comoving distances", which basically states that what we observe out in the cosmos isn't actually as old as the light year miles would suggest. This is because when the whole thing went "boom", the light from distant objects was emitted across expanding space, which made it actually travel further distance to reach us. Because of this, the visible universe is 46 billion light years in any direction. This throws the 14 billion year metric I used above a bit off, so lets just entertain that previous paragraph as if you are looking out 46 billion light years. With this small correction, the question above still stands - wouldn't this mean you are actually looking right back to "here" and that the universe isn't really expanding at an accelerating rate?
Im having trouble following this. I'll just answer like this, when it is said that something is 30 billion light years away it is in reference to distance, and not that it is 30 billion years ago.
The rest of your questions are a bit hard to follow.
But finally you said,
Also, a question on gravity... What would happen if you were to significantly slow or even stop the local time of the space of an object? i.e. time dialation.. Would gravity have a lesser to no effect on that object?
Time dialation is from one point of reference. From the other point of reference time has not slowed down. Its a relativity thing. Any object in motion experiences time slower, but only to the person observing it, to the object in motion time doesn't change. So time doesn't actually slow down physically. Heres a wiki definition,
Time dilation - Wikipedia
So during what is called time dilation, since its only from the point of reference of the observer, no gravity is NOT effected.

All great truths begin as blasphemies
I smoke pot. If this bothers anyone, I suggest you look around at the world in which we live and shut your fuckin' mouth.

This message is a reply to:
 Message 1 by AshsZ, posted 06-22-2008 1:36 PM AshsZ has replied

Replies to this message:
 Message 7 by AshsZ, posted 06-24-2008 3:45 PM onifre has replied

  
Agobot
Member (Idle past 5530 days)
Posts: 786
Joined: 12-16-2007


Message 4 of 11 (472724)
06-24-2008 1:58 PM


Redshift -
BBT claims that galaxies and stars are not moving but space between them expands/grows. If they are not moving why do scientists think that non-moving objects should cause a redshift?
Edited by Agobot, : No reason given.

Replies to this message:
 Message 5 by NosyNed, posted 06-24-2008 2:20 PM Agobot has not replied
 Message 6 by New Cat's Eye, posted 06-24-2008 3:08 PM Agobot has not replied

  
NosyNed
Member
Posts: 8996
From: Canada
Joined: 04-04-2003


Message 5 of 11 (472731)
06-24-2008 2:20 PM
Reply to: Message 4 by Agobot
06-24-2008 1:58 PM


Re: Redshift -
BBT claims that galaxies and stars are not moving but space between them expands/grows. If they are not moving why do scientists think that non-moving objects should cause a redshift?
Either all or most of the red shift has nothing to do with motion through space. The light is moving in space and when the space is stretched the light is s t r e t c h e d out.
(at least that is my non-professional understanding )

This message is a reply to:
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New Cat's Eye
Inactive Member


Message 6 of 11 (472741)
06-24-2008 3:08 PM
Reply to: Message 4 by Agobot
06-24-2008 1:58 PM


Re: Redshift -
BBT claims that galaxies and stars are not moving but space between them expands/grows. If they are not moving why do scientists think that non-moving objects should cause a redshift?
As the space between them expands, the distance between them grows. As the distance between them grows, the light traveling across that distance is red-shifted.

This message is a reply to:
 Message 4 by Agobot, posted 06-24-2008 1:58 PM Agobot has not replied

  
AshsZ
Member (Idle past 5400 days)
Posts: 35
From: Edgewater, FL USA
Joined: 05-17-2008


Message 7 of 11 (472752)
06-24-2008 3:45 PM
Reply to: Message 3 by onifre
06-24-2008 1:50 PM


When it is said that the universe is expanding at a rate faster than the SOL, what evidence is there to support this theory? We dont have a device that can measure the existence of space and even if we did, if space is expanding faster than the SOL, the information of the existence of that space expanding faster than the SOL would never be able to come to us as it is just moving away too rapidly. I have a problem with this idea - it sounds too much like a belief.
The following three answers you provided are where those "paradoxical" issues arise. Allow me to clarify my initial questions a little more.
When we peer into the cosmos, the things we see are emissions of light from objects at given distances. So if we look out to say, 46 billion light year miles away (which accounts for the comoving factor of space expansion), we are really looking at what those objects looked like ~14 billion years ago, NOT what they actually look like at this moment in time. The further away you look, the further back in time you are seeing because it has taken time for the light to reach us. The further out you look, the faster objects are moving away from us. But you are also looking further back in time - observing the velocity of those objects at a much earlier time than closer objects that are moving away at lesser velocities.
When we say that an object is 30 million light years away from us, we are saying that they are 30 million light year MILES away from us because that is the time it takes the light from those objects to cover that distance. Since our observation is based on the information provided in the light we receive, and it took 30 million years for the light to cover that distance, then we are actually seeing what that object looked like AND where it was located 30 million years ago, right?
I bought up the whole concept of comoving distance because it seems to be used as a crutch to maintain that the speed of light is always constant in a vacuum.
It is stated that the speed of light is invariable which means that any observer measuring the distance it traverses over time will always be constant in a vacuum. However, the comoving factor does effectively change the observed speed of light - the comoving factor is based on the concept that space itself is expanding, which allows for the idea of a constant speed of light to be preserved; space is just expanding so the light has to cover more distance. This explains why we can see out 46 billion light year miles in any direction but the cosmos is only ~14 billion years old. But the issue with this concept is that it relies on the idea that space is made up of discrete "holes" and that these holes are increasing in volume (space expansion) which is the explanation as to why we can see out over distances far greater than how far light would travel over the length of time the universe has existed (~14 billion years). But if space is quantized like this and the speed of light must remain constant, this would mean that if an individual space quanta were to grow in size (through expansion), everything contained within it will grow proprotionally so as to maintain the speed of light being measured by our human bodies and instruments that test the speed and observe the results - a growth phenomena that would be impossibly undetectable. If this is the mechanism of "space expansion", it would be a homogenous phenomena across the entire cosmos and could not be used to explain why the further out you look, the faster observed objects appear to recede nor can it be used to justify why we can see out to a radius further than ~14 billion light years.
The other explanation would be that there is a continual influx of space quanta into the universe - rather than a fixed number of space quanta simply growing in size, they are all staying the same size but more are being added to the cosmos. It wouldn't quite fit to say that they are being injected at one particular point as we would see a localized point that everything is expanding outward from. However, we do observe such an effect: right here from our perspective in the cosmos, everything is receding away from us so perhaps there is a local injection of space quanta right here where we are. The only problem with that idea is that if this were the case, the expansion rate of total space would fall off the further away from this point, which would cause objects further from us to appear to be moving away slower than closer objects - this isn't what we observe in the real world though.
However, going back to my original post - what our eyes tell us isn't always what is really happening. As I mentioned before, far distant objects appear to be moving away from us faster than objects closer to us, but again, the light we are seeing from those far off objects is much older and represents a time further back than the closer objects. This is the counter-intuitive, but it can be explained by the previous paragraph - a local injection of space quanta at the beginning of time would have made the matter within that small volume move outward at high velocity but as space continued to expand, the matter closer to the center of injection would not move outwards as rapidly. As more space quanta is injected over billions of years and we finally come into existence to make observations, we are peering out at far distances and see what was occuring with those objects far back in time. So they appear to be moving away from us very rapidly, but we are seeing what they were doing a loooong time ago, not what they are really doing right at this very moment.
I guess what I am getting at here, if not apparent thus far, is that what we see things doing out there in the cosmos is not the current state of affairs. The further out we look, the older the information is that we percieve. Scientists state that the universe is expanding at an accelerating rate because the further out into space they look, the greater the red-shift of the light from those objects. My qualm with that is that the further out they look, the further back in time the information their observation reveals. It is as if their conclusions are based on the idea that the light they are observing is all from the same time independent of the distance at which said objects are from us, but this absolutely is not the case because it takes time for light to travel distance and these objects are all at varying distances from us.
As for the gravity question. I am familiar with time dialation due to velocity. To clarify my hypothetical: Lets say you have a rig which has a plate that moves in an orbital pattern - not a spinning plate, but a plate that orbits like an orbital sander. Lets say you can crank the drive motor up to a speed where the orbiting velocity approaches the speed of light. Relativistic effects will begin to arise and time dialation will also kick in. In this thought experiment, the actual object is sitting right in front of you - it isn't flying by like a CERN particle. Within the local space of that orbiting plate, its time will begin to slow relative to you, the table it is on, and the earth itself. It has been found that a clock in a gravitational field will pass time different from that of a clock within a gravitational field of different intensity. My question is looking at this effect from the other side of the coin: If the relative time of an object can be affected, will this have an effect on its gravitational effect. It just seems to me that this would be the case - time and gravity are connected, as has already been proven with atomic clocks at different altitudes on the planet - we just haven't been able to affect the time element as easily to see if that effect goes the other direction....

This message is a reply to:
 Message 3 by onifre, posted 06-24-2008 1:50 PM onifre has replied

Replies to this message:
 Message 8 by New Cat's Eye, posted 06-24-2008 4:06 PM AshsZ has replied
 Message 11 by onifre, posted 06-24-2008 5:22 PM AshsZ has not replied

  
New Cat's Eye
Inactive Member


Message 8 of 11 (472760)
06-24-2008 4:06 PM
Reply to: Message 7 by AshsZ
06-24-2008 3:45 PM


minor quibble
When we say that an object is 30 million light years away from us, we are saying that they are 30 million light year MILES away from us because that is the time it takes the light from those objects to cover that distance.
There's no such thing as "Light Year Miles".
A light year is a unit of length. It is the distance light travels in one year. 1 light year = 5,878,625,373,183.61 international miles (source).

This message is a reply to:
 Message 7 by AshsZ, posted 06-24-2008 3:45 PM AshsZ has replied

Replies to this message:
 Message 9 by AshsZ, posted 06-24-2008 4:58 PM New Cat's Eye has replied

  
AshsZ
Member (Idle past 5400 days)
Posts: 35
From: Edgewater, FL USA
Joined: 05-17-2008


Message 9 of 11 (472777)
06-24-2008 4:58 PM
Reply to: Message 8 by New Cat's Eye
06-24-2008 4:06 PM


Re: minor quibble
I think we are saying the same thing.
A light year is the distance light will travel over a year. So when I say "light year miles" and quantify that with the "30 million", the object is 30 million times 5,878,625,373,183.61 miles.
So when you look at an object that is 30 million light years away from you, you are seeing what it looked like 30 million years ago. This object is also 176358761195508300000 miles away (30 million times 5,878,625,373,183.61).
Am I missing something?

This message is a reply to:
 Message 8 by New Cat's Eye, posted 06-24-2008 4:06 PM New Cat's Eye has replied

Replies to this message:
 Message 10 by New Cat's Eye, posted 06-24-2008 5:15 PM AshsZ has not replied

  
New Cat's Eye
Inactive Member


Message 10 of 11 (472780)
06-24-2008 5:15 PM
Reply to: Message 9 by AshsZ
06-24-2008 4:58 PM


Re: minor quibble
I think we are saying the same thing.
A light year is the distance light will travel over a year. So when I say "light year miles" and quantify that with the "30 million", the object is 30 million times 5,878,625,373,183.61 miles.
You'd be saying just as much by saying 30 million light years.
Do you also use the phrase "500 kilometer miles" when referring 311 miles?
Or would you call 311 miles --> 5.3x10-11 light year miles?
So when you look at an object that is 30 million light years away from you, you are seeing what it looked like 30 million years ago. This object is also 176358761195508300000 miles away (30 million times 5,878,625,373,183.61).
Am I missing something?
If the object is moving away from us, then it wasn't as far away 30 million years ago when the light that is finally reaching us left it as it is now. The distance to it now is farther than it was 30 million years ago.

This message is a reply to:
 Message 9 by AshsZ, posted 06-24-2008 4:58 PM AshsZ has not replied

  
onifre
Member (Idle past 2951 days)
Posts: 4854
From: Dark Side of the Moon
Joined: 02-20-2008


Message 11 of 11 (472782)
06-24-2008 5:22 PM
Reply to: Message 7 by AshsZ
06-24-2008 3:45 PM


When it is said that the universe is expanding at a rate faster than the SOL, what evidence is there to support this theory?
The metric space between galaxies that is measured.
When we say that an object is 30 million light years away from us, we are saying that they are 30 million light year MILES away from us because that is the time it takes the light from those objects to cover that distance. Since our observation is based on the information provided in the light we receive, and it took 30 million years for the light to cover that distance, then we are actually seeing what that object looked like AND where it was located 30 million years ago, right?
No. Light years is a measure of distance to objects in space. Heres an easy example. At .99% the speed of light it would take 7 Earth years to travel 1 light year. So if a Star was 7 light years away, and we traveled at .99% the SoL, then you would get there in 1 year. Kinda get it?
I bought up the whole concept of comoving distance because it seems to be used as a crutch to maintain that the speed of light is always constant in a vacuum.
The SoL is constant in a vacuum this has been reproduced.
the comoving factor is based on the concept that space itself is expanding,
Space is not expanding in the way you are saying it, the space in between galaxies is expanding.
This explains why we can see out 46 billion light year miles in any direction but the cosmos is only ~14 billion years old.
We do NOT see 46 billion light year 'miles'. 46 billion light years is the distance it took light to travel. Remember though light travels at the SoL so it did NOT take light 46 billion years to reach us. Since light travels at about 63,241AU(1AU is about 93 million miles), you can do the math and see just how fast light could cover those 46 billion light years.
I guess what I am getting at here, if not apparent thus far, is that what we see things doing out there in the cosmos is not the current state of affairs. The further out we look, the older the information is that we percieve. Scientists state that the universe is expanding at an accelerating rate because the further out into space they look, the greater the red-shift of the light from those objects.
The closer you get to the horizon of the observable Universe the faster things will appear however, it only appears fast from our point of view. The space between galaxies is expanding at the same rate, its only viewed faster the further we look because spacetime is curved. Galaxies that are close to us are also expanding, or I should say, the space between us and them is also expanding, at the same rate as something 30 billion light years away. It just appears slow from our point of reference.
If the relative time of an object can be affected, will this have an effect on its gravitational effect.
The time is only effected from the POV of the observer. If I was in your hypothetical orbiting thingy traveling at the speed of light I would feel no effect, the time would only effect you. From my POV 'you' are the one who is traveling at the SoL. So again I would say that time dilation, as it is defined in physics, does not effect gravity.
Remember, to the light particle, it is not traveling at any speed. It is stationary and it is us that is going toward it.

All great truths begin as blasphemies
I smoke pot. If this bothers anyone, I suggest you look around at the world in which we live and shut your fuckin' mouth.

This message is a reply to:
 Message 7 by AshsZ, posted 06-24-2008 3:45 PM AshsZ has not replied

  
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