WHR Posted August 6, 2012 Share Posted August 6, 2012 The universe is expanding, all masses flying apart, accelerating. As spots drawn on an inflating balloon. Or a stretched rubber band. Galaxies collide...... Hmmm. How do galaxies violate the first observation? Link to comment Share on other sites More sharing options...
Janus Posted August 6, 2012 Share Posted August 6, 2012 Not all masses are flying apart. For instance, the planet in the solar system are not flying apart, nor is the galaxy, nor are the local group of galaxies... All these things are gravitational bound together strongly enough to overcome the expansion. It is only at larger scales that expansion becomes the rule. Link to comment Share on other sites More sharing options...
WHR Posted August 6, 2012 Author Share Posted August 6, 2012 Righto! But aren't galaxies the things that we are seeing flying apart? I made no comment about solar system collisions, or even stellar collisions. The next thing up is galaxies, and as far as I understood, galaxies are pretty much the largest observable clusters of mass with any sort of regular geometry, i.e. cosmic "species" as it were. I do realize we have galactic clusters, but what exactly are we observing moving away from each other at an accelerating rate if it isn't galaxies? Are the galactic clusters the widgets that have decided to repel each other? Where is this dividing line being made? Link to comment Share on other sites More sharing options...
ACG52 Posted August 6, 2012 Share Posted August 6, 2012 What we see flying apart are galactic clusters, further apart than 200 million lys. Closer than that and gravity overcomes the expansion. Link to comment Share on other sites More sharing options...
WHR Posted August 6, 2012 Author Share Posted August 6, 2012 So gravity is stronger than anything closer than 200 million lyrs apart....this is the official threshold, and universal? No exceptions? So the ultimate doom of the universe is to be a bunch of black holes more than 200 million lyrs part, with expansion steadily increasing that distance. Because logic would dictate that all these clusters that are not flying apart will be overcome by gravity and consume themselves. Question. What evidence do we have that there isn't a higher order of matter clumping that goes beyond galactic clusters...lets call these galactic cluster-clusters...that are bigger than the observable universe. That in fact, the observable universe only fits into one galactic cluster-cluster...but our neighboring galactic cluster-cluster is actually getting closer to us at an accelerating rate (negating the opposite expanding observation) and as a whole, the universe is in balance. Is it speculation to assume the universe is larger than we can observe? I guess so, just like it was speculation that there was more to the universe than our own galaxy before telescopes could discern other galaxies. Link to comment Share on other sites More sharing options...
ACG52 Posted August 6, 2012 Share Posted August 6, 2012 So gravity is stronger than anything closer than 200 million lyrs apart.... Yes. We have a pretty well measured value for the Hubble constant, and that tells us how fast space is expanding, as well as allowing us to set that boundry. Question. What evidence do we have that there isn't a higher order of matter clumping that goes beyond galactic clusters There is. The largest single structure to be identified is the Sloan Great Wall, a vast sheet of galaxies that span a length of 500 million light-years, a width of 200 million light-years and a thickness of only 15 million light-years. Read more: http://www.universetoday.com/37360/structure-of-the-universe/#ixzz22jRf6S3x That's the largest we've seen so far. that are bigger than the observable universe. If it is outside the observable universe, it can't effect us, since gravity is limited to the speed of light. Is it speculation to assume the universe is larger than we can observe? Certainly not. But if you do want to speculate, you're in the wrong forum. Link to comment Share on other sites More sharing options...
WHR Posted August 6, 2012 Author Share Posted August 6, 2012 If it is outside the observable universe it can't effect us (snip) If our observable boundary of clusters and various other bodies of matter are expanding.... And somewhere outside our boundary of observable matter, if it exists, another cluster-cluster of galaxies and matter is also expanding, but not moving away from us, but instead possibly moving toward us... It is inconsequential (and can't effect us) only because light moves faster than gravity?? So we have to see it for it to matter? if we can't see it, it can't be moving toward us? And if what you are saying is logical, which it isn't, how does gravity hold things that are within the 200 million ltyr boundary together? As far as I know, 200 million light years would also be out of gravity's reach if the speed of light is the defining boundary. Does gravity move faster than the speed of light within that boundary? But if you do want to speculate...snip Science is about asking questions, I doubt one thread on this website hasn't had a healthy dose of question asking when confronted with observations. If not, it should. Otherwise I may as well go talk to a Bishop. Link to comment Share on other sites More sharing options...
swansont Posted August 6, 2012 Share Posted August 6, 2012 ! Moderator Note Please learn to use the quote function; it makes discussions much easier to follow. Click on the reply button, or the quote icon (the cartoon bubble) if you're in the editor, or simply put before and after what you are quoting. Gravity acts at the speed of light. Link to comment Share on other sites More sharing options...
ACG52 Posted August 6, 2012 Share Posted August 6, 2012 And somewhere outside our boundary of observable matter, if it exists, another cluster-cluster of galaxies and matter is also expanding, but not moving away from us, but instead possibly moving toward us... Spatial expansion means that everything (outside of gravitational binding) is moving away from everyting else, so nothing outside the observable universe is moving towards us due to expansion. It is inconsequential (and can't effect us) only because light moves faster than gravity?? So we have to see it for it to matter? It cannot effect us because gravity moves at the speed of light, and outside the observable universe expansion is occuring at effectively greater than c, so any gravitational effects from outside the observable universe can never reach us. And if what you are saying is logical, which it isn't, how does gravity hold things that are within the 200 million ltyr boundary together? As far as I know, 200 million light years would also be out of gravity's reach if the speed of light is the defining boundary. Why would you think that 200 million lys is outside either light's ability to reach us, or gravity? The observable universe is 41 billion lys across, 200 million lys is relatively close. Science is about asking questions Questions and speculations are two different things. Link to comment Share on other sites More sharing options...
WHR Posted August 6, 2012 Author Share Posted August 6, 2012 Define observable universe. Is the observable universe limited by technology? I would ask this because as far as I know, nobody has claimed that we've built the most sensitive telescope possible. If the observable universe is apt to be expanded with advances in technology, then I would question what business we have claiming with any certainty what is happening beyond what our "eyes" can see. As far as 200 million ltyrs goes, I realize that the observable universe, what we have been able to detect, is 41 billion light years across. I'm not an astronomer so I don't know in what direction the various furthest observable points are. Are they equidistant from earth? 20 billion light years away in every direction? Hmmm that would be pretty close to what I understand the age of the universe has been calculated to be... i.e. are we located in the center of this expanse? Or do we have a lopsided view and see more emptiness in one direction than the other? If we are seeing things equidistant, I would ask how fortunate we must be to actually find ourselves back at the center of the universe. Oh, I'm now very confused. You said that beyond the observable universe expansion is occurring at greater than c. Maybe I'm dumb, but how is something that is not observable being observed?? Link to comment Share on other sites More sharing options...
WHR Posted August 6, 2012 Author Share Posted August 6, 2012 From Wikipedia : http://en.m.wikipedia.org/wiki/Observable_universe Wow, there it is in black and white. We put ourselves in the center of the universe. Pictures say 1000 words. Now I know this isn't some sort of oversight that astronomers just forget to mention. It is quite obvious that observable universe is clearly defined by our most sensitive telescopes. So in reality, we are making predictions about the universe with not much more than a rock that we threw up into the sky. Link to comment Share on other sites More sharing options...
MigL Posted August 6, 2012 Share Posted August 6, 2012 Outside the observable universe spaces between galaxies/clusters is expanding faster than light can cross it. In effect it is expanding faster than c. This is not a technological limitation but a physical limitation. The observable universe is also the limit of causality since any signal that tranmits information ( all forces and effects ) is limited to c. Link to comment Share on other sites More sharing options...
JMJones0424 Posted August 6, 2012 Share Posted August 6, 2012 WHR- there's nothing particularly notable about the fact that we are at the center of our observable universe. Every observer is at the center of their observable universe. The observable universe is everything that we can, in principle, observe. Its size is based on the speed of light and the age of the universe, not on our technology. The wikipedia article from which you got the illustration clearly states as much. In Big Bang cosmology, the observable universe consists of the galaxies and other matter that humans can in principle observe from Earth in the present day, because light (or other signals) from those objects has had time to reach us since the beginning of the cosmological expansion. Assuming the universe is isotropic, the distance to the edge of the observable universe is roughly the same in every direction—that is, the observable universe is a spherical volume (a ball) centered on the observer, regardless of the shape of the universe as a whole. Every location in the universe has its own observable universe which may or may not overlap with the one centered on the Earth. Link to comment Share on other sites More sharing options...
WHR Posted August 6, 2012 Author Share Posted August 6, 2012 This is correct, I totally understand that. But we are saying that past this area, we CAN'T see, so we make up stories about what is going on there, past what we can see. So from this point forward in cosmology, we can't do science based on observation. That is essentially what has been declared. If it isn't based on observation, then is it not the same as Alice in Wonderland? Link to comment Share on other sites More sharing options...
JMJones0424 Posted August 6, 2012 Share Posted August 6, 2012 I'm not sure what stories your are referring to that are being made up. It's true that we can't possibly make direct observations about anything that lies outside the observable universe. We assume that the cosmological principle is accurate, but this is a philosophical position based on what we can observe of our corner of the universe. This could be viewed as an extension of one of the most basic assumptions of science, that physical laws are applicable everywhere. You may be interested in further reading on the problem of induction and other areas of the philosophy of science. 1 Link to comment Share on other sites More sharing options...
MigL Posted August 6, 2012 Share Posted August 6, 2012 (edited) We may as well make it up, but since it can never affect us what difference would it make ?? A lot of theories are based on one or another fundamental assumption. GR is no different, but it has proved extremely accurate when applied correctly ( it is not valid in certain situations ). Edited August 6, 2012 by MigL Link to comment Share on other sites More sharing options...
WHR Posted August 6, 2012 Author Share Posted August 6, 2012 (edited) Actually this whole assertion is quite interesting to me. I've never actually read it declared that the edge of the observable universe was a consequence of something other than the lack of our ability to observe it. It has puzzled me that we have made declarations about what is going on past what we don't see. I had assumed our lack of seeing it was attributed to technology. I had never dreamed it was based on complete lack of observational evidence or that we had seen all there is to see already!!! Honestly, with understanding a little bit about EM, my assumption has always been that the inverse square law eventually makes something vastly distant so dim that it becomes undetectable by current technology at some point. I had assumed that the uniformity in all directions of the observable universe was a function of such a reality. That the next bigger telescope will always add a few million light years of distance (at least) to what we could see. If this is true, what value is there in investments in bigger telescopes? Editing to add this. I truly believe, from the depths of my heart, that Einsteins intellect and creative thought are so intimidating to us, so revered, that nobody has the guts to really call into question how it would be that entire galaxies can "apparently" break the light speed barrier. I think he himself would question this. I don't recall him making exceptions. I don't know who came up with a way to make an exception and still claim it falls within the fundamental principles of GR. hmmm Edited August 7, 2012 by WHR Link to comment Share on other sites More sharing options...
StringJunky Posted August 7, 2012 Share Posted August 7, 2012 Editing to add this. I truly believe, from the depths of my heart, that Einsteins intellect and creative thought are so intimidating to us, so revered, that nobody has the guts to really call into question how it would be that entire galaxies can "apparently" break the light speed barrier. I think he himself would question this. I don't recall him making exceptions. I don't know who came up with a way to make an exception and still claim it falls within the fundamental principles of GR. hmmm Einstein never suggested that...he was actually a proponent of the Static Universe which he later admitted was a mistake. Edwin Hubble conceived the idea of expansion I think. Besides, the objects subject to universal expansion are not going anywhere, much less break the light-speed barrier...space is created between objects and the further you are away from a galaxy or cluster the faster it appears to be receding ie more red -shifted. Link to comment Share on other sites More sharing options...
ACG52 Posted August 7, 2012 Share Posted August 7, 2012 WHR, you make many assumptions and assertions based on pretty much complete ignorance of Relativity, cosmology and the Big Bang theory. You seem to take the postion that 'knowledge - bad, imagination - good' Link to comment Share on other sites More sharing options...
WHR Posted August 7, 2012 Author Share Posted August 7, 2012 WHR, you make many assumptions and assertions based on pretty much complete ignorance of Relativity, cosmology and the Big Bang theory. You seem to take the postion that 'knowledge - bad, imagination - good' Nope. I take the Stance that on one side we say that there is no absolute knowledge, that knowledge is amendable when new observations warrant, but yet we still call it knowledge and argue that we know. Call people who don't think they know ignorant because they haven't unquestionably accepted the current version of "know". We either know or don't know. Either the galaxies at the edge of the observable universe are moving faster than the speed of light or they aren't. Consensus does not make galaxies move at a certain speed. Some phenomenon of nature does. If we can't see a galaxy, it MAY be explained by the galaxy moving at faster than light speed, or it MAY be simply that past a certain point in the universe, we can't detect enough photons to resolve a mass. Perhaps no telescope can possibly be built to resolve a mass above the "ambient visible noise floor" when it exits beyond point X. I would also assert that we are walking on territory of circular logic. We claim the universe is a certain age because of X observation... then we say X obseration occurs or is because the universe is a certain age. We use one observation to confirm itself so to speak. I love astrophysics, have always lived cosmology. I am the first to point to the Sky when I see Jupiter and Venus and the moon all very close together as they were just a few months ago. I think we CAN find answers to questions. I just challenge these assumptions. I challenge them at my core because we are starting to poke out as far as our stick will let us poke, but we just can't accept that the answer may be beyond reach, so now we dream and create nonsensical stuff that helps with the math (dark matter and energy) and say it over and over and over again until everyone knows The words to the song. In fact ... To edit this, I think when we start stepping outside of what we can't even see, as in several BILLION LIGHT YEARS AWAY (mind staggering unfathomable distances) and make assertions about what is happening at that distance, we are walking on paper thin ice. One might say that quantum physics is as difficult to determine. I would say no. An atom and it's constituents that is within my reach, however small, seems a billion times easier to comprehend than something that can't even be detected. At least the LHC has detectors that supposedly can resolve what they are looking for. I think there isn't enough combined brainpower and computing memory on planet earth to really comprehend the distances we are talking about. Link to comment Share on other sites More sharing options...
StringJunky Posted August 7, 2012 Share Posted August 7, 2012 Nope. I take the Stance that on one side we say that there is no absolute knowledge, that knowledge is amendable when new observations warrant, but yet we still call it knowledge and argue that we know. Call people who don't think they know ignorant because they haven't unquestionably accepted the current version of "know". We either know or don't know. Science works on confidence intervals and if it is 95% or better then an idea can be considered "knowledge" ie the evidence for it is robust enough to be classed as a theory*. *"In modern science, the term "theory" refers to scientific theories, a well-confirmed type of explanation of nature, made in a way consistent with scientific method, and fulfilling the criteria required by modern science. Such theories are described in such a way that any scientist in the field is in a position to understand and either provide empirical support ("verify") or empirically contradict ("falsify") it. Scientific theories are the most reliable, rigorous, and comprehensive form of scientific knowledge". http://en.wikipedia.org/wiki/Theory (My bold) Link to comment Share on other sites More sharing options...
WHR Posted August 7, 2012 Author Share Posted August 7, 2012 OK I can't help myself. Where are all the really fast accelerating galaxies located? Logic would dictate that there has to be a few within just a few hundred million light years of the milky way that have broken the light speed barrier. They should be evenly distributed all over the place. But all the articles I read talk about having to use gravitational lensing to see "distant faint galaxies" to detect the ones that are accelerating that fast or have already broken light speed. None of our neighbors have the pep to do it? Again, based on what I've read on the Internet (which is where I get my info because I don't work at a university observatory) it sounds like we are looking at the edge of the observable universe to find the light speed breakers. Centering everything on our observation point. Is the Milky Way breaking light speed? In fact, isn't it pretty important to establish a reference point? Even if I'm talking about two trains moving away from each other at X speed....I add the speeds together to come up with the effective speed. I'll compare that to heat index vs temperature. The other train would appear to be moving twice as fast as it is in reference to the Milky Way Express. But I have to know how fast the Milky Way Express is going to know anything meaningful. And that's the one train we can't measure from another perspective. Hmmm. Science works on confidence intervals and if it is 95% or better then an idea can be considered "knowledge" ie the evidence for it is robust enough to be classed as a theory*. *"In modern science, the term "theory" refers to scientific theories, a well-confirmed type of explanation of nature, made in a way consistent with scientific method, and fulfilling the criteria required by modern science. Such theories are described in such a way that any scientist in the field is in a position to understand and either provide empirical support ("verify") or empirically contradict ("falsify") it. Scientific theories are the most reliable, rigorous, and comprehensive form of scientific knowledge". http://en.wikipedia.org/wiki/Theory (My bold) Please explain to me then how the confidence interval was so great 30 years ago when I was in school that we were taught that the universe was expanding but at a decaying rate. We learned about the Big Crunch theory. THEORY, and it was as far as i remember textbook stuff...mainstream. Nobody said anything about dark matter or energy or accelerated expansion. That was taught as knowledge 30 years ago. I was also taught that blue was blue and Hitler was a really bad guy. Are these concepts subject to revision? You can throw all kinds of links and mumbo jumbo at me, but I have a 95% confidence interval that students 30 years from now will be learning something completely different. That isn't knowledge. Knowledge is absolute in every other sphere of influence. Link to comment Share on other sites More sharing options...
StringJunky Posted August 7, 2012 Share Posted August 7, 2012 (edited) That isn't knowledge. Knowledge is absolute in every other sphere of influence. Science is about describing reality and reality is a real bastard to get a handle on and the other spheres you allude to don't have that problem...hence the adherence to rigorous discipline which you don't seem to like up to now. Science will probably never be right in the absolute sense but it is striving to be less wrong with increasing success...it's a relative thing. If science thought it was right per se, it would cease to move forward...in effect it would become like a religion. The idea of confidence levels is an important one to grasp and actually aids progress because it means scientists can't fall into complacency and are always looking for holes in theories. If you looked at the scientific method with open eyes you'll not see a more ruthless quality control system anywhere. This methodology and mind-set should inspire confidence in it for you not derision...it is anything but tunnel-visioned as a discipline. If the knowledge has changed since you were younger it shows the scientific method is working. How many revisions has The Bible or Quran had? Edited August 7, 2012 by StringJunky Link to comment Share on other sites More sharing options...
StringJunky Posted August 7, 2012 Share Posted August 7, 2012 (edited) Double post. Edited August 7, 2012 by StringJunky Link to comment Share on other sites More sharing options...
WHR Posted August 7, 2012 Author Share Posted August 7, 2012 Wow. Here is a FASCINATING website: http://www.atlasoftheuniverse.com/2billion.html It is a map of the identified superclusters out to 2 billion light years. I noticed, by picking about 30 random superclusters, all but a few of the most distant (on the outskirts with our local supercluster being central) fall on redshift scale on the most extreme end (up to .225) the neighboring superclusters with few exceptions are redshifted at the bottom end. (.014)....it is my understanding that a redshift of 1 would indicate light speed. So out to 2 billion light years, we have detected no supercluster in the hundreds (or thousands depending on the criteria) that is moving faster than 1/4 the speed of light away from our location. The "super warp" superclusters begin where?? Is a pattern emerging with the raw data? This is pretty black and white stuff if you care to question things. The distribution of warp speed superclusters should be a random pattern. Even within 2 billion light years that pattern should emerge. It should NOT be dependent of the observation point. This truly IS a geocentric view of the universe. Actually there are dozens of revisions of the bible that try to fit it into modern language. I would prefer that religion not be crossed into a scientific topic. I am not on this site to discuss religion. I would contend that the hate of religion is why most people who ravenously defend science do so. To truly free your mind and be objective, you can't have a predisposition to even think about religion, discuss it, let it poison your thought at ALL about science. They are two completely different things, or should be. Unfortunately for many however, science is the void filler in absence of religion. This is a philosophical point and off topic but I'm replying to the statement...but you really have to put religion in a box and forget about it to liberate your mind and not accept science at face value. Otherwise is to have an inversely proportional viewpoint. For every measure of lack of faith in religion, a proportional amount of faith lended to the infallibility of science. That is not a healthy thing. Distrust in one should not reinforce the other. But that is not what is evident in human nature. The most vitriolic atheist is the champion of science. The most devout of religious persons is more than typically the most superstitious against science. An agnostic such as myself is liberated and can view science with as critical an eye as religion. Link to comment Share on other sites More sharing options...
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