JMJones0424

I've embarrassed myself more than once, not afraid to do so again. What observational data are you referring to?

If the boyfriend is violent, consult local authorities. If there's friction between the two of them, then they should no longer be seeing each other. Personal conversations should not be posted for all to see on the internet.

Meh, ignore the troll. Have I explained the current data in such a way that it is understandable to you?

I am tremendously in awe that you can immediately grasp the consequences of observational data. I wish that I were able to do so as well. As it happens, I am not, nor does it appear to me that WHR is either. As such, it would be far more useful if you were to explain your position rather than just stating it as an obvious fact.

Before I try to clarify my previous post, I'd like to propose that there is no such thing as irrefutable evidence. We are dealing with science, not mathematics. There is no such thing as proof here. The only truth in science that exists are observations, and even observations are subject to interpretation and refutation if there was a problem in making the observation. The issue, as I understand it, is that the conclusion that the expansion of the universe is accelerating is not readily apparent. I think it is obvious that redshift indicates that the universe is expanding. The rest of my post will be devoted to showing how redshift evidence indicates that said expansion is accelerating. Let's start by imagining a situation where I am stationary and a supernova type Ia is receding at a fixed rate from me of 1 unit of distance per 1 unit of time. At t=0, the supernova is x distance away. At t=1, the object is x+1 distance away, at t=2, the object is x+2 distance away. The object can be accurately described as receding away from me at a fixed rate of 1distance/1time. Now, I don't have the luxury of observing one type Ia supernova for a billion or so years, so let's say that I am observing many different type Ia supernovae receding from me. Given our assumptions on the uniqueness of type Ia supernova, we can say that when I observe their relative brightness, I can correlate that to their distance from me. Also, I can observe their spectra and use the redshift of their spectra to determine their relative velocity from me. Since the speed of light is finite, I can also correlate their distance from me to the time in which the light I am observing was emitted. If the expansion of the universe were occurring at a fixed rate, I would expect a direct correlation between distance and redshift. If the expansion of the universe were gravity dominated, in that the expansion slows down over time due to the influence of gravity, I would expect redshift to be higher at farther distances (because farther equals a longer time ago). Instead, what the data shows, is that redshift is lower at farther distances and higher at closer distances than would be expected if acceleration were constant. This indicates that expansion is accelerating. It should be noted that I have not come to this conclusion by observing one type Ia supernova. I am assuming that all type Ia supernova are equivalent in brightness due to the mechanics of their evolution. While there is no evidence that contradicts this assumption, it is an assumption none the less. Likewise, I am assuming that there is nothing that will substantially alter the light and spectra of far away supernovae that would corrupt my interpretation that far away supernovae are receding slower than they would if the expansion of the universe were constant. To date, there is no evidence that this assumption is incorrect. Provide evidence otherwise and win the Nobel prize.

You can assume whatever you wish about me. I have no formal education in cosmology and what I've come to know is a result of a few years struggling to try to understand the posts of those that have the benefit of formal education. The matter is not at all intuitive, and this is a question that I, like you, have struggled with for quite some time. I'm going to do some work outside in my garden and try to think of a better way to explain the issue. Also, I am going to petition the moderators to move this thread to the Astronomy and Cosmology forum, as you are not speculating at all. You seem to me to be asking worthwhile questions about current knowledge rather than proposing an alternative.

WHR- you've raised very good questions, and the fact is that we have not been observing anywhere near long enough to provide the direct evidence that you require. The conclusion that the expansion of the universe is accelerating is an interpretation of the data from redshift of type Ia supernovae. This is important because this particular type of supernova is expected to have a fixed brightness, as the supernova occurs immediately once the white dwarf accretes enough mass. We can therefore determine the distance to the supernova based on relative brightness alone. Then, we compare the spectrum of the supernova to determine its velocity relative to us using redshift. What we find is that further galaxies containing type Ia supernova are receding from us slower than they would be if expansion was occurring at a constant rate. In other words, we have not been observing long enough to witness accelerated expansion of one particular type Ia supernova. However, since light travels at a finite speed, we see more distant objects as they were further in the past. So we can, if our assumptions are correct, witness the change in expansion over time using multiple type Ia supernova. I usually use a graph from hyperphysics to show the plot of type Ia supernova redshift over brightness, but that site seems to be down at the moment. I'll edit or add to this post with the appropriate graph once I find it. EDIT: Here's a link to a PDF of the graph, still looking for an image I can imbed. EDIT2: This is close to the specific graph I was looking for, though the inset makes it more cluttered than it needs to be. Image source Basically, what this shows is that galaxies containing type Ia supernova that are a great distance away have less redshift than would be expected if the rate of expansion were constant. Galaxies containing type Ia nearer to us have greater than expected redshift. To be honest, it took me a few months to fully wrap my head around the significance of this graph, so please, feel free to ask any follow up questions you may have. Bear in mind that the value for magnitude is opposite of what you'd expect, in that the lower the value, the brighter (and therefore nearer in type Ia supernova) the object.

I can't speak for Ringer, but it certainly had not occurred to me that a method of objectively examining and explaining our surroundings could, or in fact does, suffer from a mental disorder. You have written many things, but none can support such an absurd assertion.

Are you sure you aren't making this far more complicated than it is? The scanner sends a pulse of sound, it bounces off the metal, and then arrives back at the scanner. You know the speed that the sound moves and the amount of time it takes to go to the metal and return to the scanner. [math]speed = \frac{distance}{time}[/math] [math]distance = speed \times time[/math] You need to convert microseconds to seconds and then just do the math to find the total distance traveled by the sound pulse (scanner to object and then back to the scanner). Then cut that in half to find the distance from the scanner to the metal object.

Your religious beliefs are not spam, but neither are they science. This is a science forum. There are a plethora of sites on the internet that allow you to discuss beliefs, religious or otherwise, without requiring supporting evidence.

No one says it MUST be true elsewhere. It is a fundamental assumption of science, one that has worked quite well so far. What's the alternative?

You're given a speed (distance/time) and a time, and you need to determine a distance. Get your units sorted out and it should be pretty straightforward.

1) It's not that objects outside of our future light cone are red-shifted beyond visibility, the light they emit will never reach us because they are receding from us faster than the speed of light. Perhaps if we scale it down to velocities that we encounter regularly it will be easier to understand. Let's say you're standing on the side of the road and I'm traveling away from you in a car at 100 mph. You throw a baseball at my rear windshield at 80 mph. That baseball will never hit my rear windshield because I am traveling faster, relative to you, than the baseball is. 2)There could be galaxies within our future horizon, but the universe has not yet existed long enough for their light to reach us. It is impossible for us to make observations beyond the surface of last scattering. Note that the distance to the surface of last scattering is not the same as to the edge of the observable universe. Your "IT JUST SO HAPPENS" is invalid. This is dealt with in the second paragraph of the wikipedia article on the observable universe which you linked to previously. Yes, this is referred to as the Big Rip, and would mean that in the very far future, if the expansion of space-time continues, the observable universe would consist of only our galaxy. I agree that the existence of the universe is not dependent on our desires. Likewise, while I too find the "beginning" of the universe philosophically displeasing, I do not require observations to conform to my desires.

If you don't like the ballon analogy, I don't blame you. It is, in my opinion, responsible for more misunderstanding than nearly anything else except possibly that entropy = disorder, but that's a different discussion. However, your understanding of what the balloon analogy is supposed to represent is incorrect. It is not a model of how space-time expands. To be honest, we don't know how or why, we only have very good indications that space-time is expanding. The balloon analogy is meant to represent why every observer appears to be at the center of their universe, thus disputing the erroneous conclusion that because (generally) every galaxy is receding from us, and the further the galaxy, the more rapid the recession, we are at the center of the universe. For a somewhat better visualization, you might try this youtube video: (Edited to embed the video rather than just posting the url.)

We would continue to see the light emitted by a far away object, though increasingly red-shifted, until its recession relative to us equaled the speed of light. I am afraid, though, that you are confusing acceleration with space-time expansion. Again, I recommend reading through the cosmology tutorial. The section on distances in part 2 is particularly relevant to your question.

Your understanding, that redshift z of 1 equals recession at light speed, is incorrect. Anything receding at or greater than the speed of light would be undetectable, and by definition, lie outside of our observable universe. I fail to see any relevant similarity between your misunderstanding of the topics at hand and religion. I suggest, if you are looking for a good primer on modern cosmology, that you read through Ned Wright's cosmology tutorial.

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.

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.

As this is your thread, I will certainly grant your request.

Because this is a forum for discussion and you felt that your idea was worthy of discussion. I, too, feel your idea is worthy of discussion, and I am participating in that discussion.

I claimed nothing of the sort. I did ask, and you have yet to answer, how is common sense a valuable explanation for phenomena that are not intuitive? Or to put it another way - if the scientific method is inappropriate for evaluating some aspects of reality, 1)what are those aspects, and 2) what method is more appropriate, and why?

This is precisely why your complaint fails. I do not accept your chained dog analogy as you've yet to provide an example in which the analogy is appropriate. I do not accept that who I am, nor who you are, nor any quality of the claimant is relevant to the value of the claim being made. The scientific method, specifically the idea that claims should be verifiable, is not a hinderance to understanding. Instead, it is the means by which we have been able to rid ourselves of the notion that common sense is valuable, that one's preconceived notions are a valuable tool in judging one's surroundings. If you must rely on common sense as the supporting factor for your claim, and your common sense differs from experimental data, of what value is your common sense? If supporting data confirms your common sense, then why not rely on that objective data to support your claim?

Who I am should be irrelevant. That's the beauty of objective analysis. I've asked a specific question regarding your complaint about the scientific method. You seem to me to be claiming that common sense is an appropriate measure of the validity of an explanation. I've given an example that seems to refute your claim. Is my analysis incorrect?

OK, you've cut and paste from a site that can hardly be construed as an accurate representation of current knowledge. Do you have a particular question regarding the quote, or are you asserting it as fact? Do you understand why the quote is wrong? Also, do you understand the need to clearly delineate your own words from the text that you are quoting?

physical fitness Do you have a specific question?