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gth759k
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"accelerating" universe - details and dispute
I recently sent an email to several physics professors at CalTech and MIT with a question I have about Cosmology and only one professor (Walter Lewin) replied simply saying good luck! Its not so much of a question as it is a problem. I've talked to people about this before and the conversation quickly looses all basis in reality and data and becomes more like something out of a science fiction novel. So, if you should choose to reply please stick to the facts and leave out the suppositions. That means I don't want to hear anything like "stretchy" space-time unless you can back it up with systematic, uniform and precise data and theory, because I will not take you seriously. So, on to the problem.
According to many sources (on the web and off) ... the universe is accelerating! Very notable scientist currently argue that the universe is not only expanding, but expanding at an accelerating rate. So I set about searching for the evidence of this claim and I was pointed to many sites on redshift and spectography and physics equations. Eventually I found the image above which is most interesting to me. There are many others like it showing the same data trends. I don't know about you, but I can't think in megaparsecs, so the first thing I did was convert the units from megaparsecs to kilometers. The closest type 1a nebula on the graph in the lower left hand corner is about 35 Mpc = 1.0799 x (10^21) km and the farthest nebula in the upper right hand corner of the graph is about 635 Mpc = 1.9594 x (10^22) km. These values on the horizontal axis were approximated, as I understand using the magnitude-distance formula which uses the absolute and apparent magnitudes of the nebula to determine the distance. The vertical axis on the chart shows the (approximate) velocity in km/s of the nebula relative to us calculated using Hubble's law. Now, let me ask you a question, what does this chart show us? I've been told that this chart shows that the farther away a celestial body is the faster its going! Hmmm ... I disagree. I think this chart shows that the farther away a celestial object is, the faster it WAS going. I say that because, and I'm sure you'll agree, we see the galaxies and nebula as they WERE and not as they are. In other words, if an event was observed in M31 it would be more recent than a event observed that very hour in M82. So, do we all agree that the farther away you look, the deeper you're looking into the past? Then, when we look at the most distant objects we are seeing a picture of the early universe right? So doesn't that mean that the (farthest) fastest objects we find are a picture of the early universe too? And that the closer, more resent, (slower) objects are more recent? In that the data contained in the light from nearby galaxies shows a more recent past than the distant galaxies? Then the velocities of the closest galaxies and nebula are a better representation of what the universe is really like right now because they represent a relatively fresh past. It looks like to me, if you reconstruct the events according to the data, that the early universe was moving away from us faster than the more resent universe. Not the other way around.
I'd just like to put my thoughts out there because when people start talking about things like "stretchy" space-time, it feels like all reason and common sense just go out the window.
I recently sent an email to several physics professors at CalTech and MIT with a question I have about Cosmology and only one professor (Walter Lewin) replied simply saying good luck! Its not so much of a question as it is a problem. I've talked to people about this before and the conversation quickly looses all basis in reality and data and becomes more like something out of a science fiction novel. So, if you should choose to reply please stick to the facts and leave out the suppositions. That means I don't want to hear anything like "stretchy" space-time unless you can back it up with systematic, uniform and precise data and theory, because I will not take you seriously. So, on to the problem.
According to many sources (on the web and off) ... the universe is accelerating! Very notable scientist currently argue that the universe is not only expanding, but expanding at an accelerating rate. So I set about searching for the evidence of this claim and I was pointed to many sites on redshift and spectography and physics equations. Eventually I found the image above which is most interesting to me. There are many others like it showing the same data trends. I don't know about you, but I can't think in megaparsecs, so the first thing I did was convert the units from megaparsecs to kilometers. The closest type 1a nebula on the graph in the lower left hand corner is about 35 Mpc = 1.0799 x (10^21) km and the farthest nebula in the upper right hand corner of the graph is about 635 Mpc = 1.9594 x (10^22) km. These values on the horizontal axis were approximated, as I understand using the magnitude-distance formula which uses the absolute and apparent magnitudes of the nebula to determine the distance. The vertical axis on the chart shows the (approximate) velocity in km/s of the nebula relative to us calculated using Hubble's law. Now, let me ask you a question, what does this chart show us? I've been told that this chart shows that the farther away a celestial body is the faster its going! Hmmm ... I disagree. I think this chart shows that the farther away a celestial object is, the faster it WAS going. I say that because, and I'm sure you'll agree, we see the galaxies and nebula as they WERE and not as they are. In other words, if an event was observed in M31 it would be more recent than a event observed that very hour in M82. So, do we all agree that the farther away you look, the deeper you're looking into the past? Then, when we look at the most distant objects we are seeing a picture of the early universe right? So doesn't that mean that the (farthest) fastest objects we find are a picture of the early universe too? And that the closer, more resent, (slower) objects are more recent? In that the data contained in the light from nearby galaxies shows a more recent past than the distant galaxies? Then the velocities of the closest galaxies and nebula are a better representation of what the universe is really like right now because they represent a relatively fresh past. It looks like to me, if you reconstruct the events according to the data, that the early universe was moving away from us faster than the more resent universe. Not the other way around.
I'd just like to put my thoughts out there because when people start talking about things like "stretchy" space-time, it feels like all reason and common sense just go out the window.