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Universe is speeding up? Are we traveling with it? Dark Energy.

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  1. May 20, 2013 #1
    Hi, new and pondering with much ignorance. Hence the question marks. Had to register!

    Are we traveling, is our planet, solar system moving along with the universe expansion?
    This question, statement, is prefaced on the theory that the universe is speeding up rather than slowing down.
    I understand we have measurements of distance and time by looking at the light spectrum upon supernova explosions that have reached us? Calculating billions of years in some cases. Which has given us dark energy because the math didn't quite add up?

    If the universe were created with a bang I'd assume everything in it is not necessarily traveling in the same direction? If a Sun were traveling in an opposite direction from us due to the Bang theory, would the math/distance be skewed in some way?

    I'm trying to get my head around this. Measuring light and to derive distance from two stand still sources makes sense in my skull but when the objects are traveling away from one another at undetermined speed(btw do we know how fast we are hurling outwards through empty space and is everything in it traveling at the same speed? Direction? Are we moving?)it becomes difficult to imagine.

    I think I painted a simple enough picture. So, is it fair to think of our Universe expansion being due to the one initial bang theory in a 3-D direction? And if so, is the math to determine the distance and time of the supernova explosion accurate if our planet, solar system is traveling along with this expansion? Are the stars light we see from billion of years ago possibly traveling away from us?

    Thanks for bearing with me and any replies.
     
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  3. May 21, 2013 #2

    davenn

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    yes

    no, our solar system is rotating/orbiting around the galactic centre as are the rest of the stars and objects in our galaxy

    universal expansion isnt affecting individual stars within our galaxy ie. they are not getting further apart because of that expansion.
    The expansion does affect the distance between individual galaxies or groups of galaxies.
    Our galaxy is part of what is called the local group, some are moving apart, some are moving closer together. But the distance between our local group and other individual galaxies or groups of galaxies is changing because of the expansion of the universe

    Dave
     
  4. May 21, 2013 #3
    The Big Bang also did not occur in an explosion. Instead it was a rapid expansion of space.

    As your asking several questions relating to expansion and distance measures this article written by forum members will help.

     
  5. May 21, 2013 #4
    This related thread also has some excellent answers to your question.

    https://www.physicsforums.com/showthread.php?t=692288

    my signature has a link called lightcone calculator with it you can see the expansion history of the universe past, present or future. Here is a default setting sample from it.

    [tex]{\scriptsize\begin{array}{|c|c|c|c|c|c|}\hline R_{0} (Gly) & R_{\infty} (Gly) & S_{eq} & H_{0} & \Omega_\Lambda & \Omega_m\\ \hline 14.4&17.3&3400&67.9&0.693&0.307\\ \hline \end{array}}[/tex] [tex]{\scriptsize\begin{array}{|r|r|r|r|r|r|r|r|r|r|r|r|r|r|r|r|} \hline a=1/S&S&T (Gy)&R (Gly)&D_{now} (Gly)&D_{then}(Gly)&D_{hor}(Gly)&V_{now} (c)&V_{then} (c) \\ \hline 0.001&1090.000&0.0004&0.0006&45.332&0.042&0.057&3.15&66.18\\ \hline 0.003&339.773&0.0025&0.0040&44.184&0.130&0.179&3.07&32.87\\ \hline 0.009&105.913&0.0153&0.0235&42.012&0.397&0.552&2.92&16.90\\ \hline 0.030&33.015&0.0902&0.1363&38.052&1.153&1.652&2.64&8.45\\ \hline 0.097&10.291&0.5223&0.7851&30.918&3.004&4.606&2.15&3.83\\ \hline 0.312&3.208&2.9777&4.3736&18.248&5.688&10.827&1.27&1.30\\ \hline 1.000&1.000&13.7872&14.3999&0.000&0.000&16.472&0.00&0.00\\ \hline 3.208&0.312&32.8849&17.1849&11.118&35.666&17.225&0.77&2.08\\ \hline 7.580&0.132&47.7251&17.2911&14.219&107.786&17.291&0.99&6.23\\ \hline 17.911&0.056&62.5981&17.2993&15.536&278.256&17.299&1.08&16.08\\ \hline 42.321&0.024&77.4737&17.2998&16.093&681.061&17.300&1.12&39.37\\ \hline 100.000&0.010&92.3494&17.2999&16.328&1632.838&17.300&1.13&94.38\\ \hline \end{array}}[/tex]
     
    Last edited: May 21, 2013
  6. May 21, 2013 #5
    Just adding some more layman's terms here to add to Mordred and Dave:

    Well, According to this dude we are moving through space around 2.7 mph. This is probably wrong and just a "licked thumb in the wind" kind of thing, better people at math will have to either confirm or deny this guy's idea.

    My point in bring it up is yeah, we're moving both as a solar system and along with the universes expansion, but they aren't the same, (read the previous posts).

    To add to what Dave said, (and Mordred's very awesomely detailed post), Galaxies and stuff in Local Groups (galaxy groups still hooked by gravity)are still bound (even remotely) by gravity, so they are still sort of pulling towards each other. We are moving, but it's doubtful we'll be doing anything but following the Milky Way's rotation for the next billion years or so without some huge cataclysm, because of gravitational influence. (alot more complicated than this but..) When you start getting further out to where gravity gets weak, (like between local groups, where there is no matter for great distances... ) distances seem to be increasing, rather quickly, and we're not completely sure why, (hence dark matter/energy).

    Yes, the distances between gravitationally influenced masses seems to be increasing more than decreasing for any reason.

    Pretty much.


    Mordred pretty much covered some good ground on the rest of it. We're all traveling in opposite directions, but it's not because we were "flung" apart in all directions. The space between large bits of mass is just increasing, (red shift, doppler) and we have no real explanation for it. (yet).
     
    Last edited: May 21, 2013
  7. May 21, 2013 #6
    Hey all, thanks for the answers and subsequently the 10 new questions I now have.
    I see they have their formula bases covered when measuring distance/time as it relates to redshift.
    Visually in my mind I can't quite grip some determinations such as no center or that we cant look out past the expanding universe or in the opposite direction, which would be looking forward in time, as I see it.
    I also don't like dark matter or energy as I'm sure most of you do not either because of the lack of explanations. I would prefer to think of dark energy as an unknown source of gravity.
    But yes, layman's vision for sure.
    It was educational reading. Thanks
     
  8. May 21, 2013 #7
    Its not so much we don't like it as opposed to we wish we understood the two better. Though our understanding has improved tremendously in the last few years.

    In many ways cosmology is far better off not having to deal with a preferred center. The homogeneous,isotropic as well flat nature of our universe makes numerous aspects far easier to calculate.

    I've already covered the explosion aspect so going into more detail won't help.

    As far as dark energy goes in many ways its often considered a vacuum pressure as opposed to some strange energy form. We have a good understanding of pressure systems so its not so mysterious in and of itself. Einstein's equations predicted either an expanding or contracting universe. For that matter in a static universe the slightest deviation would cause that static universe to either expand or contract. So it wasn't much of a surprise.

    As far as dark matter itself goes were getting much closer to understanding it though we still have a ways to go. The evidence for it is constantly increasing.

    I once felt much as you did on your original post, it took me a fair amount of study to realize just how much science has considered in alternate theories. Forums such as this one is an excellent resource.

    You will find this site will help you catch up on cosmology and probably answer the 10 questions you mentioned lol. It also includes a decent tutorial

    http://www.astro.ucla.edu/~wright/cosmology_faq.html
     
  9. May 21, 2013 #8

    phinds

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    EDIT: note --- this response is to the statement directly above. I did not look at the link.

    This is not an idea that is right or wrong, it is meaningless because it just says "moving" and that is a meaningless concept because it assumes an absolute rest frame against which we can measure our movement and there is no such thing as an absolute rest frame.

    I contend that we are rock steady motionless and I am right because I am measuring that against something right next to us on earth.

    I contend that we are moving almost at the speed of light and I am right because I am measuring that against an accelerated particle at CERN.

    My point is that "movement" is only meaningful if you say RELATIVE TO WHAT?
     
    Last edited: May 21, 2013
  10. May 21, 2013 #9
    Absolutely true, and thank you for clarifying. What is funny is that is one of the first comments to that guys article after he did all this math to calculate how fast he thinks the solar system is moving was asking him to use GR based exactly on what you said.

    I guess I was trying to illustrate simply that the motion of matter in a galaxy isn't the same as the expansion of the universe. The solar system itself is moving in reference to the galactic core, the entire local group is moving away from other local groups in reference to each other, but due to the expansion of space, (dark matter/energy), rather then gravity.
     
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