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B E=mc^2 and space

  1. Apr 8, 2016 #1
    Hello everybody! I've just joined this forum looking for answers to my possibly newby questions.

    I read somewhere (don't recall the source) that the universe is expanding at a rate that is faster than the speed of light, and is slowing down. Is there any kind of relation of this expansion and the mass–energy equivalence? For instance:

    - Before the big bang, space was non-existant: could it be that there was only energy, and no mass?
    - While expanding: Is there a general increase in mass and thus loss in energy?

    Could be the lack of sleep and overuse of coffee talking, but stil...

    Pardon my English and terminology and lack of knowledge in this field: I'm a mere (interested) Belgian electrical engineer.
     
  2. jcsd
  3. Apr 8, 2016 #2

    PeroK

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    If you're an engineer, I would encourage you to try to learn some physics or cosmology properly. Your questions on this post and another I saw are essentially unanswerable, as they involve a mixture of half-truths and misconceptions given by popular science.

    If I asked you a question that mixed up all different aspects of electical engineering, how could you answer it?
     
  4. Apr 8, 2016 #3
    Well, basically I'd try to explain that you had indeed mixed up those different aspects, would try to explain how those aspects do relate to each other and which aspects don't relate. I'd also possibly try to point you to the most useful sources regarding to your questions.

    But hey, that might just be me...

    Don't know about other members on this forum, but I for one don't have all the time in the world to study all domains that interest me:
    - Music
    - Building
    - Electrical design
    - Electronical design
    - Religion
    - Physics
    - Biology
    - Cosmology
    -...

    I do have a fulltime job, some time consuming hobbies, 2 renovations and 2 small kids (and a wife...). I kind of hoped people on this forum would be so kind as to take up the role I described in the first part of my response instead of trying to tell me to skip sleep and just read some books.
     
  5. Apr 8, 2016 #4
    I think he's actually complimenting you as an engineer (with basic physics and enough mathematical knowledge) in that you can study some of these things yourself without it taking too much of your time. You will than have a better grasp on the strict definitions for the terms you've used and you will be able to understand why your questions are either invalid or unanswerable.

    For your specific questions there's a book called "a first course in general relativity", by Schutz, which requires little physics knowledge short of Newton's laws or Maxwell's equations, which I'm sure you're just as familiar with as any physicist. This book will outline the basics of our modern understanding of time and space, so you will then be able to correctly craft questions that have physical meaning.
     
  6. Apr 8, 2016 #5
    The universe is expanding very slowly. It doesn't make sense to compare the expansion to a speed however, because the speed depends on the original distance between the two points. If you mean the opposite ends of the observable universe are retreating from each other faster than light you are correct, however, if every point in space was traveling away from each other faster than light, there would be no causality. There was a time at which this was true, it was called inflation, and it happened only for the briefest time at the very beginning of the universe.

    The expansion is also not slowing down, it's speeding up. It's one of the greatest mysteries in cosmology, what's causing the universe to accelerate when gravity should be slowing it down?
     
  7. Apr 8, 2016 #6
    Sadly, due to a lack of time or maybe just other priorities, reading books about those subjects is a no-go... I'll put it on my reading list however!
     
  8. Apr 8, 2016 #7
    Thanks!
     
  9. Apr 8, 2016 #8
    Then go to Youtube and subscribe to PBS Spacetime, Minute Physics, Crash Course, vsauce... They're short clips, I often watch new ones during lunch.
     
  10. Apr 8, 2016 #9

    ProfuselyQuarky

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  11. Apr 8, 2016 #10

    Chronos

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    Cosmology employs a variety of mathematical concepts that are not easily translated into other languages. Expansion of the universe is a good example. It is mathematically trivial to show the universe is expanding even though nothing in it is actually moving in terms resembling our everyday experience. Despite the inadequacies of verbal communication ordinary humans, like us, pay for the complicated process of science and expect some kind of return on investment. The hapless scientist offers a verbal explanation hoping to appease us until some engineer, such as you, figures out how to apply this new knowledge to build a radio, computer, GPS or something else an ordinary person still has no idea how it really works.
     
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