Recent content by jmatt

  1. J

    I Some questions about this vintage periodic table

    Mine too! I think it was popular in that era.
  2. J

    I Some questions about this vintage periodic table

    Ahh ... thanks! Lot of information in one little graphic.
  3. J

    I Some questions about this vintage periodic table

    Thanks everyone. Any thoughts on the "X" and valence electrons?
  4. J

    I Some questions about this vintage periodic table

    I was recently in an art supply store and saw a print of a vintage periodic table that I thought had real aesthetic value. I bought it and like any enthusiast I hung it in my bathroom. For the past month I have been studying it as I brush my teeth and feel comfortable with 80% of the...
  5. J

    What is the Difference Between Vectors and Dual Vectors in Spacetime?

    Thanks very much for this. Very helpful!
  6. J

    Understanding Tensors for General Relativity: A Comprehensive Guide

    Hello guy with the scary picture! I highly recommend https://www.amazon.com/dp/0957389442/?tag=pfamazon01-20 . It starts with a basic review of the math you need and gently leads you through everything! It helped me a lot before I tried more academic books.
  7. J

    Spacetime Interval & Metric: Equivalent?

    Got it now. Thanks very much.
  8. J

    Spacetime Interval & Metric: Equivalent?

    Thanks! A little confused why you referred to ##ds^2## as a scalar. Isn't it a four-vector?
  9. J

    Spacetime Interval & Metric: Equivalent?

    This may seem an odd question but it will clear something up for me. Are "The spacetime interval is invariant." and the "The spacetime metric is a tensor." exactly equivalent statements? Does one imply more or less information than the other? Thanks!
  10. J

    Einstein's contribution post 1915

    Thanks all. It was the EPR paper that led to Bell's theorem as a response.
  11. J

    Einstein's contribution post 1915

    desiderata - one of the most haunting words in English.
  12. J

    Einstein's contribution post 1915

    Thanks Mentz114 very interesting reply. The man was a true giant! If you don't mind ... did anything useful come out of his work on a unified field theory? I understand he believed all physics could be described with geometry as he achieved with gravity. Did any that work contribute to physics?
  13. J

    Einstein's contribution post 1915

    Did Einstein contribute anything novel (or fundamental or of lasting importance or ... you know what I mean!) to physics after GR?
  14. J

    Understanding Tensors & General Relativity

    I forgot to mention I found the emphasis on the association between basis vectors and components to be powerful. It leads to moving beyond thinking of a vector as an arrow to thinking of it as one of many possible associations between basis vectors and components. This generalized association...
  15. J

    Understanding Tensors & General Relativity

    I enjoyed this video about tensors very much. I would recommend it to anyone seeking to understand the concept in general and general relativity specifically. https://vimeo.com/32413024 You can fast forward through the repetitive parts and try to place yourself in the role of beginner as you...
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