• magical Black Hole image

    From gah4@u.washington.edu@21:1/5 to Steve Pope on Mon Jan 27 02:58:31 2020
    On Thursday, April 11, 2019 at 11:58:41 AM UTC-7, Steve Pope wrote:
    The Event Horizon Telescope team of course deserves a huge amount
    of credit for their results.

    But it's interesting how they got there.

    Here's an article with some non-technical discussion:

    https://fivethirtyeight.com/features/forget-the-black-hole-picture-check-out-the-sweet-technology-that-made-it-possible/

    Their data is too noisy to actually create a black hole image. So
    they augment the data with (wait for it..) models of what a black
    hole should look like, and come up with the most likely black hole
    that fits the data.

    I've been noticing that astrophysicists have been doing this
    kind of thing for awhile.

    Without actually answering your question, it seems that more than astrophysicists do it.

    Why do we use DFT and DCT in DSP, because our signals tend to be
    sinusoidal. Or are the signals sinusoidal so we can use DFT and DCT?

    There is a post asking about coding theory and convolutional codes
    or other such coding systems. The ones used are the ones that can
    be done computationally fast enough. Or is it that people design
    computational systems to do the appropriate transform.

    As for sinusoids, they were convenient in the analog days, as you
    can generate and filter them with RLC filters. But now in the digital
    days, does that argument still hold? If radio was invented now,
    would modulated sinusoid transmitters be used?

    As for cosmic background, there is a very accurate fit to the
    expected distribution.

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