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My July fund-raising campaign, celebrating the 13th anniversary of the start of this website, has now ended. This was the second most successful monthly fund-raising campaign ever. Thank you again to everyone who has who donated or subscribed. It is difficult to explain what your support means to me.


You can still donate or subscribe to support my work if you wish, either by giving a one-time contribution or a regular subscription. There are four ways of doing so:


1. Zelle: This is the only internet method that charges no fees. All you have to do is use the Zelle link at your internet bank and give my name and email address (zimmerman at nasw dot org). What you donate is what I get.


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The spiral galaxy M91

spiral galaxy M91
Click for full release image.

Cool image time! The image to the right, reduced to post here, was released today by the Space Telescope Science Institute as part of a regular program using the Hubble Space Telescope to photograph galaxies.

This observation is part of an effort to build a treasure trove of astronomical data exploring the connections between young stars and the clouds of cold gas in which they form. To do this, astronomers used Hubble to obtain ultraviolet and visible observations of galaxies already seen at radio wavelengths by the ground-based Atacama Large Millimeter/submillimeter Array.

The galaxy is estimated to be about 55 million light years away, and is thought to have a supermassive black hole at its center with a mass somewhere between 9 and 38 million times the mass of the Sun.

Genesis cover

On Christmas Eve 1968 three Americans became the first humans to visit another world. What they did to celebrate was unexpected and profound, and will be remembered throughout all human history. Genesis: the Story of Apollo 8, Robert Zimmerman's classic history of humanity's first journey to another world, tells that story, and it is now available as both an ebook and an audiobook, both with a foreword by Valerie Anders and a new introduction by Robert Zimmerman.

The ebook is available everywhere for $5.99 (before discount) at amazon, or direct from my ebook publisher, ebookit. If you buy it from ebookit you don't support the big tech companies and the author gets a bigger cut much sooner.

The audiobook is also available at all these vendors, and is also free with a 30-day trial membership to Audible.

"Not simply about one mission, [Genesis] is also the history of America's quest for the moon... Zimmerman has done a masterful job of tying disparate events together into a solid account of one of America's greatest human triumphs."--San Antonio Express-News


  • Typo alert: last sentence: “… is thought to have a supermassive black hole at its center with a mass somewhere between 9 and 38” — presumably: million — “times the mass of the Sun.” [probably not billion]

  • Michael McNeil: Yup, I forgot to type “million.” Fixed.

  • GaryMike

    If rotation is a fundamental organizing principle of 4-dimensional space-time, what can we infer from speculations about its equivalent in higher dimensional places, like those of 10- or 11- dimensional String theories. Just a lessor variation of vibratory behavior?

    Why do black holes seem to rotate if they are outside the normal 4-D space-time environment? Lipstick on a pig?

  • GaryMike asked: “Why do black holes seem to rotate if they are outside the normal 4-D space-time environment?”

    Perhaps they don’t. It may be that our 4D perception ‘sees’ rotation. And maybe the Universe is rotating around the black hole. Eye of the beholder, and all.

  • wayne

    check this (first one) out– some great factoids.
    (For our black hole, Sagittarius A*, the event horizon is spinning at about 30% the speed of light.)

    Black Hole Spin
    The Science Asylum (2019)

    More to your point, explore the Kerr Metric.

    Kerr Metric Video 1,
    Tensor Calculus Robert Davie

  • wayne


    This Guy addresses some of what you might be getting at. Upper-level undergrad & heavy on math, he has literally hundreds of hours available, but you should be able to zero in to some, just on the titled topics.

    “My background is in string theory and I teach both particle physics and general relativity…”

  • GaryMike


    Thank you. Finally, some stimulation.

    No, this is not a date.

  • GaryMike

    Perhaps oddly, I came to understand the underlying conceptual frameworks without knowing any of the math. I’ve spent 40 years trying to learn Spanish (family pressures) without much success. Math, for me and a lot of others, has always been a foreign language. In fact, it is.

    The coursework linked above, I don’t really use it to understand the work of the course. I actually get quite a lot of it (even earned income explicating for paying students).

    I use the coursework to backwards engineer the math I never understood up front because my teachers/professors either didn’t know the material themselves, or weren’t able to communicate the material in understandable ways.

    Thank you for pointing me to additional material.

    I know that I don’t know enough.


  • GaryMike

    Again, at risk of aggrandizing by quoting myself: “Why do black holes seem to rotate if they are outside the normal 4-D space-time environment?”

    It was an imprecise expression of my intended question.

    Do black hole singularities rotate? Would they have to, since they’re no longer actual participants in our own 4-D reality?

    If they do rotate, do they rotate the same way 4-D objects outside the event horizon(s) do, or chaotically as they rotate in multiple higher than 4-D dimensions simultaneously, not sharing the same coordinate system origins?

    How fast could they “chaotically” spin before overcoming structurally coherent gravitational compression, assuming that they are still subject to gravitational compression?

    Why won’t the Simulation allow us to see inside event horizons?

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