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My February birthday fund-raising campaign for Behind the Black it now over. I sincerely and with deep gratitude thank all those who donated. Without your support I could not keep doing this, not so much because of the need for income to pay the bills, but because it tells me that there are people out there who want me to do this work. For those who did not contribute during the campaign, please consider adding your vote of support to Behind the Black, by giving either a one-time contribution or a regular subscription, in any one of the following ways:


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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Betelgeuse is closer and smaller than previously thought

Betelgeuse's fading
Images taken by Europe’s
Very Large Telescope in Chile

The uncertainty of science: A new analysis by scientists of Betelgeuse, triggered by its dip in brightness in 2020, has concluded that the red giant star is both closer and smaller than previously estimated.

Their analysis reported a present-day mass of 16.5 to 19 solar mass—which is slightly lower than the most recent estimates. The study also revealed how big Betelgeuse is, as well as its distance from Earth. The star’s actual size has been a bit of a mystery: earlier studies, for instance, suggested it could be bigger than the orbit of Jupiter. However, the team’s results showed Betelgeuse only extends out to two-thirds of that, with a radius 750 times the radius of the sun. Once the physical size of the star is known, it will be possible to determine its distance from Earth. Thus far, the team’s results show it is a mere 530 light years from us, or 25 percent closer than previously thought.

The research also suggested that the star is in the initial stages of burning helium rather than hydrogen, and so it likely more than 100,000 years from going supernova.

As for the dimming, the scientists concluded (as other have) that the dimming in ’20 was due to the passage of a dust cloud in front of the star.

Conscious Choice cover

Now available in hardback and paperback as well as ebook!


From the press release: In this ground-breaking new history of early America, historian Robert Zimmerman not only exposes the lie behind The New York Times 1619 Project that falsely claims slavery is central to the history of the United States, he also provides profound lessons about the nature of human societies, lessons important for Americans today as well as for all future settlers on Mars and elsewhere in space.

Conscious Choice: The origins of slavery in America and why it matters today and for our future in outer space, is a riveting page-turning story that documents how slavery slowly became pervasive in the southern British colonies of North America, colonies founded by a people and culture that not only did not allow slavery but in every way were hostile to the practice.  
Conscious Choice does more however. In telling the tragic history of the Virginia colony and the rise of slavery there, Zimmerman lays out the proper path for creating healthy societies in places like the Moon and Mars.


“Zimmerman’s ground-breaking history provides every future generation the basic framework for establishing new societies on other worlds. We would be wise to heed what he says.” —Robert Zubrin, founder of founder of the Mars Society.


All editions are available at Amazon, Barnes & Noble, and all book vendors, with the ebook priced at $5.99 before discount. The ebook can also be purchased direct from my ebook publisher, ebookit, in which case you don't support the big tech companies and I get a bigger cut much sooner.


Autographed printed copies are also available at discount directly from me (hardback $24.95; paperback $14.95; Shipping cost for either: $5.00). Just email me at zimmerman @ nasw dot org.


  • Robert related: “The research also suggested that the star is in the initial stages of burning helium rather than hydrogen, and so it likely more than 100,000 years from going supernova.”

    That seems like an incredibly short time for things that hang around for billions of years. While I am aware of the main sequence fuel cycle, I had no idea it happened on that sort of timescale. I am sure there are many on the forum who can shed some light.

  • LocalFluff

    Betelgeuse is too bright for the Gaia space telescope. So I don’t think it is known how it moves, whether it will be closer or further away from the Sun in 100,000 years. Its variability (huge sunspots and flares) also makes it tricky to pinpoint its distance and radial movement. Only 10 or so years ago, tables had it at only 470 light years distance, then they almost doubled the estimation, and now 530 ly.

    @Blair K Ivey
    Betelgeuse is only 8 million years old. More massive stars have higher pressure from gravity and burn their fuel much faster, a larger core is fusing. Betelgeuse is only about 18 times as massive as the Sun, there are stars 100+ the mass of the Sun that exist for less than a million years. That’s why more massive stars are much less frequent, they don’t necessarily form more rarely, they just live 1/1000th or so as long as stars less massive than the Sun. Still, the spirals in galaxies are visible because of the small share of massive stars that dominate the brightness of 100s-1000s of times more common red dwarfs and Sun-like stars. Galactic gas is compressed in a standing spiral wave so that stars form much more easily there. And the massive stars don’t live long enough to leave the spiral where they formed.

  • wayne

    can’t find the chart I want, but when a star starts ratchetting up the periodic table toward iron, the end is ‘relatively near.’

    …” it takes 100,000 years for the carbon to burn into oxygen, 10,000 years for the oxygen to burn into silicon, and one day for the silicon to burn into iron… “

  • wayne

    “Stages in the Life of a 25 Solar Mass Star”
    -hydrogen burning – 7 million years
    helium – 700K years
    cabon – 600 years
    neon – 1 year
    oxygen – 6 months
    silicon – 1 day

  • LocalFluff

    It takes on average 10,000 years for a photon generated in the fusing core of the Sun to reach the surface and beam out through space. There’s so much compact stuff in the way of its 400,000 miles random walk. In your example, virtually no light from the post Helium fusion would become visible until it goes supernova.

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