Author Archives: Allen Versfeld

About Allen Versfeld

Allen is an amateur astronomer, an IT professional, a podcaster, a father of five growing kids, a barely competent chess player, and the owner and publisher of the Urban Astronomer podcast and website. He has formerly served as Director of the Astrophotography and Citizen Science sections of the Astronomical Society of South Africa. You can find his personal social media feed on Mastodon!

Degenerate Matter

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To understand degenerate matter, we’ve got to step back and look at regular normal matter first.  If you’ve had even a rudimentary physics education (high-school level or higher), you’ll be aware of the gas laws.  Pressure and volume are proportional to temperature, so that if you increase the temperature, the gas will try to expand (and if it is prevented by expanding by being sealed in a container, the pressure rises).  These principles explain how a hot air balloon flies, … Continue reading →

What is a Supermoon?

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  A Supermoon is a Full Moon which appears larger than usual in our skies.  The Moon’s orbit is not perfectly circular, but is elliptical.  This means that there is a point in its orbit that is closer to Earth than any other (called ‘Perigee’) and a point that is further (‘Apogee’).  The orbit takes 27.3 days, so the Moon is at Perigee exactly once every 27.3 days.  However, the cycle of phases takes a little longer (Because they are … Continue reading →

What is light?

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Dear Urban Astronomer   I just read your article about “what is the speed of light.”  I’m so surprised (and amazed) that light travels faster in a vacuum than in (atmosphere?) – does this mean that LIGHT is actual…”stuff” ? It might sound silly to you, but I find it quite hard to comprehend! Does this mean that light has a “mass”?  It’s very cool, and opens up a whole new world of symbolic drama-movie themes.   Jody     … Continue reading →

Six Thousand Years, or 13.7 Billion?

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Every now and then, when people learn that the Urban Astronomer is a Christian, some wag asks “So why should we take you seriously if you believe that the universe is six thousand years old?”.  And I battle to answer, because where do you start with such a retarded question? See, the latest round of partisan thinking is “Almighty Skeptical Atheism” vs “Almighty Faith-based Literalist Christianity” (since, as the dominant religion in the West, Christianity is the obvious target for … Continue reading →

Polishing

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Wow… Fifteen month’s after I first laid hands on my glass, I have finally begun polishing.  Let me say up front that so far no part of the process has been anything like I imagined.  I’ve read the literature, I’ve read personal accounts like this one, and none of them conveyed the sheer diabolical nature of a brand new pitch lap at the beginning of polishing!  The coefficient of friction was a meaningless term, as it switched from “superglue” to … Continue reading →