This is, to a large extent, a companion piece to my post about leap seconds, in which I described how the irregular rotation of the Earth means that the time as measured by our atomic clocks would fall out of synchrony with the actual movement of the sun in the sky, were it not for … Continue reading The Advent Of Atomic Time
Tag Archives: Astronomy
Pole Stars Of Other Planets?
When I wrote about Philip Latham’s juvenile science-fiction novel Missing Men Of Saturn (1953) recently, I pointed out that Latham had made an astronomically well-informed guess about a possible pole star for Saturn’s moon Titan. Latham (a professional astronomer) knew the orientation of Saturn’s rotation axis, which would have allowed him to deduce the location … Continue reading Pole Stars Of Other Planets?
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Which Way Does Space Station V Rotate?
The “Phenomena” posts have been a little tied up with abstruse orbital mechanics and obscure revisions to lists of Scottish hills, of late, so I thought it might be time for a break from all that. So this post is about something superficially trivial in the film 2001: A Space Odyssey, which has mildly annoyed … Continue reading Which Way Does Space Station V Rotate?
Keplerian Orbital Elements
1. All planets move in elliptical orbits, with the sun at one focus.2. A line that connects a planet to the sun sweeps out equal areas in equal times.3. The square of the period of any planet is proportional to the cube of the semimajor axis of its orbit. Kepler’s Laws of Planetary Motion (formulated … Continue reading Keplerian Orbital Elements
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Same Sun, Other Skies
A section of the horizon was etched sharply against a pearly region of the sky. Every pointed irregularity of that part of the horizon was in keen focus. Above it, the sky was in a soft glow (fading with height) a third of the way to the zenith. The glow consisted of bright, curving streamers … Continue reading Same Sun, Other Skies
Why Does The Illuminated Side Of The Moon Sometimes Not Point At The Sun?
I took the above panoramic view, spanning something like 120 degrees, in a local park towards the end of last year. The sun was almost on the horizon to the southwest, at right of frame. The moon was well risen in the southeast, framed by the little red box in the image above. After taking … Continue reading Why Does The Illuminated Side Of The Moon Sometimes Not Point At The Sun?
We Are Stardust (Supplement)
I published my original “We Are Stardust” post some time ago, introducing the infographic above, which shows the cosmic origins of the chemical elements that make up our bodies, according to mass. At that time I concluded that Joni Mitchell should actually have sung “We are 90% stardust,” because that’s the proportion of our body … Continue reading We Are Stardust (Supplement)
We Are Stardust
A few months ago I ran into the periodic table above, detailing the cosmological origins of the chemical elements. And it occurred to me that I could quantify Joni Mitchell’s claim that “we are stardust”. How much of the human body is actually produced by the stars? But before I get to that, I should probably explain a little about the various categories indicated by the colours in the chart above.
Strange Moon
A couple of weeks ago, I reviewed three books about the activities of 161 (Special Duties) Squadron, RAF, during the Second World War. For this post, I want to talk specifically about the cover of Hugh Verity’s memoir and personal history of 161 Squadron, We Landed By Moonlight (Revised Edition), published in 2000 by Crécy. … Continue reading Strange Moon
Harvest Moon
In the northern hemisphere, the Harvest Moon falls on 1 October in 2020, which is what provokes this post. The Harvest Moon is defined as the full moon that occurs closest to the autumnal equinox, which fell on 22 September (in the northern hemisphere, in 2020). You can find many lists of “names of the … Continue reading Harvest Moon