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
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
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?
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)
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.
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
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
In short, taking every thing into consideration, the British empire in power and strength may be stated as the greatest that ever existed on earth, as it far surpasses them all in knowledge, moral character, and worth. On her dominions the sun never sets. Before his evening rays leave the spires of Quebec, his morning … Continue reading Does The Sun Set On The British Empire?
The year 2020, newly begun as this post is published, is a leap year. I’ve written before about leap years, and how the occasional leap day added to the end of February keeps our calendar year synchronized with the seasons. For more on that topic, see my posts about February 30th and the Equinox. But … Continue reading Leap Seconds
[D]espite Maskelyne being portrayed in popular literature as a self-seeking academic astronomer with a less-than-personable style, the stories of his interaction with the Nautical Almanac [human] computers reveals that he went to some lengths to provide stop-gap employment to mathematically inclined people, as well as providing long-term stable employment for those with families to support. … Continue reading Rebekah Higgitt (Ed.): Maskelyne