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Posted: June 17, 2025

Mars and Regulus rendezvous in the western twilight

By Dan Hicks

On June 17, Red Planet Mars and blue-white subgiant Regulus will come to within a degree of each other; their respective magnitudes being essentially the same – 1.4 and 1.3. However, at 23:30 MDT, when receding outside-track Mars will be 16 light-minutes behind us on our inside-track orbit, Regulus will be 79 lightyears away –2,600,000 times further out; so, like many Earthly couples, their perceived “compatibility” is a cosmic illusion.

Mars is half Planet Earth’s size, but “Regulus A” – the big dog in a four-star system – is four times our sun’s mass and 300 times brighter, a whirling ellipsoid spinning on a 16-hour rotation – a 15% rotation velocity increase would cause the ginormous distorted gravity-bound gas-mass to suffer a flywheel-styled disintegration (our sun has a leisurely 25-day rotation rate equatorially).

Lead image: The enchanting first full moon of our meteorological summer. The Strawberry Moon rises behind clouds in the southeast at altitude 4 degrees, Cranbrook. June 10. Minutes later, our June full moon rose into a clear nautical twilight sky; our m eteorological summer runs from June 1st to August 31. Astronomical twilight began at 23:34 and end at 03:50 the next day; at this time of year, “night ” itself never comes to our 4 9 degrees north latitude locale. Dan Hicks photo


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