Planet Earth spins a full 360°, about its axis, every 24 hours.
From either hemisphere, the night sky always rotates about our celestial poles.
Terminating the Little Dipper’s handle, Polaris lies within 1° of Earth’s true north pole.
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But this won’t always be true.
Gravitational tugs lead to precession, causing our tilt’s direction to migrate.
Additionally, our axis “wobbles” over time, varying in inclination.
Over ~26,000 year timescales, our axis completes a 360° rotation.
Bright Polaris will pass within 0.45° of “true north” after 80 more years.
~12,000 years later, Vega becomes Earth’s brightest pole star: within 5° of true north.
5000 years ago, Thuban was the closest pole star of all: within 0.2° of celestial “north.”
Meanwhile, the southern pole has been “starless” for millennia.
Beginning in the year ~5000, a series of excellent “south pole” stars will appear.
The best ones include:
two prominent “False Cross” stars.
In the year ~7000, both poles will simultaneously possess pole stars.
Enjoy Polaris while we have it; after 2102, today’s “North Star” will consistently worsen.
Mostly Mute Monday tells an astronomical story in images, visuals, and no more than 200 words. Talk less; smile more.