Thursday's lunar eclipse covers 96% of the moon; two of its 5.5 hours are near-invisible

The two duration figures in the Associated Press account are the ones worth writing down. The partial phase, with the moon inside the dark core of Earth's shadow, runs more than three hours ^[4]. The whole event, from first contact with the faint outer shadow to last, runs five and a half hours ^[5]. Subtract one from the other and under two and a half hours of penumbral shading is split between the two ends, roughly seventy-five minutes at each ^[1]. AP itself calls that outer shadow the faintest, outermost edge of the shadow ^[6], which is a polite way of saying the opening and closing stretches of the advertised window look like an ordinary full moon.

The interesting number is the gap between the two audience figures: better than two billion people are positioned for a fragment of the eclipse rather than the whole run ^[2]. On the Pacific side that fragment arrives late, because the moon is rising in Hawaii, and the eastern Pacific along with northwestern parts of the US and Canada start after the event is under way ^[10].

AP explains the pairing of eclipses with the coincidence that the moon is 400 times smaller than the sun, which is 400 times farther away, so the two appear the same size ^[13]. That coincidence is what makes solar totality possible; it is not what places this eclipse a fortnight after the one that crossed Greenland, Iceland and Spain ^[11][12]. The report also reaches for NASA's record-breaking Artemis II lunar flyby in April ^[22], which has nothing to do with Thursday's geometry, and for the space station commander, Jessica Meir, who says orbit offers a unique perspective on eclipses and auroras ^[21]. Ten people are placed to test that claim: seven aboard the International Space Station and three on China's outpost ^[20].

For the ground, the scarcity argument is the real one. This is the year's second lunar eclipse and its fourth eclipse of any kind ^[15], so two of the four were solar ^[3]. March already gave the Americas a genuine total lunar eclipse, shared with Australia and eastern Asia ^[16]. Thursday is the consolation prize, and the next complete blackout belongs to Asia and Australia on New Year's Eve 2028 ^[17].