Rare hybrid solar eclipse races across Australia and Indonesia on Thursday
The rarest of solar eclipses is occurring on Thursday and will be visible from western Australia and Indonesia. It will include both an annular eclipse, named for the annulus or “ring of fire” created as the Moon covers only the middle of the Sun, and total eclipse when the Sun is completely covered.
Hybrid solar eclipses start and end with an annular eclipse, with a total eclipse in between. Only about 3% of eclipses are hybrid ones because they occur when the Moon is just at the edge of its varying distance from the Earth required to create a total eclipse.
As the eclipse beings, the Moon is just far enough to not appear quite large enough in the sky to completely cover the Sun. Less than two minutes and 640 miles later, the curvature of the Earth closes the distance of the Moon just enough for its apparent diameter enough to create a total eclipse be visible along a 7,200 mile path stretching northwestward. As the curvature of the Earth again increases the distance the shadow must travel, the eclipse turns back to an annular one at a point south of the Marshall Islands.
Totality will be visible only across the tip of a cape along Australia’s coral coast in the extreme northwest and a few hundred thousand residents of East Timor and West Papua Indonesia. The small town of Exmouth, Australia, a former U.S. naval base in World War II, has been preparing for visitors for years.
As the Moon’s shadow moves at around 3,000 mph across the south Pacific, the distance to the Moon increases, making it appear smaller in the sky, transitioning the eclipse back to a hybrid one.
Rare, but not the rarest
You might remember the eclipse visible at sunrise in November 2013. It was the rarest of the rare. This hybrid solar eclipse which began annular, transitioned to total, but not back to annual. Looking at NASA's list of solar eclipses spanning 5000 years, these asymmetric hybrid solar eclipses occur less than every 200 years on average.
This kind of eclipse must occur just as the Moon's orbit begins bringing it closer to Earth, keeping that Earth-Moon distance essentially constant by essentially canceling out the curvature of the Earth.
Our next eclipse
An annular solar eclipse will sweep from Oregon to Texas on Saturday October 14, 2023. North Carolina will see a partial solar eclipse between 11:56 am and 2:46 pm. The Moon will cover about half the Sun by 1:20 pm.
A total eclipse will sweep across Mexico then into the US from Texas to Maine on Monday April 8, 2024. This will also be a partial eclipse for North Carolina, beginning at 1:59 pm, reaching 82% coverage of the Sun by 3:16 pm. The show will be over at 4:29 pm.
