27 August 2015

"It's a bird, it's a plane, it's..." SUPERMOON!

12 Elul 5775

The next six weeks could bring anything, but the whole world feels like something really big is coming. I'm wondering if the moon is predictive of that...

Forget the 'Supermoon': What's Actually Happening at Lunar Perigee

...The most important result of the moon's elliptical orbit is that sometimes the moon is closer to the Earth, and sometimes farther away. The time when the satellite is nearest is called "perigee" and the time when it is farthest is called "apogee."

What skywatchers are most interested in is perigee, the date and time when the moon is closest to Earth. This month, perigee occurs on Sunday, Aug. 30, at 11 a.m. EDT (1500 GMT), about 18 hours after full moon. At that time, the moon will be 222,631 miles (358,290 kilometers) away from Earth.

...The important thing for astronomers is that the perigee distance is less than 223,690 miles (360,000 km). When the moon gets this close, its most important effect on the Earth — the ocean tides — gets stronger. On the day of perigee and the three days following, Earth will have larger tides than usual.

Looking ahead to next month, full moon will fall on Sunday, Sept. 27, at 10:51 p.m. EDT (0251 GMT on Sept. 28), and perigee just 51 minutes earlier, at 10 p.m. This perigee will be the closest in 2015, at 221,753 miles (356,877 km). The result will be the largest full moon of the year and even larger high tides. Notice that both events happen in the evening, when the moon will be well placed in the sky.

...The September full moon will also pass through the Earth's shadow, causing a total eclipse of the moon, visible on the evening of Sept. 27 in North and South America, and the morning of Sept. 28 in Europe and Africa. 

[This will the fourth of the so-called "tetrad of blood moons" and the first day of Sukkot.]